Biological Assessment

For Willamette Planning Province of Oregon 

for FY 2018 LAA Projects 

Within the Willamette National Forest

With a Potential to Modify Habitat and/or Disrupt Northern Spotted Owls

Prepared by the interagency Level 1 Team (terrestrial subgroup) for the Willamette Planning 

Province: 

Paul Bridges Fish and Wildlife Service

Brett Carre Columbia River Gorge National Scenic Area

John DeLuca NW Oregon District, Bureau of Land Management

Joe Doerr Willamette National Forest

Chuti Fiedler Mt Hood National Forest

Kim Garner Fish and Wildlife Service

Roy Price NW Oregon District, Bureau of Land Management

Bridgette Tuerler Fish and Wildlife Service

August 1, 2017

The signature below acknowledges that this biological assessment (BA) was developed by the Forest 

Service with extensive technical assistance from the Fish and Wildlife Service in assessing the status 

and environmental baseline of potentially affected listed species and critical habitat, and in analyzing 

the biological impacts of the proposed projects on those listed species and critical habitat. Our 

participation in development of the BA was intended to expedite the Endangered Species Act section 

7 compliance process by ensuring consideration of best available scientific information and by 

assisting the Forest Service in analyzing the impacts of the proposed action on listed species and 

critical habitat as the basis for the effect determinations. We appreciate the opportunity to provide 

technical assistance on the content of the BA.

Photo by Alan DyckMt Hood NF

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TABLE OF CONTENTS

I. Introduction...............................................................................................................................................11

A. Purpose of the Assessment .................................................................................................................11

B. Scope of the Assessment.....................................................................................................................11

C. Definitions ................................................................................................................................................13

D. Guidance to Unit Biologist ................................................................................................................24

Submitting projects for biological assessment ......................................................................................24

After the biological opinion is issued.......................................................................................................24

Reinitiation ..................................................................................................................................................24

E. Compliance with Planning Decisions and Interagency Consultation Policy..................................24

F. Consultation History.................................................................................................................................25

II. Description of the Proposed Action ...............................................................................................25

A. General Standards.................................................................................................................................26

B. Implementation Consultation Dates ....................................................................................................31

C. Action Area ...............................................................................................................................................31

III. Status of Spotted Owls ......................................................................................................................32

Supplemental Information.............................................................................................................................33

Effects from Disturbance ..............................................................................................................................33

Effects from Habitat Modification.................................................................................................................33

Territorial spotted owls..................................................................................................................................33

Beneficial Effects from Treatments .........................................................................................................34

Home Range ..............................................................................................................................................35

Core Area – 0.5 miles ...............................................................................................................................35

Nest Patch ..................................................................................................................................................36

Summary of Home Range, Core Area, and Nest Patch - Potential Impacts ....................................37

Dispersing spotted owls ................................................................................................................................38

Considerations for local impacts on Spotted Owl Prey Species.............................................................38

Flying squirrels ...........................................................................................................................................38

Woodrats.....................................................................................................................................................39

Rabbits and hares......................................................................................................................................39

Red tree voles ............................................................................................................................................40

Prescribed Fire.........................................................................................................................................40

Barred Owls in the Action Area....................................................................................................................41

Does logging expand the range of barred owls? ..................................................................................42

Do silviculture treatments that thin, create early seral, or create edge habitat favor barred owls 

over spotted owls?.....................................................................................................................................42
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Does reducing the amount of older forests on the landscape increase competition between 

barred and spotted owls? .........................................................................................................................43

Summary of Effects to Spotted Owls and their Territories due to Habitat Alteration and Barred 

Owls .............................................................................................................................................................43

IV. Status of Spotted Owl Critical Habitat............................................................................................44

Conservation Role of Critical Habitat......................................................................................................44

Physical or Biological Features and Primary Constituent Elements ..................................................45

Analysis Scales ..........................................................................................................................................45

Action area..............................................................................................................................................45

Subunit ....................................................................................................................................................45

Unit...........................................................................................................................................................46

Range wide.............................................................................................................................................46

V. Environmental Baseline.....................................................................................................................46

A. Status of the Spotted Owl in the Action Area ....................................................................................46

Project Area................................................................................................................................................47

Spotted Owl Habitat...................................................................................................................................48

Demographic Information .........................................................................................................................48

Distribution of Protected Land Use Allocations .....................................................................................51

B. Status of Spotted Owl Critical Habitat.................................................................................................52

Project Area................................................................................................................................................52

Special Management Considerations .....................................................................................................52

West Cascades/Coast Ranges of Oregon and Washington ...........................................................52

Critical Habitat Units in the Willamette Planning Province Action Area.............................................53

Unit 6: West Cascades South.............................................................................................................54

Subunit WCS 2...................................................................................................................................54

Subunit WCS 3...................................................................................................................................54

Subunit WCS 4...................................................................................................................................54

Subunit WCS 5...................................................................................................................................54

VI. Effects of the Proposed Action........................................................................................................54

A. Direct and Indirect Effects of Spotted Owl Habitat Modification .....................................................55

Analytical Framework for analyzing impacts to critical habitat............................................................66

Effects Determinations for Spotted Owl Critical Habitat.......................................................................66

B. Direct and Indirect Effects of Habitat Modification on Spotted Owls and their Critical Habitat in 

the Action Area by Activity Type..................................................................................................................67

Harvest – Habitat Remove (HH Remove)..............................................................................................72

General Effects to spotted owls-HH Remove....................................................................................72

General Effects to Critical Habitat – HH Remove .............................................................................72
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Project Effects– HH Remove ...............................................................................................................73

Detroit Ranger District.......................................................................................................................73

Sweet Home Ranger District............................................................................................................75

McKenzie River Ranger District.......................................................................................................75

Harvest – Habitat Downgrade (HH Downgrade)...................................................................................78

General Effects.......................................................................................................................................78

General Effects to Critical Habitat – HH Downgrade........................................................................78

Project Effects – HH Downgrade.........................................................................................................78

Sweet Home Ranger District............................................................................................................78

McKenzie River Ranger District.......................................................................................................79

Harvest – Habitat Maintain (HH Maintain)..............................................................................................81

General Effects.......................................................................................................................................81

General Effects to Critical Habitat – HH Maintain.............................................................................81

Project Effects – HH Maintain ..............................................................................................................81

Detroit Ranger District.......................................................................................................................82

Sweet Home Ranger District............................................................................................................82

McKenzie River Ranger District.......................................................................................................83

Harvest in Non-Habitat..............................................................................................................................84

General Effects.......................................................................................................................................84

General Effects to Critical Habitat – Harvest and Other Treatments in Non-Habitat...................84

Project Effects – Harvest in Non-Habitat............................................................................................84

Detroit Ranger District.......................................................................................................................84

Sweet Home Ranger District............................................................................................................85

Fuels Treatment.........................................................................................................................................85

General Effects.......................................................................................................................................85

General Effects to Critical Habitat – Fuels Treatment......................................................................86

Project Effects – Fuels Treatment.......................................................................................................86

Detroit Ranger District.......................................................................................................................86

McKenzie River Ranger District.......................................................................................................88

Down salvage.............................................................................................................................................90

Individual tree removal..............................................................................................................................90

Terrestrial Habitat Enhancement.............................................................................................................90

General Effects.......................................................................................................................................90

General Effects to Critical Habitat – Terrestrial Habitat Enhancement..........................................91

Project Effects – Terrestrial Habitat Enhancement...........................................................................91

Detroit Ranger District.......................................................................................................................91

Sweet Home Ranger District............................................................................................................91
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Special Habitat Restoration......................................................................................................................92

General Effects.......................................................................................................................................92

General Effect on Critical Habitat – Special Habitat Restoration....................................................92

Project Effects – Special Habitat Restoration....................................................................................92

Detroit Ranger District.......................................................................................................................92

Sweet Home Ranger District............................................................................................................93

Middle Fork Ranger District..............................................................................................................93

Road Construction.....................................................................................................................................94

General Effects.......................................................................................................................................94

General Effect on Critical Habitat – Road Construction...................................................................95

Project Effects – Road Construction ...................................................................................................95

Detroit Ranger District.......................................................................................................................95

Middle Fork Ranger District..............................................................................................................96

Disruption-Only Activities..........................................................................................................................96

General Effects.......................................................................................................................................96

General Effects to Critical Habitat and Late Successional Reserves – Disruption-only .............96

Project Effects – Disruption-Only Activities........................................................................................97

C. Direct and Indirect Effects of Disturbance to Spotted Owls.........................................................97

D. Effects to Areas of Concern .............................................................................................................97

E. Recovery Action 32 ...............................................................................................................................97

F. Recovery Action 10 ...............................................................................................................................98

Effects to specific known and potential spotted owl sites ....................................................................99

Detroit Ranger District.......................................................................................................................99

Sweet Home Ranger District..........................................................................................................102

McKenzie River Ranger District.....................................................................................................103

Middle Fork Ranger District............................................................................................................105

G. Special Management Considerations for Critical Habitat ..........................................................106

West Cascades/Coast Ranges of Oregon and Washington .............................................................106

VII. Cumulative Effects ............................................................................................................................110

VIII. Literature Cited...............................................................................................................................111

Appendix A. Summary Tables for Proposed Projects in this Consultation ...................................117

Appendix B. Willamette National Forest..................................................................................................146

Owl Site Information and Narratives for Known Projects Proposed by the Willamette National 

Forest.............................................................................................................................................................160

Appendix C. Potential Spotted Owl Site Considerations ....................................................................182
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Scientific Basis for Potential Spotted Owl Sites ......................................................................................183

Spatial Use of Forest Landscapes ........................................................................................................183

Habitat Availability in Core Areas and Home Ranges........................................................................185

Core Area..............................................................................................................................................185

Home Range.........................................................................................................................................185

Site Occupancy ........................................................................................................................................186

Spotted Owl Habitat at Known and Potential Site Scales......................................................................186

Home Range (1.2 mile radius or about 2,895 acres) .....................................................................187

Core Area (0.5 mile radius or 503 acres).........................................................................................187

Nest Patch (300 meters or 70 acres)................................................................................................187

Potential Site (1.2 miles or about 2,895 acres) ...............................................................................188

Potential Site Delineation........................................................................................................................188

Literature Cited in Appendix C...................................................................................................................190

Appendix D. Northern Spotted Owl Status of the Species and Range-wide Baseline. ...............193

Appendix E. Recovery Action 10 Priority Site Ranking.......................................................................261

Background and Need ................................................................................................................................262

RA 10 prioritization process used in this BA............................................................................................262

Processes to Determine the RA10 Priority: .............................................................................................263

General Process (sites with recent surveys): ......................................................................................263

Historic Status Process (sites without a sufficient number or type of recent surveys): .................264

Appendix F. Acronyms.................................................................................................................................270
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TABLES

Table 1. WILLAMETTE NATIONAL FOREST AND RESPECTIVE COUNTIES ......................................................11

Table 2. DISTURBANCE AND DISRUPTION DISTANCES FOR THE SPOTTED OWL DURING THE BREEDING 

PERIOD. FOOTNOTES LISTED ON THE FOLLOWING PAGE. .........................................................22

Table 3. Description of proposed habitat modification by activity type................................................28

Table 4. Summary of effects determinations to spotted owl sites based on habitat 

conditions in the nest patch, core area and home range as a result of habitat 

treatment. ...........................................................................................................................37

Table 5. Current status of the spotted owl and its habitat –Willamette NF .........................................50

Table 6. Late-successional reserves and associated spotted owl habitat within the Willamette 

National Forest. ..................................................................................................................51

Table 7. Spotted owl suitable habitat in LSR/Wilderness complexes within the Willamette 

National Forest. ..................................................................................................................52

Table 8. Acres of northern spotted owl critical habitat by subunit and habitat type for 

subunits that occur on the Willamette National Forests1....................................................53

Table 9. Rational for effects determinations to spotted owls from actions that remove, 

downgrade or maintain spotted owl habitat........................................................................56

Table 10. Summary of effects determinations to spotted owls from habitat modification (not 

including associated disturbances) performed in compliance with the standards 

listed in Section II. ..............................................................................................................57

Table 11. Rationale for effects determinations to spotted owl critical habitat from actions that 

remove, downgrade or maintain spotted owl habitat. ........................................................58

Table 12. Summary of effects determinations to spotted owl critical habitat from habitat 

modification in spotted owl critical habitat performed in compliance with the 

standards listed in Section II. .............................................................................................60

Table 13. Determination of effect due to disturbance/disruption. Footnotes are on the next 

page....................................................................................................................................61

Table 14. Rationale for Disturbance/Disruption Effects Determinations ............................................64

Table 15. Known projects proposed by administrative units and their effects to spotted owls. ...........69
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SUMMARY TABLES

Table A- 1. Levels of treatment proposed by each administrative unit in this consultation. ...............118

Table A- 2. Harvest Habitat Remove proposed in this consultation. ..................................................119

Table A- 3. Harvest Habitat Downgrade proposed in this consultation. .............................................121

Table A- 4. Harvest Habitat Maintain proposed in this consultation. ..................................................122

Table A- 5. Fuels Treatment proposed in this consultation. ...............................................................123

Table A- 6. Road Construction proposed in this consultation.............................................................124

Table A- 7.Special Habitat Restoration proposed in this consultation...............................................125

Table A- 8. Terrestrial Enhancement proposed in this consultation. ..................................................126

Table A- 9. Harvest in Non-Habitat proposed in this consultation. .....................................................127

Table A- 10. Proposed acres of treatment in spotted owl suitable, dispersal and nonhabitat...............................................................................................................................128

Table A- 11. Proposed acres of treatment in spotted owl habitat and non-habitat by activity 

type and habitat functionality change...............................................................................129

Table A- 12. Proposed acres of treatment activities in spotted owl critical habitat. ..........................130

Table A- 13. Proposed acres of treatment in spotted owl critical habitat by activity type and 

habitat functionality change..............................................................................................131

Table A- 14. Proposed habitat modification in spotted owl critical habitat subunits..........................132

Table A- 15. Effects to spotted owls by activity. ............................................................................134

Table A- 16. Proposed projects in Late Successional Reserves. ......................................................135

Table A- 17. Proposed projects in RA 32 Habitat..............................................................................135

Table A- 18. Environmental baseline of northern spotted owl sites with habitat removal or 

activities proposed in 300-meter nest patches.................................................................136

Table A- 19. Summary of effects to spotted owl sites with habitat removal or activities in the 

nest patch.........................................................................................................................138
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TABLE OF FIGURES

Figure 1. Map of Action Area for consultation. Action area reflects treatment units buffered by 

one mile..............................................................................................................................12

Figure 2. Copy of Figure 3-183 from the BLM Proposed Resource Management Plan Final 

EIS that depicts spotted owl dispersal limited habitat. .......................................................17

Figure 3. From Figure 3-183, a closer view of the south end of the Willamette Valley that 

provides the only current landscape path for genetic exchange available to 

spotted owls located in the Coast Range and the Cascades Range.................................18

Figure 4. Annual proportion of Spotted Owl territories with Barred Owl detections (BO 

covariate) (Forsman, et al. 2011) .......................................................................................42
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I. Introduction

A. Purpose of the Assessment

This document was prepared pursuant to the Endangered Species Act of 1973, as amended, to 

describe and evaluate the potential effects of the proposed action (described in Section II) on the 

northern spotted owl (Strix occidentalis caurina) (hereafter, “spotted owl”), a federally-listed 

threatened species (USFWS 1990; entire) and its critical habitat. 

This document addresses habitat modification activities that are likely to adversely affect spotted owls 

or their critical habitat, or both. Adverse effects might occur from habitat modification, from the 

disruption of normal spotted owl breeding behavior, or from both. 

Projects in this Biological Assessment may include portions which may affect but are not likely to 

adversely affect (MA-NLAA) spotted owl habitat. Some projects may be entirely MA-NLAA with 

respect to spotted owl habitat but may affect and are likely to adversely affect (MA-LAA) spotted owls 

due to disruption. Activities which may disrupt spotted owls at known spotted owl sites or potential 

nest patches but do not modify habitat are also addressed in this document. 

The proposed action would have no effect on the Oregon spotted frog (Rana pretiosa) or Wolverine 

(Gulo gulo) because these species do not occur within the affected areas of the projects.

B. Scope of the Assessment

This document addresses Federal lands on the Willamette National Forest which is within the 7.2 

million-acre Willamette Planning Province, one of twelve planning provinces managed within the 

boundary of the Northwest Forest Plan (USDA & USDI 1994a: E-19). Federal lands within the 

Willamette Planning Province are managed by five administrative units: the Upper Willamette Field 

Office of the Northwest Oregon District of the U.S. Bureau of Land Management (BLM), the 

Cascades Field Office of the Northwest Oregon District BLM, the Columbia River Gorge National 

Scenic Area, the Mt. Hood National Forest, and the Willamette National Forest. The only projects in 

this consultation are on the Willamette National Forest. Table 1 lists the counties within which this

National Forest lies. For the purposes of this consultation, the action area includes lands within the 

Willamette National Forest associated with the proposed projects and non-federal and Federal lands 

within 1 mile of the proposed projects (Figure 1). This action area enables the interagency team to 

more fully understand the cumulative effects of the action on such a wide-ranging species as the 

spotted owl within the context of a larger landscape. A one-mile buffer of the proposed projects is 

included in the action area because it is the maximum disturbance distance associated with blasting

(Table 2).

This document describes and evaluates the potential effects of specific activities (described Table 3) 

that may adversely affect the spotted owl or its critical habitat (or CH) by modifying or removing 

spotted owl habitat or physical and biological features of critical habitat. The document also evaluates 

disturbances of the species associated with these activities within the distances and time periods 

shown in Table 2. 

Table 1. WILLAMETTE NATIONAL FOREST AND RESPECTIVE COUNTIES

Administrative Unit Counties

Willamette National Forest Marion, Linn, Lane, Douglas

This consultation is “batched” in that it evaluates only those types of activities that have been 

determined by the Interagency Level 1 Team (terrestrial subgroup) to be appropriate for batched-level 

consultations. Such activities are routine in that (1) the administrative units either implement them or 
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Figure 1. Map of Action Area for consultation. Action area reflects treatment units buffered by 

one mile.

approve their implementation almost every year; (2) the standards under which these activities may 

proceed are well established; and (3) the potential impacts of these activities are well known. 
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Projects conducted or approved under authority of the “Secure Rural Schools and Community SelfDetermination Act of 2000, Public Law 106-393” may be included as part of proposed activities in 

addition to those projects conducted by routine agency appropriations or cooperative funding. 

Projects under this authority are on or adjacent to Federal lands within the action area. These 

projects are not identified separately in this document from other activities funded by normal 

appropriations.

Any activity proposed by an administrative unit for implementation or approval, that is not consistent 

with the descriptions and standards in this document or falls outside the scope would be addressed in 

a separate consultation.

C. Definitions

For the purposes of this consultation, the following definitions are used in relation to potential effects 

to spotted owls. A list of acronyms used in this document is shown in Appendix F.

Canopy Cover: The proportion of ground area (forest floor) directly covered by the vertical projection 

of the tree crowns (aerial view). Canopy cover is to be calculated at the scale of the cutting unit and 

includes new roads and landings within and adjacent to the cutting unit. It does not include roads 

outside the cutting units when these roads are not parallel to the edge of the cutting unit, or riparian 

reserves, unless thinning in riparian reserves.

When measured in the field, cover is expressed as percent coverage of an area intercepted by 

foliage. Cover is considered the area of the ground covered by a vertical projection of the canopy, 

while closure is an estimate of the angular projection of the canopy (Jennings et al. 1999, p. 59). 

Cover is also evaluated using aerial photography (and used interchangeably with closure in some 

studies) and measures the canopy surface and between-crown gaps. These remotely sensed efforts 

are generally reported as categorical conditions (e.g., open to fully closed) or as an overall empirical 

value for a stand and likely reflects the dominant and co-dominant trees, depending on the study.

 The following provides information on the background of the decision to use canopy cover.

Because the terms canopy cover and canopy closure are often used inter-changeably in the 

literature and among resource professionals despite technically being considered different 

measurements (Jennings et al. 1999, p. 63), we believe it important to make the distinction that in this 

document, and which may not be applicable for other biological assessments or opinions or 

elsewhere in the range of the spotted owl, the Forest Service is using canopy cover to characterize 

pre- and post- treatment characterization of spotted owl habitat. Characterizing canopy by using 

“cover” has relied on the Level 1 Team’s determination of the best available information and 

practicality for each consultation, as appropriate. 

There is little dispute in the literature that canopy cover or closure is just one of several stand level 

indicators in estimating the likelihood of use of a stand by a spotted owls and that relatively high 

canopy cover or closure correlates with presence and use by spotted owls. However, inconsistent 

methodology and estimation methods do not necessarily lend themselves to a definitive standard for 

use of an area by spotted owls. 

The U.S. Fish and Wildlife Service (USFWS) uses current and expected residual canopy in its 

evaluation of potential impacts to spotted owls. Canopy is believed to be important to spotted owls 

because of prey associations (Forsman et al. 1984, pp. 55-56), acting as a thermal mediator 

(Forsman et al. 1984, pp.29-30, Barrows 1981, p. 308 and Thomas et al. 1990, pp.171 and 278) and 

providing concealment cover for predator protection (Thomas et al. 1990, pp. 299-300). However, 

canopy alone is unlikely to provide good insight into a stands ability to provide owl habitat. Rather, it 

is one of the factors associated with use. Most likely, it is the combination of several factors in 

variable quantities that influence the likelihood of occupancy. For example, lower quantities of one 
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factor may be ameliorated by higher quantities of other. Generally, however; there is little evidence 

that stands with <40 percent canopy cover are substantially used by owls, and that 40 to 60 percent 

canopy may not preclude use if other features are present (e.g. perches and relatively higher prey 

density), while stands with canopy cover >60 percent are most commonly used by spotted owls for 

nesting and roosting (e.g., Davis et al. 2016, p. 17 Table 3; Bond et al. 2009, pp. 1120, 1122). 

Nesting, roosting and foraging habitat function evaluation has to take all of the fundamental elements 

into consideration, and none should be considered in isolation.

Habitat: A general term that encompasses spotted owl nesting/roosting, foraging, and dispersal 

habitat. It is important to recognize that nesting/roosting habitat also provides for spotted owl foraging 

and dispersal, and foraging habitat also provides for spotted owl dispersal. In this consultation habitat

refers to both suitable and dispersal habitat (unless specifically identified as either suitable or 

dispersal habitat). 

Suitable Habitat: Is a combination of nesting/roosting habitat and foraging habitat. Suitable habitat 

also provides for the highest quality dispersal opportunities and will be analyzed as such. Suitable 

habitat provides for Physical or Biological Features (PBFs) 1-4 USFWS (2012a, pgs. 71906-71908) 

when occurring in critical habitat.

Nesting and Roosting Habitat (NRF): USFWS 2012a (page 71906) states, “Nesting and roosting 

habitat provides structural features for nesting, protection from adverse weather conditions, and cover 

to reduce predation risks for adults and young. In many cases this habitat type also provides for 

foraging.” 

In this consultation, Nesting and Roosting Habitat is mutually exclusive of Foraging Habitat and 

Dispersal Habitat for accounting purposes1. Nesting and Roosting Habitat provides for spotted owl 

nesting, roosting, foraging and dispersal and is referred to in this consultation as NRF. In critical 

habitat, NRF provides for Physical and Biological Features (PBFs) 1-4. NRF also provides for high 

quality dispersal opportunities and will be analyzed as such.

Stands for nesting and roosting are generally characterized by USFWS (2012a, page 71907):

1. Moderate to high canopy cover (60 to over 80 percent);

2. Multilayered, multispecies canopies with large (20–30 in or greater dbh) overstory trees;

3. High basal area (greater than 240 ft2/ac);

4. High diversity of different diameters of trees;

5. High incidence of large live trees with various deformities (e.g., large cavities, broken tops, 

mistletoe infections, and other evidence of decadence);

6. Large snags and large accumulations of fallen trees and other woody debris on the ground; 

and sufficient open space below the canopy for spotted owls to fly.

 

1Habitat often supports more than one phase of spotted owl behavior, but habitat is counted and 

tallied into categories based on only one phase of spotted owl life history needs.
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Foraging Habitat: Habitat that provides for spotted owl foraging, but not nesting and roosting. This 

habitat varies greatly across the range of the species (USFWS 2012a, page 71907).

In this consultation, foraging habitat is distinct from NRF and Dispersal Habitat for accounting 

purposes, and provides for PBFs 1, 3, and 4 when occurring in critical habitat. Foraging habitat also 

provides for high quality dispersal opportunities and will be analyzed as such.

Stands for foraging in the West Cascades/Coast Ranges of Oregon are generally characterized by 

USFWS (2012a, page 71907):

Stands of nesting and roosting habitat; or younger forests with some structural characteristics (legacy 

features) of old forests, hardwood forest patches, and edges between old forest and hardwoods;

1. Moderate to high canopy cover (60 to over 80 percent); 

2. A diversity of tree diameters and heights;

3. Increasing density of trees greater than or equal to 31 in dbh increases foraging habitat 

quality (especially above 12 trees per ac);

4. Increasing density of trees 20 to 31 in dbh increases foraging habitat quality (especially 

above 24 trees per ac);

5. Increasing snag basal area, snag volume (the product of snag diameter, height, estimated 

top diameter, and including a taper function (North et al. 1999, p. 523)), and density of snags 

greater than 20 in dbh all contribute to increasing foraging habitat quality, especially above 4 

snags per ac;

6. Large accumulations of fallen trees and other woody debris on the ground; and

7. Sufficient open space below the canopy for spotted owls to fly.

Other considerations: When assessing foraging habitat in a project area, the unit biologist will also 

consider inclusion of stands that support flying squirrels, including stands that might be too densely 

forested for spotted owls to fly through. “Densities of northern flying squirrels are particularly 

sensitive to thinning in young Douglas-fir forests, for at least 12 years after treatment...A conservative 

strategy would strive to maintain adequate area and connectivity of dense, closed-canopy forests 

within managed landscapes to maintain northern flying squirrel populations, by leaving areas of 

young forest unthinned.” (Manning et al. 2012, p. 123). While conducting a landscape-scale 

assessment of impacts to spotted owls, the unit biologist will also assess northern flying squirrel 

habitat in each project area, including both young and late-successional forests, to aid in the 

determination of which, if any, young stands should considered foraging habitat. Flying squirrels 

consisted of 38.6 to 58.3 percent of the Oregon Coast range spotted owls’ diet in Forsman et al. 2004 

(p. 219). Unthinned stands may serve as squirrel population sources and ultimately benefit spotted 

owls (Forsman et al. 2004, p. 223).

Dispersal habitat: Habitat that supports the transience and colonization phases of dispersal, which 

spotted owls can fly through.

USFWS (2012a page 71906) states: “we expect dispersal success is highest when dispersers move 

through forests that have the characteristics of nesting-roosting and foraging habitats. Although 

spotted owls may be able to move through forests with less complex structure, survivorship is likely 

decreased. Dispersal habitat, at a minimum, consists of stands with adequate tree size and canopy 

cover to provide protection from avian predators and at least minimal foraging opportunities;”...“but 

such stands should contain some roosting structures and foraging habitat to allow for temporary 

resting and feeding during the transience phase.” 

In this consultation, dispersal habitat is distinct from NR and foraging habitat for accounting purposes 

and provides for PBFs 1 and 4 when occurring in critical habitat.

Stands for dispersing are generally characterized by USFWS (2012a, page 71907):

1. Habitat supporting the transience phase of dispersal, which include
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a. Stands with adequate tree size and canopy cover to provide protection from avian 

predators and minimal foraging opportunities; in general this may include, but is not limited to, 

trees with at least 11 in dbh and a minimum 40 percent canopy cover; and

b. Younger and less diverse forest stands than foraging habitat, such as even-aged, polesized stands, if such stands contain some roosting structures and foraging habitat to allow for 

temporary resting and feeding during the transience phases:

2. Habitat supporting the colonization phase of dispersal, which is: 

a. Equivalent to nesting and roosting habitat with sufficient foraging opportunities (either in 

the nesting and roosting habitat and or with additional foraging habitat), but may be smaller in 

area than that needed to support nesting pairs.

Dispersal-Limited Habitat: Any dispersal, foraging, or nesting/roosting habitat that falls outside an 

area assessed as dispersal-capable habitat using the best available science. Davis et al. (2016, p. 

12, NWFP NSO 20 year review) provides the current (2017) best science for estimating dispersalcapable habitat and the results from their modeling of dispersal-limited habitat is depicted in Figures 2 

and 3 (based on Figure 3-183 of the FEIS for the BLM’s Proposed RMP for Western Oregon [USDIBLM 2016]). If future science or data supersedes this analysis, then it would be used to determine 

dispersal-limited habitat. See the two following maps and notice the dispersal limited habitat at the 

south end of the Willamette Valley that provides the only current landscape path for genetic exchange 

available to spotted owls located in the Coast Range and the Cascades Range.

Analysis of Dispersal Habitat as Suitable within Spotted Owl Site Territories with Low 

Amounts of Suitable Habitat

If the current amount of suitable (nesting/roosting and foraging) habitat is below 50% in the Core Area 

and/or below 40% in the Provincial Home Range of a known or potential site, then the unit biologist 

evaluated whether all or some of the dispersal habitat in the site territory is necessary for successful 

site occupation and reproduction. In territories where dispersal habitat is thought to be supporting 

nesting and rearing of young (i.e. the owl pair is relying on the “next best habitat” due to the low 

amount of suitable habitat), the effects of treating dispersal habitat are analyzed the same as for 

treating suitable habitat. The general rationale for this assumption is that dispersal habitat will provide 

some of the attributes of suitable such as: roosting, foraging, prey and thermal protection around a 

nest, and habitat to rear young. The amount and quality of dispersal habitat (i.e., its forage attributes), 

and the amount of deviation below the 40/50% thresholds for suitable habitat in the Core 

Area/Provincial Home Range respectively, influence this rationale for analyzing effects to dispersal 

habitat functioning as suitable habitat.

Non-Habitat but Capable: Areas that are not currently forested but could be forest in the future, and 

young forest. These areas do not currently meet, but have the potential to eventually meet the 

definition of dispersal, foraging, or nesting/roosting habitat. When this stand type is within critical 

habitat, it provides for PBF 1.

Non-Forest and Incapable: Non-forested areas that would not develop into a forest area capable of 

supporting spotted owl life history needs (i.e. parking lot, lake, talus soil). This habitat does not 

provide for any PBFs of spotted owl critical habitat.

Forest and Incapable: Small patches of forest significantly separated from other forest-capable 

areas and not capable of developing into a forest supporting spotted owl life history needs (e.g. a 

park in downtown Portland). This forest type does not provide for any PBFs of spotted owl critical 

habitat.

Critical Habitat: The specific areas within the geographic area, occupied by the spotted owl at the 

time it was listed, that contain the PBFs that are essential to the conservation of endangered and 

threatened species and that may need special management or protection (See USFWS 2012a).
LAA Biological Assessment- Willamette NF-FY 2018

17

Figure 2. Copy of Figure 3-183 from the BLM Proposed Resource Management Plan Final EIS that depicts spotted owl dispersal limited 

habitat.
LAA Biological Assessment- Willamette NF-FY 2018

18

Figure 3. From Figure 3-183, a closer view of the south end of the Willamette Valley that provides the only current landscape path for 

genetic exchange available to spotted owls located in the Coast Range and the Cascades Range.
LAA Biological Assessment- Willamette NF-FY 2018

19

Known Spotted Owl Site: The recovery plan (USFWS 2011, p. G-4) defines a site as “Any location

where territorial spotted owls are known to be present, were historically present, or may be present in 

unsurveyed habitat.” Sites are based on activity centers which are identified based on territorial 

spotted owl behavior in order of preference: a nest location, juveniles or concentrated single or pair 

activity; or some point in the immediate vicinity. Sites are mapped as point data.

Nesting or non-nesting activity centers often shift from year to year within a site territory, or to a 

neighboring site. These activity center shifts will result in one of the following outcomes support: 1) an 

existing site center, 2) a new or existing alternate site center within an existing site territory, or 3) a 

different existing or newly established known site (i.e., a new master site number).

NOTE: In large part, administrative data policy determines how activity center and site center 

locations are established and attributed in databases. However, regardless of data curation practices, 

current and past spotted owl detection locations, activity centers, and alternate site centers should 

always be considered when managing for spotted owls and determining effects under ESA 

consultation. Potential impacts should be analyzed for all site centers (including alternatives) within a 

single site, including consideration for all spotted owl detections and activity centers. The need to 

manage for some alternate site centers may be unnecessary due to the alternative territory being 

unable to support territorial spotted owls (e.g. extensive habitat loss or other compelling reasons why 

spotted owls would not use the area, including best professional judgement). These situations and 

rational for the territories being unable to support territorial spotted owls need to be validated in 

analysis and documented in the project worksheets. Additionally, if the situation is complex, it should 

be discussed with the USFWS.

Potential Spotted Owl Site: An area able to support a territory of resident spotted owls (i.e. a 

potential breeding pair), where owls are not known to occur, but where surveys have not been 

conducted to protocol. This is used for determining effects to spotted owls where survey data are 

insufficient. See Appendix D for a further discussion on potential spotted owl sites.

Territory: an area that is or potentially could be occupied by territorial (resident) spotted owls. A 

territory will have a home range, core area and nest patch. Because we usually lack telemetry data, 

we will use circles, best available habitat and/or survey data to describe these areas (see their

definitions below).

Nest Patch (or Stand): 300 meters (radius circle) around a known or potential owl site, where a 

spotted owl would be most likely to select a nest tree. This is based on habitat usage by spotted owls 

within the Central Cascades Study Area, located on the Willamette National Forest.

Core Area: 0.5 miles (radius circle) around a known or potential spotted owl site (approximately 500 

acres), which delineates the area most heavily used for nesting, roosting, foraging and rearing young. 

Bingham & Noon (1997, p. 136) defined the core area as that portion of a spotted owl breeding 

season home range that received disproportionately high use for nesting, roosting and foraging; they 

suggested that 60-70% of spotted owl reproducing season activity occurred in about 20 percent of the 

home range. 

Although Courtney et al. (2004:5-5) observed that core area sizes vary greatly among owls, Bingham 

& Noon (1997), Wagner & Anthony (1999), Franklin et al. (2000), and Irwin et al. (2000 and 2005) 

collectively suggest a core area of approximately 500 acres and the Spotted Owl Recovery Plan 

modeling used a core area of approximately 500 acres (USFWS 2011, p. C-15).

Home Range (or Median Provincial Home Range): An estimated area for habitat use by a spotted 

owl pair. For the Oregon Cascades, this estimate is 1.2 miles (radius circle) around a known or 

potential spotted owl site (Forsman et al. 1984, p. 18; Meslow and Miller, 1989, p. 2; Thomas et al. 

1990 p. 194, Table I1; USDA & USDI, 1994b, p.12). See Appendix F for a detailed explanation of 
LAA Biological Assessment- Willamette NF-FY 2018

20

home range.

Habitat Maintained (HHM): Refers to silvicultural activities that alter forest stand characteristics but 

maintain the components of spotted owl habitat within the stand such that spotted owl life history 

requirements are supported (i.e. the functionality of the habitat used by spotted owls remains intact 

post silvicultural activity). 

For spotted owl suitable habitat (also known as NRF2) a canopy cover of greater than 60 percent 

along with other habitat elements (e.g. including snags, down wood, dominated by large overstory 

trees, tree-height class-diversity, and older hardwoods) will be maintained post silvicultural activity to 

adequately provide for spotted owl nesting, roosting, and foraging within the stand. It is important to 

understand that maintaining a canopy cover of 60% alone is not sufficient to insure that the stand is 

maintained.

For spotted owl dispersal habitat a canopy cover of greater than 40 percent along with other habitat 

elements (e.g. including snags, down wood, tree-height class-diversity, and older hardwoods) will be 

maintained after silvicultural activity to adequately provide for spotted owl dispersal.

Proposed silvicultural activities will maintain the characteristics of spotted owl suitable and dispersal 

habitat in affected stands for each site-specific action. In addition, in the case of suitable-maintained, 

the administrative unit biologist is responsible for assessing the juxtaposition of the affected stand 

within the surrounding forest landscape3to ensure that appropriate effects to spotted owls are 

documented.

Available scientific literature provides support for the finding that forest stands can be altered in a 

manner that is not necessarily expected to change the habitat function for spotted owls (Forsman et 

al. 1984, pp.16, 17, 57; USFWS 2011, pp. III-15-17; Irwin et al. 2015 entire). Examples of silvicultural 

activities that may fall into this category are light to moderate thinning, down salvage, individual tree 

removal, and prescribed burning.

Habitat Downgraded: To cause spotted owl nesting/roosting habitat to become foraging or dispersal 

habitat, or to cause foraging habitat to become dispersal habitat.

Habitat Removed: Refers to silvicultural activities that:

 Alter spotted owl suitable habitat such that it no longer supports nesting, roosting, foraging, and 

dispersal (i.e., suitable habitat becomes non-habitat after treatment); or 

 Alter spotted owl dispersal habitat so that the habitat no longer supports dispersal (i.e., dispersal 

habitat becomes non-habitat after treatment). 

Disturbance/Disruption

In the early critical breeding season (March 1-July 15), disturbance and disruption distances are 

measured from the nest tree (if known) or the edge of a nest patch. Once the young have fledged, 

generally in the latter part of the breeding season (July 16-September 30), disturbance and disruption 

distances are measured from the location of the young at time of disruption, if known. If the location of 

the young is not known, distances are measured from the edge of the nest patch.

 

2 Nesting, roosting and foraging (NRF) habitat.

3 Site specific information may reveal a local concern for a spotted owl pair that is relying on the harvest unit. An example: a 

spotted owl pair’s home range contains sub optimal levels of foraging habitat so that any impact, even minor, may contribute 

to the inability of the spotted owl pair to support successful reproduction.
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Breeding Period: The breeding period for spotted owls is March 1 through September 30. The 

critical breeding period is March 1 through July 15.

Disturbance Distance: The distance from the project boundary outward within which the action 

is likely to cause a spotted owl, if present, to be distracted from its normal activity. Except as 

stated in Table 2, the disturbance distance is 0.25 mile from nesting spotted owls during the 

breeding period. The unit wildlife biologist may increase or decrease these disturbance distances 

according to the best available scientific information and site-specific conditions, such as the 

topography and the duration, frequency and magnitude of the disturbance. For individual tree 

removal, it is the opinion of USFWS that chain saw and heavy equipment noise activities that 

occur with duration of less than one day are not likely to cause a reduction in breeding success.

The unit wildlife biologist is responsible for ensuring that the correct effects determination has 

been made for each project. The unit biologist may increase or decrease the disruption distance 

based on site-specific information, such as topography and the duration, frequency and 

magnitude of the disturbance or disruption. If a spotted owl site is surveyed to protocol and the 

spotted owls are determined to be non-nesting, the unit biologist may determine that no 

disturbance or disruption would occur and lift the associated restrictions on activities within 

disruption distances during the year of survey.
LAA Biological Assessment- Willamette NF-FY 2018

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Table 2. DISTURBANCE AND DISRUPTION DISTANCES FOR THE SPOTTED OWL DURING THE 

BREEDING PERIOD. FOOTNOTES LISTED ON THE FOLLOWING PAGE.

Disturbance Source

Disturbance 

Distance Disruption Distance

Entire Breeding Period 

(March 1 – September 30)

Critical Breeding Period

(March 1 – July 15

Latter Breeding Period

(July 16 – September 30

Aircraft: Small fixed-wing aircraft* 

(Cessna 185, etc.)* 0.25 mile 110 yards NA

Blasting 1 mile

0.25 mile1

100 yards (injury)2

100 yards (injury)2

Burning (prescribed fires, pile 

burning) 0.25 mile 0.25 mile3 NA

Chainsaws (includes felling 

hazard/danger trees) 0.25 mile 65 yards4 NA

Heavy equipment for road 

construction, road repairs, bridge 

construction, culvert replacements, etc. 

Includes brushing, maintenance, hauling, 

etc. of non-drivable roads, and road 

decommissioning.

0.25 mile 65 yards4 NA

Helicopter*: Chinook 47d 0.5 mile 265 yards5

100 yards6

(hovering only)

Helicopter*: Boeing Vertol 107, 

Sikorsky S-64 (SkyCrane) 0.25 mile 150 yards7

50 yards6

(hovering only)

Helicopter*: K-MAX, Bell 206 L4, 

Hughes 500 0.25 mile 110 yards8

50 yards6

(hovering only)

Light maintenance (e.g., road 

brushing and grading) at campgrounds, 

administrative facilities, and roads

0.25 mile NA9 NA

Log hauling on open roads 0.25 mile NA9 NA

Pile-driving (steel H piles, pipe piles)

Rock Crushing and Screening 

Equipment

0.25 mile 120 yards1 ≤ 5 yards (injury)

Tree Climbing 25 yards 25 yards10 NA10

Footnotes for this table are found on the following page.
LAA Biological Assessment- Willamette NF-FY 2018

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Footnotes for Table 2

Disturbance sources and distances in table are for single events based on generalized conditions. In order to 

determine final effects to spotted owl behavior, including rearing of young in the later non-critical part of the 

breeding period, unit biologists should consider the amount, frequency and duration of all disturbance sources; 

current breeding status based on surveys if available; and area-specific factors such as habitat amount and 

orientation as well as topography. For individual tree removal, it is the opinion of USFWS that chain saw and 

heavy equipment noise activities that occur with duration of less than one day are not likely to cause a reduction 

in breeding success.

1

Impulsive sound associated with blasts and pile-driving is highly variable and potentially injurious at close 

distances. We selected a 0.25-mile radius around blast sites as a disruption distance based on observed 

prairie falcon flush responses to blasting noise at distances of 0.3 – 0.6 miles from blast sites (Holthuijzen et 

al. 1990, p. 273). We have conservatively chosen a distance threshold of 120 yards for impact pile-driving and 

rock-crushing operations to avoid potential hearing loss effects and to account for significant behavioral 

responses (e.g. flushing) from exposure to continuous sounds from impact pile driving.

2 Exposure to peak sound levels that are >140 dBA are likely to cause injury in the form of hearing loss in birds 

(Dooling and Popper 2007, pp. 23-24). We have conservatively selected 100 yards as an injury threshold 

distance based on sound levels from experimental blasts reported by Holthuijzen et al. (1990, p. 272), which 

documented peak sound levels from small blasts at 138 – 146 dBA at a distance of 100 m (110 yards).

3 Based on recommendations presented in Smoke Effects to Northern Spotted Owls (USFWS 2008, p. 4).

4 Based on Delaney et al. (1999, p. 67) which indicates that spotted owl flush responses to above-ambient 

equipment sound levels and associated activities are most likely to occur at a distance of 65 yards (60 m) or 

less.

5 Based on an estimated 92 dBA sound-contour from sound data for the Chinook 47d presented in Newman et 

al. (1984, Table D.1).

6 Rotor-wash from large helicopters is expected to be disruptive at any time during the nesting season due the 

potential for flying debris and shaking of trees located directly under a hovering helicopter. Hovering rotorwash distance is based on a 300-ft. radius rotor-wash zone for large helicopters hovering at < 500 above 

ground level (from WCB 2005, p. 2 – logging safety guidelines). We reduced the hovering helicopter rotorwash zone to a 50-yard radius for all other helicopters based on the smaller rotor-span for all other ships.

7 Based on an estimated 92 dBA sound contour from sound data for the Boeing Vertol 107 the presented in the 

San Dimas Helicopter Logging Noise Report (USFS 2008, chapters 5, 6).

8 Based on Delaney et al. (1999, p. 74), which concluded that a buffer of 105 m (115) yards for helicopter 

overflights would eliminate flush responses from military helicopter overflights. The estimated 92 dBA sound 

contours for these helicopters is less than 110 yards (e.g., K-MAX (100 feet) (USFS 2008, chapters 5, 6), and 

Bell 206 (85-89 dbA at 100 m)(Grubb et al. 2010, p. 1277).

9 NA = not applicable. Based on information presented in Tempel and Gutiérrez (2003, p. 700), Delaney et al. 

(1999, p. 69), and Kerns and Allwardt (1992, p. 9), we anticipate that the few spotted owls that select nest 

sites in close proximity to open roads either are undisturbed by or habituated to the normal range of sounds 

and activities associated with these roads.

10 Based on Swarthout and Steidl (2001, p. 312) who found that 95 percent of flush responses by spotted 

owls due to the presence of hikers on trails occurred within a distance of 24 m.

* Aircraft normally use above ground level (AGL) as a unit of measure. For instance to not cause a disruption 

by medium and small helicopters during the late breeding season, the AGL would be 350 feet. 350 feet AGL 

would account for 200 foot tall trees that NSOs would be occupying plus the 50 yards disruption distance.
LAA Biological Assessment- Willamette NF-FY 2018

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D. Guidance to Unit Biologist

Submitting projects for biological assessment

The Level 1 Team relies on the unit wildlife biologist to make a preliminary determination of effect for 

each proposed project. In cases where the unit biologist offers a determination that differs from 

previous determinations made by the Level 1 Team for similar actions, the unit biologist should 

provide a clear rationale for their determination. The determinations of effect in this document

represent final determinations by the Level 1 Team. 

After the biological opinion is issued

The Level 1 Team relies on the unit wildlife biologist to ensure that the individual projects 

implemented under this consultation and the associated biological opinion comply with the standards 

in both documents. The biologist, in all cases, is to use site-specific information to verify the 

determination of effect for each proposed project and, when warranted, modify the determination 

made in this document by the Level 1 Team. The following bullets identify situations where the unit 

biologist might use site-specific information to modify the effects determination made by the Level 1 

Team. 

 If the biologist determines that the effect of a proposed project would exceed the level stated in 

this document, the action agency must discontinue the project, modify the project to conform to 

the determination in this document, or reinitiate consultation on the project. The biologist must 

inform the authorized officer of the modified determination of effect and these requirements. 

 The biologist also may reduce a determination of effect based on site-specific information. For 

example, if a project would occur within the disruption distance of a known nest location, but the 

biologist determines that a disruption would not occur because of topographic features or other 

site-specific information, the biologist may lower the effects determination. In all cases, the 

biologist must document their determination and rationale in the case file. Before lowering the 

determination, the biologist must get the approval of their Level 1 Team representative or a Level 

1 Fish and Wildlife Service representative. 

Reinitiation

Page 4-60 of the Consultation Handbook lists four situations that trigger the need to reinitiate 

consultation on a proposed project:

 The amount or extent of incidental take is exceeded.

 New information reveals effects of the agency action that may affect listed species or critical 

habitat in a manner or to an extent not considered in this opinion.

 The agency action is subsequently modified in a manner that causes an effect to listed 

species or critical habitat not considered in this opinion.

 A new species is listed or critical habitat designated that may be affected by the action.

The unit biologist should review those provisions and inform the authorized officer of any requirement 

to reinitiate consultation. The Level 1 Team also is available to help the unit wildlife biologist, as 

requested, apply this consultation and review site-specific situations.

E. Compliance with Planning Decisions and Interagency Consultation 

Policy 

The activities of the proposed action comply with the Record of Decision and the Standards and 

Guidelines of the NWFP (USDA & USDI 1994a; entire) and the Land and Resource Management 

Plan of the Willamette NF, as amended. This document was prepared by the Interagency Level 1 
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25

Team (terrestrial subgroup) in accordance with Interagency Streamlined Consultation Procedures for 

Section 7 of the Endangered Species Act (USFWS and NMFS 1998).

F. Consultation History

This BO is “batched” in that it evaluates only those projects that have been determined by the 

Interagency Level 1 Team (terrestrial subgroup) to be appropriate for this batched-level consultation. 

Such projects involve activities that are: (1) routine in that administrative units either implement them 

or approve their implementation almost every year; (2) the standards under which these activities will

proceed are well established; and (3) the potential impacts of these activities are well known. 

This batched approach should provide a better perspective of the aggregate impacts of numerous 

small projects across the Willamette Planning Province. This effort to address impacts to listed 

species within the province concurrently will more efficiently use staff time by permitting increased 

discussion of projects with impacts to listed species while they are still in the planning phase. 

The proposed projects and their actions will comply with the Record of Decision and the Standards 

and Guidelines of the NWFP (USDA and USDI 1994a), and with the Willamette National Forest Land 

and Resource Management Plans. That is, any activity which is not wholly consistent with the NWFP, 

as well as the applicable Resource Management Plan, is not covered by the following BO. 

The U.S. Forest Service (FS) prepared the BA. The Willamette Province Terrestrial Level 1 

Terrestrial Team worked on project review and edits throughout 2017. The final BA was accepted by 

the Willamette Province Terrestrial Level 1 team and finalized on August 1, 2017.. 

II. Description of the Proposed Action

The proposed action contains eight proposed projects. There are no conceptual projects under this 

consultation. Table 3 describes the types of activities evaluated by this document and the conditions 

under which each activity may proceed. Together, these activities constitute the proposed action. 

Proposed projects occur on all four Ranger Districts of the Willamette National Forest and total 6,951 

acres of habitat treatment. 

On the Detroit Ranger District, a large timber sale and restoration project called Highway 46 would 

treat about 4,091 acres including 3,061 acres of Harvest Habitat Maintain, 553 acres of Harvest 

Habitat Remove, 107 acres of Harvest in Non-habitat, 198 acres of Fuels Treatment, 2 acres of Road 

Construction, 159 acres of Terrestrial Habitat Enhancement, and 11 acres of Special Habitat 

Restoration. Restoration actions of this project include sugar pine restoration, thinning to accelerate 

the development of late successional forest in Late Successional Reserve (LSR), huckleberry 

enhancement, meadow restoration, high-quality early seral creation, and harvest of wood for logs for 

riparian restoration (”fish logs”).

On the Sweet Home Ranger District, a large timber sale and restoration project called Trout Creek 

would treat about 1,171 acres including 395 acres of Harvest Habitat Maintain, 88 acres of Harvest 

Habitat Downgrade, 201 acres of Harvest Habitat Remove, 181 acres of Harvest in Non-habitat, 3

acres of Special Habitat Restoration and 303 acres of Terrestrial Habitat Enhancement. 

On the McKenzie River Ranger District, Park Thin would have 78 acres of Habitat Harvest 

Downgrade and 7 acres of Harvest Habitat Remove. Q Thin would have 36 acres of Habitat Harvest 

Downgrade, 7 acres of Harvest Habitat Remove and 27 acres of Harvest Habitat Maintain. The Lower 

South Fork McKenzie River Floodplain Restoration Project would have 103 acres of Harvest Habitat 

Remove to provide “fish logs” for a large riparian restoration project below the Cougar Reservoir. 

The Three Sisters Risk Reduction Hazardous Fuels Treatment Project would have Fuel Reduction 

treatments on 1,205 acres within 150 feet of roadways.
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On the Middle Fork Ranger District, the Bear Mountain Meadow Restoration would have 218 acres of 

Special Habitat Restoration and the Road 24 Reroute would have 8 acres of road construction to 

relocate a road away from a fish stream.

A summary of the activities proposed by the administrative units is found in Appendix A. The

proposed action includes all processes needed to plan, evaluate, survey, prepare and complete 

activities including, but not limited to: falling, bucking, hauling, post-harvest burning, fuel reduction 

treatments (such as shredding, chipping, mastication, etc. of small diameter fuels), and firewood 

sales. Firewood cutting may occur at unit landings or decks placed during timber sale operations via 

the Administrative Unit permit system. It may occur as soon as the unit is released back to the 

Administrative Unit, but may extend over several seasons.

In addition to the descriptions and conditions in Table 3, the following standards are common to all 

proposed activities (i.e., any proposed activity that does not meet all of the standards in this section is 

not addressed by this document).

A. General Standards

1. To help ensure compliance with the provisions of this consultation and the associated 

opinion, a wildlife biologist shall participate in the design and implementation of all proposed 

activities.

2. All proposed activities should consider the analyses for the management of federally listed 

species contained in pertinent watershed analyses.

3. The removal of a spotted owl nest tree is not included in this document. If a nest tree is a 

hazard, it should be addressed by a separate consultation under the provisions of emergency 

consultation.

4. None of the activities in this document would remove spotted owl habitat in areas where postactivity habitat conditions would create a barrier or strong filter to spotted owl movement and 

survival, in the opinion of the unit wildlife biologist.

5. All activities in LSRs will be consistent with the appropriate LSR Assessment or will be 

reviewed by the Regional Ecosystem Office for consistency with the NWFP, as required by 

the NWFP.

All activities in Adaptive Management areas will be consistent with the appropriate 

management plan.

6. Activities that change the functionality of suitable habitat addressed by Recovery Action 32 

(RA32) are generally avoided in this consultation. This is habitat that meets the definition of 

suitable habitat as described in the 2011 Revised Recovery Plan for the Northern Spotted 

Owl (USFWS 2011, pp. III-42-47) and in memos that provide guidance to administrative unit 

biologists in identifying such habitat (USDA Forest Service 2012; USDI BLM 2012a; USDI

BLM 2012b). 

Projects proposed in such suitable habitat in this document have been reviewed for 

consistency with the Recovery Plan by the Level 1 Team and are discussed in Section G. 

Recovery Action 32.

7. When logistically feasible, proposed activities will be modified to avoid disrupting spotted 

owls. Activities may be moved beyond the disruption distance of known nest sites or potential 

nest patches, conducted outside the disruption period or implemented during years when 

survey protocol determines that nest sites are unoccupied. None of the proposed projects 

addressed in this consultation will cause disruption to spotted owls.

8. If the disruption distance for prescribed burning is reduced below 0.25 miles by the project 

wildlife biologist based on site-specific conditions or design criteria (e.g. burning only when 

winds are carrying smoke away from the nest patch), the presence of smoke in the nest 

patch must be monitored during implementation. The results of that monitoring must be 

provided to the Agency Level 1 Team member within 60 days of conducting the burning. The 
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27

intent is to avoid visible smoke in and below the canopy of the nest patch. As a minimum, 

monitoring will include the date and time of ignition, weather conditions, the duration of the 

burn, and the closest distance visible smoke came to the nest patch. If smoke enters the 

nest patch (undesirable outcome) that would violate the biological opinion for this 

consultation. The agency would need to cease operations, monitor and record the percent of 

the nest patch exposed to smoke, the duration of that exposure, and the relative visibility of 

smoke in the nest patch. Monitoring is not needed if the nest patch is surveyed to protocol 

and found to be inactive during the time of implementation.

9. Each administrative unit shall submit to the USFWS a GIS shapefile or geodatabase 

(hereafter feature class) of activities addressed by this document, with the exception of 

Individual Tree Removal. Individual Tree Removal is only included in the submitted feature 

class when it adversely affects spotted owls or adversely affects critical habitat. The 

administrative unit shall submit a feature class of such trees to the USFWS prior to project 

implementation unless it is a danger tree. If human health or safety is involved with individual 

tree removal, submission of this feature class to the USFWS may occur after the project has 

been implemented.

10. At the end of each calendar year, the administrative units will complete a project 

implementation and monitoring form to show actual levels of effect. This form should be 

forwarded to the USFWS to fulfill the monitoring report requirements. Monitoring completes 

the regulatory requirements of the ESA by documenting the actual effects to the subject 

species. If this consultation gets incorporated into a web-based monitoring design, the 

administrative units will submit the monitoring to USFWS in that format. 

Monitoring will ensure that actual levels of effects do not exceed the effects or potential injury 

anticipated by this document and its associated biological opinion.
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Table 3. Description of proposed habitat modification by activity type.

ACTIVITY TYPE DESCRIPTION

LAND USE 

ALLOCATION

HARVEST –

HABITAT REMOVE

(HH REMOVE)

Harvest – Habitat Remove refers to harvest activities which remove current spotted owl 

habitat such that functionality after treatment is non-habitat. This activity also refers to 

activities in non-habitat that permanently remove non-habitat that is capable of becoming 

habitat (e.g., harvesting trees in non-habitat to expand a parking lot).

Unit of measure is acres harvested.

In suitable spotted owl habitat, Harvest – Habitat Remove is the 

removal of overstory or other habitat components to the point that it 

no longer supports spotted owl nesting, roosting, foraging, and 

dispersal. Harvest might be described as clear-cut, removal of 

habitat, seed tree retention, first or second phase shelterwood cut, 

selective cut, etc. Habitat lost is canopy cover, roosting and nesting 

trees, foraging areas, and some large down woody material. Snags 

and down woody debris may be created as a part of this activity. 

Units are often burned after harvest to reduce fuel load. 

For the purposes of this effects analysis, any activity that results in 

less than 60% canopy cover in suitable habitat is considered habitat 

removal.

MATRIX OR AMA,

WITH ASSOCIATED 

RIPARIAN 

RESERVES 

In dispersal habitat, Harvest – Habitat Remove changes the habitat 

to the point that the stand no longer supports spotted owl roosting 

and foraging, which are the functions necessary to support 

movement and survival (e.g, understory structure would not remain 

in the unit to support the prey base). For the purposes of this effects 

analysis, any activity that results in less than 40% canopy cover in 

dispersal habitat is considered habitat removal.

Gap Treatments: Gaps greater than three acres in dispersal habitat 

and gaps that exceed 10% of the stand are considered “habitat 

removal” to be included in the HH Remove Activity type unless the 

unit biologist provides justification for a different determination.

MATRIX OR AMA,

WITH ASSOCIATED 

RIPARIAN 

RESERVES

HARVEST –

HABITAT 

DOWNGRADE 

(HH DOWNGRADE)

Harvest – Habitat Downgrade and its associated activities modify 

spotted owl suitable habitat to the extent that the stand no longer

supports nesting, roosting, or forage but continues to support 

spotted owl dispersal. Treatment can improve forest health or long 

term structural characteristics of a stand, or provide commodity 

outputs.

Openings may be created for diversity of habitat as long as overall 

stand canopy cover and dead wood quantities meet or exceed 

forest plan standards. Gaps greater than one acre are considered 

“habitat removal”. Units with gaps less than or equal to one acre 

which are greater than 10% of the stand are also considered 

“habitat removal” unless the unit biologist provides justification for a 

different determination (as shown in Appendices B-C).

Unit of measure is acres harvested.

MATRIX OR AMA,

WITH ASSOCIATED 

RIPARIAN RESERVES
LAA Biological Assessment- Willamette NF-FY 2018

29

ACTIVITY TYPE DESCRIPTION

LAND USE 

ALLOCATION

HARVEST –

HABITAT MAINTAIN

(HH MAINTAIN)

Harvest – Habitat Maintain refers to harvest activities which maintain current spotted 

owl habitat functionality after treatment.

Unit of measure is acres harvested.

Within spotted owl suitable habitat, Harvest – Habitat Maintain is 

the partial removal of the overstory for commodity outputs and/or 

forest health where the stand continues to support spotted owl

nesting, roosting and foraging immediately after treatment. It might 

be described as commercial thinning, density management, 

selective cut, partial cut, mortality (standing) salvage, or under 

burning for fuel reduction. Average canopy cover within the stand 

remains above 60% and sufficient coarse woody debris, understory 

structure and snags remain to support nesting and the prey base. 

See the USFWS 2007 white paper “Effects of Habitat Thinning on 

Northern Spotted Owls” p2.

Gaps greater than one acre are considered “habitat removal”. Units 

with gaps less than or equal to one acre which are greater than 

10% of the stand are also considered “habitat removal” unless the 

unit biologist provides justification for a different determination (as 

shown in Appendices B-E).

MATRIX OR AMA,

WITH ASSOCIATED 

RIPARIAN RESERVES

OUTSIDE OF NSO

CRITICAL HABITAT

Within spotted owl suitable habitat, Harvest – Habitat Maintain 

activities described above for Wildlife Urban Interface fire breaks 

and/or forest health that are consistent with LSR assessments and 

spotted owl recovery objectives. 

Gaps greater than one acre are considered “habitat removal”. Units 

with gaps less than or equal to one acre which are greater than 

10% of the stand are also considered “habitat removal” unless the 

unit biologist provides justification for a different determination (as 

shown in Appendices B-E).

LSR OR NSO

CRITICAL HABITAT

Within dispersal habitat, Harvest – Habitat Maintain can be 

implemented for forest health, to improve the structural 

characteristics of a stand or to provide commodity outputs. In some 

instances, this treatment can have long-term benefits to spotted 

owls by encouraging late-successional characteristics to develop 

more rapidly. This treatment maintains the functionality of dispersal 

habitat after treatment. For example, average canopy cover within 

the stand remains above 40% and sufficient coarse woody debris 

and understory structure remain in the unit to support the prey 

base. Openings may be created for diversity of habitat. In LSRs, the 

size and dispersal of openings must meet LSR standards and 

guidelines.

Gaps greater than three acres in dispersal habitat and gaps that 

exceed 10% of the stand are considered “habitat removal” to be 

included in the HH Remove activity type.

ANY LAND USE 

ALLOCATION
LAA Biological Assessment- Willamette NF-FY 2018

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ACTIVITY TYPE DESCRIPTION

LAND USE 

ALLOCATION

FUELS TREATMENT 

Fuels treatments reduce fuel loading around values at risk and/or 

communities to establish a defensible perimeter for public health 

and safety in the event of wildfires. Values at risk include protected 

land use allocations, structures, private land, etc. Communities are 

adjacent to federal lands and have been threatened by wildfires in 

the past. Currently there are limited fuel breaks around such areas 

to assist firefighters in containing the spread of wildfires. 

Treatments would reduce the vertical and horizontal continuity of 

fuels. Future maintenance activities will require separate 

consultation.

Treatments may include, but are not limited to, prescribed burning, 

thinning (removal of trees ≤ 11 inch dbh), whipfelling, mastication, 

etc. Functionality of suitable habitat may be downgraded to 

dispersal habitat. 

Removal of suitable habitat in LSR would meet LSR assessment 

guidelines or have concurrence from the Regional Ecosystem 

Office -Late Successional Working Group. 

Unit of measure is acres treated.

ANY LAND USE 

ALLOCATION

TERRESTRIAL 

HABITAT 

ENHANCEMENT

This type of activity includes habitat enhancement in suitable or 

dispersal habitat for watershed health, wildlife, or botany that 

modifies forest habitat by changing the canopy cover, or altering 

snag or coarse woody debris composition of the stand. 

No nesting structure (e.g., broken top, platform, nesting cavity) 

would be removed or damaged. Projects may include the use of 

hand tools or chainsaws for tree-topping or bottom girdling to create 

snags or wildlife trees, or tree felling for coarse woody debris. 

All treatment units would maintain an average canopy cover of 60% 

in suitable habitat, or 40% canopy cover in dispersal habitat.

Openings up to 1 acre in size in suitable habitat and 3 acres in size 

in dispersal habitat may be created for diversity of habitat. Treated 

trees would be left on site or moved to improve habitat at other 

project areas. 

In LSRs, the size and dispersal of openings must meet LSR 

guidance.

Unit of measure is acres treated or individual trees removed. 

ANY LAND USE 

ALLOCATION1

SPECIAL HABITAT 

RESTORATION

This activity would restore the size and/or vegetative composition of 

meadow/shrub, meadow/shrub/savanna, oak, prairie habitats, or 

other unique habitats which have been encroached by conifers or 

some hardwood species through burning or other means. 

Trees encroaching on these habitats would be removed or heavily 

thinned. Scattered conifer and/or hardwood trees may be retained. 

This activity may occur in either suitable or dispersal habitat.

Unit of measure is acres treated. 

ANY LAND USE 

ALLOCATION
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ACTIVITY TYPE DESCRIPTION

LAND USE 

ALLOCATION

ROAD 

CONSTRUCTION

This activity includes new road construction as well as 

reconstruction of existing roads when such actions require the 

removal of spotted owl habitat or may cause disruption of known 

spotted owl sites or potential nest patches. Roadway openings 

should be consistent with LSR Assessment in LSR land use 

allocation. 

Temporary road construction and/or landings are reported as part of 

the unit acres if the effects determination for both is the same. If, 

however, the effects determination for the temporary road and/or 

landing construction is greater than that for the associated activity, 

then road and/or landing acres are reported separately under this 

activity type.

Unit of measure is acres treated. 

ANY LAND USE 

ALLOCATION

HARVEST IN NONHABITAT

This activity generally has “no effect” to spotted owls outside of 

critical habitat, as no spotted owl habitat is modified. However, in 

spotted owl critical habitat, harvest in non-habitat may affect critical 

habitat by delaying the development of dispersal and/or suitable 

habitat. 

In critical habitat, harvest in non-habitat is generally proposed to 

increase the structure in stands that are currently even-aged and 

have simplified structure.

Unit of measure is of acres treated.

ANY LAND USE 

ALLOCATION IN 

NSO CRITICAL 

HABITAT

DISRUPTION ONLY

Activities which generate noise above ambient levels within the 

disruption distances (Table 2) of a known spotted owl site or 

potential nest patch. These activities do not modify and have no 

effect on spotted owl habitat. Such activities may disrupt the 

behavior patterns and reproductive success of breeding spotted 

owls or cause injury.

Unit of measure is the number of activities.

ANY LAND USE 

ALLOCATION1

B. Implementation Consultation Dates

All projects in this consultation require a NEPA document or decision notice. These projects do not 

have a date for completion. 

C. Action Area

The action area is defined by 50 CFR 402 to mean “all areas to be affected directly or indirectly by the

federal action and not merely the immediate area involved in the action.” For the purposes of this 

consultation, the action area includes lands within the Willamette National Forest associated with the 

proposed projects and non-federal and Federal lands within 1 mile of the proposed projects. This 

action area enables the interagency team to more fully understand the cumulative effects of the 

action on such a wide-ranging species as the spotted owl within the context of a larger landscape. A 

one mile buffer of the proposed projects is included in the action area because it is the maximum 

disturbance distance associated with blasting (Table 2).
LAA Biological Assessment- Willamette NF-FY 2018

32

III. Status of Spotted Owls 

The spotted owl was listed as a threatened species in 1990 because of widespread loss of suitable 

habitat across the species range and the inadequacy of existing regulatory mechanisms to conserve 

the species (55 FR 26114 [June 26, 1990]). Many populations of spotted owls continue to decline, 

especially in the northern parts of the species’ range, where populations have declined by as much as 

80 percent since 1990. While past and current habitat loss continues to threaten spotted owl 

populations, even though loss of habitat due to timber harvest has been greatly reduced on Federal 

lands for the past 2 decades (USFWS 2011, p. vi), increasing competition from the non-native barred 

owl (Strix varia) is now a significant threat to the continued existence of the northern spotted owl 

(USFWS 2011). 

The full Status of the spotted owl is in Appendix D for the efficiency of producing this BA, as the 

status of the species is produced by the Northern Spotted Owl Consultation Coordination Team and 

contains extensive references. 

Although the following information is in the incorporated Status of the spotted owl, we are including it 

here to highlight the current condition of the spotted owl population. 

There are no current estimates of the total population size of spotted owls because many areas 

across the range of the species remain unsurveyed (USFWS 2011, p. A-2). Spotted owl demography 

studies use estimates of fecundity (reproduction) and apparent survival to determine if populations 

within 11discrete study areas in California (3), Oregon (5), and Washington (3) are increasing, 

stationary, or decreasing. Spotted owl populations declined range-wide at an estimated rate of 3.8 

percent per year from 1985 to 2013 (Dugger et al. 2015, p. 57). The rates of population decline vary 

by study area, with the greatest rates of decline occurring in Washington and northern Oregon 

(Dugger et al. 2015, p. 70). The factors that influence spotted owl demography are not fully 

understood, but habitat quality and quantity, annual weather patterns, and the presence of barred 

owls are all factors that affect spotted owl survival, reproduction, and local population trends 

(Forsman et al. 2011, pp. 67-72, Dugger et al. 2015, pp. 93-99). An overall decline in apparent 

survival rates (the probability that an owl will survive from one year to the next) is the most significant 

factor driving the declining population trends across the range of the species (Forsman et al. 2011, 

pp. 63-64). There is now strong evidence that barred owls have negatively affected spotted owl 

populations, primarily by decreasing apparent survival and increasing rates of local territory 

abandonment (Dugger et al. 2015, p. 58). 

The loss of nesting, roosting, and foraging habitat was a major cause of the spotted owl’s decline 

over the past century. Habitat loss is still considered to be a threat to the spotted owl, as habitat 

continues to be lost to wildfires, timber harvest, and other natural disturbances (Davis et al. 2016, p. 

36). Monitoring of spotted owl habitat in the NWFP area from 1993 to 2012 indicated nesting/roosting 

habitat declined from 9.09 million acres to 8.95 million acres on Federal lands during the monitoring 

period, a loss of about 1.5 percent (Davis et al. 2016, p. 5). Across all lands (Federal and nonfederal), habitat declined from approximately 12.5 million acres to 12.1 million acres, a loss of 3.4 

percent (Davis et al. 2016, p. 22). Wildfire has been the major cause of habitat loss on Federal lands, 

while timber harvest is the primary cause of habitat loss on non-federal lands. Although the 

maintenance, enhancement and restoration of NRF habitat is a key element in the conservation of 

spotted owls, it may no longer be the primary factor affecting population stability in either the short or 

long term due to the rapidly increasing trend of barred owl populations (Davis et al. 2011, p. 18). 

The 2011 Revised Recovery Plan for the Northern Spotted Owl (Recovery Plan) (USFWS 2011, 

entire) identified past and ongoing habitat loss and competition from barred owls as the primary 

threats to the survival and recovery of spotted owls at this time. The Recovery Plan includes 

Recovery Actions specific to addressing barred owl competition and habitat loss. For barred owl 

competition, Recovery Actions include the implementation of a barred owl removal experiment, 

management to reduce the effect of barred owls on spotted owls, and the retention and restoration of 

high quality spotted owl habitat to buffer the effects of barred owl competition in the short term 

(USFWS 2011, p. III-65, 67), While long-term maintenance and restoration of additional habitat on 

Federal lands, as envisioned under the NWFP, remains essential to the spotted owl’s recovery 
LAA Biological Assessment- Willamette NF-FY 2018

33

(USFWS 2011, pp. III-41), additional conservation measures addressing competition from barred 

owls that were not envisioned under the NWFP may ultimately be needed to recover the species in 

the face of the barred owl expansion into the Pacific Northwest (Dugger et al. 2011, p. 99, USFWS 

2011, p. III-65).

Supplemental Information 

Below is additional information to supplement the Northern Spotted Owl Consultation Coordination 

Team status of the species:

Effects from Disturbance

The Level 1 Team has concluded that noise, smoke and human presence in the canopy can result in 

a significant disruption of breeding, feeding, or sheltering behavior of the spotted owl such that it 

creates the potential for injury to individuals (i.e., injury in the form of harassment). For a significant 

disruption of spotted owl behavior to occur as a result of disturbance caused by a proposed action, 

the disturbance and the spotted owl(s) must be in close proximity to one another (see Table 6, 

USFWS 2003, entire). Human presence on the ground is not expected to cause a significant 

disruption of behavior because spotted owls do not seem to be startled by those situations (USFWS 

2003, p.14 and USFWS 2005b, p.2). 

Spotted owl reactions to smoke and close human presence in the canopy, and excessive noise levels 

at or in the immediate vicinity of spotted owls are expected to include the following: flushing from the 

nest site, which would leave eggs or young exposed to predation; causing a juvenile to prematurely 

fledge, which would increase its risk of predation; interrupting foraging activities, which would result in 

the reduced fitness or even mortality of an individual; or disrupting roosting activities which would 

cause a spotted owl to relocate. A spotted owl that may be disturbed at a roost site is presumably 

capable of moving away from disturbance without a significant disruption of its behavior. Spotted owls 

forage primarily at night. Therefore, projects that occur during the day are not likely to disrupt its 

foraging behavior. The potential for effects is mainly associated with breeding behavior at an active 

nest site. The breeding season for spotted owls within the action area is March 1 through September 

30.

In the Central Cascades, 86 percent of spotted owl young fledge (i.e., leave the nest tree) by June 30 

(Turner, pers. comm. 1999). Based on Forsman et al. (1984, p.37) observations that most young

spotted owls were capable of short, clumsy flights between trees within one week after fledging, it is 

likely that two weeks would allow sufficient development of owlets to achieve sustained flight. 

Therefore, the spotted owl critical period in the Willamette Planning Province is considered to be 

March 1 through July 15. After July 15, it is presumed that most fledgling spotted owls are capable of 

sustained flight and can move away from harmful disturbances. Therefore, disturbance from most 

proposed actions within disturbance distances of an active nest during the latter portion of the 

breeding period (between July 16 and September 30), may affect, but is not likely to adversely 

affect, spotted owls (see Table 2).

However, disturbances associated with the use of large helicopters, such as a Chinook 47 D, are 

considered to have a greater impact than smaller helicopters, due to the intensity of the noise and 

wind disturbance associated with rotor wash. Blasting is also considered to have a greater impact on 

spotted owls due to the noise intensity. Thus, activities requiring the use of large helicopters or 

blasting within disruption distances of an active nest may affect and are likely to adversely affect,

nesting spotted owls during the entire breeding period (March 1 – September 30).

Effects from Habitat Modification

Territorial spotted owls

Habitat modification can remove habitat or maintain the current habitat functionality. Habitat 

modification activities that reduce the quality of suitable or dispersal habitat while retaining the 
LAA Biological Assessment- Willamette NF-FY 2018

34

structural characteristics of the affected stand that still allow it to support its original function are said 

to maintain habitat. This generally includes a reduction in canopy cover to approximately >60 percent 

in suitable habitat and >40 percent in dispersal habitat, when other habitat elements (including snags, 

down wood, tree-height class-diversity, and older hardwoods) are retained, post-harvest, at levels 

that provide for the original function of the stand. The administrative unit biologist is responsible for 

ensuring prescriptive activities account for these non-conifer structural elements and making correct 

effects determinations for each individual action. Since the functionality of this habitat is retained, the 

impacts on the ability of spotted owls to nest, forage or move across the landscape are anticipated to 

be insignificant. In some cases the juxtaposition of the affected stand within the surrounding forest 

landscape may contribute to the inability of a spotted owl pair to support successful reproduction. An 

example is treatment of suitable or dispersal stands within a nest patch. 

Generally, removing or maintaining dispersal habitat is not expected to immediately affect territorial 

spotted owls, as these owls concentrate on suitable habitat to support their life needs. If treatment in 

dispersal habitat will slow down the development of dispersal habitat into suitable habitat, then the 

treatment may negatively affect territorial spotted owls from slowing down the development of suitable 

habitat to support a home range. In areas where there are no current home ranges, dispersal habitat 

may be important for the development of future home ranges to support territorial spotted owls. 

The removal of suitable habitat has an indirect effect on spotted owl populations by reducing the 

amount of potential nesting or foraging habitat. These effects on a local spotted owl population are 

greater when the amount of suitable habitat remaining post-harvest is limited in the area. Loss of 

nesting structure may reduce the number of breeding pairs if other nesting habitat is limited. Loss of 

foraging habitat could reduce the amount of food available to nearby adult and juvenile spotted owls, 

which could affect their survival or ability to reproduce if other foraging options are limited. 

Downgraded suitable habitat is expected to preclude spotted owl nesting for an undetermined period 

of time: generally 10 to 30 years depending on the post-harvest condition of the stand. However, 

downgraded suitable habitat still would be expected to support the movement of spotted owls across 

the landscape and provide some foraging opportunities. 

Modification that maintains unoccupied suitable habitat is expected to have less of an impact on 

spotted owls because no individual territorial spotted owls would be directly affected by the 

treatments and because the function of these stands would be retained, thus limiting any indirect 

effects. 

The removal or downgrading of unoccupied suitable habitat would not directly injure individual 

territorial spotted owls. However, the removal or downgrading of unoccupied suitable habitat could 

preclude future spotted owl occupancy for a period of time, thus indirectly negatively affecting the 

species. This effect could last for 80 years or more depending on the post-treatment condition of the 

stand. Modification that maintains unoccupied suitable habitat is expected to have less of an impact 

on spotted owls because no individual territorial spotted owls would be directly affected by the

treatments and because the function of these stands would be retained, thus limiting any indirect 

effects. 

Beneficial Effects from Treatments

There may also be short and/or long-term beneficial effects associated with habitat modification, 

particularly thinning in reserves, when they are designed to encourage faster development of latesuccessional characteristics. Thinning within non-matrix lands is implemented to increase growth 

rates and crowns by reducing competition for the retained trees, to make currently unsuitable nest 

trees and trees of marginal habitat quality become suitable nest trees sooner than without treatment. 

These thinning treatments also encourage currently suitable trees to maintain full crowns and branch 

development, and to create holes and gaps in the stand that will increase stand complexity and 

improve habitat by creating greater stand diversity for spotted owls and their prey base. In some 

cases, a short term adverse effect to the spotted owl by Harvest - Habitat Remove may result in a 

long term benefit by providing structural diversity. 
LAA Biological Assessment- Willamette NF-FY 2018

35

Home Range

Habitat modification within the home range can directly and indirectly influence the likelihood of 

spotted owls occupying, breeding and persisting at known and potential sites. When suitable habitat 

is reduced to below 40 percent within a home range, spotted owl occupation and breeding success is 

likely to be diminished, including a potential for injury to spotted owls due to habitat loss.

Home range size is influenced by the degree of forest fragmentation and proportion of mature and old 

forest. The size of home ranges increase in more fragmented landscapes as well as those that 

contain a smaller proportion of mature and old forest (Courtney et al. 2004, pp. 5-5, 5-6). On the 

Willamette Planning Province, the home range of spotted owls is generally a 1.2 mile radius circle or 

about 2,955 acres (Thomas et al. 1990 p. 194, Table I1; USDA & USDI, 1994b, p.12; Forsman et al., 

1984, p. 18, Table 1 and p. 20; Meslow and Miller, 1989, p. 2).

Analysis indicates that injury to spotted owls due to habitat modification could occur when suitable 

habitat is removed and, after treatment, comprises less than 40 percent of the home range (USFWS 

2005a entire). Bart and Forsman (1992, pp. 95, 98), Bart (1995, pp. 944, 945), Ripple et al. (1997, 

pp.151, 155, 156, 157), and Forsman et al. (2005, pp. 365, 372-375) suggest that as the amount of 

suitable habitat in a spotted owl’s home range decreases, there is a corresponding decrease in the 

capability of the site to provide for owl occupancy, reproduction and survival. Bart and Forsman 

(1992, pp. 98, 99) found that areas with less than 20 percent suitable habitat had few spotted owls 

and less reproductive success than areas with more suitable habitat. Bart and Forsman (1990, p. 2 

and fig. 2) found that areas with less than 40 percent older forest had significantly few young fledged 

per pair. In Ripple et al. (1997, pp.151, 155, 157), results suggest that spotted owl reproductive rates 

may be directly related to the proportion of old forest in the landscape. Based on these studies, it is 

likely that at least 40 percent or higher suitable habitat is necessary for maintaining spotted owl life 

history functions at the home range scale. Site-specific conditions may warrant deviations from this 

assumption.

Activities that maintain the extent and function of suitable habitat within a home range (such as light 

to moderate thinning) are generally not likely to result in adverse effects to spotted owls. At some 

sites, younger stands of foraging habitat without potential nest trees are essential to occupation and 

reproduction of spotted owls because nesting, roosting and forage (i.e., suitable) habitat comprises 

less than 40 percent of the home range and less than 50 percent of the core area. Downgrading of 

such foraging habitat to dispersal habitat may result in effects similar to the downgrading of nesting 

and roosting habitat, including adverse effects and potential injury to spotted owls.

Core Area – 0.5 miles

Habitat modification within the core area can directly and indirectly influence the likelihood of spotted 

owls occupying, breeding and persisting at known and potential sites. Breeding behavior, including 

rearing of young, is more affected by habitat conditions at this scale compared to the home range. 

When suitable habitat is removed to below 50 percent within the core area, spotted owl occupation 

and breeding success is likely to decline, including a potential for injury to spotted owls. 

Rosenberg and McKelvey (1999, entire) reported that spotted owls are “central place” animals with 

habitat use focused on the core area. In the Willamette Province, the core area of spotted owls is 

generally a 0.5 mile radius circle or 503 acres. Studies consistently show that the amount of mature 

and old forest is an important predictor of site occupancy by spotted owls. This finding is particularly 

acute at the spatial scale of a spotted owl core use area (USFWS 2009, pp. 35-44). Bingham & Noon 

(1997, p.136) suggested that 60-70 percent of spotted owl activity during the nesting season occurred 

in about 20 percent of the home range. Habitat-fitness and landscape models have demonstrated the 

importance of habitat amount within core areas. For example, Meyer et al. (1998, pp. 5, 36, 47) 

examined landscape indices associated with spotted owl sites versus random plots on BLM lands 

throughout Oregon. Across the provinces, landscape indices highly correlated with the probability of 

spotted owl occupancy included the percent of older forest (30 percent) within the 500 acres 

surrounding the site. 
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36

In their northwest California study, Zabel et al. (2003), as discussed in USFWS 2009, pp.40, 41, and 

Figure III.C.5), found that the highest probability of occupancy occurred when the core area scale 

consisted of 60 to 70 percent nesting-roosting habitat and 30 to 40 percent foraging habitat. The 

averages for all combinations of habitat associated with a high probability (>0.70) of occupancy were 

48 percent nesting-roosting habitat and 28 percent foraging habitat.

In their southern Oregon study area, Dugger et al. (2005, pp. 874-877) showed that when spotted owl 

core areas had at least 50-60 percent older forest habitat, spotted owl fitness (i.e., survival and 

reproduction) was relatively higher than in core areas with lesser amounts.

In summary, habitat composition in spotted owl core areas varies by region and study. Based on the 

above studies, this consultation assumes that it is necessary for a spotted owl core area to have 50 

percent or more suitable habitat to maximize spotted owl life history functions. The 50 percent 

threshold seems to measure when a significant impairment of spotted owl life history functions is 

most likely to occur. This assumption and the corresponding threshold value rely largely on research 

conducted by Dugger et al. (2005 entire), including unpublished habitat-fitness models.

Activities that maintain suitable habitat within a core area (such as light to moderate thinning) are 

generally not likely to have adverse effects to spotted owls, although site-specific conditions factor 

into this determination. At some sites, younger stands of foraging habitat without potential nest trees

are essential to occupation and reproduction of spotted owls because nesting, roosting and forage 

(i.e., suitable) habitat comprises less than 40 percent of the home range and less than 50 percent of 

the core area. Downgrading of such foraging habitat to dispersal habitat may result in effects similar 

to the downgrading of nesting, roosting and forage habitat, including adverse effects and potential 

injury to spotted owls.

Nest Patch

Habitat modification within the nest patch is likely to directly and indirectly affect the occupancy, 

breeding and persistence at known and potential sites. Breeding behavior, especially selection of a 

suitable nest tree or trees, predator defense of the nest tree and rearing of young is more affected by 

habitat conditions at this scale compared to the home range or core area. When forest habitat is 

downgraded or removed within a nest patch, spotted owl occupation and breeding success is likely 

diminished, including a potential for injury to spotted owls due to habitat loss.

The rationale for determining effects due to habitat removal in the nest patch is based on the 

importance of spotted owls selecting and maintaining nest trees (including alternate nest trees) and 

an immediate area needed for rearing of young. These activities are increasingly important near a 

nest tree.

Removal of any suitable or dispersal habitat within a 300 meter radius nest patch would likely result in 

an adverse effect and may potentially injure spotted owls, depending on the amount of habitat 

removed. Similarly, typical light to moderate thinning of any suitable or dispersal habitat in the nest 

patch would likely result in an adverse effect to spotted owls. Potential injury of spotted owls due to 

habitat loss can depend on the amount of habitat removed or suitable habitat degraded.

The best available information (Thomas et al. 1990, p 62 and Appendix D; Hershey 1995, pp. 28, 29, 

52, 53; Courtney et al. 2004, pp. 5-16 thru 5-18) indicates the two key elements of spotted owl habitat 

within a nest patch to be: (1) canopy cover of dominant, co-dominant and intermediate trees (conifers 

and hardwoods) and (2) quality and amount of down wood. A primary basis for determining the 

effects of thinning in a nest patch is a review of management recommendations provided by Glenn et 

al. (2004, pp. 48, 49 ) and Meiman et al. (2003 pp. 1259-1261) for a no-harvest strategy (including 

thinning) in the immediate area of a spotted owl nest site.

Some activities in a nest patch may warrant an effects determination of “may affect, not likely to 

adversely affect (NLAA)” spotted owls. In forest stands likely to be used by spotted owls, 

management activities implemented outside of the breeding season and that retain the current 

condition of these attributes within a nest patch may be NLAA especially when total habitat 

modification occurs in insignificant amounts. Some examples of such activities are: road 

decommissioning, trail and road maintenance, culvert replacement, manual vegetation maintenance, 
LAA Biological Assessment- Willamette NF-FY 2018

37

special forest product removal, limited hazard tree removal, and, possibly, some light intensity fuels 

reduction treatments to reduce fire risk.

Salvage of dead standing and down trees after stochastic events such as wind-throw and wildfire may 

also reasonably warrant a “may affect, not likely to adversely affect” determination if the amount of 

removal is low and sufficient amounts of these habitat attributes are retained. Additionally, activities in 

non-habitat may have the same “may affect, not likely to adversely affect” determination, depending 

on treatment intensity and its effect on future habitat trajectories.

Summary of Home Range, Core Area, and Nest Patch - Potential Impacts

Table 4 summarizes the determination of effects at the home range, core area, and nest patch scales 

described above. In determining the effects of activities on spotted owls, site- and activity-specific 

information may result in different effects determinations from this general analytical framework. 

These “thresholds” are not absolute, but a starting point for the analysis of effects to spotted owls. 

Each owl site is evaluated independently and site-specific factors may indicate that a different 

determination is warranted.

Table 4. Summary of effects determinations to spotted owl sites based on habitat 

conditions in the nest patch, core area and home range as a result of habitat

treatment.

Current Habitat Habitat after treatment

Habitat removal or downgrading Effect1 Potential for Injury1

Nest patch – any habitat condition Nest patch – any habitat condition after 

treatment LAA Yes

Scenarios below are for treatments outside the nest patch and where suitable habitat is removed or downgraded to 

dispersal habitat.

Core area contains > 50% suitable habitat and 

Home range contains > 40% suitable habitat

Core area contains > 50% suitable habitat and

Home range contains > 40% suitable habitat LAA No

Core area contains > 50% suitable habitat and

Home range contains < 40% suitable habitat LAA Likely

Core area contains < 50% suitable habitat and

Home range contains > 40% suitable habitat LAA Likely

Core area contains < 50% suitable habitat and

Home range contains < 40% suitable habitat LAA Likely

Core area contains > 50% suitable habitat and

Home range contains < 40% suitable habitat

Core area contains > 50% suitable habitat and

Home range contains < 40% suitable habitat LAA Likely

Core area contains < 50% suitable habitat and

Home range contains < 40% suitable habitat LAA Likely

Core area contains < 50% suitable habitat and

Home range contains > 40% suitable habitat

Core area contains < 50% suitable habitat and

Home range contains > 40% suitable habitat LAA Likely

Core area contains < 50% suitable habitat and

Home range contains < 40% suitable habitat LAA Likely

Core area contains < 50% suitable habitat and

Home range contains < 40% suitable habitat

Core area contains < 50% suitable habitat and

Home range contains < 40% suitable habitat LAA2 Likely2

This table shows common scenarios analyzed. Site-specific conditions may result in different effects determinations for a specific site based 

professional judgment.

1 Effects determinations, including potential for injury due to habitat loss, apply both to known sites and potential sites.

2 Survey data and other local information may show known or likely resident pairs at known sites with habitat conditions below the thresholds 

specified above. In such instances, even though pre-activity conditions were already below thresholds, activities could result in a “may 

affect, likely to adversely affect (LAA)” determination, including the potential for injury due to habitat loss.
LAA Biological Assessment- Willamette NF-FY 2018

38

Dispersing spotted owls

Removal of dispersal habitat is expected to reduce spotted owl movement through the treated 

stand(s). Thus the ability of spotted owls to move across portions of the landscape where dispersal 

habitat has been removed depends entirely on the habitat condition of the surrounding lands. 

Removing suitable habitat will eliminate foraging and roosting opportunities, in addition to reducing 

spotted owl movement through the treated stand(s). Downgrading suitable habitat will also result in 

limited foraging and lack ample protection from avian predators and weather while roosting. 

Downgrading suitable habitat is expected to still supporting spotted owl movement. Thus again the 

ability of spotted owls to move across the landscape, with sufficient foraging opportunities and roost 

sites, near where habitat has been removed depends entirely on the habitat condition of the 

surrounding lands. 

Maintaining dispersal or suitable habitat should allow spotted owls dispersing to continue to use those 

stands for dispersal since the function of the stand to support dispersing spotted owls is expected to 

be retained. 

Considerations for local impacts on Spotted Owl Prey Species

Some spotted owl primary prey species, such as northern flying squirrels (Holloway and Smith 2011, 

entire) will avoid regeneration harvests post-treatment. This is anticipated due to the reduction in 

habitat features that are important to these species, including canopy cover, mid-story canopy, snags, 

and down coarse wood in harvested areas. These harvested areas will become much more 

inhospitable to flying squirrels which are tied to complex mid-story canopies. Red tree vole 

populations will be impacted as well, due to removal of nest structures, intact canopies and their food 

source. Populations of woodrats and brush rabbits may increase after regeneration harvests, as 

these species regularly occur in early seral habitats (Maser et al. 1981, pp. 128-129; Williams et al.

1992, p. 210; Innes et al. 2007, p. 1528).

Spotted owl prey species will be affected by the thinning of young stands. Effects of thinning on the 

primary prey species of spotted owls are discussed below.

Flying squirrels

Northern flying squirrels comprise approximately 50% of the prey biomass in diets of spotted owls 

in the region of the analysis area (Forsman et al. 2004, p. 219). The vast majority of studies 

indicate that thinning young stands (similar to those proposed for thinning under this consultation) 

causes a decrease in squirrel densities, at least in the near term (11-13 years after harvest; 

Manning et al. 2012, pp. 120-123). Some studies have not found any significant short-term 

differences in densities, but meta-analysis demonstrated that these studies lacked the statistical 

power or proper research design to support their assertions (Holloway and Smith 2011, pp. 670-

672). See Manning et al. (2012, entire) and Wilson and Forsman (2013, entire) for a thorough 

review of research on the effects of thinning young stands on densities of northern flying 

squirrels.

Thinning substantially reduces the abundance of large live trees and large snags, habitat features 

which appear to be among the most important determinants of habitat quality for flying squirrels 

(Manning et al. 2012, p. 122). The abundance of hypogeous fungi and mid-story structural 

complexity (and associated protective cover that it provides on the glide path of flying squirrels) 

have been suggested as additional drivers of flying squirrel densities. However, these 

hypotheses have not been tested (Manning et al. 2012, p. 121).

Thinning treatments proposed under this consultation promote mid-story development. They are 

designed to reduce inter-tree competition and therefore accelerate the development of large live 

trees, which eventually turn into large snags. Over the long term, thinning young stands should 

therefore cause an improvement in the habitat of northern flying squirrels. However, the length of 

time between thinning and recovery of flying squirrel habitat suitability in young stands is 

unknown (Wilson and Forsman 2013, p. 87).
LAA Biological Assessment- Willamette NF-FY 2018

39

Wilson (2010, p.140) also reported most thinning is likely to suppress flying squirrel populations 

for several decades, but expected the eventual long-term benefits of variable-density thinning for 

squirrels to be positive. While an emphasis on developing mid-story tree layers is critical if the 

goal is to accelerate late-seral conditions and promote prey for spotted owl, there can be shortterm effects to flying squirrels. Wilson (2010, p. 99) states that “Variable-density thinning had a 

negative effect on flying squirrel populations during four out of the first five years following 

treatment, but not significantly so after that period. Likewise, there was an additional significant 

forest interaction with thinning during 1994 and 1996, but not beyond that point. This supported 

the conclusion that squirrels recovered from the short-term effects of thinning within 3-4 years 

post-thinning as reported by Carey (2001).” 

Wilson (2010, pp.139-140) suggests a few considerations to reduce short-term effects to flying 

squirrels while trying to create more forest complexity that would benefit them in the long-term. 

The proposed action incorporates some of those considerations via the aggregate and dispersed 

retention features, including: 

 retention of existing large decadent trees and snags; 

 retention of no-treatment areas (e.g., “skips” and Riparian Reserves) to provide travel 

corridors from adjacent late seral habitats and across the landscape; 

 retention of a range of tree size classes throughout the stand; 

 improvement of foraging opportunities by promoting the development of understory and 

shade-tolerant tree species throughout the stand; and 

 maintenance of canopy cover within the stands (e.g., lightly and moderately thinned 

areas) which would provide protective cover from predators, as well as provide a tree 

density that allows squirrels to adequately glide between trees and move through a stand 

in order to access foraging areas. 

Sollmann et al. (2016, abstract) offers the following “Whereas thinning had negative effects on 

northern flying squirrel density on the scale of a thinning treatment unit, our results suggest that 

these effects were largely absorbed by the heterogeneous landscape, as animals shifted their 

distribution into un-thinned areas without a decline in overall density. This highlights the need to 

incorporate the landscape context when evaluating the effects of forest management on wildlife.”

Woodrats

Woodrats comprise approximately 20% of the biomass in spotted owls’ diets in the region of the 

analysis area (Forsman et al. 2004, p. 219). Mixed results have been reported in studies that 

examined effects of thinning on woodrats. Dusky-footed woodrats occur in a variety of conditions, 

including both old, structurally complex forests and younger seral stages, and are often 

associated with streams (Carey et al. 1999, p. 73; Williams et al. 1992, pp. 207-208; Sakai and 

Noon 1993, pp. 376-378; Hamm and Diller 2009, pp. 100-101). Research has suggested that 

thinning or associated practices (e.g., burning slash piles) could be detrimental to dusky-footed 

woodrats if it reduces hardwoods, shrubs or downed wood, yet treatments could ultimately benefit 

woodrats if they result in growth of shrubs or hardwoods over time (Williams et al. 1992, p. 210; 

Innes et al. 2007, p. 1528). 

There have been no studies addressing bushy-tailed woodrat occurrence in or near the action 

area. In the dry forests of eastern Washington, bushy-tailed woodrats are more abundant in 

forests with more large snags, dwarf mistletoe brooms, and partly decayed logs. Incidental loss 

of these habitat features as a result of thinning may cause a decrease in bushy-tailed woodrats; 

however, this hypothesis has not been tested (Lehmkuhl et al. 2006, pp. 374-375).

Rabbits and hares

Brush rabbits and snowshoe hares collectively comprise approximately 10% of the diet of spotted 

owls in the region of the analysis area (Forsman et al. 2004, p. 219). Brush rabbits, as their 

name implies, occur in thickets and other brushy habitats (Maser et al. 1981, pp. 128-129). 
LAA Biological Assessment- Willamette NF-FY 2018

40

Thinning treatments and regeneration harvests promote brushy habitat, and by extension 

populations of brush rabbits. Snowshoe hares inhabit mature and immature coniferous forests 

(Maser et al. 1981, p. 124). Although no studies on the effects of forest management practices 

on snowshoe hares have been conducted in western Oregon, research in the panhandle of Idaho 

indicates that thinning and clearcut treatments cause a short-term (10-15 years) decrease in 

snowshoe hare populations, but populations of hares are similar or greater than unmanaged 

mature forests within 15-40 years (Thornton et al. 2012, pp. 136-138).

Red tree voles

Red tree voles comprise approximately 2% of prey biomass in the diet of spotted owls in the 

region of the analysis area (Forsman et al. 2004, p. 219). This arboreal species also appears to 

be negatively impacted by thinning. From Wilson and Forsman (2013, p. 83): “Small trees in 

young forests generally have insufficient food resources (conifer needles) in a single tree to 

support breeding females, so individuals often forage in multiple trees surrounding their nests 

(Swingle and Forsman 2009). In closed-canopy forest, they can simply travel across interlocking 

branches to reach adjacent trees. Thinning breaks these connections and voles must travel down 

the bole and across the ground to reach other trees. This not only increases their energetic 

demands, it also puts them at additional exposure to predation. Second, red tree voles build

nests of small twigs and conifer needles on platforms created by dwarf mistletoe, epicormic 

branching, forked boles, and other irregularities in tree-branching patterns. If trees with complex 

structure are removed during thinning, it may greatly reduce the ability of young tree voles to find 

suitable nest substrates. Third, young tree voles have limited dispersal ability, and the absence of 

red tree voles across much of northwest Oregon suggests that they may not be able to disperse 

across broad areas of intensively managed forest (Maser et al. 1981).”

Wilson and Forsman (2013, pp. 84-85) recommend several relevant strategies to reduce known and 

potential negative effects of thinning on spotted owl prey:

 Accelerate and monitor mid-story development by maintaining the desired balance of 

understory seedlings and saplings through underplanting, early thinning of saplings, and 

patchy brush control, where necessary.

 Include very young (<25 year-old) stands in the mix of stands targeted for restoring late-seral 

forest.

 Retain some young high-density forest on the landscape. Manning et al. (2012 pp. 121-123) 

also recommend this action, emphasizing management for connectivity of unthinned, young 

stands.

 Experimentally evaluate alternative prescriptions to thinning, specifically those that focus 

solely on maintaining untreated “skips” (i.e., patches of trees left unthinned) and creating 

gaps (removing patches of trees). 

With the habitat preferences of prey species in mind, unit biologists have determined whether 

proposed silvicultural treatments would maintain or downgrade spotted owl habitat. The likelihood 

and degree of effects to spotted owl prey species will vary based on site-specific conditions, such as 

the intensity and magnitude of treatments.

Prescribed Fire

Fire has both short and long-term negative and beneficial effects to small mammals, depending on 

the species and the severity of fire (Fontaine and Kennedy 2012, entire). Some small mammals may 

be directly impacted due to smoke or the inability to escape. Other small mammals may not be 

affected if they are mobile, protected within large downed coarse wood, or able to move underground 

or up a tree. However, there may be long-term benefits from a low intensity burn in that the expected 

increased plant vigor, forage production, and tree mortality resulting from spring burning could 
LAA Biological Assessment- Willamette NF-FY 2018

41

facilitate cavity creation and resultant denning opportunities. Another expected benefit is the likely 

decrease in potential for a stand replacement event in the drier forests found within the action area.

Barred Owls in the Action Area

While Appendix D summarizes information on the range-wide status of the species for spotted owls, 

additional information is provided in this section on the threat of barred owls relative to the action

area.

The Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011: pp. III-62-68) identifies 

competition from the barred owl as an important threat to the spotted owl. Since barred owls are more 

aggressive and more habitat generalists but also use the same habitats and prey as spotted owls,

they are believed to be out competing spotted owls for habitat and food (USFWS 2011: p. III-62-68, 

Wiens 2012: Abstract). Within the demographic study areas, there has been an almost steady 

increase in the number of barred owls as measured by the proportion of spotted owl sites with barred 

owls detected, with as many as 60 percent of the spotted owl sites having barred owls detected 

(Forsman et al. 2011, p. 80, see Figure 4). Forsman et al. (2011, pp. 69-70) found evidence barred 

owl detections were important sources of variation, and had negative effects on spotted owl apparent 

survival and recruitment.

The Biological Opinion for the BLM Proposed Resource Management Plan (PRMP) states “In the 

course of this PRMP section 7 consultation process during the last three years, and since publication 

of the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011; recovery plan), it has 

become ever clearer that the spotted owl is most threatened by competition with the increasingly 

common barred owl. Although habitat loss due to timber harvest and wildfire remains an important 

long term threat to the spotted owl, the Service now believes this threat is secondary in importance to 

the conservation of the spotted owl” (USFWS 2016: p. 4). 

Dugger et al. (2011: entire) modeled extinction and colonization rates for spotted owl pairs in the 

South Cascade Demographic Study Area where barred owls were detected on some home ranges. 

They found that extinction rates for spotted owls increased with decreasing amounts of old forest in 

the core area, and that the effect was 2-3 times greater when barred owls were detected. They also 

found that colonization rates for spotted owls decreased as the distance between patches of old 

forest increased (i.e. increased habitat loss and fragmentation) and that barred owl presence similarly 

decreased the rate of colonization of spotted owl pairs. They concluded that conserving large blocks 

of contiguous old-forest habitat was important for reducing interference competition between the two 

owl species. They mapped old-forest habitat as generally >100 years of age with trees DBH >35 cm 

(K. Dugger, personal communication, 2012). Wiens (2012, pp. 45-49) also found that the relative 

probability of spotted owls selecting a location for reproduction was reduced if the location was in 

close proximity to the core-use area of a barred owl.

Locally, the Cascades Field Office-BLM tries to survey its known spotted owls annually. During 2015, 

barred owls were documented in 39 (71%) of the 55 known spotted owl sites surveyed. Barred owl 

numbers have been increasing substantially each year within their data set. In 2007, it was 21%, 

2010 was 48%, and 2013 was 68%. There were 23 known spotted owl sites occupied by barred owl 

pairs during the 2015 survey year. Single barred owl responses attributed for the remaining 16 sites. 

In addition, there were 21 pairs and 92 single barred owl detections not associated with known 

spotted owl sites. Seventeen barred owl juveniles were detected during 2015, of which 10 were in 

known spotted owl sites. In contrast, 1 juvenile spotted owl was detected.

There is concern that timber harvest and other silvicultural activities may directly or indirectly affect 

the interaction between barred owls and spotted owls and increase the competitive advantage for 

barred owls. The three areas of concern frequently mentioned are: a) logging may expand the range 

of barred owls; b) silvicultural treatments that thin forests, create early seral habitat, or create edge 

habitat may favor barred owls over spotted owls; and c) logging that reduces the amount of older 

forests may increase the competition between the two species by reducing the amount of preferred 

habitat available. Each concern is addressed individually below.
LAA Biological Assessment- Willamette NF-FY 2018

42

Figure 4. Annual proportion of Spotted Owl territories with Barred Owl detections (BO 

covariate) (Forsman, et al. 2011)

Does logging expand the range of barred owls?

The barred owl removal Draft Environmental Impact Statement (USFWS 2012b, pp. 43-44) 

specifically considered and rejected an alternative to use forest habitat management to favor spotted 

owls and hinder barred owls. They reasoned that there are no known forest conditions where spotted 

owls have a competitive advantage over barred owls. Pearson and Livezey (2003, p. 272) state that 

managing forests to benefit spotted owls over barred owls may not be possible because both species 

use the same type of old-growth habitat. Barred owls successfully colonized Olympic National Park in 

areas that never had timber harvest (Courtney et al 2004, pp. 7-13). Old growth reserves appear to 

be supporting large populations of barred owls, and in many cases there are more barred owls than 

spotted owls in the reserves (Pearson and Livezey 2003, p.271). USFWS (2011, p. 1-8) assumes 

barred owls now occur at some level in all areas used now or in the past by spotted owls. We provide 

information above showing that barred owls are widely established in the action area. Therefore we 

conclude there is no scientific support that the silvicultural treatments assessed in this Supplemental 

BA will expand the range of barred owls.

Do silviculture treatments that thin, create early seral, or create edge habitat favor 

barred owls over spotted owls?

A detailed review for the spotted owl recovery plan found much evidence that barred owls prefer oldgrowth and older forest habitat, not early seral or edge habitat (USFWS 2011, pp. B-10-12). In 

portions of the spotted owl’s range, barred owl populations are increasing while spotted owls are 

declining, to some degree independently of forest management history in the area (Courtney et al. 

2004, pp. 7-37). 

Wiens (2012, entire) conducted a thorough study of the interaction between barred and spotted owls 

in the moist temperate forests of western Oregon by radio tracking 29 spotted owls and 28 barred 

owls in 36 neighboring territories over a 2-year period. He found that both owl species had similar use 

of young, mid-seral, and mature forests and that both species avoided areas within 135 meters of 

forest/non-forest edges. Both species avoided open areas and young forests less than 60 years of 

age and used mature conifer forests (60-120 years of age) proportional to their availability within the 

landscape (second order selection). Wiens’ study contains the most detailed information applicable to 

the action area, comparing the use of younger forest by the two species.
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43

The available information does not provide support for the hypothesis that thinning young and mature 

forest or the creation of early seral habitat or forest edge selectively favors barred owls over spotted 

owls in the action area.

Does reducing the amount of older forests on the landscape increase competition 

between barred and spotted owls?

Information presented above indicates that both barred owls and spotted owls prefer older forest 

habitat. The Northern Spotted Owl Recovery Plan recognized this mutual preference stating 

“Because barred owls compete with spotted owls for habitat and resources for breeding, feeding, and 

sheltering, ongoing loss of habitat has the potential to intensify the competition by reducing the total 

amount of these resources available to the spotted owl and bring barred owls into closer proximity 

with the spotted owl.” (USFWS 2011, p. I-9). To reduce or minimize this threat, the Service developed 

Recovery Action 32 (USFWS 2011, p. III-67) which recommends conserving and restoring older, 

multi-layered forests across the range of the spotted owl. 

In the 15 year meta-analysis of spotted owl populations, Forsman et al. (2011, p. 77) wrote: 

“In view of the continued decline of spotted owls in most study areas, it would be wise to 

preserve as much high-quality habitat in late successional forests for spotted owls as 

possible. This recommendation is comparable to (Recovery Action 32) in the final 

recovery plan for northern spotted owls (USFWS 2011), but we believe a more inclusive 

definition of high-quality habitat is needed than the rather vague definition provided in

the 2011 recovery plan. Much of the habitat occupied by NSOs and their prey does not 

fit the classical definition of ‘old-growth’ as defined by Franklin and Spies (1991), and a 

narrow definition of habitat based on (this) criteria would exclude many areas currently 

occupied by NSOs. Second, we believe more information on competitive interactions 

between northern spotted owls and barred owls is needed. A recent study by D. Wiens 

at Oregon State University ...will provide some of this information for western Oregon, 

but similar information is needed for other parts of the range of spotted owls.”

The Wiens (2012, pp. 34, 49-53, 102) study found that spotted owls and barred owls both prefer 

conifer forests >120 years of age with dominant overstory trees >90 cm dbh. Use of such forests was 

2-5 times greater than their availability. Loss of these old forests is likely to increase the competition 

between the two owl species for territorial space with negative impacts to spotted owls. Wiens (2012, 

p. 42) found a significant decline in survival of spotted owls as the percent of old conifer forest in the 

general home range dropped below 35%. He recommended that conifer forests greater than 120

years of age be protected to avoid further increasing the competition pressure from barred owls.

The above study is applicable to our action area. We analyzed both any loss of conifer forests greater 

than 120 years of age, as well as any loss of habitat fitting the description of Recovery Action 32, 

when evaluating how the proposed actions may affect interspecific competition with barred owls. 

Summary of Effects to Spotted Owls and their Territories due to Habitat Alteration 

and Barred Owls 

There are also generalized effects to spotted owls, due to a combination of barred owls and habitat 

modification.

Some of the proposed activities would remove or degrade habitat conditions for both barred and 

spotted owls within the home range of known spotted owl sites. The likelihood of barred owls 

occurring within the home range of most spotted owl sites in the action area is high, including multiple 

barred owl pairs residing within a single spotted owl site.

As previously mentioned both species use mid-seral and older types of conifer forest and prefer older 

forests, especially for nesting. However, barred owls appear to use a wider range of forest types 

compared to spotted owls (Dugger et al. 2011, p. 2466; Wiens et al. 2014, p. 32). When manipulation 

of habitat (e.g., timber harvest) alters habitat conditions for both barred owls and spotted owls, the 

relative effect on barred owls may be lesser because they do not appear as dependent on older 

forests as spotted owls. 
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44

Some spotted owls appear to be able to successfully defend territories and reproduce when barred 

owls are present (Dugger et al. 2011, p. 2466; Wiens et al. 2014, pp. 26-29), but the mechanism that 

allows this is currently unknown and such behavior often does not occur. Also all 5 spotted owls that 

attempted to nest within 1.5 km of a barred owl nest failed during incubation (Wiens et al 2014, p. 29). 

As mentioned above, when barred owls are present, the effect of habitat modification on spotted owl 

pair survival (estimated as the probability of extinction of a single territory) may be exacerbated by 2-3 

times (Dugger et al. 2011, pp. 2463, 2465). The relative effect of barred owls on site extinction 

probability increases as the proportion of older forest habitat at the core area scale decreases 

(Dugger et al. 2011, p. 2465). Barred owl effects on spotted owl survival and colonization appear to 

be substantial and additive to the effects of reduction and fragmentation of habitat in spotted owl 

home range areas. Habitat loss accompanied by spotted owl exclusion from other habitat due to 

barred owl competition, has a disproportionate increase in the effects to spotted owls compared to 

habitat loss alone.

While the effects described above vary in occurrence and intensity among individual spotted owl 

territories, overall they are relevant assumptions used to assess typical effects of habitat modification 

and barred owl competition.

IV. Status of Spotted Owl Critical Habitat 

On December 4, 2012, the final rule for critical habitat for spotted owls was published (USFWS 

2012b), and became effective on January 3rd, 2013. The revised critical habitat currently includes 

approximately 9,577,969 acres in 11 units and 60 subunits in California, Oregon, and Washington. 

The full Status of the spotted owl critical habitat is in Appendix D for the efficiency of producing this 

BA, as the status of the species and its critical habitat is produced by the Northern Spotted Owl 

Consultation Coordination Team and contains extensive references. 

Although the following information is in the incorporated Status of the spotted owl and its critical 

habitat, we are including it here to highlight the current need of critical habitat to support the spotted 

owl population within the Willamette Province. 

Conservation Role of Critical Habitat

The role of spotted owl critical habitat is:

 To ensure sufficient habitat to support stable, healthy populations of spotted owls across the 

range and within each of the 11 recovery units, 

 To ensure distribution of northern spotted owl habitat across the range of habitat conditions 

used by the species, and 

 Incorporate uncertainty, including potential effects of barred owls, climate change and 

wildfire-disturbance risk.

Critical habitat protections are also meant to work in concert with other recovery actions such as 

barred owl management (USFWS 2012a, p. 71879). Recovery actions include:

1. Conserve the older growth, high quality and occupied forest habitat as necessary to meet 

recovery goals. This includes conserving old growth trees and forests on Federal lands 

wherever they are found (emphasis added), and undertake appropriate restoration treatment 

in the threatened forest types.

2. Implement science-based, active vegetation management to restore forest health, 

especially in drier forests in the eastern and southern portions of the spotted owl’s range. 

This includes managing NWFP forests as dynamic ecosystems that conserve all stages of 

forest development (e.g., old growth and early seral), and where tradeoffs between shortterm and long-term risks are better balanced. The NWFP should be recognized as an 

integrated conservation strategy that contributes to all components of sustainability across 

Federal lands.
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45

3. Encourage landscape-level planning and vegetation management that allow historical 

ecological processes, such as characteristic fire regimes and natural forest succession, to 

occur on these landscapes throughout the range of the spotted owl. This approach has the 

best chance of resulting in forests that are resilient to future changes that may arise due to 

climate change (USFWS 2012a, p. 71881).

Physical or Biological Features and Primary Constituent Elements 

The designation of critical habitat for spotted owl uses the term primary constituent element. The new 

critical habitat regulations (USFWS and NOAA 2016: 81 FR 7214) replace this term with physical or 

biological features (PBFs). This shift in terminology does not change the approach used in conducting 

our analysis, whether the original designation identified primary constituent elements, PBFs, or 

essential features. In this consultation, the term PBF means primary constituent element as 

appropriate for the specific critical habitat. 

The CH rule identified the PBFs needed for the conservation of the spotted owl. The PBFs are the 

forested areas that are used or likely to be used by the spotted owl for nesting, roosting, foraging, or 

dispersing (USFWS 2012a, p. 71904). The PBFs are the specific characteristics that make habitat 

areas suitable for nesting, roosting, foraging, and dispersal (USFWS 2012a, pp. 71906-71908). The 

PBFs include: 

1) forest types in early-, mid-, or late-seral stages; and specific habitat that provides for

2) nesting/roosting, 

3) foraging, and 

4) transience and colonization phases of dispersal. 

Any activity occurring within CH that impacts any of these PBFs may adversely affect spotted owl CH.

Analysis Scales

The consultation process evaluates how a proposed action is likely to affect the capability of the 

critical habitat to support the spotted owl by considering the action area and scales at which lifehistory requirements are based (USFWS 2012b, p. 71940). Such alterations may include, but are not 

limited to, those that alter the PBFs essential to the conservation of a species or that preclude or 

significantly delay development of such features (USFWS and NOAA 2016, p 7216).

Action area

 The impact of the proposed action on the ability of the affected critical habitat to continue to 

support the life history functions supplied by the PBFs (i.e. territories that can support 

occupancy and landscapes that can support dispersing spotted owls). 

Subunit

 The extent of the proposed action, both its temporal and spatial scale, relative to the critical 

habitat subunit within which it occurs. 

 The specific purpose for which the affected subunit was identified and designated as critical 

habitat. 

 The impact of the proposed action on the subunit’s value for conservation of spotted owls. 

 The overall consistency of the proposed action with the intent of the recovery plan or other 

landscape-level conservation plans. 

 The special importance of project scale and context in evaluating the potential effects of 

timber harvest to spotted owl critical habitat. 
LAA Biological Assessment- Willamette NF-FY 2018

46

Unit

 The extent of the proposed action, both its temporal and spatial scale, relative to the critical 

habitat unit within which it occurs. 

 The aggregate effects of all completed activities in the critical habitat unit. 

 The impact of the proposed action on the unit’s value for conservation of spotted owls. 

Range wide

 The extent of the proposed action, both its temporal and spatial scale, relative to the entire

critical habitat network’s value for the conservation of spotted owls.

V. Environmental Baseline

A. Status of the Spotted Owl in the Action Area

Spotted owl habitat and population data for the Willamette National Forest is shown in Appendix B. 

Spotted owl activity center data were updated for new activity centers detected up to 2017. However, 

there are also many activity centers that have not been surveyed since 1996 or earlier, and that may 

no longer be occupied by spotted owls.

Table 5 describes the status of the spotted owl and its habitat within the Willamette National Forest. 

Data are organized into protected and unprotected land allocations to demonstrate the ability of the 

Province to provide habitat for spotted owls. 

Protected land allocations include: LSRs and associated Riparian Reserves, 100-acre LSRs and 

Congressional Reserves (such as wilderness, Wild and Scenic Rivers, etc.).

Unprotected land allocations include: Matrix, Adaptive Management Areas, and Administratively 

Withdrawn Areas as well as Riparian Reserves associated with these areas. Activities in Riparian 

Reserves must comply with the Aquatic Conservation Strategy. As shown in Table 5, 54% of the total 

suitable acres in the Willamette National Forest are protected. This also includes suitable habitat 

within Critical Habitat Units. In addition, 72% of the total spotted owl activity centers are located in 

protected land allocations. Current suitable habitat data are updated annually to account for past 

habitat removal, updated GIS databases and land exchanges. Spotted owl activity center data are 

updated as new locations are identified.

Table 5 narrows the scope of analysis to reflect the status of the spotted owl and its habitat within the 

LSRs in Willamette National Forest. The data indicate that a majority of the LSRs have greater than 

50 percent NRF (suitable) habitat. Conditions of individual LSRs may depart from the average. For 

example, LSR RO209 is composed of only 34 percent suitable habitat, but adjoins the Opal Creek 

Wilderness Area which combined produce an area with 60% suitable habitat (Table 6). Analyses are 

based on the most recent data and are updated as new information or more accurate mapping 

becomes available and/or when land is acquired or exchanged.

Large blocks of spotted owl habitat composed of LSRs and adjacent wilderness areas are described 

in Table 6. Note that not all LSRs are associated with wilderness areas. Also, some LSRs and 

wildernesses align with more than one wilderness complex. 

Overall, the LSR/wilderness complexes provide 59% percent suitable habitat. Two of the complexes 

have less than 50 percent suitable habitat (RO214/Mt Jefferson Wilderness and Mt Washington

Wilderness), however. Both are high elevation wilderness areas. Analyses are based on the most 

recent data and are updated as new information or more accurate mapping becomes available and/or 

when land is acquired or exchanged.
LAA Biological Assessment- Willamette NF-FY 2018

47

Davis et al. (2016: entire) conducted the NWFP monitoring to show trends in spotted owl habitat over 

the first 20 years of implementation from 1994 to 2013. They found a net decrease of 1.5% in spotted 

owl nesting/roosting habitat on Federal lands from 9,089,700 acres in 1993 to 8,954,000 in 2013 

(abstract summary not paginated). Gross losses on Federal lands were 473,000 acres from wildfires 

(-5.2% loss), 116,100 acres from timber harvest (-1.3% loss), and 59,800 acres from insect and 

diseases (-0.7% loss). Because the gross losses were greater than the net losses, it indicates that 

the process of forest succession is compensating for some of the habitat loss.

Dispersal habitat increased by 2.2 percent on Federal lands, but dispersal capable landscapes 

decreased by 5 percent due to habitat losses on the surrounding non-federal lands. Large wildfires 

continue to be the major loss of spotted owl habitat on federal lands and most of these losses 

occurred within the conservation network of large reserves designed for spotted owl conservation.

The 20-year monitoring sub-areas don’t specifically match the Willamette National Forests, but, within 

the Western Cascades, there was a net gain of 27,100 acres of spotted owl nesting/roosting habitat 

(1.5% increase) on Federal lands, despite gross losses of 101,500 acres (-4.3% loss) (Davis et. al. 

2016, p. 21). The losses include 34,900 acres dues to timber harvest, 63,000 acres due to wild fires, 

and minor losses due to insects and unspecified causes. Within the Western Cascades, there was 

a net gain of 122,200 acres of spotted owl dispersal habitat (3.4% increase) on Federal lands, despite 

gross losses of 121,500 acres (-3.7% loss) (Davis et. al. 2016, p. 31). The losses of dispersal habitat 

include 28,300 acres due to timber harvest, 89,300 acres due to wild fires, and minor losses due to 

insects and unspecified causes. Recruitment of dispersal habitat on Federal lands in the Western 

Cascades is more than compensating for habitat losses with the recruitment rate about twice the rate 

of dispersal habitat loss. 

The analysis of dispersal-capable landscapes found no loss of landscape connectivity in the interior 

of Federal lands within the Western Cascades (Davis et al. 2016, Figure 9-p.33). There has been no 

loss in landscape connectivity for spotted owls that exists along a wide corridor across the Cascade 

Range from the Canadian border south into northern California. However, substantial loss to 

dispersal capable areas has occurred along the south west area of the Willamette Province adjacent 

to the Willamette Valley and this loss extends south across a connection area between the Oregon 

Coast and Cascades Range south of the Willamette Valley. There also has been some areas of 

dispersal-capable landscape loss and a few small areas of gain along the eastern edge of the range 

of spotted owl in the east side Cascades area in the northern half of Oregon.

There are no Spotted Owl Areas of Concern on the Willamette National Forest.

Project Area

Spotted owl habitat occurs within the project area (Appendix B, Table B-2). All eight projects included 

in this consultation are in the West Cascades. Proposed activities of these projects include 3,405

acres of dispersal habitat, 505 acres of non-habitat, 1,705 acres of foraging habitat and 1,336 acres 

of NRF habitat (Table A-11). Of these West Cascades acres, 4,120 are in West Cascades South 

(WCS)-3 and 994 are in WCS-4 (Table A-14).

Sixty six spotted owl sites are within the project area, all in the West Cascades. Twenty six sites have 

proposed activities that occur in nest patches or remove habitat (Appendix A, Table A-18. Nineteen of 

these Activity Centers are in CH subunit WCS-3, one is in CH subunit WCS-4, and six are not in CH. 

Seven of the sites have Core Areas and/or general home ranges that are below threshold levels for 

suitable habitat (Table A-18). The other 19 sites have greater than 50% suitable habitat in the Core 

Areas and greater than 40% suitable habitat in the general home ranges.
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

48

Spotted Owl Habitat

Mountainous terrain, high precipitation and coniferous forests generally characterize the action area 

on the west side of the Cascades. On the east side, low precipitation provides a drier, colder climate 

and a shorter fire return interval with a corresponding difference in vegetation. The primary vegetation 

on the east side of the Cascades is ponderosa pine and lodgepole pine. Lodgepole pine is more 

susceptible to insects and disease, and there are large areas of lodgepole which have been killed by 

disease and insect infestations.

Projects on the west and east side of the Cascades are generally analyzed separately in these 

consultations, since ecological conditions differ significantly between the two areas. All projects in this 

consultation are on the west side of the Cascades.

Table 5 shows the status of northern spotted owl habitat and the estimated number of nest sites 

within the Willamette National Forest. Nest sites are based survey data from 1990 to 2016. There is 

an assumption that historic sites have a high likelihood of continued occupancy based on unpublished 

data from the Tyee Northern Spotted Owl Demographic Study Area (Lint pers. comm. 2008, Dugger 

et al. 2009 entire).

Although only spotted owl territories located on FS lands have been summarized in Table 5; sitespecific analysis of projects have analyzed all territories that overlap with a proposed action. When 

assessing the habitat use or potential disruption of territorial spotted owls that use a local project 

area, a home range diameter of 2.4 miles is used. This site-specific project area analysis of resident 

spotted owl/territories is referred to as the analysis area. 

Demographic Information

The Central Oregon Cascades Northern Spotted Owl Demography Project is located on the H.J. 

Andrews Forest (HJA), which is in the Willamette National Forest. Monitoring of spotted owl 

populations has occurred here since 1987 (Dugger et al. 2015, p. 63). Dugger et al. (2015 entire) 

describe the results of a long-term meta-analysis of northern spotted owl demography from 11 study 

areas across the range of the species. For the three areas in Washington (CLE, RAI and OLY), the 

upper 95 percent confidence intervals were also below 1.0, indicating declining populations in 

Washington. Of the five study areas in Oregon (COA, HJA, TYE, KLA, and CAS), two of the areas 

(COA and HJA) had declining populations as represented with upper confidence intervals below 1.0. 

The other three areas, located in southern Oregon (TYE, KLA and CAS) had stationary population 

trends due to the upper confidence intervals overlapping 1.0. In northern California, two study areas 

(NWC and HUP) had declining populations whereas GRD had a stationary population. Overall, 

spotted owl populations were declining on 7 of the 11 (more northerly) individual study areas. For the 

more southern portion of the species range (i.e., southern Oregon and northern California), spotted 

owl populations were either stable or the precision of the demographic estimates were not sufficient 

to detect declines.

For the meta-analysis (all 11 areas combined), the lambda estimate for the past 20 plus years of 

monitoring was 0.962. This value represents a 3.8 percent average annual decline during the 20 plus 

year time period, and an increased rate of decline (3.8% vs. 2.9%) since the last meta-analysis was 

conducted in 2009. The rate of decline in the HJA demographic area was 3.5% per year, similar to 

the overall range-wide trend.

Another way to evaluate population trends is through realized population change estimates. This 

analysis compares the spotted owl population remaining at each study area in 2011 relative to the 

starting population (i.e., year of initial survey). For the individual study areas combined per state, 

Washington’s realized population change showed a decline of 55 to 77 percent. For Oregon, the 

decline was 31 to 68 percent and for California the decline was 32 to 55 percent, excluding a 

treatment area where barred owls where removed. On the HJA demographic area, the decline was 

nearly 50% (Dugger et al. 2015, p.72). 
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

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Substantial annual variation in fecundity was observed among study areas with support for declining 

trends in 8 areas including HJA (Dugger et al 2015, p.91). The top-ranked models in the metaanalysis of fecundity weakly supported that additive negative effects of the amount of suitable habitat 

in the “core” area, barred owl presence, and amount of edge habitat (Dugger et al 2015, pp. 58 and 

83). Note that the meta-analysis definition of “core habitat” is more similar in size to the general home 

range used in this BA analysis and not our BA definition of core area. Also the meta-analysis 

suggestion that fecundity should decrease with increasing suitable habitat is contrary to predictions. 

In the individual analysis of study areas, suitable habitat was positively related to the number of 

young fledged in 7 study areas (Dugger et al. 2015, pp. 81-82). However, in only four of these areas 

the covariate coefficients did not overlap zero, so there was little support for a strong relationship 

between habitat and fecundity in most areas, including HJA. Apparent annual survival was declining 

on 8 (CLE, RAI, HJA, TYE, CAS, NWC, HUP, GRD) of the 11 study areas (Dugger et al. 2015, p. 87). 

There was strong support for a negative effect of barred owls on apparent survival in 10 of 11 study 

areas (p. 58). Climate variables influenced survival in 10 of 11 study area with the range-wide metaanalysis suggesting that spotted owl survival is higher when the Pacific Decadal Oscillation is in a 

warming phase and the Southern Oscillation Index is negative. Few strong effects were found relative 

to habitat on survival. 

Barred owl presence was strongly associated with spotted owl local extinction (i.e. an occupied 

territory not being occupied the following year) rates in all 11 study areas (p. 58). Habitat covariates 

were related to spotted owl extinction in 8 of 11 areas and greater amounts of suitable habitat were 

generally associated with decreased extinction rates. 

The Dugger et al.2015 demographic study was the first time that an occupancy analysis had been 

conducted across the range of the owl. The analysis suggests occupancy rates for northern spotted 

owls are declining on all study areas (Dugger et al. 2015, p. 74). In Washington, occupancy rates 

declined from 56-100% in 1995 to 11-26% in 2013. In Oregon rates declined from 61-88% in 1995 to 

28-48% in 2013. (HJA had the highest occupancy rates declining from 88% to 48% during that time 

(p. 79). In California, rates declined from 75-92% to 38-55% during a comparable period. Barred owl 

presence had a strong negative effect on colonization rates for owl pairs in 5 of 11 study areas and 

the total amount of suitable habitat was positively associated with colonization rates in 5 study areas 

as well (p. 58). In summary Dugger et al.( 2015, p. 96) found strong positive associations between 

habitat characteristics, especially increased amounts of nesting and roosting habitat and territory 

colonization rates by northern spotted owls across all study areas. They note that this finding has 

been reported previously (Sovern et al 2014 entire). They also found increased amounts of nesting 

and roosting habitat associated with decreased extinction rates in many areas similar to previous 

findings by Dugger et al. (2011 entire) and Sovern et al (2014 entire). Habitat relationships 

counterintuitive to past studies were detected on the GDR area in northern California, but spotted 

owls exhibit more use of younger stands and greater dependency on woodrats in that area compared 

to the Willamette Province. Dugger et al. (2015, p. 95-96) suggest that barred owls likely displace 

spotted owls from their territories and the adult spotted owls, unless they can find a new unoccupied 

territory, may survive for years as non-territorial ”floaters” that do not contribute to population 

recruitment.

The meta-analysis included data collected through 2013. Population monitoring of the HJA Andrews 

demographic area has continued from 2014 to 2016 (Dugger et al. 2016 entire). About 170 spotted 

owl sites were monitored in those years. Sites occupied by a pair has continued a steady decline 

since 2013 with 30% occupancy in 2014, 26% occupancy in 2015, and 18% occupancy in 2016 

(Dugger et al. 2016, p. 18-19). The number of young produced per pair was high in 2014 and 2015 at 

1.22 young/pair and 1.13 young/pair, respectively, and extremely low in 2016 at 0.03 young/pair. 

(Dugger et al. 2016, p. 22-23). The year 2016 represented the third nearly complete nest failure 

documented since monitoring began in 1988 (op cit.). 

Most of the private land base is devoted to commercial timber production and now is on a 35-40 year 

harvest rotation. The project analysis therefore assumes that private lands are all non-habitat for 

spotted owls. Some of the private land may become dispersal habitat for a short-time before the final 

harvest but, because we have no practical way to identify those acres, because any such dispersal 

habitat would last for only a few years before it is re-harvested and becomes non-habitat, and 
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

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because there is no reasonable certainty that this situation will change, we have just assumed the 

private land is all non-habitat.

Table 5. Current status of the spotted owl and its habitat –Willamette NF

WILLAMETTE NATIONAL FOREST Total Acres

Protected1 Unprotected2

Non Forest Service 

land within 

administrative unit 

boundary

Total 

Acres

% of 

Total Total Acres % of Total

Total 

Acres

% of 

Total

Acres within Boundary4 1,799,325 854,349 47% 944,9773 53% 111,3783 6%

Acres of Ownership5 1,687,947 854,349 51% 833,599 49%

Suitable Habitat – Capable Acres6 1,420,449 684,447 48% 735,613 52%

Suitable Habitat – Current Acres7 806,274 439,359 54% 366,916 46%

Known Spotted Owl Sites Number of 

Sites Protected % of Total Unprotected % of Total

Spotted Owl Sites8 621 449 72% 172 28%

Spotted Owl Sites with ≥ 50% 

suitable habitat in the core area 442 329 74% 113 26%

Spotted Owl Sites with ≥ 40% 

suitable habitat in the provincial 

home range

483 357 74% 126 26%

Spotted owl sites with ≥ 50% 

suitable habitat in the core area 

AND ≥ 40% suitable habitat in the 

provincial home range

415 310 75% 105 25%

1 Acres in this column are comprised of: Late Successional Reserves (LSR) and associated Riparian Reserves, 100-

acre LSRs, Congressionally Withdrawn Areas.

2 Acres in this column are comprised of: Matrix, Adaptive Management Areas, and Administratively Withdrawn 

Areas including associated Riparian Reserves. Administratively Withdrawn Areas are included in the unprotected 

column because technically these areas are not designed to provide spotted owl habitat but rather to serve some other 

function such as “recreation and visual areas, back country, and other areas where management emphasis precludes 

scheduled timber harvest” (USDA, and USDI 1994a, p. A-4). The administrative land and resource management 

plan may protect and/or reduce the likelihood that spotted owl habitat located within Administratively Withdrawn 

Areas would be modified. 

3 Non-federal land is included in the Unprotected columns in this row only.

4 Acres in this row include both federal and non-federal lands within administrative boundaries. These acres are 

derived from corporate GIS data, which were last updated in 2013. All non-BLM or non-Forest Service acres are 

considered “unprotected.”

5 Acres shown in this row and all subsequent rows show only federal lands in the Willamette Planning Province.
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

51

6 Federal land that is capable of producing suitable spotted owl habitat, regardless of its current habitat.

7 Suitable habitat is defined as nesting, roosting, and foraging habitat.

8 Spotted owl sites represent pairs or resident singles based on 2016 updates. The Land Use Allocation of the site 

center determines whether it is shown in the protected or unprotected columns.

Data has been updated to reflect changes due to past harvest, land exchanges, GIS updates or new locations of 

spotted owl sites. 

Distribution of Protected Land Use Allocations

Protected land use allocations include LSRs, 100-acre spotted owl activity center LSRs, and 

Congressional Reserves. Additionally, Riparian Reserves are in protected land use allocations. 

Although important for spotted owl conservation, these land use allocations do not contribute equally 

to the large clusters of spotted owls/habitat needed for spotted owl recovery. It is important to analyze

data for the LSRs and adjacent wilderness areas that form the effective clusters of spotted owl 

populations.

Table 6 shows the amount of suitable habitat in the LSRs on the Willamette National Forest. 

However, LSRs alone do not contain the entire protected meta-population clusters of spotted owls 

and habitat. Many of these LSRs are adjacent to wilderness areas, which increases the size of the 

cluster, the amount of current and future suitable habitat, and the number of current and future 

spotted owls. Thus the LSR/wilderness complexes are the true “effective” meta-population clusters 

that will directly contribute to spotted owl recovery. Suitable habitat in wilderness areas and 

associated LSRs within the action area is shown in Table 7. 

Although this analysis is not directly comparable to the analysis done in the biological opinion of the 

NWFP (USFWS 1994, entire), it indicates that although some spotted owl sites located in LSRs and 

LSR/wilderness complexes might have home ranges that extend into unprotected land allocations, 

the large majority of these sites are likely to persist through time due to sufficient levels of protected 

suitable habitat within their home ranges. 

Table 6. Late-successional reserves and associated spotted owl habitat within the Willamette 

National Forest. 

LATE-SUCCESSIONAL 

RESERVES

TOTAL ACRES1 CAPABLE ACRES SUITABLE ACRES

% SUITABLE

(OF CAPABLE)

RO2092 3,102 2,797 950 34%

RO213 57,167 55,218 36,460 66%

RO214 40,015 38,013 19,815 52%

RO215 27,822 25,558 16,610 65%

RO216 604 602 461 77%

RO217 9,860 9,372 8,057 86%

RO218 26,241 24,626 17,076 69%

RO219 66,023 65,344 35,855 55%

RO220 51,391 48,559 29,881 62%

RO221 16,612 15,965 10,313 65%

RO222 92,840 90,272 56,602 63%
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LATE-SUCCESSIONAL 

RESERVES

TOTAL ACRES1 CAPABLE ACRES SUITABLE ACRES

% SUITABLE

(OF CAPABLE)

TOTAL 319,677 376,326 232,080 62%

1

Includes only federal land within late successional reserves. Any overlapping wilderness acres have been removed 

from this table and are shown in the following table.

2 Opal Creek Wilderness is coincident with RO209 over a large portion of the LSR. In this table, Opal Creek 

Wilderness acres are not listed. See the following table for a combination of RO209 and Opal Creek Wilderness 

acres.

Table 7. Spotted owl suitable habitat in LSR/Wilderness complexes within the Willamette 

National Forest.

LSR / WILDERNESS COMPLEX TOTAL ACRES

CAPABLE 

ACRES

SUITABLE 

ACRES3

% SUITABLE 

OF CAPABLE

RO209/Opal Creek Wilderness 25,590 20,152 12,039 60%

RO213/Middle Santiam Wilderness 65,866 63,535 44,505 70%

RO214/Mt. Jefferson Wilderness 111,646 82,941 26,529 32%

RO215/Menagerie Wilderness 32,740 30,417 21,369 70%

RO218/Three Sisters Wilderness 212,972 159,769 97,019 61%

RO220/Waldo Lake Wilderness 85,540 79,409 55,338 70%

RO221/Diamond Peak Wilderness 35,548 31,045 24,723 80%

Mt. Washington Wilderness 40,223 17,033 3,994 23%

TOTAL 610,125 484,301 285,516 59%

B. Status of Spotted Owl Critical Habitat

Project Area

Within the project areas, PBFs occur (Table A-14) and, in association with PBFs outside the project 

area, support spotted owl territories (Table A-18).

Special Management Considerations

Special management considerations for PBFs are from the Final Critical Habitat Rule (USFWS 

2012a, pp. 71909-71910). Following is a summary of the special management considerations 

considered in this document. All of the action area is in the west Cascades.

West Cascades/Coast Ranges of Oregon and Washington

Special management considerations or protection may be required in areas of moist forests to 

conserve or protect older stands that contain spotted owl sites or contain high-value spotted owl 

habitat. Silvicultural treatments are generally not needed to maintain existing old-growth forests on 

moist sites. In contrast to dry and mesic forests, short-term fire risk is generally lower in the moist 

forests that dominate on the west side of the Cascade Range, and occur east of the Cascades as a 

higher elevation band or as peninsulas or inclusions in mesic forests. Disturbance based 

management for forests and spotted owls in moist forest areas should be different from that applied in 

dry or mesic forests. Efforts to alter either fuel loading or potential fire behavior in these sites could 
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

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have undesirable ecological consequences as well. Furthermore, commercial thinning has been 

shown to have negative consequences for spotted owls and their prey. Active management may be 

more appropriate in younger plantations that are not currently on a trajectory to develop old-growth 

structure. These stands typically do not provide high-quality spotted owl habitat, although they may 

occasionally be used for foraging and dispersal.

In general, to advance long-term spotted owl recovery and ecosystem restoration in moist forests in 

the face of climate change and past management practices, special management considerations or

protections may be required that follow these principles as recommended in the 2011 Revised 

Recovery Plan (USFWS 2011, p. III–18):

1. Conserve older stands that have occupied or high-value spotted owl habitat as described in 

RA 10 (includes all territories, occupied or not), and RA 32 (older, high quality, and more 

structurally complex stands that support spotted owl recovery). On Federal lands, this 

recommendation applies to all land-use allocations.

2. Management emphasis needs to be placed on meeting spotted owl recovery goals and longterm ecosystem restoration and conservation. When there is a conflict between these goals, 

actions that would disturb or remove the essential PBFs of spotted owl CH need to be 

minimized and reconciled with long-term ecosystem restoration goals.

3. Continue to manage for large, continuous blocks of late-successional forest.

4. In areas that are not currently late-seral forest or high-value habitat and where more 

traditional forest management might be conducted (e.g. Matrix), these activities should 

consider applying ecological forestry prescriptions. 

These special management considerations or protections apply to Units 1, 2, 4, 5 and 6 of the revised 

critical habitat. In this document, all proposed projects occur in Unit 6.

Critical Habitat Units in the Willamette Planning Province Action Area 

Special management considerations or protection are required in all subunits in the action area to 

address threats from current and past timber harvest and competition with barred owls (USFWS 

2012a). Additional specific expectations for each subunit are summarized below. Acres of each 

habitat type on federal lands are shown in Table 8.

In this consultation, known projects are only proposed in subunits WCS 3 and WCS 4. However, the 

other units and subunits in the action area are included in the discussion below.

Table 8. Acres of northern spotted owl critical habitat by subunit and habitat type for 

subunits that occur on the Willamette National Forests1.

CRITICAL HABITAT 

SUBUNIT

SUITABLE HABITAT DISPERSAL HABITAT

NON-HABITAT (BUT 

FOREST CAPABLE)

Northwest Oregon BLM

WCS-2 1,920 2,048 647

WCS-3 15,522 3,787 3,572

WCS-4 56 4 22

WCS-5 6 0 1

Mt. Hood National Forest

WCS-2 70,518 45,171 29,116

WCS-3 39 20 11

Willamette National Forest

WCS-2 15 12 0
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CRITICAL HABITAT 

SUBUNIT

SUITABLE HABITAT DISPERSAL HABITAT

NON-HABITAT (BUT 

FOREST CAPABLE)

WCS-3 184,954 60,499 46,400

WCS-4 234,697 77,082 63,599

WCS-5 62 30 32

1Acres are shown for all subunits that overlap on the Forests and include the acres of the subunits that 

occur on BLM and on the Mt Hood NF.

Unit 6: West Cascades South

This unit contains 1,355,198 acres with six subunits. Either a portion or all of these six subunits fall 

within the action area. The unit is located on the west side of the Cascades, with a few small areas 

east of the Cascades in WCS 1. Four subunits overlap the Willamette National Forest and are 

described below.

Subunit WCS 2

Of the 150,105 acres of this subunit, about 96% (144,832 acres) occur on the Mt Hood and 

Willamette National Forests. This subunit is located primarily in Clackamas County with a small part 

in Marion County. This subunit is expected to function primarily for demographic support to the overall 

population, as well as north-south connectivity between subunits (USFWS 2012a, p.71925).

Subunit WCS 3

Of the 319,736 acres in this subunit, about 91% (291,923 acres) occur on the Mt Hood and 

Willamette National Forests. This subunit is located in Marion, Linn and Lane counties. This subunit 

is expected to function primarily for demographic support to the overall population, as well as northsouth connectivity between subunits.

Subunit WCS 4

Of the 379,130 acres in this subunit, about 99% (375,378 acres) occur on the Willamette National 

Forest. Most of this subunit is located in Lane County, with a small portion in Douglas County. This 

subunit is expected to function primarily for demographic support to the overall population, as well as 

north-south connectivity between subunits.

Subunit WCS 5

Of the 356,415 acres in this subunit, only 124 acres are located on the Willamette National Forest.

Most of this subunit is located in Lane County, with a small portion in Douglas County. This subunit is 

expected to function primarily for demographic support to the overall population, as well as northsouth and east-west connectivity between subunits and critical habitat units.

VI. Effects of the Proposed Action

According to the Endangered Species Act Consultation Handbook (USFWS and NMFS 1998, p. xvi), 

a “may affect” determination is required when a proposed action may pose any effects to listed 

species or designated Critical Habitat. When any adverse effects to listed species may occur as a

direct or indirect result of the proposed action or its interrelated or interdependent actions, a “likely to 

adversely affect” determination is appropriate. However, when effects to listed species are expected 

to be discountable, insignificant or entirely beneficial, “is not likely to adversely affect” is the 

appropriate conclusion. Insignificant effects relate to the size of the impact and should never reach 

the level where potential injury to owl sites would occur. Discountable effects, as described in the 

consultation handbook, are those extremely unlikely to occur. Based on best judgment, a person 
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

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would not: (1) be able to meaning-fully measure, detect, or evaluate insignificant effects; or (2) 

expect discountable effects to occur. The proposed action may impact the spotted owl in a variety of 

ways, and at differing levels, depending on where and when a project occurs. The following analysis 

of potential effects addresses this species with respect to each activity type. 

Direct and indirect effects: Direct effects are the immediate consequences of the proposed action. 

A thinning treatment, for example, causes the immediate modification of habitat. Indirect effects occur 

over time periods following implementation of the proposed action. For example, certain thinning 

treatments are done for forest health and, over time, will accelerate forest growth and the earlier 

creation of late-successional forest conditions. In the short-term, such a treatment may cause an 

adverse or negligible direct effect. Over the long-term, such a treatment would beneficially affect 

spotted owls, indirectly.

Interrelated and interdependent actions: Interrelated actions are those that are part of a larger 

action and depend on the larger action for their justification. Interrelated actions are related to the 

Federal action, but do not depend on the Federal action. Interdependent actions are those that might 

occur independently of the larger action, but which have no independent utility apart from the action 

under consideration. Interdependent actions depend on the Federal action and would make no sense 

without the Federal action. 

A. Direct and Indirect Effects of Spotted Owl Habitat Modification

When implemented in accordance with the standards listed in Section II, the Interagency Level 1 

Team determined that the activity types in spotted owl habitat described in Table 3 would have the 

effects shown in Table 9 and 10 due to habitat modification. Effects determinations for spotted owl 

Critical Habitat (USFWS 2012a, pp. 71937-71943) are found in Table 11 and 12. Rationale for these 

determinations of effects is shown in Table 9 for spotted owl habitat and Table 11 for spotted owl 

critical habitat. Effects to spotted owls due to disturbance are shown in Table 13 and the rationale for 

these effects is summarized Table 14.
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Table 9. Rational for effects determinations to spotted owls from actions that remove, 

downgrade or maintain spotted owl habitat.

ACTION

EFFECT TO 

NSO RATIONALE FOR EFFECT DETERMINATION

REMOVE 

SUITABLE 

HABITAT

MA-LAA1

Timber harvest that removes the structural and vegetative components of occupied suitable 

habitat at the stand level is likely to adversely affect the ability of the affected spotted owl(s) to 

forage, nest, or shelter. Even though some structural components such as snags, clumps of 

large trees and down wood will be retained to meet existing NWFP requirements, the overall 

effect will be to set back stand conditions. Set-back for spotted owl dispersal is estimated at 30-

40 years and over 80 years before stand conditions again support spotted owl nesting, roosting 

and foraging. 

The removal of suitable spotted owl habitat may affect the success of spotted owls to raise 

young, because 1) if a nest tree is removed, the pair will not be able to produce young until a 

suitable replacement nest has been established, and 2) if foraging habitat is limited near a nest 

tree and more foraging habitat is removed the spotted owl pair may not be able to obtain enough 

food to successfully fledge their young.

DOWNGRADE 

SUITABLE 

HABITAT

MA-LAA1

Timber harvest that downgrades the structural and vegetative components of occupied suitable 

habitat at the stand level is likely to adversely affect the ability of the affected spotted owl(s) to 

breed, feed, or shelter. Although the affected stands will continue to function as dispersal habitat 

(since many trees will be retained), nesting structure will likely be reduced or eliminated in the 

area and the quality of foraging and roosting structures within the stand will be diminished. The 

stands will retain a 40 percent or greater canopy cover in addition to some structural 

components (snags, clumps of large trees, down wood) to meet existing NWFP requirements. 

Immediately after harvest, the success of spotted owls to raise young is likely to be adversely 

affected because 1) if a nest tree is removed, the pair will not be able to produce young until a 

suitable replacement nest has been established, and 2) if foraging habitat is limited near a nest 

tree, as more foraging habitat is removed, the spotted owl pair will not be able to obtain enough 

food to successfully fledge their young. However, after the initial impact of timber harvest 

downgrading suitable habitat, the shrub layer would regenerate sooner compared to areas 

where suitable habitat is removed. Over time the understory habitat conditions for prey would 

recover more rapidly in stands where suitable habitat is downgraded rather than removed.

MAINTAIN 

SUITABLE 

HABITAT

MA-NLAA2

Timber harvest or prescribed burning that maintains suitable habitat is not likely to have a 

measurable effect on the ability of spotted owls to breed, forage, or shelter since the stand will 

retain its ability to function for the breeding, foraging and roosting of resident spotted owls. 

These stands will retain a 60 percent or greater canopy cover in addition to some structural 

components (snags, clumps of large trees, down wood) to meet existing NWFP requirements. 

Additionally, the activity would not result in adverse effects to occupation or reproduction at the 

site scale.

MA-LAA1

Any timber harvest that maintains suitable habitat at the stand scale but occurs within a nest 

patch is likely to adversely affect the spotted owl due to its proximity to the nest tree. Also, 

thinning of suitable habitat in a core area, where habitat is maintained but suitable habitat will 

constitute less than 50 percent of the core area after treatment, may adversely affect the spotted 

owl if the amount of available habitat being treated covers a large portion of the area. Forage 

habitat would be suboptimal in these cases and any impact, even minor, may contribute to the 

inability of the spotted owl pair to support successful reproduction.

REMOVE OR 

MAINTAIN 

DISPERSAL 

HABITAT

MA-NLAA2

Any timber harvest that removes or maintains dispersal habitat at the stand scale but occurs 

outside of a nest patch is not likely to adversely affect the spotted owl due to its distance from 

the nest tree. Per Standard 4, page 26, sufficient post-activity habitat would remain for spotted 

owl dispersal, which should provide ample foraging opportunities for resident spotted owls.

MA-LAA1

Any timber harvest that removes or maintains dispersal habitat at the stand scale but occurs 

within a nest patch is likely to adversely affect the spotted owl due to its proximity to the nest 

tree or when dispersal habitat is used for foraging by a territorial pair. Also removal of dispersal 

habitat in spotted owl home ranges that are below threshold levels of suitable habitat when the 

dispersal habitat is functioning as the “next best” habitat and supporting nesting and rearing of 

young.

1 MA-LAA = May affect and is likely to adversely affect. 2 MA-NLAA = May affect, but is not likely to adversely affect.
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

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Table 10. Summary of effects determinations4 to spotted owls from habitat modification (not 

including associated disturbances) performed in compliance with the standards 

listed in Section II. 

ACTIVITY TYPE SUITABLE HABITAT DISPERSAL

HARVEST – HABITAT

REMOVED 

MA-LAA since suitable habitat would be 

removed.

MA-LAA when it occurs in nest patch of a known or 

potential spotted owl site.

MA-LAA when, in the opinion of the unit biologist, 

habitat supports foraging and the loss would negatively 

affect the functionality of a PHR, including nest patch, or 

limit regional spotted owl movement and survival.

MA-NLAA when habitat loss would not negatively 

affect the functionality of a PHR, including nest patch, or 

limit regional spotted owl movement and survival.

HARVEST – HABITAT 

DOWNGRADE

MA-LAA since suitable habitat is 

downgraded to dispersal habitat. Not Applicable

HARVEST – HABITAT 

MAINTAIN

MA-LAA when (1) suitable habitat is 

downgraded to dispersal or removed as a 

result of the treatment, (2) in the opinion of 

the unit biologist, treatment would negatively 

affect the functionality of a PHR, or (3) 

treatment occurs in the nest patch of a known 

or potential site.

MA-NLAA when treatment would not 

negatively affect the functionality of a PHR, 

including nest patch,

MA-LAA when treatment (1) occurs in a nest patch of 

a known or potential site, (2) habitat supports foraging 

and the treatment negatively affects the functionality of 

a PHR or (3) limits regional spotted owl movement and 

survival.

MA-NLAA when treatment would not negatively affect 

the functionality of a PHR, including nest patch, or limit 

regional spotted owl movement and survival.

FUELS TREATMENT

SPECIAL HABITAT 

RESTORATION

TERRESTRIAL HABITAT 

ENHANCEMENT

ROAD CONSTRUCTION

DOWN SALVAGE

MA-LAA when, in the opinion of the unit 

biologist, treatment would negatively affect 

the functionality of a PHR or occurs in the

nest patch of a known or potential site.

MA-NLAA when treatment would not 

negatively affect the functionality of a PHR, 

including nest patch.

MA-LAA when treatment occurs in the nest patch of a 

known or potential site.

MA-NLAA when treatment would not negatively affect 

the functionality of a PHR, including nest patch, or limit 

regional spotted owl movement and survival.

INDIVIDUAL TREE 

REMOVAL

MA-LAA when (1) a nest tree is removed or 

(2) nesting structure is removed when such 

structure is limited in the stand. 

MA-NLAA when nest trees and limited 

nesting structure are maintained.

MA-NLAA since nesting structure would not be 

removed.

See Section IV for effect determination explanations. Determinations apply to known and potential spotted owl sites even if 

the nesting status is unknown. PHR = Provincial Home Range

 

4 MA-LAA (May Affect, Likely to Adversely Affect) MA-NLAA (May Affect, Not Likely to Adversely Affect)
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Table 11. Rationale for effects determinations to spotted owl critical habitat from actions 

that remove, downgrade or maintain spotted owl habitat. 

Action Effect to 

NSO Rationale for Effect Determination

Remove 

suitable 

habitat

MA-LAA1

Timber harvest that removes the structural and vegetative components of 

suitable habitat at the stand level is likely to adversely affect the ability of 

spotted owl CH to provide foraging (PBF 3), nesting, or sheltering (PBF 2). 

Even though some structural components such as snags, clumps of large trees 

and down wood will be retained to meet existing NWFP and RMP requirements, 

the overall effect will be to set back stand conditions thus delaying the further 

development of spotted owl habitat. Set-back for spotted owl dispersal (PBF 4) 

is estimated at 30-40 years and over 80 years before stand conditions again 

support spotted owl nesting, roosting (PBF 2) and foraging (PBF 3). 

The removal of suitable spotted owl habitat directly removes PBF 2, limits the 

diversity of PBF 1 and affects the success of spotted owls to raise young, thus 

reducing the ability of CH to contribute to the survival and recovery of spotted 

owls.

Downgrade 

suitable

habitat

MA-LAA1

Timber harvest that downgrades the structural and vegetative components of 

suitable habitat within CH at the stand level is likely to adversely affect the 

PBF’s thus reducing the ability of spotted owls to breed (PBF 2), feed (PBF 3), 

or shelter (PBF 2). Although the affected stands will continue to function as 

dispersal habitat (PBF 4)(since many trees will be retained), nesting (PBF 2) will 

likely be reduced or eliminated in the area and the quality of foraging (PBF 3) 

and roosting structures (PBF 2) within the stand will be diminished. 

These effects will begin immediately after harvest, reducing the success of 

spotted owls to raise young (PBF 2), and to forage (PBF 3), thus reducing the 

ability of spotted owl CH to support survival and recovery of spotted owls.

However, after the initial impact of timber harvest downgrading PBF 3, the 

stand, including understory components including the shrub layer would 

regenerate sooner than areas where suitable habitat is removed. Over time the 

understory habitat conditions for prey (PBF 3) would recover more rapidly in 

stands where suitable habitat is downgraded rather than removed.

Maintain 

suitable 

habitat

MANLAA2

Timber harvest or prescribed burning that maintains the PBF’s of spotted owl 

CH in suitable habitat is not likely to have a measurable effect on the ability of 

spotted owls to breed (PBF 2), forage (PBF 3), or shelter (PBF 2) since the 

stand will retain its ability to function for the breeding, foraging and roosting of 

resident spotted owls. These stands will retain a 60 percent or greater canopy 

cover in addition to some structural components (snags, clumps of large trees, 

down wood) to meet existing RMP or NWFP requirements, as applicable. 

Therefore spotted owl CH will continue to function and support survival and 

recovery of spotted owls.

MA-LAA1

Any timber harvest that maintains suitable habitat at the stand scale but occurs 

within a nest patch is likely to adversely affect the spotted owl CH because the 

close proximity to the nest tree would reduce the function of PBF 2. Also, 

thinning of suitable habitat in a core area, where habitat is maintained but 

suitable habitat will constitute less than 50% of the core area after treatment, 

may adversely affect the spotted owl CH by impairing its’ ability to support 
Effects of the Proposed Action LAA Biological Assessment- Willamette NF- FY 2018

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Action Effect to 

NSO Rationale for Effect Determination

potential spotted owl territories across the landscape. Forage habitat would be 

suboptimal in these cases and any impact, even minor to PBF 3, may contribute 

to the inability of the spotted owl CH to function to support survival and recovery 

of spotted owls.

Remove or 

maintain 

dispersal 

habitat

MANLAA2

Any timber harvest that maintains dispersal habitat at the stand scale but occurs 

outside of a nest patch is not likely to adversely affect the spotted owl CH 

because the PBF’s will also be maintained. Per Standard 10, page 24, sufficient 

post-activity habitat would remain to support functions of PBF 3 and PBF 4.

Also removal of dispersal habitat in spotted owl CH may be NLAA if the removal 

doesn’t reduce the stands ability to function as dispersal (PBF 4) and does not 

appreciably delay the development of suitable habitat within CH.

MA-LAA1

Any timber harvest that removes or maintains dispersal habitat at the stand 

scale but occurs within a nest patch is likely to adversely affect spotted owl CH 

because it adversely affects the function of PBF 2 as the proximity to the nest 

tree is so close. Or when dispersal habitat is necessary as foraging habitat 

(PBF 3) in order to support a functional spotted owl territory. This scenario may 

occur when threshold levels of suitable habitat are below optimal levels and the 

dispersal habitat is functioning as the “next best” habitat and supporting nesting 

and rearing of young (PBF 2).

1 MA-LAA = May affect and is likely to adversely affect.

2 MA-NLAA = May affect, but is not likely to adversely affect.
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Table 12. Summary of effects determinations5 to spotted owl critical habitat from habitat 

modification in spotted owl critical habitat performed in compliance with the 

standards listed in Section II.

ACTIVITY TYPE IN CHU SUITABLE HABITAT DISPERSAL 

HARVEST – HABITAT 

REMOVED 

MA-LAA since PBFs would be removed and stand 

functionality would be negatively altered.

MA-LAA if any of the following conditions exist:

 Occurs in nest patch of a known or potential 

spotted owl site as these actions would alter 

PBF 2.

 When, in the opinion of the unit biologist, 

PBFs would be altered, either directly or 

indirectly, and treatment would reduce the 

ability of the action area* to support spotted 

owl dispersal.

 When, in the opinion of the unit biologist, 

PBFs would be altered, either directly or 

indirectly, and treatment would delay the 

ability of the stand to develop suitable habitat 

(compared to untreated), and the delay in 

developing suitable habitat will also delay the 

functionality of the landscape to support 

breeding spotted owls, irrelevant of 

occupancy status.

MA-NLAA when, in the opinion of the unit 

biologist, PBFs would be altered but direct and 

indirect effects to the functionality of the action 

area* and the change in function of the stand to 

develop suitable habitat in the future stand 

(compared to untreated), would be discountable, 

insignificant or entirely beneficial, regardless of 

spotted owl occupancy.

* Or other local landscape area, whichever is 

smaller.

HARVEST – HABITAT 

MAINTAIN

MA-LAA if any of the following conditions exist::

 Occurs in nest patch of a known or potential 

spotted owl site.

 When, in the opinion of the unit biologist, 

PBFs would be altered and treatment would 

negatively affect the functionality of the stand, 

either directly or indirectly, regardless of 

spotted owl occupancy.

MA-NLAA when, in the opinion of the unit biologist, 

PBFs would be altered but direct and indirect 

effects to the functionality of the stand would be 

discountable, insignificant or entirely beneficial, 

regardless of spotted owl occupancy.

FUELS TREATMENT

SPECIAL HABITAT 

RESTORATION

TERRESTRIAL HABITAT 

ENHANCEMENT

ROAD CONSTRUCTION 

DOWN SALVAGE

HARVEST – HABITAT 

DOWNGRADE

MA-LAA since PBF 2 and 3 would be reduced or 

eliminated and stand functionality would be 

downgraded.

Not Applicable

INDIVIDUAL TREE 

REMOVAL

MA-LAA when nesting structure would be removed 

(PBF 2) and, in the opinion of the unit biologist, 

such structure is limited in the stand, regardless of 

spotted owl occupancy. 

MA-NLAA when, in the opinion of the unit biologist, 

a PBF would be altered but direct and indirect 

effects to the functionality of the stand would be 

discountable, insignificant or entirely beneficial, 

regardless of spotted owl occupancy. 

MA-NLAA since PBFs would not be altered.

See Section IV for effect determination explanations. Nest patch determinations apply to both known and potential spotted owl

sites even if the nesting status is unknown.

 

5 MA-LAA (May Affect, Likely to Adversely Affect) MA-NLAA (May Affect, Not Likely to Adversely Affect)
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Table 13. Determination of effect due to disturbance/disruption. Footnotes are on the next page.

DISTURBANCE SOURCE

NO EFFECT1

MARCH 1 – SEPT 

30

DISTURBANCE DISTANCE1 DISRUPTION DISTANCE1

DIRECT INJURY AND/

OR MORTALITY1

ENTIRE BREEDING PERIOD

CRITICAL BREEDING 

PERIOD

LATTER BREEDING 

PERIOD

NLAA

MARCH 1 – SEPT 30

LAA – HARASS

MARCH 1 – JULY 15

LAA – HARASS

JULY 16 – SEPT 

30

LAA – INJURY

MARCH 1 – SEPT 30

Aircraft, small fixed wing

(e.g., Cessna 182, 185, etc.) > 0.25 mile 111 yards to 0.25 mi ≤ 110 yards NA NA

Blasting > 1 mile 0.25 mile to 1 mile ≤ 0.25 mile2 NA ≤ 100 yards (injury)2

Burning (prescribed fires, pile burning, 

underburning, etc.) > 1 mile 0.25 mile to 1 mile ≤ 0.25 mile3 NA NA

Chainsaw use (includes felling 

hazard/danger trees)

> 0.25 mile 66 yards to 0.25 mile ≤ 65 yards4 NA NA

Heavy Equipment (e.g., road 

construction, road repair, bridge 

construction, culvert replacements, 

etc.)

> 0.25 mile 66 yards to 0.25 mile ≤ 65 yards4 NA NA

Helicopter: Chinook 47d > 0.5 mile 266 yards to 0.5 mile ≤ 265 yards5 ≤ 100 yards6

(hovering only) NA

Helicopter: Boeing Vertol 107, Sikorsky 

S-64 (Sky Crane) > 0.25 mile 151 yards to 0.25 mile ≤ 150 yards7 ≤ 50 yards6(hovering only) NA

Helicopter: K-Max, Bell 206 L4, Hughes 

500) > 0.25 mile 111 yards to 0.25 mi ≤ 110 yards8 ≤ 50 yards6(hovering only) NA

Light maintenance (e.g., road brushing 

and grading) at campgrounds, 

administrative facilities, and heavily 

used roads

> 0.25 mile ≤ 0.25 mile NA9 NA NA

Log hauling on heavily used roads (FS 

maintenance levels 3, 4 and 5) > 0.25 mile ≤ 0.25 mile NA9 NA NA

Pile driving (steel H piles, pipe piles)

Rock crushing and screening equipment > 0.25 mile 120 yards to 0.25 mile ≤ 120 yards10 NA ≤ 5 yards (injury)10
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DISTURBANCE SOURCE

NO EFFECT1

MARCH 1 – SEPT 

30

DISTURBANCE DISTANCE1 DISRUPTION DISTANCE1

DIRECT INJURY AND/

OR MORTALITY1

ENTIRE BREEDING PERIOD

CRITICAL BREEDING 

PERIOD

LATTER BREEDING 

PERIOD

NLAA

MARCH 1 – SEPT 30

LAA – HARASS

MARCH 1 – JULY 15

LAA – HARASS

JULY 16 – SEPT 

30

LAA – INJURY

MARCH 1 – SEPT 30

Tree Climbing > 66 yards 26 yards to 65 yards ≤ 25 yards11 NA NA

Footnotes for Table 13

NA = Not Applicable NLAA = “Not Likely to Adversely Affect LAA = “Likely to Adversely Affect ≥ “is greater than or equal to” ≤ “is less than or equal 

to”

1 Distances are measured from occupied spotted owl nest tree or fledgling location. If these are not identified, distances are from the edge of nest patch (for 

both known and potential spotted owl sites.

2

Impulsive sound associated with blasts is highly variable and potentially injurious at close distances. We selected a 0.25-mile radius around blast sites as a 

disruption distance based on observed prairie falcon flush responses to blasting noise at distances of 0.3 – 0.6 miles from blast sites (Holthuijzen et al. 

1990, p. 273). Exposure to peak sound levels that are >140 dBA are likely to cause injury in the form of hearing loss in birds (Dooling and Popper 2007, pp. 

23-24). We have conservatively selected 100 yards as an injury threshold distance based on sound levels from experimental blasts reported by Holthuijzen 

et al. (1990, p. 272), which documented peak sound levels from small blasts at 138 – 146 dBA at a distance of 100 m (110 yards).

3 Based on recommendations presented in Smoke Effects to Northern Spotted Owls (USFWS 2008, p. 4).

4 Based on Delaney et al. (1999, p. 67) which indicates that spotted owl flush responses to above-ambient equipment sound levels and associated activities 

are most likely to occur at a distance of 65 yards (60 m) or less.

5

. Based on an estimated 92 dBA sound-contour (approximately 265 yards) from sound data for the Chinook 47d presented in Newman et al. (1984, Table 

D.1).

6

. Rotor-wash from large helicopters is expected to be disruptive at any time during the nesting season due the potential for flying debris and shaking of trees 

located directly under a hovering helicopter. The hovering rotor-wash distance for the Chinook 47d is based on a 300-ft. radius rotor-wash zone for large 

helicopters hovering at < 500 above ground level (from WCB 2005, p. 2 – logging safety guidelines). We reduced the hovering helicopter rotor-wash zone 

to a 50-yard radius for all other helicopters based on the smaller rotor-span for all other ships.

7

. Based on an estimated 92 dBA sound contour from sound data for the Boeing Vertol 107 the presented in the San Dimas Helicopter Logging Noise Report 

(USFS 2008, chapters 5, 6).

8

. The estimated 92 dBA sound contours for these helicopters is less than 110 yards (e.g., K-MAX (100 feet) (USDA 2008, chapters 5, 6), and Bell 206 (85-

89 dbA at 100 m) (Grubb et al. 2010, p. 1277).
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9

. NA = Based on information presented in Tempel and Gutiérrez (2003, p. 700), Delaney et al. (1999, p. 69), and Kerns and Allwardt (1992, p. 9), we 

anticipate that spotted owls that select nest sites in close proximity to open roads either are undisturbed by or habituate to the normal range of sounds and 

activities associated with these roads.

10. Impulsive sound associated with pile-driving is highly variable and potentially injurious at close distances. A review compiled by Dooling and Popper (2007, 

p. 25) indicates that birds exposed to multiple impulses (e.g., pile driving) of sound at 125 dBA or greater are likely to suffer hearing damage. We have 

conservatively chosen a distance threshold of 120 yards for impact pile-driving to avoid potential effects to hearing and to account for significant behavioral 

responses (e.g. flushing) from exposure to loud, impulsive sounds. Based on an average maximum sound level of 110 dBA at 50 ft. for pile-driving, 

exposure to injurious sound levels would only occur at extremely close distances (e.g., ≤ 5 yards). 

11. Based on Swarthout and Steidl (2001, p. 312) who found that 95 percent of flush responses by spotted owls due to the presence of hikers on trails 

occurred within a distance of 24 m.
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Table 14. Rationale for Disturbance/Disruption Effects Determinations

Disturbance 

Type Time Period Effect Rationale for Effects Determinations

Mechanical 

noise 

(other than 

large 

helicopters)

Mar 1 – Jul 15 LAA

Noise effects vary and may cause little to no significant disruption depending on 

site- and activity-specific factors and an individual’s tolerance to noise. In the worstcase scenario, adults can move from noise, likely causing increased predation to 

young, missed feedings, or premature fledging, which could result in a reduce 

fitness or death of young. However, we anticipate noise from actions will only 

increase the likelihood of injury to young through potentially increased predation of 

abandoned young.

Jul 15 – Sept 30 NLAA

Spotted owls are still developing flight and hunting skills and are heavily cared for 

by parents. However, most have fledged by this date and are believed to be able to 

move short distances to stay with the parents being displaced.

Helicopters

Mar 1 - Jul 15 LAA

Noise/rotor wash can significantly disrupt birds. The worst-case scenario is that 

adults can move from noise, causing increased predation to young, missed 

feedings, or premature fledging, which could result in a reduce fitness or death of 

young. However, we anticipate likely injury only when large helicopter noise is within 

close proximity of nests which may result in the flushing of adults and which may 

cause increased predation or premature fledging. Since hovering near spotted owl

nests and historic nests/centers is limited, we do not anticipate mortality from rotor 

wash.

Jul 16 – Sept 30 LAA

Spotted owls are still developing flight and hunting skills and are heavily cared for 

by parents. While most young have fledged, the greater noise may cause the 

parents to travel greater distances to avoid the noise, and therefore the young who 

are not as skilled flyers yet are potentially more susceptible to predation.

Smoke 

(prescribed 

burns)

Mar 1 - Jul 15 LAA

Controlled burns will occur in the understory and will not remove or reduce the 

function of habitat. Burns will be low-moderate intensity and are not likely to cause 

mortality. Smoke should mostly travel in one direction since burns are conducted 

when winds are fairly low and not highly variable. Assuming four nautical directions, 

there is a 1⁄4 chance of smoke continuously flowing toward nests (likelihood 

decreases further from nest). The 0.25-mile buffer is for a worst-case scenario. 

USFWS does not anticipate direct mortality to spotted owls from smoke/fire, but 

injury to young is possible if adults temporarily move from area, leaving eggs or 

young exposed to predation. 

Jul 15 – Sept 30 NLAA

Spotted owls are still developing flight and hunting skills and are heavily cared for 

by parents. However, most have fledged by this date and are believed to be able to 

move short distances to stay with the parents being displaced.

On-ground 

human 

presence

Mar 1 – Sept 30 NLAA Spotted owls have not shown any flushing from a nest due to human presence on 

the ground.

In-canopy 

human 

presence

Mar 1 - Jul 15 LAA Spotted owls may flush from a nest due to human presence in the tree canopy 

(based on expert judgment of spotted owl biologists in USFWS 2003, p. 18).

Jul 15 – Sept 30 NLAA Most young are fledged and likely able to move from tree climbers.
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The analysis of potential effects encompasses all actions associated with the proposed project. 

Habitat modification can remove current dispersal habitat or maintain the current habitat functionality 

of either suitable or dispersal habitat. Removal of dispersal habitat is expected to limit spotted owl 

movement through the treated stand(s). Thus the ability of spotted owls to move across portions of 

the landscape where dispersal habitat has been removed depends entirely on the habitat condition of 

the surrounding lands. 

The removal of suitable habitat has an indirect effect on spotted owl populations by reducing the 

amount of potential nesting or foraging habitat. These effects on a local spotted owl population are 

greater when the amount of suitable habitat remaining post-harvest is limited in the area. Loss of 

nesting structure may reduce the number of breeding pairs if other nesting habitat is limited. Loss of 

foraging habitat could reduce the amount of food available to nearby adult and juvenile spotted owls, 

which could affect their survival or ability to reproduce if other foraging options are limited.

Downgraded suitable habitat is expected to preclude spotted owl foraging, roosting, and nesting for 

varying periods of time, depending on the silvicultural prescription and the condition of the stands at 

the time of treatment. However, downgraded suitable habitat still would be expected to support the 

movement of spotted owls across the landscape and provide some foraging opportunities.

Habitat modification activities that reduce the quality of suitable or dispersal habitat while retaining the 

structural characteristics of the affected stand that still allow it to support its original function are said 

to maintain habitat. This generally includes a reduction in canopy cover to approximately >60 percent 

in suitable habitat and >40 percent in dispersal habitat, when other habitat elements (including snags, 

down wood, tree-height class-diversity, and older hardwoods) are retained, post-harvest, at levels 

that provide for the original function of the stand. The administrative unit biologist is responsible for 

ensuring prescriptive activities account for these non-conifer structural elements and making correct 

effects determinations for each individual action. Since the functionality of this habitat is retained, the 

impacts on the ability of spotted owls to nest, forage or move across the landscape are anticipated to 

be insignificant. In some cases the juxtaposition of the affected stand within the surrounding forest 

landscape may contribute to the inability of a spotted owl pair to support successful reproduction. An 

example is treatment of suitable or dispersal stands within a nest patch.

In all cases, timber harvest within the disruption distance of a spotted owl nest during the critical 

breeding season may adversely affect the reproductive capability of individual nesting spotted owls 

(see Table 2).

The removal of dispersal habitat is expected to limit spotted owl movement through the treated stand. 

Thus the ability of spotted owls to move across the landscape near where dispersal habitat has been 

removed depends entirely on the habitat condition of the surrounding lands. 

Maintaining dispersal habitat should allow spotted owls to continue to use those stands for dispersal 

since the function of the stand as dispersal habitat is expected to be retained.

The removal or downgrading of unoccupied suitable habitat would not directly injure individual spotted 

owls. However, the removal or downgrading of unoccupied suitable habitat could preclude future 

spotted owl occupancy for a period of time, thus indirectly negatively affecting the species. This effect 

could last for 80 years or more depending on the post-treatment condition of the stand. Modification 

that maintains unoccupied suitable habitat is expected to have less of an impact on spotted owls 

because no individual spotted owls would be directly affected by the treatments and because the 

function of these stands would be retained, thus limiting any indirect effects.

Modification that maintains unoccupied suitable habitat is expected to have less of an impact on 

spotted owls because no individual spotted owls would be directly affected by the treatments and 

because the function of these stands would be retained, thus limiting any indirect effects. 

There may also be short and/or long-term beneficial effects associated with habitat modification, 

particularly thinning in reserves, when they are designed to encourage faster development of latesuccessional characteristics. Thinning within non-matrix lands is implemented to increase growth 
Effects of the Proposed Action LAA Biological Assessment- Willamette NF-FY 2018

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rates and crowns by reducing competition for the retained trees, to make currently unsuitable nest 

trees and trees of marginal habitat quality become suitable nest trees sooner than without treatment. 

These thinning treatments also encourage currently suitable trees to maintain full crowns and branch 

development, and to create holes and gaps in the stand that will increase stand complexity and 

improve habitat by creating greater stand diversity for spotted owls and their prey base. In some 

cases, a short term adverse effect to the spotted owl by Harvest - Habitat Remove may result in a 

long term benefit by providing structural diversity.

Analytical Framework for analyzing impacts to critical habitat

The following analysis relies on two components to support the determinations: 

1) The Environmental Baseline evaluates the current condition of spotted owl critical habitat and

its recovery role in the action area.

2) The Effects of the Action determines the direct and indirect impacts of the proposed Federal 

action and the effects of any interrelated or interdependent activities on spotted owl critical 

habitat and/or its recovery role in the action area.

The analysis uses the intended range-wide and provincial scale recovery functions of spotted owl 

critical habitat and the role of the action area relative to those intended functions as the context for 

evaluating the effects of the proposed Federal action. In short, a non-adverse modification 

determination is warranted by the USFWS if the proposed action is consistent with maintaining the 

intended recovery role of spotted owl critical habitat in the action area.

Activities occurring within designated critical habitat that would impact any PBF or would appreciably 

slow or preclude the development of any PBF at the stand scale, may adversely affect spotted owl 

critical habitat. Effects to critical habitat that are discountable, insignificant or entirely beneficial at the 

stand scale are unlikely to adversely affect critical habitat. 

There can also be short and/or long-term potential beneficial effects to critical habitat associated with 

habitat modification, particularly thinning designed to encourage faster development of latesuccessional characteristics. Thinning within non-matrix lands is implemented to increase growth 

rates and crowns by reducing competition for resources and to make currently unsuitable nest trees 

and trees of marginal habitat quality become suitable nest trees sooner than without treatment. Such 

thinning treatments also encourage currently suitable trees to maintain full crowns and branch 

development, and to create holes and gaps in the stand that will increase stand complexity and 

improve habitat by creating greater stand diversity for spotted owls and their prey. 

In some instances, particularly on the east side of the Cascades, some of the suitable habitat in 

critical habitat requires treatment to reduce fire hazard thereby retaining it as suitable habitat for the 

long-term recovery of the spotted owl. Even though at the stand scale, the effect may be adverse in 

the short-term as described below; in the long-term these activities are proposed to maintain recovery 

potential.

Effects Determinations for Spotted Owl Critical Habitat

A “may affect, likely to adversely affect” determination for spotted owl critical habitat that triggers 

the need for completing an adverse modification analysis under formal consultation is warranted in 

cases where a proposed Federal action will: 

1) Reduce the quantity or quality of existing spotted owl nesting, roosting, foraging, or dispersal 

habitat (PBFs 2, 3 and 4) to an extent that it would likely adversely affect the ability of that 

PBF to provide for breeding, feeding, or sheltering;

2) Result in the removal or degradation of a known spotted owl nest tree when that removal 

significantly reduces the ability of spotted owl critical habitat to support spotted owl nesting 

(PBF 2); or 

3) Prevent or appreciably slow the development of spotted owl PBFs that currently do not 

contain all of the essential features, but have the capability to do so in the future.
Effects of the Proposed Action LAA Biological Assessment- Willamette NF-FY 2018

67

Effects determinations for spotted owl critical habitat on the Willamette National Forest are generally 

made at the stand scale. For example, negative effects to an individual tree within spotted owl critical 

habitat will not necessarily equate to a determination of likely to adversely affect if the impacts to 

spotted owls are not measureable at the stand scale. In such cases an adverse modification analysis 

would not be triggered as part of a formal consultation because those effects are not measureable at 

the stand, or any larger, scale.

The numbered actions above would adversely affect spotted owl critical habitat because they impact 

the ability of critical habitat to provide for the survival or recovery of the spotted owl at the stand or 

greater scale regardless of current occupancy status by a spotted owl. 

Adverse effects to an individual tree within spotted owl critical habitat will not trigger the need to 

complete an adverse modification analysis under formal consultation if those effects are not 

measurable at the stand level. Most modifications that are likely to adversely affect critical habitat are 

ones that set back stand development (i.e. regeneration harvest, or thinning that reduces the late 

successional conditions to such an extent that the stand no longer supports resident spotted owls). 

A “may affect, not likely to adversely affect” determination for spotted owl critical habitat is 

warranted in cases where a proposed Federal action will: 

1) Not reduce the quantity or quality of existing spotted owl nesting, roosting, foraging, or 

dispersal habitat (PBFs 2, 3 and 4) at the stand level to an extent that it would be likely to 

adversely affect the stand’s ability to provide for breeding, feeding, sheltering, or dispersal of 

an individual spotted owl; 

2) Not reduce the quality of existing spotted owl nesting, roosting, foraging or dispersal habitat 

(PBFs 2, 3 and 4) at the territory or landscape level to an extent that it would likely adversely 

affect the territory or landscape’s ability to provide the PBF’s of spotted owl critical habitat.

3) Not result in the removal or degradation of a spotted owl nest tree when that removal reduces 

the likelihood of spotted owls nesting within the stand; or 

4) Not prevent or appreciably slow the development of spotted owl habitat at the stand scale in 

areas of critical habitat that currently do not contain all of the PBFs, but have the capability to 

do so in the future.

Such actions are not likely to adversely affect spotted owl critical habitat because forested stands will 

maintain their function to support spotted owls in a manner as before treatment at the stand scale and 

will not slow the development of future late succession conditions. Most modifications that are not 

likely to adversely affect critical habitat are designed to accelerate stand development (i.e. thinning in 

non-habitat or dispersal to promote late succession conditions), or enhance a component of the stand 

(i.e. snag creation). Additional modifications that are not likely to adversely affect critical habitat are 

spread out through the stand and do not affect the function of the PBFs, but may be completed for 

reasons other than development of late-successional conditions (i.e. danger trees, fish trees).

In Appendix A, Summary Tables A-12, A-13, and A-14 portray the activities and effects within critical 

habitat associated with the proposed action.

B. Direct and Indirect Effects of Habitat Modification on Spotted Owls 

and their Critical Habitat in the Action Area by Activity Type

The best available science was used to develop assumptions within a general analytical framework 

and determine the effects of proposed activities to known and potential sites. Uncited effects 

determinations below are the conclusions by the Level 1 team applicable only to the effects of 

proposed activities within the Willamette Planning Province. Unit biologists are responsible for, and 

have supplied, details on the rationale for effects determinations.
Effects of the Proposed Action LAA Biological Assessment- Willamette NF-FY 2018

68

Table 15 and Appendix A identify eight projects proposed and the effects determination to the spotted 

owl and its critical habitat in compliance with the standards in Section II. Only the Willamette National 

Forest has projects subject to this consultation.

Individual administrative unit tables are shown in Appendices B. Table B1 details the effects to 

spotted owls and spotted owl critical habitat by individual project. Additional information is provided in 

the spreadsheets and narratives for each administrative unit that accompanies this biological 

assessment. 

The locations of the projects proposed in this biological assessment are known. A narrative for some 

of the projects are included in Appendix B where the narrative provides additional detailed project 

information that is not discussed in this assessment. 

Spotted owl sites that would be affected by the proposed activities are discussed in the RA10 section 

and are summarized in Appendix A, Table A-18 and A-19.

No projects included in this consultation would remove spotted owl habitat in areas where postactivity habitat conditions would create a barrier or strong filter to spotted owl movement and survival, 

in the opinion of the unit wildlife biologist.
Effects of the Proposed Action LAA Biological Assessment- Willamette NF-FY 2018

69

Table 15. Known projects proposed by administrative units and their effects to spotted owls.

Ranger 

District Project Name Proposed Activity Acres LUA Current Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

Effect-Disruption 2012 CHU 

Subunit

CHU

2012 

acres

Effect 

to 2012 

CHU

Detroit 

RD Highway 46 Harvest Habitat Remove 316 Matrix Foraging Habitat removed LAA NLAA WCS 3 316 LAA

Detroit 

RD Highway 46 Harvest Habitat Remove 148 Matrix Dispersal Habitat removed NLAA NLAA WCS 3 125 NLAA

Detroit 

RD Highway 46 Harvest in Non-habitat 2 Matrix Nonhabitat Non-habitat NE NLAA WCS 3 2 NLAA

Detroit 

RD Highway 46 Harvest Habitat Remove 15 Matrix Foraging Habitat removed LAA NLAA WCS 3 15 LAA

Detroit 

RD Highway 46 Harvest Habitat Remove 29 Matrix Dispersal Habitat removed NLAA NLAA WCS 3 29 NLAA

Detroit 

RD Highway 46 Harvest Habitat Remove 29 Matrix Foraging Habitat removed LAA NLAA WCS 3 29 LAA

Detroit 

RD Highway 46 Harvest Habitat Remove 16 Matrix Dispersal Habitat removed NLAA NLAA WCS 3 16 NLAA

Detroit 

RD Highway 46 Special Habitat Restoration 8 Matrix Foraging Habitat removed LAA NLAA WCS 3 8 LAA

Detroit 

RD Highway 46 Special Habitat Restoration 3 Matrix Dispersal Habitat removed NLAA NLAA

Detroit 

RD Highway 46 Harvest in Non-habitat 24 Matrix Nonhabitat Non-habitat NE NLAA

Detroit 

RD Highway 46 Road Construction 2 Matrix Foraging Habitat removed LAA NLAA WCS 3 2 LAA

Detroit 

RD Highway 46 Harvest Habitat Maintain 530 Matrix Foraging Habitat maintained NLAA NLAA WCS 3 525 NLAA

Detroit 

RD Highway 46 Harvest Habitat Maintain 2 LSR Foraging Habitat maintained NLAA NLAA

Detroit 

RD Highway 46 Harvest Habitat Maintain 1859 Matrix Dispersal Habitat maintained NLAA NLAA WCS 3 1530 NLAA

Detroit 

RD Highway 46 Harvest Habitat Maintain 670 LSR Dispersal Habitat maintained NLAA NLAA WCS 3 524 NLAA

Detroit 

RD Highway 46 Harvest in Non-habitat 81 Matrix Nonhabitat Non-habitat NE NLAA WCS 3 64 NLAA

Detroit 

RD Highway 46 Fuels Treatment 107 LSR NR(F) Habitat maintained NLAA NLAA WCS 3 35 NLAA

Detroit 

RD Highway 46 Fuels Treatment 63 Matrix Foraging Habitat maintained NLAA NLAA WCS 3 63 NLAA

Detroit 

RD Highway 46 Fuels Treatment 28 Matrix Dispersal Habitat maintained NLAA NLAA WCS 3 28 NLAA

Detroit 

RD Highway 46 Terrestrial Habitat Enhancement 30 Matrix Foraging Habitat maintained NLAA NLAA WCS 3 30 NLAA
Effects of the Proposed Action LAA Biological Assessment- Willamette NF-FY 2018

70

Ranger 

District Project Name Proposed Activity Acres LUA Current Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

Effect-Disruption 2012 CHU 

Subunit

CHU

2012 

acres

Effect 

to 2012 

CHU

Detroit RD Highway 46 Terrestrial Habitat 

Enhancement 80 Matrix Dispersal Habitat maintained NLAA NLAA WCS 3 80 NLAA

Detroit RD Highway 46 Terrestrial Habitat 

Enhancement 28 Matrix Dispersal Habitat maintained NLAA NLAA

Detroit RD Highway 46 Terrestrial Habitat 

Enhancement 17 Matrix Nonhabitat Non-habitat NE NLAA

Detroit RD Highway 46 Terrestrial Habitat 

Enhancement 4 Matrix Foraging Habitat maintained NLAA NLAA WCS 3 4 NLAA

Sweet 

Home RD Trout Creek Harvest Habitat Remove 68 Matrix Foraging Habitat removed LAA NLAA WCS 3 47 LAA

Sweet 

Home RD Trout Creek Harvest Habitat Remove 59 AMA Foraging Habitat removed LAA NLAA WCS 3 54 LAA

Sweet 

Home RD Trout Creek Special Habitat Restoration 3 AMA Foraging Habitat removed LAA NE WCS 3 3 LAA

Sweet 

Home RD Trout Creek Harvest in Non-habitat 8 LSR Nonhabitat Non-habitat NE NLAA WCS 3 8 NLAA

Sweet 

Home RD Trout Creek Harvest Habitat Downgrade 83 Matrix Foraging downgraded to dispersal LAA NLAA

Sweet 

Home RD Trout Creek Harvest Habitat Downgrade 5 AMA Foraging downgraded to dispersal LAA NLAA WCS 3 5 LAA

Sweet 

Home RD Trout Creek Harvest Habitat Remove 60 Matrix Dispersal Habitat removed NLAA NLAA WCS 3 36 NLAA

Sweet 

Home RD Trout Creek Harvest Habitat Remove 14 AMA Dispersal Habitat removed NLAA NLAA

Sweet 

Home RD Trout Creek Terrestrial Habitat Enhancement 303 AMA Foraging Habitat maintained NLAA NE WCS 3 246 NLAA

Sweet 

Home RD Trout Creek Harvest Habitat Maintain 117 Matrix Dispersal Habitat maintained NLAA NLAA WCS 3 27 NLAA

Sweet 

Home RD Trout Creek Harvest Habitat Maintain 278 AMA Dispersal Habitat maintained NLAA NLAA WCS 3 78 NLAA

Sweet 

Home RD Trout Creek Harvest in Non-habitat 173 AMA Nonhabitat Non-habitat NE NLAA WCS 3 62 LAA

McKenzie 

River RD

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Harvest Habitat Remove 53 Matrix Foraging Habitat 

removed LAA NE WCS 3 53 LAA

McKenzie 

River RD

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Harvest Habitat Remove 46 AMA Dispersal Habitat 

removed NLAA NE WCS 3 6 NLAA

McKenzie 

River RD

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Harvest Habitat Remove 4 AMA Foraging Habitat 

removed LAA NE
Effects of the Proposed Action LAA Biological Assessment- Willamette NF-FY 2018

71

Ranger 

District Project Name Proposed Activity Acres LUA Current Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

Effect-Disruption 2012 CHU 

Subunit

CHU

2012 

acres

Effect 

to 2012 

CHU

McKenzie 

River RD Park Thin Harvest Habitat Remove 7 AMA Foraging Non-habitat LAA NLAA

McKenzie 

River RD Park Thin Harvest Habitat Downgrade 78 AMA Foraging downgraded to dispersal LAA NLAA

McKenzie 

River RD Q Thin Harvest Habitat Remove 7 AMA Foraging downgraded to dispersal LAA NE WCS 3 7 LAA

McKenzie 

River RD Q Thin Harvest Habitat Downgrade 36 AMA Foraging Non-habitat LAA NE WCS 3 36 LAA

McKenzie 

River RD Q Thin Harvest Habitat Maintain 27 AMA Dispersal Habitat maintained NLAA NE WCS 3 27 NLAA

McKenzie 

River RD

Three Sisters Risk 

Reduction HF 

Treatment

Fuels Treatment 312 Matrix NR(F) Habitat 

maintained LAA NLAA WCS 4 81 LAA

McKenzie 

River RD

Three Sisters Risk 

Reduction HF 

Treatment

Fuels Treatment 351 Admin 

withdrawn NR(F) Habitat maintained LAA NLAA WCS 4 345 LAA

McKenzie 

River RD

Three Sisters Risk 

Reduction HF 

Treatment

Fuels Treatment 162 AMA NR(F) Habitat 

maintained LAA NLAA WCS 4 77 LAA

McKenzie 

River RD

Three Sisters Risk 

Reduction HF 

Treatment

Fuels Treatment 380 LSR NR(F) Habitat 

maintained LAA NE WCS 4 377 LAA

Middle 

Fork RD

Bear Mountain 

Meadow 

Restoration

Special Habitat 

Restoration 186 Matrix Nonhabitat Non-habitat NE NLAA WCS 4 89 NE

Middle 

Fork RD

Bear Mountain 

Meadow 

Restoration

Special Habitat 

Restoration 14

Admin 

withdrawn

Nonhabitat Non-habitat NE NLAA WCS 4 14 NE

Middle 

Fork RD

Bear Mountain 

Meadow 

Restoration

Special Habitat 

Restoration 4

LSR100ac NR(F) Habitat 

maintained NLAA NLAA WCS 4 4 NLAA

Middle 

Fork RD

Bear Mountain 

Meadow 

Restoration

Special Habitat 

Restoration 14 Matrix NR(F) Habitat maintained NLAA NLAA WCS 4 7 NLAA

Middle 

Fork RD Road 24 Reroute Road Construction 6 Matrix NR(F) Habitat removed LAA NLAA 0 NE

Middle 

Fork RD Road 24 Reroute Road Construction 2 Matrix Dispersal Habitat removed NLAA NLAA 0 NE
 LAA Biological Assessment- Willamette NF-FY 2018

72

Harvest – Habitat Remove (HH Remove)

General Effects to spotted owls-HH Remove

Suitable habitat: Removal of suitable habitat could impact spotted owls by removing the structural 

components required by spotted owls to reproduce. Some structural components such as snags, 

clumps of large trees, and down wood would be retained to meet existing NWFP requirements. 

However, the overall effect to suitable spotted owl habitat is that it will be set back up to 40 years

before it provides stand conditions suitable for spotted owl dispersal and up to 80 years or more

before it once again functions as suitable spotted owl habitat. The removal of such habitat may affect 

the success of spotted owls to raise young for the following reasons:

1) If a nest tree is removed, the pair will not be able to produce young until a suitable replacement 

nest has been established or they find another nest tree in another location.

2) If foraging habitat is limited near a nest tree, and additional foraging habitat is removed, the 

spotted owl pair may be unable to obtain enough food to successfully fledge their young. This 

may cause the pair to relocate to a nest site with sufficient foraging to support nesting which may 

delay nesting or require excessive energy to relocate to a different location.

Therefore, this type of harvest may affect, and is likely to adversely affect spotted owls directly 

and indirectly since such removal may impair the breeding or forage opportunities for resident spotted 

owls.

Dispersal habitat: Removal of dispersal habitat generally may affect, but is not likely to 

adversely affect (direct and indirect) spotted owls because sufficient habitat would remain in the 

area (see standard #4) to facilitate spotted owl dispersal and treatment would occur outside of known 

and potential nest patches. 

However, in some instances removal of dispersal habitat may affect, and is likely to adversely 

affect (direct and indirect), spotted owls because the activity occurs within a nest patch affecting 

territorial pairs or it would limit the ability of spotted owls to disperse across the landscape.

General Effects to Critical Habitat – HH Remove

Suitable habitat: Removal of suitable habitat could impact spotted owl critical habitat by removing 

the PBFs that support spotted owl reproduction and roosting while dispersing. Some structural 

components such as snags, clumps of large trees, and down wood would be retained to meet existing 

NWFP requirements. However, the overall effect to PBFs 2, 3 and 4 is that they will be set back up to 

40 years before they provide stand conditions suitable for spotted owl dispersal and up to 80 years of 

more before they once again provide conditions for breeding and sheltering. 

The removal of such habitat directly removes PBF 2, limits the diversity of PBF 1, and affects the 

success of spotted owls to raise young, thus reducing the ability of CH to contribute to the survival 

and recovery of spotted owls.

Therefore, this type of harvest may affect, and is likely to adversely affect (directly or indirectly) 

spotted owl critical habitat since such removal may impair the breeding or forage potential provided 

by the critical habitat.

Dispersal habitat: Removal of dispersal habitat could impact spotted owl critical habitat by delaying 

the development of suitable habitat at the stand level because dispersal habitat (PBF 4) develops 

over time into PBFs 2 and 3. However, thinning treatments in even-aged, dense stands of dispersal 

habitat may be beneficial to critical habitat in the long term by increasing structure in the stand.

This action may affect and is likely to adversely affect spotted owl critical habitat directly or 

indirectly where removal of dispersal would delay development of the stand into suitable habitat 

compared to no treatment. However, if there is sufficient suitable habitat available after treatments for 

any potential owl territories, then delaying the attainment of suitable habitat by removing dispersal 

may effect, but is not likely to adversely affect critical habitat.
 LAA Biological Assessment- Willamette NF-FY 2018

73

Removal of dispersal habitat in a nest patch may affect and is likely to adversely affect spotted owl 

critical habitat directly and indirectly because such activity could impact the potential for supporting 

spotted owl reproduction.

If removal of dispersal habitat does not delay the development of the stand into suitable habitat 

compared to no treatment, this action may affect, but is not likely to adversely affect spotted owl 

critical habitat directly or indirectly.

Non-habitat: Removal of non-habitat as used in this document is the “permanent” removal of nonhabitat that is capable of becoming owl habitat and developing PBFs 2, 3 and 4. If an action affects 

the ability of a stand to support those functions in the future it may affect and is likely to adversely 

affect spotted owl critical habitat. If the area of non-habitat that is removed is small and would not 

contribute to future loss of PBFs measurable at a stand scale, the action may affect, but is not likely 

to adversely affect spotted owl critical habitat. There is no removal of non-habitat in the proposed 

actions evaluated in this document.

Project Effects– HH Remove

There are five projects that would have HH Remove activities affecting a total of 313 acres of 

dispersal habitat and 558 acres of suitable (foraging) habitat (Appendix A, Table A- 2). Four of these 

projects (affecting 212 acre of dispersal habitat and 521 acres of suitable habitat) are in critical 

habitat. 

Detroit Ranger District

Highway 46 This timber harvest and restoration project would have HH Remove on 360 acres of 

foraging (suitable) owl habitat and 193 acres of dispersal habitat, all in matrix allocation, for a total of 

553 acres. 

About 316 acres of foraging habitat and 148 aces of dispersal habitat would use HH Remove to 

restore sugar pine. Sugar pines primary range extends from northern Mexico, through the Sierra 

Nevada, Northern California, and Southern Oregon. The very northern extent of is range is in the 

Hwy 46 project area. Sugar pines are moderately shade tolerant, particularly when they are young, 

needing some protection from the sun as they establish. As they get older their tolerance for 

competition decreases, and other species can out-compete them if lower intensity disturbances, 

primarily wildfire, do not thin stand densities. These wildfires not only help prolong the existence of 

the established sugar pine, they are also essential for their regeneration (Sugihara and McBride, 

1992 entire). Fire suppression over the last 100 years, extensive logging, and the introduction of 

white pine blister rust at the turn of the 20th century have reduced the sugar pine population across 

its range (Waring and Angell 2011:2). Most of the sugar pine found in the project area are lone large 

trees surrounded by dense Douglas-fir stands. Only one area of naturally regenerating sugar pine 

was found during project reconnaissance. The presence of these trees means that sugar pine has 

been part of this landscape for a long time and now appears to be losing its place and the ecosystem 

which supports them due to the lack of disturbance. Disturbance, previously by wildfire, allowed 

sugar pine to regenerate. Approximately 15-20 years ago a local drought caused extensive mortality 

in the large sugar pine which were under stress from Douglas fir encroachment. Climate change may 

increase the threat to sugar pines which are under competition stress. 

Proposed treatments aim to both protect and reinvigorate existing sugar pine as well as 

reestablishing it in areas suitable to its prolonged existence. Prescriptions include shelterwood with 

reserve cuts, broadcast burning, planting of rust resistant stock, and pre-commercial regeneration 

release. The sugar pine restoration includes skips and dominant tree release (DTR) to increase 

structural diversity and enable natural recruitment of young trees. Eight units have been selected for 

this treatment the proposed project. Sugar pine will also be planted in other units in gaps created for 

early seral in DTRs created for species diversity. 

Shelterwood with reserves would be thinned to 10-20 trees per acre (except for one unit that would 

have 20-30 trees per acre) with reserve trees spread across the treatment unit. Sugar pine and any 
 LAA Biological Assessment- Willamette NF-FY 2018

74

legacy trees would not be cut. Also any trees over 30” dbh would not be cut unless needed for safety 

or operational concerns. Any trees over 30” dbh that was needed to be fallen would be left on site.

Under burning is proposed to occur on 93 acres of sugar pine restoration. A prohibition on burning in 

units where burning could cause disruption to nesting spotted owls will be in effect from March 1 –

July 15.

The sugar pine treatment is focused on restoring an ecosystem which is at the northern tip of the 

range of the sugar pine and will remove spotted owl habitat in the harvested stands as canopy cover 

will be reduced to about 20 percent. Large sugar pine will be maintained and younger trees will be 

encouraged to grow which over time will restore dispersal and foraging habitat. Dispersal habitat is 

expected to regrow in the treated areas in approximately 40 years and foraging habitat should 

reestablish in about 80 years. The presence of large legacy sugar pine would enhance the future owl 

habitat in the stand by providing roosting and potential nest trees.

Fifteen acres of foraging habitat and 29 acres of dispersal habitat would be removed by wildlife gap 

creation of one to three acres in size in 12 units. Three to five trees per acre would be left in each 

gap favoring sugar pine, western white pine, incense cedar, noble fir and western redcedar, if 

available. Large trees with top or bole damage would be selected if present, as leave trees. Wildlife 

gaps of one to three acres are proposed in 12 thinning treatment units. These gaps would contribute 

to the quality of early seral habitat as described above as well as adding species and structural 

complexity at both the stand and landscape level. Because of the small size of the openings and the 

trees retained, dispersal and suitable habitat would regenerate more quickly than in a traditional 

larger regeneration harvest unit.

Lastly 29 acres of foraging habitat and 16 acres of dispersal habitat will have HH Remove to create 

quality early seral habitat. Currently less than 2% of the watershed area is in early seral habitat when 

it is estimated historically about 9% was in early seral. The early seral habitat creation is proposed in 

four units which are generally on gentle slopes, south facing, suitable plant association types favoring 

vine maple, avoiding rhododendron and bear grass. The dispersal habitat is plantations ranging in 

age from 38 to 53 years. The foraging habitat is a 123 year-old fire generated stand that was 

previously thinned. The units will have green tree, downed wood and snag retention consistent with 

the NWFP requirements. Dispersal habitat is expected to regenerate in about 40 years while foraging 

habitat would regenerate in about 80 years, post-treatment.

Broadcast burning is proposed to occur on 67 acres of quality early seral habitat and gaps. A 

prohibition on burning in units where burning could cause disruption to nesting spotted owls would be 

in effect from March 1 – July 15.

All of the HH Remove described above is in Critical Habitat Subunit WCS 3, except of 23 acres of 

sugar pine restoration in dispersal habitat that is in not in critical habitat. Thus HH Remove would 

remove 360 acres of foraging habitat and 170 acres of dispersal habitat in critical habitat in matrix 

allocation. As described above the proposed actions are designed to restore sugar pine (441 acres 

of CH) and create quality early seral habitat (89 acres of CH). Removal of habitat could impact 

spotted owl critical habitat by removing the PBFs that support spotted owl foraging and dispersal, but 

not nesting/roosting as none of the affected habitat is NRF habitat. Some structural components 

such as snags, clumps of large trees, and down wood would be retained to meet existing NWFP 

requirements. However, the overall effect to PBFs 3 and 4 is that they will be set back up to 40 years

before they provide stand conditions suitable for spotted owl dispersal and up to 60-80 years before 

they once again provide conditions for foraging. The sugar pine restoration may improve forest 

resiliency in the face of climate change and benefit spotted owl habitat in the very long-term by 

retaining unique forest biodiversity. While the HH Remove treatments in CH were not specifically 

designed to benefit owls, impacts were mitigated by designing the treatments to reduce impacts to 

owl territories and avoid NRF habitat.

None of the HH Remove treatments are in LSR.

The effect determination of HH Remove for Highway 46 would be LAA for general habitat 

modification and to Critical Habitat.
 LAA Biological Assessment- Willamette NF-FY 2018

75

Sweet Home Ranger District

Trout Creek This timber harvest and restoration project would have HH Remove on 68 and 59 acres

of foraging (suitable) owl habitat in matrix and Adaptive Management Areas (AMA), respectively, and 

on 60 and 14 acres of dispersal habitat, in matrix and AMA, respectively, for a total of 201 acres. The 

treatments in the foraging habitat are natural fire-regenerated stands ranging from about 116 to 150 

years of age. The dispersal habitat are plantations that are about 40 to 67 years of age.

HH Remove in foraging habitat includes a 47-acre heavy thinning with a prescribed burn to create 

large numbers of snags and reduce the canopy to 15% cover to create high-quality early seral 

habitat. About 60% of the stand would have no treatment thus resembling moderate severity patch 

burn. Seventy six acres of HH Remove in foraging habitat in mixed deciduous-conifer stands along 

roadsides would remove conifers to create a hardwood fuel break by stimulating red alder, big-leaf 

maple and other deciduous trees that are less conducive to fire spread. Canopy cover would be 

reduced to about 30% comprised primarily of hardwood species. Two acres of HH Remove would 

restore a rare oak/savannah microsite in a 135 year-old fire regenerated stand and two acres of HH 

Remove is for expansion of a rock pit in a thinning unit in a 120-year old fire regenerated stand.

HH Remove in dispersal habitat includes 52 acres of early seral habitat creation in three units ranging 

in size from 6 to 36 acres, 4 acres of heavy thinning to promote Tribal foods, and 18 acres of roadside 

hardwood fuel breaks similar to what was described in the foraging habitat. Early seral creation 

would have green tree, snag and wood retention consistent with NWFP Standards and Guidelines for 

regeneration harvest.

In about 40 years post-harvest, the early seral stands and oak restoration stands would develop into 

dispersal habitat. Suitable spotted owl habitat would develop after 80-140 years post-harvest, and 

the stands could achieve characteristics that fit the Recovery Action 32 description due to the 

retention of legacy trees that would exist in the stands at that time. The fuel treatment and heavy thin 

stands would regenerate to dispersal habitat in about 10-15 years post-harvest. Suitable spotted owl 

habitat would develop after 50 years or less post-harvest. Also the fuel break treatment could have 

some beneficial effects to spotted owls by reducing the risk of fires spreading across the treated 

roadways. 

Of the HH Remove described above, about 47 and 54 acres of foraging (suitable) owl habitat in 

matrix and AMA, respectively, and 36 acres of dispersal habitat in matrix are in Critical Habitat 

Subunit WCS 3. The treatment in dispersal habitat in CH is a 36 acre early seral creation unit. The 

treatments in foraging habitat in CH include the 47-acre heavy thinning with a prescribed burn and 54 

acres of hardwood fuel breaks.

Removal of habitat could impact spotted owl critical habitat by removing the PBFs that support 

spotted owl foraging and dispersal, but not nesting/roosting as none of the affected habitat is NRF 

habitat. Some structural components such as snags, clumps of large trees, and down wood would be 

retained to meet existing NWFP requirements, and additional snags and deadwood would be created 

in the early seral units. However, the overall effect to PBFs 3 and 4 is that they will be set back up to 

40 years in the early seral units and 10-15 years in the heavy thin and fuel break units before they 

provide stand conditions suitable for spotted owl dispersal and 40 to 80 years of more before they

once again provide conditions for foraging. While the HH Remove treatments in CH were not 

specifically designed to benefit spotted owls, impacts were mitigated by designing the treatments to 

reduce impacts to spotted owl territories and avoid NRF habitat. Also the fuel treatments could 

benefit spotted owls by reducing the risk of wildfire spread. 

None of the HH Remove treatments are in LSR.

The effect determination of HH Remove for Trout Creek would be LAA for general habitat 

modification and to Critical Habitat.

McKenzie River Ranger District

Lower South Fork McKenzie River Floodplain Restoration This project would have HH Remove 

on 53 and 4 acres of foraging (suitable) owl habitat in matrix and AMA, respectively, and on 46 acres 
 LAA Biological Assessment- Willamette NF-FY 2018

76

of dispersal habitat in AMA for a total of 103 acres. The tree removal would be used to supply about 

4,000 logs for a large-scale river restoration project below the Cougar Reservoir on the South Fork of 

the McKenzie River. The purpose of the Lower South Fork McKenzie River Floodplain Enhancement 

project is to restore, to the extent practicable, the physical, chemical, and biological processes that 

maintain a healthy and resilient floodplain ecosystem. A well-functioning floodplain will provide 

diverse habitat for aquatic and terrestrial communities, including ESA-Threatened spring Chinook 

salmon and bull trout. Trees harvested from upland areas for wood would be pushed over with heavy 

equipment to keep the root wad attached which has more ecological value in the riparian system.

Twenty eight upland units would be harvested to supply the wood source. Consultation for the 

riparian portion of the treatment is covered under ARBO II. The entire project is described in greater 

detail in a project narrative in Appendix B.

This project would remove about 57 acres of foraging spotted owl habitat with a post-treatment 

habitat type of non-habitat in stands that are 120-130 years old. Fifty three acres would maintain a 

minimum canopy cover of 30%, contain five 3-acre gaps, and two 2-acre unthinned skips which have 

concentrations of legacy trees. One of these skips is on the stand edge, and thus would not 

contribute to additional effects. Two additional small gaps of 2 acres in foraging habitat would be 

created adjacent to a road. The amount of down wood left would meet or exceed Forest Plan 

standards and guidelines of 240 lineal feet or 2 down trees/acre. It is also expected that the units

would have at least one large snag/acre. Both designated skips contain large snags which are

expected to be maintained. 

About 46 acres of dispersal habitat would be removed in scattered gaps ranging from 1-3 acres in 

size in 60-80 year old stands that were recently thinned. Three additional gaps in dispersal habitat are 

also planned and will be used for wood and helicopter staging areas, as well.

Leave trees would be marked. Trees which show sign of insect or disease would be retained for 

natural snags or down wood. In addition, trees with crooked stems, forked tops, defects, or broken 

tops would be retained for wildlife habitat benefits.

Those snags that do not pose a safety concern would be retained to support habitat for spotted owl 

prey base as well as primary cavity excavators. If falling is required, most snags will be left on site as 

downed wood if they do not pose a fire risk. Existing large down woody material will be maintained for 

habitat diversity, and full tree lengths will be retained as much as possible.

The thinnings would not remove any existing downed wood from the stands or commercially harvest 

any existing snags. Snags that are hazards to the logging operations may be fallen and left on site, 

but the intent is to maintain existing snags where feasible. The amount of dead wood retained would 

meet Forest Plan standards and guidelines. Tree, shrub, and grass/forb forage planting or seeding 

may or may not occur in the gaps.

Following thinning and gap treatments, fuels may be treated to reduce wild fire risk by piling and 

burning, by limited broadcast burning, and by firewood sales. Fuel treatments would be planned to 

protect all remaining live trees and snags.

The proposed treatments will result in a loss of foraging habitat that may last about 25 years in the 

thinned units and over 80 years in the 3-acre gaps. The gaps would retain all trees above 36 inches 

and under 18 inches since these diameters are not suitable for transport to the Lower South Fork 

McKenzie River project area. From a tree size standpoint, the thinning treatments may improve the 

growth response of the remaining trees in the thinned units. In these naturally regenerated stands, 

conifer trees would be removed across the 16-36” size class. Older fire regenerated stands, or 

mature stands, which are commonly associated with stands over 80 years of age show positive 

growth responses to thinning. Latham and Tappeiner (2002:143) showed that trees over 150 years 

old will respond to thinning with basal area growth “significantly greater ... for 15 to 63% of the trees.” 

Mature stands often have long term benefits of a variety of thinning densities which last 20-30 years 

(Latham and Tappeiner, 2002:144-145). Additionally 110-year old trees in heavy thinning stands 

showed a positive growth response which was 30 percent greater than that of the controls 

(Williamson 1982:10).
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77

It will take about 40 years for the created gaps to recover to dispersal habitat conditions for spotted 

owls. Thinned areas surrounding the gaps are likely to recover to dispersal habitat within about 15 

years. The mix of gaps, surrounded by the thinned stand would take about 80 years to recover to 

foraging habitat conditions. At that time, the overall stand condition is likely to be improved over the 

current stand condition, since it would have improved vertical and horizontal diversity. The 

unharvested stands adjacent to the small gaps may show edge benefits with increased development 

of understory shrubs and forbs which have broad ecosystem benefits.

Of the HH Remove treatments in this project, 53 acres in foraging habitat in matrix and 6 acres in 

dispersal habitat in AMA are in Critical Habitat Subunit WCS 3. Gap size in dispersal habitat in Critical 

Habitat is limited to 2 acres in size and these were located outside 0.5 mile nest core areas to reduce 

impacts. While there may be few or none as a result of a previous timber sale, any trees in these 

gaps under 14” diameter would be left. 

Removal of habitat would impact spotted owl critical habitat by removing the PBFs that support 

spotted owl foraging and dispersal, but not nesting/roosting as none of the affected habitat is NRF 

habitat. Some structural components such as snags, clumps of large trees, and down wood would be 

retained to meet existing NWFP requirements. The overall effect is that PBFs 3 and 4 would be 

adversely affected at the stand scale. Dispersal habitat (PBF 4) would be removed for about 10 

years until the stands reach 40% canopy. Foraging habitat (PBF 3) would be setback 25 years in the 

thinning units and up to 80 years in the gaps. Field review of the stands dropped any concentrations 

of legacy trees or inclusions of potential RA 32 habitat from the treatment units. Longer-term the 

thinning may improve stand structural characteristics for PBFs 2, 3, and 4 for spotted owls. Also 

while the action is not designed to directly benefit spotted owls, it will provide important wood 

structure in a river that will benefit two ESA-listed fish species.

None of the HH Remove treatments are in LSR.

The effect determination of HH Remove for Lower South Fork McKenzie River Floodplain 

Enhancement would be LAA for general habitat modification and to Critical Habitat.

See the project narrative in Appendix B for more details.

Park Thin and Q Thin. The McKenzie River Ranger District is proposing two commercial timber 

sales in stands 80 to 120 years old that are foraging habitat for spotted owls. The main effect of the 

treatments would downgrade spotted owl habitat to dispersal and these projects are described in 

detail in the following HH Downgrade section and the project narratives in Appendix B. However, 

each project would have up to 7 acres of gaps up to three acres in size that would remove suitable

spotted owl habitat. The purpose of the gaps would be to increase the diversity of shrub and forage 

habitat. Two to three trees per acre in clumps or as individual trees would be retained in the gaps to 

add diversity and provide for future recruitment of snags and down woody material.

The gaps would regenerate to suitable foraging habitat in about 60 to 80 years. The effect to the 

stand from the overall treatment would be improved spotted owl habitat in the long-term as described 

in the HH Downgrade section. Both projects are located in areas where spotted owls are unlikely to 

nest due to currently fragmented habitat.

The 7 acres of gaps in the Q Thin are in Critical Habitat Subunit 3. Park Thin is not in CH. Removal 

of habitat would impact spotted owl critical habitat by removing the PBFs that support spotted owl 

foraging and dispersal, but not nesting/roosting as none of the affected habitat is NRF habitat. 

Dispersal habitat (PBF 4) would recover in about 40 years when the gaps reach 40% canopy. 

Foraging habitat (PBF 3) may take 60 to 80 years to recover in the gaps. The Q Thin project is 

located in habitat that is highly fragmented and thought to be unoccupied by the project biologist.

None of the HH Remove treatments are in LSR.

The effect determination of HH Remove for Park Thin would be LAA for general habitat 

modification and NE to Critical Habitat. The effect determination of HH Remove for Q Thin 

would be LAA for general habitat modification and to Critical Habitat.
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78

Harvest – Habitat Downgrade (HH Downgrade)

General Effects

Harvest – Habitat Downgrade would modify spotted owl suitable habitat to the extent that it no longer 

serves the function of nesting, roosting and foraging. It may, however, continue to function as 

dispersal habitat. Although the affected stands will continue to function as dispersal habitat (since 

many trees will be retained), nesting structure will likely be reduced or eliminated in the area and the 

quality of foraging and roosting structures within the stand will be diminished. The stands will retain a 

40 percent or greater canopy cover in addition to some structural components (snags, clumps of large 

trees, down wood) to meet existing NWFP requirements. Conceptually, HH downgrade could also 

reduce NRF to foraging, but no such treatment is proposed in this assessment. Only foraging habitat 

is downgraded in the proposed actions evaluated here. 

Immediately after harvest, the success of spotted owls to raise young is likely to be adversely affected 

because: 1) if a nest tree is removed, the pair will not be able to produce young until a suitable 

replacement nest has been established or will have to relocate to a new tree, and 2) if foraging 

habitat is limited near a nest tree, as more foraging habitat is removed, the spotted owl pair will not be 

able to obtain enough food to successfully fledge their young. However, after the initial impact of 

timber harvest downgrading suitable habitat, the shrub layer would regenerate sooner compared to 

areas where suitable habitat is removed. Over time the understory habitat conditions for prey would 

recover more rapidly in stands where suitable habitat is downgraded rather than removed.

Since this activity would remove suitable habitat by downgrading it to dispersal, Harvest – Habitat

Downgrade may affect and is likely to adversely affect spotted owls directly and indirectly by 

impairing the breeding or forage opportunities of resident spotted owls.

General Effects to Critical Habitat – HH Downgrade

Timber harvest that downgrades the structural and vegetative components of suitable habitat within 

CH at the stand level is likely to adversely affect the PBF’s thus reducing the ability of spotted owls to 

breed (PBF 2), feed (PBF 3), or shelter (PBF 2). Although the affected stands will continue to function 

as dispersal habitat (PBF 4)(since many trees will be retained), nesting (PBF 2) will likely be reduced 

or eliminated in the area and the quality of foraging (PBF 3) and roosting structures (PBF 2) within the 

stand will be diminished. 

These effects will begin immediately after harvest, reducing the success of spotted owls to raise 

young (PBF 2), and to forage (PBF 3), thus reducing the ability of spotted owl CH to support survival 

and recovery of spotted owls. However, after the initial impact of timber harvest downgrading PBF 3, 

the stand, including understory components and shrub layer would regenerate sooner than areas 

where suitable habitat is removed. Over time the understory habitat conditions for prey (PBF 3) would 

recover more rapidly in stands where suitable habitat is downgraded rather than removed. Since this 

activity would remove PBFs 2 and 3 by downgrading it to dispersal, HH Downgrade may affect and 

is likely to adversely affect spotted owl critical habitat either directly or indirectly by impairing the 

breeding or forage opportunities for resident spotted owls and reducing roosting opportunities for 

dispersing spotted owls.

Project Effects – HH Downgrade

There are three projects, one on the Sweet Home Ranger District and two on the McKenzie River 

Ranger District, that would have HH Downgrade activities, affecting a total of 202 acres of foraging

(suitable) habitat (Appendix A, Table A- 3). Two of the projects affect a total of 41 acres of foraging 

habitat in critical habitat.

Sweet Home Ranger District

Trout Creek This timber harvest and restoration project would have HH Downgrade on 83 and 5 

acres of foraging (suitable) owl habitat in matrix and AMA, respectively, for a total of 88 acres in three 
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79

stands. The treatments in the foraging habitat are natural fire-regenerated stands ranging from about 

120 to 130 years of age. 

Units would be thinned to about 50% canopy cover using variable density thinning. The purpose of 

the treatments are to encourage stand health, vigor, species diversity and structural complexity in the 

stands. Untreated skips would comprise 16 to 40% of the stands. Post-harvest, some snag and 

downed logs may be created in or near the units. Grapple piling and broadcast burning may be used 

to reduce fuels created by the thinning treatments.

Five acres of thinning treatment would be done to favor hardwood species in order to promote tall 

bugbane. Tall bugbane is a former Region 6 sensitive plant species that continues to be a species of 

Forest concern. Populations on the Sweet Home RD have declined sharply for reasons unknown. 

The plant prefers cool micro-climates with a bigleaf maple component that the treatment site 

provides. This thinning would be done to enhance the mid-story maple component. The 

development of the hardwoods would also add diversity to the stand and improve foraging habitat for 

spotted owls in the long-term.

The treated stands will retain 40-80 trees per acre post-harvest and are expected to develop back 

into foraging habitat in about 10-15 years and into old growth conditions in about 50-100 years. The 

thinning treatments should promote canopy development, tree diameter growth and understory 

development and is likely to improve spotted owl habitat long-term. 

Of the HH Downgrade described above, only the 5 acres of thinning to favor hardwoods and promote 

tall bugbane is in Critical Habitat Subunit WCS 3. Downgrade of foraging habitat to dispersal habitat 

would impact spotted owl critical habitat by removing PBF 3 that supports spotted owl foraging for 

about 10-15 years. Longer-term, the treatment may improve PBFs 2, 3, and 4 by promoting canopy 

development, tree diameter growth and multi-storied stand structure. It is estimated that in 50-100 

years this stand would be high-quality NRF habitat post-treatment. 

None of the HH Downgrade treatments are in LSR.

The effect determination of HH Downgrade for Trout Creek would be LAA for general habitat 

modification and to Critical Habitat.

McKenzie River Ranger District

Park Thin. The McKenzie River Ranger District is proposing to treat by HH Downgrade 

approximately 78 acres in a stand that is 80-120 years old and classified as foraging habitat. The 

proposed treatment is a fire-regenerated stand of predominately Douglas-fir with a minor component 

of western hemlock. The stand is currently in the beginning of the understory reinitiation stage of 

development.

Treatments would include 63 acres of commercial thinning and a 15-acre area that would be left 

unharvested as a skip to improve structural diversity. Thinning would primarily remove smaller, 

unhealthy trees that would be logged with skyline equipment. The purpose of this project is to 

increase stand health and vigor; accelerate development of structural complexity, and provide for 

timber harvest. Seven acres of gaps up to 3 acre in size were evaluated in the previous section as 

HH Removed.

Currently there are approximately 126 trees per acre, with an average diameter of 19.2 inches. This 

homogeneous stand is overstocked with declining vigor that leads to poor tree health, growth is 

severely limited, and competition mortality is ongoing. The stand is also at densities that limit the

long-term survival and growth of understory regeneration, which limits the development of a more 

complex vertical canopy structure. 

Thinning treatments, totaling 63 acres will result in a stand with approximately 40 percent canopy 

cover and 55-65 residual trees per acre. The project will primarily leave the biggest and healthiest 

trees with the largest crowns. The desired tree spacing in the thinning area will range between 18 to 

36 feet, providing diversity in a more open environment to promote understory development by 

reducing competition for light, water, and soil nutrients. This project will accelerate development of 
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80

larger conifer trees and meet all environmental requirements for soil, water, air, and wildlife habitat 

quality.

The proposed treatment would release residual overstory and understory trees, increasing their 

growth, size, and vigor and increase overall stand health. It would also accelerate the vertical 

structural complexity of the stand and species diversification by releasing understory trees and plants. 

Retention of existing snags and down wood, as well as some skipped, untreated areas would also 

increase stand diversity over time. See the project narrative in Appendix B for more details.

Because a minimum of a 40% canopy cover would be maintained, the stand would remain as 

dispersal habitat after treatment. With this level of canopy retention, it would be expected to again 

reach suitable (foraging) habitat stand quality in about 15 years, and the overall stand structure is 

expected to result in improved owl habitat long-term compared to no-treatment. The Park Thin 

treatment is located outside of any known owl home ranges and in an area that is highly fragmented 

and not expected to support owl nesting.

This project is not in LSR or critical habitat.

The effect determination of HH Downgrade for Park Thin would be LAA for general habitat 

modification and NE to Critical Habitat.

Q Thin. The McKenzie River Ranger District is proposing to treat by HH Downgrade approximately 

36 acres of foraging habitat in a stand that is 80-120 years old. The proposed treatment is a fireregenerated stand of predominately Douglas-fir with a minor component of western hemlock, Pacific 

silver fir and grand fir. The stand is currently in the beginning of the understory reinitiation stage of 

development.

The treatments in foraging habitat and its expected effects to owl habitat are the same as described 

above for Park Thin. Because a minimum of a 40% canopy cover would be maintained, the stand 

would remain as dispersal habitat after treatment. With this level of canopy retention, it would be 

expected to again reach suitable (foraging) habitat stand quality in about 15 years, and the overall 

stand structure is expected to result in improved owl habitat long-term compared to no-treatment. 

See the project narrative in Appendix B for more details. The treatments are not expected to affect 

the functionality of any owl home ranges as described in the Effects to Known and Potential Owl Sites 

discussion.

All of the HH Downgrade is in Critical Habitat Subunit 3. Without treatment, the project biologist 

estimates the stands would continue to slowly develop into higher quality suitable foraging habitat 

(PBF 3) over the next 40 years and improve even more over time. Downgrade of foraging habitat to 

dispersal habitat by temporarily reducing canopy to 40% would impact spotted owl critical habitat by 

removing PBF 3 that supports spotted owl foraging for about 15 years. In the longer-term, the thinning 

should create more vegetation layers, larger-sized trees, and greater canopy development compared 

to no-treatment which would benefit PBF 3. Sufficient dispersal habitat would be maintained to 

provide for the life-history needs for dispersal for any spotted owls using this area. Therefore the 

action is not expected to adversely affect dispersal habitat (PBF 4) in critical habitat. 

The treatments would not delay and could accelerate the development of PBF 2 (nesting/roosting 

habitat). Because the treatments are expected to increase diameter, crown radius, and crown ratio of 

individual trees, they are expected to improve the quality of PBF 2 in the long term and may be 

beneficial to PBF 2. Some of the created slash piles would be retained, which would benefit the 

woodrat prey base of spotted owls. There is also an opportunity to enhance snag and large down 

wood habitat if KV funding is available which would further improve habitat quality.

This project would not affect late-successional reserves.

The effect determination of HH Downgrade for Q Thin would be LAA for general habitat 

modification and to Critical Habitat.
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81

Harvest – Habitat Maintain (HH Maintain)

General Effects

Harvest – Habitat Maintain activities are expected to maintain the current functionality of spotted owl 

habitat after treatment (i.e., current suitable habitat would remain suitable and current dispersal 

habitat would remain dispersal). 

Suitable habitat: HH Maintain activities in suitable habitat generally may affect, but are not likely 

to adversely affect spotted owls because this activity would maintain the canopy cover of stands 

used for nesting, roosting, and foraging at 60 percent or higher. Stands would also retain a 

combination of snags, down woody debris, suitable nest trees, plus horizontal and vertical canopy 

depth and structure sufficient to continue to support prey species and spotted owl nesting and 

foraging quality similar to pretreatment levels. 

However, in some instances, maintaining suitable habitat may affect and is likely to adversely 

affect (direct and indirect) spotted owls because the impacts of this activity may contribute to the 

inability of a spotted owl pair to successfully reproduce due to the juxtaposition of the treated stand 

and its surrounding forest landscape (e.g., commercial thinning in a nest patch where current spotted 

owl habitat would retain its functionality after treatment).

Dispersal habitat: HH Maintain activities in dispersal habitat generally may affect, but are not 

likely to adversely affect spotted owls because canopy cover would be maintained at 40% or 

higher. Stands would also retain a combination of snags, down logs, and live tree understory 

structure sufficient to support at least a minimal prey base, which would continue to facilitate spotted 

owl dispersal. 

However this activity may affect and is likely to adversely affect (direct and indirect) spotted owls if

dispersal habitat is limited in the area or the activity occurs within a nest patch. Such activities within 

a known site can result in adverse effects due to reducing the ability of a spotted owl pair to 

successfully forage and reproduce.

General Effects to Critical Habitat – HH Maintain

Suitable Habitat: Harvest in suitable habitat would maintain the canopy cover of stands used for 

nesting, roosting and foraging (PBFs 2,and 3) at 60% or higher, would not remove potential nest trees 

(PBF 2) and would leave sufficient coarse woody debris, understory structure and snags to support 

nesting and prey (PBFs 2,and 3). Treatment in suitable habitat either would accelerate the 

development of multi-structured stands or, at a minimum, would not slow the trajectory of the stand to 

contribute to the recovery of the spotted owl. Therefore, this activity may affect, but is not likely to 

adversely affect (directly or indirectly) spotted owl critical habitat since the physical and biological 

features of nesting, roosting and foraging would be maintained at a stand scale and the stand would 

continue to function as suitable habitat after treatment.

This activity may affect and is likely to adversely affect critical habitat when treatments 

meaningfully reduce and/or delay or preclude achievement of PBFs within treated stands.

Dispersal Habitat: Harvest in dispersal habitat would maintain a canopy cover of 40% or higher to 

allow spotted owl movement across the landscape (PBF 4) and would leave sufficient coarse woody 

debris and understory structure in the stand to support the prey base (PBF 3). Treatment in dispersal 

habitat either would accelerate the development of multi-structured stands or, at a minimum, would 

not slow the trajectory of the stand to contribute to the recovery of the spotted owl. Therefore, this 

activity may affect, but is not likely to adversely affect (directly or indirectly) critical habitat since 

the ability of this habitat to provide for spotted owl survival and recovery would not be reduced at the 

stand scale as habitat functionality would be maintained.

Project Effects – HH Maintain

There are three projects, one each on the Detroit, Sweet Home, and McKenzie River Ranger 

Districts, that would have HH Maintain activities, affecting a total of 532 acres of foraging (suitable)
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82

habitat and 2,951 acres of dispersal habitat (Appendix A, Table A- 4). All three projects would have 

some of these treatments in Critical Habitat affecting a total of 525 acres of foraging (suitable) habitat 

and 2,186 acres of dispersal habitat.

Detroit Ranger District

Highway 46 This timber harvest and restoration project would have HH Maintain on 530 and 2 acres

of foraging (suitable) owl habitat in matrix and LSR, respectively. The project would have HH 

Maintain on 1,859 and 670 acres of dispersal habitat in matrix and LSR, respectively. The total acres 

of HH Maintain treatment for the project would be 3,064 acres.

All of the HH Maintain treatments are variable density thinnings with 0.25 to 0.5 acre gaps, dominant 

tree release, and under burning to increase stand health and vigor. The HH Maintain treatments are 

in overstocked stands where trees are competing for sunlight, water, and nutrients causing reduced

tree growth and vigor. Stands treated include both previously logged and fire regenerated stands that 

lack stand structure. Treatments in foraging habitat are mostly fire regenerated stands that are about 

90 years old and lack stand structure. Treatments in LSR would be in stands less than 80 years old. 

Total acres proposed for treatment are approximately 3,117 acres. Thinning unit acres include 

approximately 30% skips which are not treated.

Spotted owl habitat would be maintained with these treatments. Treatments of foraging habitat would 

maintain at least 60% canopy cover, while treatments in dispersal habitat would maintain at least 40% 

canopy cover. This treatment is expected to increase spotted owl habitat quality over time by 

improving stand structure and diversity in the areas treated. Currently these stands lack multi-canopy 

characteristics. With thinning the recruitment of an understory is expected to be initiated and overall 

tree size diameters would increase compared to no-treatment. 

Five hundred and twenty five acres of proposed HH Maintain in foraging habitat in matrix allocation is 

in Critical Habitat Subunit WCS3. Five hundred and twenty four and 1,530 acres of proposed HH 

Maintain in dispersal habitat in LSR and matrix allocation, respectively, is in Critical Habitat Subunit 

WCS3. HH Maintain in suitable habitat would maintain the canopy cover of stands used for foraging 

(PBF 3) at 60% or higher and would leave sufficient coarse woody debris, understory structure and 

snags to support nesting and prey (PBF 3). Harvest in dispersal habitat would maintain a canopy 

cover of 40% or higher to allow spotted owl movement across the landscape (PBF 4) and would leave 

sufficient coarse woody debris and understory structure in the stand to support the prey base (PBF 

3). Treatments in both suitable and dispersal habitat would accelerate the development of multistructured stands, tree diameters and overstory crown development. This would improve PBFs 2, 3, 

and 4 in the long-term in the stands compared to no treatment.

Two acres and 524 acres of proposed HH Maintain in foraging and dispersal habitat, respectively, are

in LSR. None of the treated stands in LSR are older than 80 years of age and all commercial thinning 

treatments in LSR are consistent with the Mid-Willamette LSR Assessment (USDA & USDI. 1998a

entire) and all standards and guidelines of the Northwest Forest Plan. The HH Maintain treatments in 

LSR are in single-stored stands less than 80 years of age and are designed to accelerate the 

development of late-successional characteristics of the stands.

The effect determination of HH Maintain for Highway 46 would be NLAA for general habitat 

modification and to Critical Habitat.

Sweet Home Ranger District

Trout Creek This timber harvest and restoration project would have HH Maintain on 117 and 278

acres of dispersal habitat in matrix and AMA, respectively. The total acres of HH Maintain treatment 

for the project would be 395 acres.

All the HH Maintain proposed in dispersal habitat is in existing plantations and include some gaps not 

larger than 2 acres in size. Treatments would not remove any existing downed wood from the stands 

or commercially harvest any existing snags. Snags that are hazards to the logging operations may 

be fallen and left on site, but the intent is to maintain existing snags where feasible. The amount of 
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83

dead wood retained would meet Forest Plan standards and guidelines. Tree, shrub, and grass/forb 

forage planting or seeding are proposed is some gaps.

Acres shown are the treatment acres. Unthinned skips are designed in harvest units. In all layouts, 

unharvested areas are located for riparian buffers and to protect survey and manage species, special 

habitat areas, and other resource considerations. These may or may not be included in the units as 

unthinned skips, depending on whether the units are drawn to include or exclude these areas. Postharvest some snag and downed logs may be created in or near the units. Fuel created by thinning 

activities will be treated to reduce wild fire risk by grapple piling and broadcast burning in some units. 

Spotted owl dispersal habitat would be maintained with these treatments at least 40% canopy cover.

These units are expected to close their canopies back to pre-harvest conditions within 7-10 years. 

However, habitat suitability for flying squirrels, the main prey of spotted owls in the central Oregon 

Cascades, may take longer to recover. HH Maintain thinning of dispersal habitat would benefit overall 

forest structural development and improve long-term (>25 years) spotted owl habitat conditions

compared to no-treatment. 

Twenty seven and 78 acres of proposed HH Maintain in dispersal habitat in matrix and AMA 

allocations, respectively, would be in Critical Habitat Subunit WCS3 for a total of 105 acres. Harvest 

in dispersal habitat would maintain a canopy cover of 40% or higher to allow spotted owl movement 

across the landscape (PBF 4) and would leave sufficient coarse woody debris and understory 

structure in the stand to support the prey base (PBF 3). Treatments in dispersal habitat would 

accelerate the development of multi-structured stands, tree diameters and overstory crown 

development. This would improve PBFs 2, 3, and 4 in the long-term in the stands compared to no 

treatment at the stand level. There would be a much longer delay of PBFs 2, 3 and 4 in the gaps 

which could be up to two acres in size within the units. The small amount of gaps in the stands and 

the overall canopy maintained in the thinning treatments together with the large amount of skips

would not limit spotted owl movement at the stand or landscape scale. Also loss of PBFs 2 and 3 in 

the gaps would not delay the time needed before the stands would support foraging and 

nesting/roosting or limit the functionality of spotted owl territories in the future. 

None of the HH Maintain treatments are in LSR.

The effect determination of HH Maintain for Trout Creek would be NLAA for general habitat 

modification and to Critical Habitat.

McKenzie River Ranger District

Q Thin. This timber harvest project proposes 27 acres of HH Maintain in dispersal habitat in AMA. 

The 80-120 stand that is proposed for treatment is mostly foraging habitat and was described in the 

above HH Downgrade section. The 27 acres of the stand that is dispersal habitat is a portion that 

was thinned in 1989 as part of a previous timber sale (Three Bears) and currently has a more open 

canopy than the rest of the stand (i.e. less than 60% canopy cover). The McKenzie River Ranger 

District is proposing to rethin this part down to about 40% canopy cover maintaining it as dispersal 

habitat.

All of the HH Maintain is in Critical Habitat Subunit WCS3. Re-thinning the 27 acres will setback the 

development of foraging habitat (PBF 3) by about 15 years or more by reducing canopy cover. It also 

will likely damage any understory shrub and tree release that the original thin initiated thus setting 

back multi-layered stand-development that supports foraging habitat. The thinning will continue to 

foster diameter growth and crown development in the residual trees, attributes that would support 

nesting/roosting habitat (PBF2) in the long-term when a multi-layered forest developed. Snags and 

downed wood would be retained at levels that meet or exceed NWFP standards and guidelines, but 

the reharvest would reduce long-term deadwood sources. The rethinning is being proposed to 

provide timber harvest and not restore critical habitat. However, the temporary set-back of the 

development of suitable habitat on these 27 acres is not expected to affect the functionality of any 

spotted owl territory currently or in the future as described in the Effects to Known and Potential Owl 

Sites discussion.

This project would not affect LSRs.
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84

The effect determination of HH Maintain for Q Thin would be NLAA for general habitat 

modification and to Critical Habitat.

Harvest in Non-Habitat

General Effects

Generally, treatments in non-habitat have no effect on spotted owls, since the stands are not 

currently spotted owl habitat. However, thinning treatments designed to improve forest health in 

stands that are currently not spotted owl habitat may have indirect beneficial effects to the spotted owl 

because such treatments could accelerate the growth of forest conditions needed by the spotted owl. 

Such treatments may have a beneficial effect on spotted owl habitat in the long term.

General Effects to Critical Habitat – Harvest and Other Treatments in Non-Habitat

Generally, treatments in non-habitat have no immediate effect on spotted owl critical habitat, since 

the stands are not currently habitat. However, effects to critical habitat need to also address the 

effects to the recovery and longer-term conservation of spotted owls. Thinning treatments designed 

to improve forest health in stands that are currently not spotted owl habitat may have indirect 

beneficial effects to the spotted owl because such treatments could accelerate the growth of forest 

conditions needed by the spotted owl future dispersal (PBF4), foraging (PBF3) and nesting/roosting 

(PBF2). Such treatments may affect, but are not likely to adversely affect spotted owl critical 

habitat because of the long term beneficial effects to habitat. 

Regeneration harvest, prescribed burning, and other treatments in non-habitat that set-back the 

development of dispersal, foraging and nest/roosting habitat could have adverse effects to critical 

habitat if the actions would limit the future dispersal of owls on the landscape or reduce the future 

functionality of spotted owl territories. In these instances, the actions in non-habitat may affect and 

are likely to adversely affect critical habitat.

Project Effects – Harvest in Non-Habitat

There are two projects, one on the Detroit Ranger District and one on Sweet Home Ranger District, 

which would have Harvest in Non-Habitat activities, affecting a total of 288 acres (Appendix A, Table 

A- 9). A total of 136 acres of the treatments are in Critical Habitat Subunit WCS3. None of the 

treatments are in known or likely owl nest patches.

Detroit Ranger District

Highway 46 This timber harvest and restoration project would have 107 acres of Harvest in NonHabitat, all in matrix allocation. Two acres of the harvest would be for sugar pine restoration where 

the thinning would retain existing sugar pine in a plantation and is aimed at promoting their survival 

and growth on the site. Twenty four acres of treatment in non-habitat would be for visual maintenance 

in a young stand surrounding the lookout. Trees that are or may potentially block the visibility would 

be cut and left on site. Eighty one acres of commercial thinning is proposed in existing plantations 

that are currently non-habitat. These stands currently lack multi-canopy characteristics and the 

thinning is expected to improve spotted owl habitat long-term by promoting understory development 

and increasing tree diameter growth and canopy structure.

The two acres of proposed sugar pine restoration and 64 acres of the commercial thinnings are in 

Critical Habitat Subunit WCS3. The treatments would have no immediate effect to critical habitat 

because the affected stands are currently non-habitat. The commercial thinning is not expected to 

delay the development of spotted owl habitat and would promote stand characteristics that would 

improve dispersal (PBF4) and suitable (PBFs 2 and 3) habitat long-term. The sugar pine restoration 

treatment may initially reduce the canopy cover in the non-habitat more than a traditional thin, but, 

with only two acres treated, the development of dispersal habitat would not be appreciatively delayed. 

Longer-term, maintaining sugar pine on this site would likely benefit forest resilience, given the 

threats of climate warming and increased fire risk, and could benefit critical habitat long-term.
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85

The effect determination of Harvest in Non-Habitat for Highway 46 would be NE for general 

habitat modification and NLAA to Critical Habitat.

Sweet Home Ranger District

Trout Creek This timber harvest and restoration project would have 181 acres of Harvest in NonHabitat of which 8 acres would be in LSR and the remainder would be in AMA allocation. 

The eight acres of treatment in LSR is a commercial thin to about 50% designed to favor existing 

hardwoods in a plantation adjacent to a recreational trailhead. Six acres of the 14-acre stand would 

not be treated. The action would reduce fire risk at the trailhead and adjacent to a road. The thinning 

would likely improve forest structure for spotted owls in 7 to 15 years and develop dispersal habitat 

conditions faster than if the stand was left to develop naturally. The activity would be consistent with 

the Mid-Willamette LSR Assessment (USDA & USDI. 1998a entire) and all standards and guidelines 

of the NWFP.

The remaining 173 acres would be commercial thinnings in 12 stands that were clearcut during the 

period 1981-1985. The acres given are the treatment acres. Most units would have untreated skips 

that comprise about 10% to nearly 50% of the stand. Currently these stands are too dense for spotted 

owls to readily fly through. Three units totaling 60 acres would be thinned to about 30% canopy cover. 

The remaining units would be thinned to about 50% cover including one unit that would have gaps up 

to about three acres in size. Fuel treatment with pile and broadcast burning are proposed in some of 

the units. Thinning treatments are expected to improve forest structure and spotted owl habitat in 7 to 

15 years and are expected to develop into dispersal habitat faster than if left untreated due to the 

current dense stocking in the stand. 

The 8 acres of Harvest in Non-Habitat in LSR and 62 acres of commercial thinning to 50% canopy 

without gaps would be in Critical Habitat Subunit WCS3. These thinning treatments are expected to

accelerate the development of dispersal and suitable habitat in overstocked stands. 

The effect determination of Harvest in Non-Habitat for Trout Creek would be NE for general 

habitat modification and NLAA to Critical Habitat due to beneficial effects.

Fuels Treatment

This activity pertains to fuels treatments not associated with another activity. Fuels treatments 

associated with other activities include post-harvest burning, which are discussed under the HH 

Maintain or HH Remove activity. Fuel treatments may also occur under Prescribed Burning, Special 

Habitat Restoration, or Terrestrial Habitat Enhancement activities.

General Effects

Fuels treatment may remove, downgrade, or maintain suitable habitat and/or remove or maintain 

dispersal habitat. This activity would reduce fuel loading around values at risk and/or communities in 

order to establish a defensible perimeter for public health and safety in the event of wildfires. Amount 

and intensity of treatment depends on site-specific conditions.

Fuels Treatment may affect and is likely to adversely affect spotted owls (directly and indirectly)

when:

1. Suitable habitat is removed or downgraded to dispersal habitat,

2. Impacts of the activity contribute to the inability of a spotted owl pair to successfully 

reproduce due to the juxtaposition of the treated stand with its surrounding forest landscape 

(e.g., burning in a nest patch), or

3. This activity limits the ability of spotted owls to disperse across the landscape.

Where current spotted owl functionality is retained after treatment and no disruption occurs due to 

smoke or noise, this activity may affect, but is not likely to adversely affect spotted owls (directly 
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86

and indirectly) since the functionality of the current habitat would be maintained (i.e., suitable habitat 

would remain suitable and dispersal habitat would remain dispersal after treatment).

Fuels treatments in non-habitat would have no effect on spotted owls due to habitat modification, 

since the stands are not currently spotted owl habitat. 

General Effects to Critical Habitat – Fuels Treatment

Fuel treatments that maintains the PBF’s of spotted owl CH in suitable habitat are not likely to have a 

measurable effect on the ability of spotted owls to breed (PBF 2), forage (PBF 3), or shelter (PBF 2) 

since the stand will retain its ability to function for the breeding, foraging and roosting of resident 

spotted owls. These stands will retain a 60 percent or greater canopy cover in addition to some 

structural components (snags, clumps of large trees, down wood) to meet existing RMP or NWFP 

requirements, as applicable. Therefore the spotted owl CH will continue to function and support 

survival and recovery of spotted owls and this activity may affect, but is not likely to adversely 

affect critical habitat directly or indirectly. Exceptions to this are fuel treatments that maintain PBFs 2 

and 3 at the stand scale but occurs within a nest patch because even small reductions in canopy 

cover and other structural and vegetative components that support breeding, feeding, and sheltering 

in close proximity to the nest tree would reduce the function of PBF 2. Such treatments in the nest 

patch may affect and are likely to adversely affect critical habitat directly and/or indirectly. Also, 

fuel treatments in suitable habitat in a core area, where PBFs 2 and 3 are maintained but suitable 

habitat will constitute less than 50% of the core area after treatment, may adversely affect the spotted 

owl CH by impairing its’ ability to support potential spotted owl territories across the landscape. 

Forage habitat would be suboptimal in these cases and any impact, even minor to PBF 3, may 

contribute to the inability of the spotted owl CH to function to support survival and recovery of spotted 

owls.

Any fuel treatment that maintains dispersal habitat at the stand scale but occurs outside of a nest 

patch is not likely to adversely affect the spotted owl CH because the PBF’s will also be maintained, 

provided sufficient post-activity habitat would remain to support functions of PBF 3 and PBF 4 (as per 

General Standard 4). Also removal of dispersal habitat in spotted owl CH may be NLAA if the removal

doesn’t reduce the stands ability to function as dispersal (PBF 4) and does not appreciably delay the 

development of suitable habitat within CH.

Where suitable habitat is removed in critical habitat to provide a fuels break, this action may affect 

and is likely to adversely affect (directly or indirectly) critical habitat in the short term by removing 

suitable habitat. However, construction of a fuel break may benefit the overall stand in the long term 

by providing a defensible area for firefighters should a wildfire occur in the stand.

Fuel treatments in non-habitat in CH have no effect on CH when they do not change the 

development of future PBFs 2, 3, or 4 in the stand. If the fuel treatment appreciably delays 

development of structural and vegetative components that support dispersal (PBF 4), breeding

(PBF2), feeding (PBF 3) and/or sheltering (PBF 2), then the action may affect and is likely to 

adversely affect CH. If the fuel treatment accelerates the development of the PBFs or results in 

improved future quality to the PBFs, then the action may affect, but is not likely to adversely affect

critical habitat indirectly.

Project Effects – Fuels Treatment

There are two projects, one on the Detroit Ranger District and one on the McKenzie River Ranger 

District, which would have Fuels Treatment. These would affect a total of 1,312 acres of NRF habitat, 

63 acres of foraging habitat, and 28 acres of dispersal habitat (Appendix A, Table A- 5). Both projects 

would have treatments in critical habitat affecting a total of 915 acres of NRF habitat, 63 acres of 

foraging habitat, and 28 acres of dispersal habitat.

Detroit Ranger District

Highway 46 This project proposes Fuel Treatments in 107 acres of NRF habitat, 63 acres of foraging

habitat, and 28 acres of dispersal habitat in the area surrounding the Breitenbush Hot Springs Resort

and the Breitenbush and Devils Creek summer home tracts for a total of 198 acres of treatment. The 
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87

treatment in NRF habitat is in LSR while the other treatments are in matrix allocations. Much of the 

area that surrounds the structures within these communities is dense older forest with heavy fuel 

loadings and narrow road access that could inhibit fire suppression activities in the event of a wildlire. 

The purpose of these treatments is to reduce the intensity of any wildfires that may impact these 

communities in the future through the establishment of defensible space or increasing the distance 

between vegetation and structures. Adequate defensible space allows for firefighters to remain at or 

near structures during a wildfire to provide for protection of the structure while providing a safe 

environment in which firefighters can operate. Hazardous fuel treatments are also intended to reduce 

fuel loadings along the road systems in and around these communities. This will allow for the safe 

ingress and egress of firefighting resources and the public throughout these communities during a fire 

and increase the ability to effectively utilize road systems as fire control lines. Reducing hazardous 

fuels and improving defensible space around structures would increase both firefighter safety and the 

probability of success in protecting these communities.

Hazardous fuels treatments include non-commercial thinning and pruning of trees less than 7 inches 

in diameter and treating the resulting fuels through burning or chipping. Under burning, hand piling 

and burning are proposed on 169 acres of the Fuel Treatments. A prohibition on burning in treatment 

areas where burning could cause disruption to nesting spotted owls would be in effect from March 1 –

July 15. All work will be done with hand treatments only, no mechanical treatments will be used.

Burning would be minimized to the greatest extent possible.

Some areas of shrubs and trees would be retained in “skips” to provide vegetation buffers to minimize 

visual impacts. The 300 meter area around a new Activity Center point where a single spotted owl 

resident was documented in 2016 would not be treated. Existing snags and downed wood would be

maintained and the Fuel Treatment would meet all Forest Plan requirements for deadwood retention.

This treatment would result in loss of understory cover but would maintain spotted owl habitat by 

maintaining overstory cover, all trees greater than 7” dbh, and existing dead wood which would 

maintain a prey base for spotted owls. Also the treatments would be adjacent to roads and homes in 

an active summer residence which should make the habitat less desirable for spotted owls.

One hundred and seven acres of treatment in NRF habitat overlaps with LSR RO214. Fuel 

treatments in LSR are consistent with the Mid-Willamette LSR Assessment (USDA & USDI. 1998a, p. 

151-152)

Thirty five acres of the NRF habitat in the LSR was identified as RA32 stands by the project biologist. 

Some reduction in understory cover would occur as a result of the proposed treatments. Large snags 

and downed wood would be maintained and the stand should continue to provide habitat conditions 

that would provide for nesting, roosting, and dispersal (e.g., trees with nesting structure and all 

overstory canopy cover). Although there would likely be some reduction in spotted owl prey, such as 

snowshoe hares due to removal of the trees less than or equal to 7” dbh, maintaining the mid- and

overstory cover would maintain habitat for flying squirrel and red tree voles and provide for spotted 

owl foraging as well. In this instance, the District has prioritized the need to reduce fuel and provide 

for public safety as justification to accept some reduction in the quality of the RA32 stands in the 

residential interface. Also reducing the fuels and providing safer road access could help prevent a 

fire that was inadvertently started in the residential area from spreading into the surrounding spotted 

owl habitat.

Of the proposed Fuel Treatments, 35 acres of NRF habitat, 63 acres of foraging habitat, and 28 acres 

of dispersal habitat, for a total of 126 acres, are in Critical Habitat Subunit WCS3. The treatments in 

suitable habitat would maintain the PBF’s of spotted owl and would not likely to have a measurable 

effect on the ability of spotted owls to breed (PBF 2), forage (PBF 3), or shelter (PBF 2) since the 

stand would retain its ability to function for the breeding, foraging and roosting of resident spotted 

owls if they were present. These stands would retain a 60 percent or greater canopy cover in addition 

to some structural components (snags, clumps of large trees, down wood) to meet existing RMP or 

NWFP requirements. Therefore the spotted owl suitable CH will continue to function and support 

survival and recovery of spotted owls. 
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88

Fuel treatments in dispersal habitat in CH would maintain dispersal habitat at the stand scale by 

retaining sufficient post-treatment habitat to function as dispersal (PBF 4) and would not delay the 

development of suitable habitat. No barriers to dispersal would be created by the Fuel Treatments 

and other project activities in these areas.

The effect determination of Fuel Treatments for Highway 46 would be NLAA for general habitat 

modification and to Critical Habitat.

McKenzie River Ranger District

Three Sisters Risk Reduction Hazardous Fuels Treatment This project proposes Fuel Treatments 

on up to 1,205 acres of NRF habitat, of which 312 acres are in matrix allocation, 351 acres are in 

Administratively Withdrawn allocation, 162 acres are in AMA, and 380 acres are in LSR. Some of the 

proposed areas treated may be foraging, dispersal or non-habitat, but, because field verification has 

not been done, this assessment will use a worst-case analysis that all the habitat is NRF. Up to 

about 500 acres of the proposed treatment would be in RA 32 stands.

The Fuel Treatment project would treat about 52 miles of roadside stands by cutting, then chipping or 

pile burning understory trees greater or equal 10” dbh, as well as shrubs. On about 46 miles, 

treatments would occur within 150 feet of road systems surrounding the Three Sisters Wilderness 

Area. On about 6 miles, treatments would occur on both sides of the road, with a 300-foot total 

treatment width. Some of the larger material may be sold as poles or firewood. 

This treatment aims to provide pre-established strategic suppression/containment opportunities for 

wildfires burning within and adjacent to the Three Sisters Wilderness. It would reduce the abundance 

of ladder fuels within the road corridors and create a fuel profile more favorable to suppression 

efforts. Fire fighter and public risk would be reduced during wildfire suppression. It would also 

enhance visual aspects by reducing the density of the understory and increasing visual access to the 

unique qualities of the Road 19 corridor for travelers. 

The proposed project is needed to create pre-established strategic suppression/containment 

opportunities along Three Sisters Wilderness boundary and main access routes. If a wildfire became 

established beyond initial attack, the strategic suppression/containment areas would aid fire 

managers by giving more options to manage the fire with less risk to fire fighters and the public. Due 

to fire suppression over the past 100+ years, the forest has lost many of the mosaic characteristics 

from natural fire (variation of late/mid/early open and closed). With continuous ladder fuels (horizontal 

and vertical) throughout the project area, fire has the ability for high rates of spread, intensity and 

potential for spotting which creates greater risk for firefighters and the public. Fire may also spread 

into sensitive wildlife habitat areas such as active spotted owl 300 meter nest patches where the 

burning could adversely affect this species.

The treatment locations include:

a) Segment A: Rd. 1993 (from east side of Cougar Dam to jct. w/ Rd. 2638-356) on wilderness 

side of road; 150’ next to road.

b) Segment B: Rd. 1994 to jct. of Rd. 19 (from East Fork/Echo day use area, down to jct. of Rd. 

500 then along Rd. 500 to jct. with Rd. 19) on wilderness side; 150’ next to road.

c) Segment C: Rd. 19 to jct. of Rd. 1964 (from Cougar Crossing to Frissell Crossing) east side 

of road; 150’ next to road.

d) Segment D: Rd. 1964 (from jct. with Rd. 19 to end at the jct. of 485 and 455) north side of 

road; 150’ next to road.

e) Segment E: Rd. 19 from the jct. of Rd. 1964 to of Rd. 1958 (from Frissell Crossing to Box 

Canyon) east side of the road; 150’ next to road.

f) Segment F: Rd. 1958 to the end both sides of road; 150’ each side of road.

g) Segment H: Rd. 310 (from jct. w/ Rd. 1958 to end) east side of road; 150’ next to road.

Specific details include:

a) Treatments would occur within 150 feet of roads. Thinning would occur by hand with 

chainsaws. Chippers may be used to chip slash along roads where feasible and safe to do 

so. Equipment would remain in road prism.
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b) Sapling and pole sized conifers 7 - 10 inches dbh would be thinned and coordinated with 

Timber for feasibility for use of larger material. No trees greater than 10 inches dbh would be 

cut unless deemed a hazardous snag. In this case, the snag may be cut with the bole of the 

snag left on site as down woody material for wildlife habitat.

c) All deciduous trees and brush < 3 inches would be cut unless noted below. All diseased 

deciduous trees < 10 inches would be cut.

d) No living sugar pine, white pine, or madrone would be cut. No red cedar > 3 inches (stump 

height) would be cut.

e) Stump height will be as low to the ground as possible, but no greater than 6 inches or 4 

inches above natural obstacles (rocks, logs, etc.)

f) Approximately two slash piles/acre would be created and left for wildlife habitat. Coordination 

with wildlife for the number of piles remaining in each phase would occur throughout the 

project.

g) Maintain 80-foot no-treatment buffer along all Class 1 & 2 streams and a 30-foot no-treatment 

buffer along Class 3 & 4 streams and wetlands.

h) No treatment will occur within 300 meters spotted owl nest sites or within 100-acre LSRs.

i) Slash treatments will consist of chipping or hand piling and pile burning. Pile burning would 

occur in the fall, winter, or early spring (October – April). No spring burning would occur within 

the disruption distance for smoke during the critical breeding period.

j) Areas along roadsides with steep high cut banks or extremely steep fill slopes may be 

skipped.

k) Seasonal operating restrictions on cutting and mechanical equipment will be applied where 

needed to reduce disturbance to northern spotted owls and other sensitive wildlife species. 

These would be applied near nest patches to reduce any potential for disruption to spotted 

owls. 

l) No treatments would occur in nesting habitat more than 0.7 miles from known activity centers 

or outside the area surveyed as part of the HJA Demographic Study Area, unless two years 

of surveys were conducted prior to implementation. No treatments would occur within a 300-

meter buffer of any new activity centers that might be found during these surveys.

The effects of the Fuel Treatments on owl habitat would be similar to what was described above for 

Highway 46 except that trees and shrubs up to 10” in diameter would be removed and the treatments 

would occur within 150’ of open roads. Like Highway 46, the Fuel Treatment would maintain the

existing habitat at the stand level while degrading the understory quality and foraging conditions. 

Given the level of treatment and the existing high quality of much of the habitat that would be treated, 

the project biologist determined that the overall cumulative effect of the project was likely to adversely 

affect spotted owls. The effects of this project could last for 20-30 years until the understory 

vegetation including conifers up to 10” dbh reestablish. The understory vegetation removal treatments

may increase the distance that the roadside edge intrudes into suitable and dispersal spotted owl 

habitat and thus would further reduce habitat quality somewhat. The roadside fire break may improve 

the ability to reduce wildfire spread and fire risks to spotted owl nest patches, nest cores, critical 

habitat and LSRs.

Nest patches would be protected from treatments. Of eight known spotted owl core areas that overlap 

on the treatments, less than 10 acres (<2%) of any core area would be have Fuel Treatments so the 

functionality of owl home ranges would be maintained.

Three hundred and eighty acres of treatment in NRF habitat overlaps with the Horse Creek LSR 

RO218. The proposed fire Fuel Treatment is expected to have a very minor effect to the Horse Creek 

LSR characteristics along Forest road edges. While there would be a loss of understory stand 

structure next to the roads, overall late successional forest habitat would be maintained in the 

affected stands. The project biologist reported that this activity would be consistent with the goals of 

the Horse Creek LSR because it would help protect the forest stands from stand-replacing wildfire by 

increasing the road fire break effectiveness. Fuel treatments in LSR are consistent with the MidWillamette LSR Assessment (USDA & USDI. 1998a, p. 151-152).

Up to 500 acres of the treatment would occur in RA32 habitat. Reduction in understory cover would

occur as a result of the proposed treatments adjacent to roadways. Large snags and downed wood 
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90

would be maintained and the stand should continue to provide habitat conditions that would provide 

for nesting, roosting, and dispersal (e.g., trees with nesting structure and all overstory canopy cover). 

Although there would likely be some reduction in spotted owl prey, such as snowshoe hares, due to 

removal of the trees and shrubs less than or equal to 10” dbh, maintaining the mid- and overstory 

cover would maintain habitat for flying squirrel and red tree voles and provide for spotted owl foraging 

as well. In this instance, the District has prioritized the need to reduce fuel and increase fire fighters 

ability to safely hold a fire along the roadways as justification to accept some reduction in the quality 

of the RA32 stands. Also improved firefighting ability adjacent to the roads could help prevent further 

spread of fire into RA32 habitat and other spotted owl habitat on the opposite side of the road from 

the wilderness.

Of the proposed Fuel Treatments, 880 acres of NRF habitat are in Critical Habitat Subunit WCS4. 

The roadside fuels reduction treatment would have limited effects to structural stand characteristics 

because the understory treatment area would be limited to 150 feet from roads in all but six miles, 

where treatments would occur on both sides of the road. Snags are expected to remain limited within 

treatment area because many have been and are expected to continue to be removed if they become 

roadside hazards. Some snags and trees will fall into the 150-foot treatment zone from the stand 

interior and provide large down wood habitat. The treatments in suitable habitat would maintain 

nesting and roosting trees and overstory canopy (PBF 2) and the ability of spotted owls to disperse at 

the stand and landscape level (PBF 4). Removal of understory trees and shrubs up to 10” dbh would 

degrade foraging habitat by negatively affecting understory cover that support owl prey (PBF 3). 

Some reduction of understory cover from the Fuel Treatments could persist for up to 30 years before 

the original understory condition was restored. Retention of overstory and most mid-story cover would 

be maintained and areas more than 150 feet from the road would not be directly affected, so the 

stands would continue provide for foraging (PBF 3). Functionality of the existing critical habitat at the 

stand level would be maintained by continuing to function and support survival and recovery of 

spotted owls. Benefits to owl habitat could occur from greater ability to safely control fire spread. 

Although habitat functionality would be maintained, because the project would measurably degrade 

the understory foraging component of the suitable habitat at a cumulative level over substantial acres, 

the effect determination of Fuel Treatments for Three Sisters Risk Reduction Hazardous Fuels 

Treatment would be LAA for general habitat modification and to Critical Habitat.

Down salvage

No down salvage projects are proposed in this consultation.

Individual tree removal

No individual tree removal projects are proposed in this consultation.

Terrestrial Habitat Enhancement

General Effects

Terrestrial habitat enhancement is expected to maintain suitable and/or dispersal habitat. This 

treatment modifies forested habitat by changing the canopy cover or by altering snag or coarse 

woody debris composition of the stand to enhance watershed health, wildlife, or botanical resources. 

Although individual trees or small groups of trees may be treated within spotted owl suitable habitat or 

dispersal habitat, no suitable nest trees would be selected and all treated trees would remain on site. 

In addition, all treatment units would maintain an average canopy cover of at least 60 percent in 

suitable habitat or 40 percent average canopy cover in dispersal habitat, and would not occur within 

the disruption distance of known spotted owl sites or potential nest patches. 

Because no suitable nest trees would be treated, and minimal impact to the suitability of the area for 

spotted owl use is anticipated, terrestrial habitat enhancement activities may affect, but are not 

likely to adversely affect spotted owls. The creation of snags in areas where snags are insufficient 

would have indirect beneficial effects because such treatments would accelerate the growth of forest 

conditions needed by the spotted owl.
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General Effects to Critical Habitat – Terrestrial Habitat Enhancement

Terrestrial habitat enhancement treatments in critical habitat may alter the PBFs of critical habitat, 

which may result in insignificant short-term impacts, but some treatments may facilitate the 

development of late-successional habitat characteristics and promote recovery over the long-term 

within designated critical habitat. Therefore this action may affect but is not likely to affect critical

habitat.

Project Effects – Terrestrial Habitat Enhancement

There are two projects that propose Terrestrial Habitat Enhancement activities affecting a total of 337

acres of suitable (foraging) habitat, 108 acres of dispersal habitat and 17 acres of non-habitat 

(Appendix A, Table A- 8) for a total of 462 acres. This activity would affect 280 acres of suitable 

(foraging) habitat and 80 acres of dispersal habitat that is in CH for a total of 360 CH acres affected.

Detroit Ranger District

Highway 46 This project proposes Terrestrial Habitat Enhancement that would affect 34 acres of 

foraging habitat, 108 acres of dispersal habitat, and 17 acres of non-habitat for a total of 159 acres in 

matrix allocation.

Four acres of Terrestrial Habitat Enhancement would cut or push over trees and move them to 

streams for fish logs in foraging habitat. No commercial harvest would occur. At least 60% canopy 

cover would be maintained in the stand and, although some forest structure would be lost, the stand 

would still be maintained as foraging habitat.

The remaining 155 acres of terrestrial enhancement would enhance huckleberry production for Tribal 

and other personal use by non-commercially thinning trees less than 7 inches dbh on five units where 

huckleberries are currently established. The huckleberries are being shaded out by small diameter 

conifers and the understory diversity is declining. On 25 acres underburning or piling and burning is 

proposed to stimulate huckleberry growth. A seasonal restriction on burning in units where burning 

could cause disruption to nesting spotted owls would be implemented from March 1 – July 15. 

Because this action is only affecting trees less than 7” dbh, it would maintain the existing spotted owl 

habitat.

The four acres of fish log enhancement in foraging habitat and 30 and 80 acres of huckleberry 

enhancement in foraging and dispersal habitat, respectively, are in Critical Habitat Subunit WCS4. All 

treatments in CH would maintain the functionality of the existing spotted owl habitat by maintaining 

forest structure needs to support foraging (PBF 3) and/or dispersal (PBF 4). The treatments are not 

expected to delay the development of the stands into future NRF habitat.

The effect determination of Terrestrial Habitat Enhancement for Highway 46 would be NLAA 

for general habitat modification and to Critical Habitat.

Sweet Home Ranger District

Trout Creek This project proposes to underplant 303 acres in 5 fire-generated stands between 116 

and 140 years of age with western red cedar and incense cedar to promote a multi-layered stand and 

increase tree species diversity. No other treatments, such as commercial timber harvest, would occur 

in these stands which are currently classified as foraging habitat. All areas are in AMA allocation and 

246 acres are in Critical Habitat Subunit WCS 3. The hand planting would have no effect to spotted 

owls from disturbance. If successful, this would be an entirely beneficial effect by accelerating the 

development of multilayered forest structure which would improve foraging habitat and cover for 

nesting/roosting habitat, thus promoting PBFs 2 and 3 in the long-term. 

The effect determination of Terrestrial Habitat Enhancement for Trout Creek would be NLAA 

for general habitat modification and to Critical Habitat.
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Special Habitat Restoration

General Effects

Special habitat restoration would restore the size and/or vegetative composition of meadow/shrub, 

meadow/shrub/savanna, oak, or prairie habitats which have been encroached by conifers or some 

hardwood species through burning or other means. Trees encroaching on these habitats would be 

removed or heavily thinned. Scattered conifer and/or hardwood trees may be retained. Some burning 

may occur in spotted owl habitat along the edges of the restoration areas to minimize grounddisturbing impacts.

Small impacts, generally less than one acre, from special habitat restoration may affect, but is not 

likely to adversely affect spotted owl habitat since the functionality of suitable or dispersal habitat at 

the stand level to provide nesting, roosting, foraging, or dispersal for spotted owls would be 

maintained. However, openings larger than one acre in size where suitable habitat is removed may 

affect and is likely to adversely affect spotted owl habitat as it would affect the habitat functionality 

of the stand.

In some instances, special habitat restoration may affect, and is likely to adversely affect spotted 

owls directly and indirectly if:

1. Suitable habitat is downgraded to dispersal habitat,

2. Impacts of the activity may contribute to the inability of a spotted owl pair to successfully 

reproduce due to the juxtaposition of the treated stand with its surrounding forest landscape 

(e.g., burning in a nest patch), and/or

3. If this activity limits the ability of spotted owls to disperse across the landscape.

General Effect on Critical Habitat – Special Habitat Restoration

Small impacts, generally less than one acre, from special habitat restoration may affect, but are not 

likely to adversely affect spotted owl critical habitat directly or indirectly since the functionality of 

suitable or dispersal habitat at the stand level to provide nesting, roosting, foraging, or dispersal for 

spotted owls would be maintained. However, openings larger than one acre in size where suitable 

habitat is removed may affect and is likely to adversely affect spotted owl critical habitat as it 

would affect the habitat functionality of the stand. Where dispersal habitat is removed, effects may 

affect and are likely to adversely affect if they meet conditions 2 or 3 above or if they delay the 

development of future suitable habitat and contribute to the loss of functional owl home ranges in the 

future.

Project Effects – Special Habitat Restoration

There are three projects that propose Special Habitat Restoration activities affecting a total of 18 

acres of NRF habitat, 11 acres of foraging habitat, 3 acres of dispersal habitat and 200 acres of nonhabitat (Appendix A, Table A- 7) for a total of 232 acres. This activity would affect 11 acres of NRF 

habitat, 11 acres of foraging habitat, and 103 acres of non-habitat that is in CH for a total of 125 CH 

acres affected.

Detroit Ranger District

Highway 46 This project proposes 11 acres of Special Habitat Restoration to restore meadow habitat 

in two locations in matrix allocation. One 8-acre meadow that is now considered foraging habitat has 

been encroached on by lack of ridgeline fire. Soil type, old aerial photos and plant species were used 

to determine the original meadow location. Trees in the original meadow area would be cut, larger 

trunks removed and slash burned after treatment. A second 3-acre meadow that is considered 

dispersal habitat is a narrow linear feature with dry meadow plant species that is being encroached by 

conifers. Trees would be felled, trunks harvested and the slash burned. The meadows would be 
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restored to provide forb/grass habitat for a variety of species including grouse, deer, elk and various 

butterflies and bees that have been observed using these areas.

The classification of the meadow areas as dispersal and foraging habitat is due to both their 

juxtaposition to surrounding forest habitat and the size and abundance of conifers that have 

encroached into these areas. The restoration treatments are considered habitat removal. It is 

estimated that, without further treatments, it would take about 40 years to restore dispersal habitat on 

these sites and 80 years or more to restore foraging habitat. No barriers to spotted owl movement 

would be created and the loss of habitat would not affect the functionality of any spotted owl home 

ranges.

The 8 acres of foraging habitat that would be removed is in Critical Habitat Subunit WCS 3. Because 

of long-term fire suppression, grass meadows are relatively scarce on the Detroit Ranger District and 

provide unique habitat for a wide-range of species. Meadow restoration is an important long-term 

restoration goal for the District that the Highway 46 project addressed. In this instance, the District 

has prioritized the need to restore this former meadow over allowing 8 acres of CH that is currently 

foraging habitat to continue to develop. The location and size of the treatment and the amount of 

suitable owl habitat in the project area is such that the action would not affect the functionality of owl 

territories. See Section G. Special Management Considerations for Critical Habitat for more 

discussion of this issue.

The effect determination of Special Habitat Restoration for Highway 46 would be LAA for 

general habitat modification and to Critical Habitat.

Sweet Home Ranger District

Trout Creek This project proposes 3 acres of Special Habitat Restoration to enhance Oregon white 

oak at two sites in AMA allocation. At one site comprising one acre, conifer trees around existing oaks 

in a riparian reserve would be fallen and left on site to release the oaks. At a second site comprised 

of two acres, conifers would be fallen and left to release oak and madrone. Both sites are in 135 

year-old stands that are currently foraging habitat. 

The falling of the conifer trees is considered habitat removal because the canopy will be initially 

reduced below 40%. However, because deciduous trees would be released, the fallen trees would 

remain as coarse woody debris, and the small size of the treatment units, the area is expected to 

recover into foraging habitat in 20 years or less without further treatments. 

Both proposed treatment areas are in Critical Habitat Subunit WCS 3. The treatments would 

temporarily reduce canopy and forest structure that support dispersal (PBF4) and foraging (PBF3) 

and may have long term reduction on forest structure that provides nest trees (PBF 2) by falling the 

larger conifers. The trees fallen and left should benefit foraging in the long-term however when 

canopy cover is restored. 

Oak and madrone forests are rather uncommon features on the Sweet Home Ranger District and 

valuable for a wide variety of species including fungi and lichens. Because of the scarcity of oak and 

madrone stands, they are a priority for restoration and maintenance on the District where they are 

found. The District views this proposed action as an ecological restoration opportunity for the Trout 

Creek project. Impacts to CH are minimized by the small size of the treatments and by leaving the 

fallen conifers as a source of deadwood. Due to the location and small size of the treatment areas, 

the action should not affect the functionality of any owl territories. See Section G. Special 

Management Considerations for Critical Habitat for more discussion of this issue.

The effect determination of Special Habitat Restoration for Trout Creek would be LAA for 

general habitat modification and to Critical Habitat.

Middle Fork Ranger District

Bear Mountain Meadow Restoration This project proposes Special Habitat Restoration on 186 

acres of non-habitat in matrix allocation, 14 acres of non-habitat in administratively withdrawn 

allocation, 14 acres in NRF habitat in matrix allocation and 4 acres in NFR habitat in a 100-acre LSR 
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for a total treatment area of 218 acres. Treatments may include whipfelling, prescribed burning, and 

invasive plant control. Trees 11” dbh or less would be cut and piled, and piles may either be burned 

or left on site as wildlife habitat. Two treatment units totaling 59 acres would be limited to cut and pile, 

and invasive plant control treatments because a portion of the units overlap a nest patch. Up to 18 

acres of meadow habitat would be treated within the nest patch. Prescribed burning may occur on the 

remaining 141 acres of meadow habitat with fire allowed to back into adjoining suitable (NRF) habitat 

up to 100 feet. 

Up to 18 acres of NRF habitat could be affected by a low intensity burn that would reduce the 

understory story cover but maintain the habitat as NRF. None of this habitat is RA 32 stands.

Seasonal restrictions from March 1 – July 15 would be placed on all project activities. Protocol 

surveys are planned in the project area for 2017 and 2018 as part of a larger landscape scale project. 

Seasonal restrictions could be waived if protocol surveys are completed and no disruption would 

occur.

The purpose of the treatments is to maintain the grass-forb meadow habitat to benefit deer, elk, 

pollinating insects and a variety of species that select meadow habitat. Historically the meadow 

areas are thought to have been maintained by fire, wetter ground and the high elevation of the site 

that lead to slower tree growth. Many of the meadow areas had scattered groups of trees that were 

logged previously as part of larger clearcut units. The proposed burning would setback tree 

encroachment that had occurred since then. Other parts of the proposed treatment units have never 

been logged.

The proposed treatment in non-habitat should have no effect on spotted owls. It should also not 

affect the nest patch since the only treatment would be to cut and pile conifer saplings in non-habitat 

meadows and treat weeds within the 300-meter buffer surrounding the Activity Center. Treatments 

would not occur during the critical breeding period unless nesting owls were not present based on 

surveys. Underburning in the adjacent forest in Unit 1 outside the nest patch would maintain the 

suitable habitat and reduce future fire risk to owl habitat. 

The proposed Special Habitat Restoration would occur on 89 acres of non-habitat in matrix allocation, 

14 acres of non-habitat in administratively withdrawn allocation, 7 acres in NRF habitat in matrix 

allocation and 4 acres in NFR habitat in a 100-acre LSR that is in Critical Habitat Subunit WCS 4 for a 

total treatment of 114 acres in the critical habitat subunit. The 103 acres of treatment in non-habitat 

are in grass-forb dominated areas that are not considered critical habitat however (USFWS 2011, pp. 

71918). The only affect to critical habitat would be underburning up to 11 acres of NRF habitat within 

100 feet of the meadow areas. As discussed above this activity is expected to maintain forest 

structure providing PBFs that will support nesting/roosting (PBF 2), foraging (PBF 3), and dispersal 

(PBF 4) post treatment and potential longer-term beneficial effects by reducing future fire risks to the 

stand. See Section G. Special Management Considerations for Critical Habitat for more discussion of 

this issue.

Four acres of Special Habitat Restoration, consisting of allowing the prescribed burn to back up to 

100-feet into forest habitat surrounding the meadows, would occur within a 100-acre LSR. This 

proposed project would maintain the current conditions of the stands and is consistent with the South 

Cascades LSR Assessment that allows for prescribed burning in LSRs to reduce fire risks (USDA & 

USDI. 1998b, pp.162-164).

The effect determination of Special Habitat Restoration for Bear Mountain Meadow 

Restoration would be NLAA for general habitat modification and to Critical Habitat.

Road Construction

General Effects

Road construction is generally expected to maintain suitable and/or dispersal habitat at the stand 

level. Some limited suitable and/or dispersal may be removed and/or suitable habitat may be 

downgraded
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Suitable habitat: Small impacts, generally less than one acre, from road construction may affect, but 

is not likely to adversely affect spotted owls since the functionality of suitable habitat at the stand level 

to provide nesting, roosting and forage for spotted owls would be maintained. However, openings

larger than one acre in size where suitable habitat is removed may affect and is likely to adversely 

affect spotted owls directly and indirectly because it would remove suitable habitat.

Dispersal habitat: Road construction that removes dispersal habitat, where (in the opinion of the 

unit biologist) dispersal habitat would not be limiting in the area after treatment may affect, but is not 

likely to adversely affect spotted owls due to habitat modification. 

In some instances, road construction may affect, and is likely to adversely affect spotted owls directly 

and indirectly if:

1. A non-discountable amount of suitable habitat is removed,

2. Suitable habitat is downgraded to dispersal habitat,

3. Impacts of the activity may contribute to the inability of a spotted owl pair to successfully 

reproduce due to the juxtaposition of the treated stand with its surrounding forest landscape 

(e.g., burning in a nest patch), and/or

4. If this activity limits the ability of spotted owls to disperse across the landscape.

General Effect on Critical Habitat – Road Construction

Small impacts, generally less than one acre, from road construction may affect, but are not likely to 

adversely affect spotted owl critical habitat since the PBFs that provide nesting, roosting, foraging, 

or dispersal for spotted owls at the stand level would be maintained. 

Removal of suitable habitat greater than one acre for road construction in some cases may affect 

and is likely to adversely affect spotted owl critical habitat by permanently removing PBFs within 

the road prism and constructing a road. Despite permanent habitat removal, in most instances this 

action would not alter the habitat function of the surrounding stand.

Project Effects – Road Construction

There are two proposed Road Construction projects in this consultation which would remove 6 acres 

of NRF habitat, 2 acres of foraging habitat and 2 acres of dispersal habitat, all in matrix allocations

(Appendix A, Table A-6). Two acres of removal of foraging habitat would occur in critical habitat.

Detroit Ranger District

Highway 46 This project proposes Road Construction that will remove 2 acres of foraging habitat in 

matrix allocation that is within Critical Habitat Subunit WCS 3. The action is being proposed to 

restore hydrologic processes in the Short Lake area because the current road has disrupted the 

natural flow of water.

This proposal would close and decommission a road accessing Short Lake and the area beyond the 

lake. The road would be re-routed and a connector road would be built to connect the road system in 

a different location. Approximately one mile of road would be removed and 0.2 miles of road built to 

change the road alignment. Road building in the new route location would permanently remove an 

estimated 2 acres of low quality foraging habitat in a previously thinned stand. Approximately 10 

acres of the current road would be converted to bare soil conditions which will return to dispersal 

habitat in approximately 40 years and foraging habitat in about 80 years. The action would not affect 

the functionality of any spotted owl territories.

The action would remove the forest conditions that support foraging and dispersal (PBFs 3 and 4) 

and prevent the development of PBF 2 on two acres of CH. In the very long-term 10 acres of forest 

capable of providing PBFs 2, 3, and 4 would be restored. The District proposes this action in CH for 

overall ecological restoration in order to restore natural hydrologic processes that the current road 

has disrupted and views the loss of two acres of CH as an acceptable tradeoff for the ecological 
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96

benefits of the action. See Section G. Special Management Considerations for Critical Habitat for 

more discussion of this issue.

The effect determination of Road Construction for Highway 46 would be LAA for general 

habitat modification and to Critical Habitat.

Middle Fork Ranger District

Road 24 Reroute This project proposes Road Construction that will remove 6 acres of NRF habitat 

and 2 acres of dispersal habitat in matrix allocation. None of the activity would be in Critical Habitat 

or RA 32 stands. 

The District is proposing to relocate 0.6 miles of the paved Road 24 away from Salmon Creek to 

address erosion issues. The portion of old road being bypassed would be decommissioned and the 

site restored. Salmon Creek has been moving to the north for decades and is progressively eroding 

the bank alongside a portion of Road 24. Currently, the creek is within 20 feet of the road in some 

places. Road 24 is a main access route for the District and relocation would be a long term fix to 

provide continued road access for resource management and public access.

This project would construct approximately 0.7 miles of new road through suitable and dispersal 

habitat within the matrix land allocation. The proposed reroute has been flagged on the ground by 

engineering staff and could permanently remove a maximum of 8 acres of spotted owl habitat (6 

suitable, 2 dispersal), but pending final design would likely result in less habitat removed. 

Approximately 4 acres of the road construction (2 acres of suitable and 2 acres of dispersal) would 

occur within two thinning units that were slated for treatment as part of the Oakridge-Westfir Thinning 

and Fuel Reduction (OWTFR) project which was consulted on previously. Treatments have not yet 

occurred and were expected to result in maintenance of dispersal habitat and downgrading of suitable 

to dispersal.

The project occurs outside of known owl home ranges and designated critical habitat. Protocol 

surveys were conducted in suitable habitat within 1.2 miles of the project area in 2016 and no spotted 

owls were detected (barred owls were present). The second year of protocol surveys will be 

completed in 2017. If a new spotted owl nest patch is discovered during 2017 surveys, seasonal 

restrictions may be implemented to avoid disruption and/or consultation may be reinitiated if located 

in the project area. Spot checks would be completed in 2018-2019 as needed if implementation is 

delayed.

Overtime, the road that was decommissioned would return to forested owl habitat except for those

sections that become part of Salmon Creek. The action would have long-term benefits to listed fish 

species that use Salmon Creek by moving the road away from the stream. 

The effect determination of Road Construction for Road 24 Reroute would be LAA for general 

habitat modification and NE to Critical Habitat.

Disruption-Only Activities

General Effects

Disruption-only activities are those which do not modify habitat but which occur during the disruption 

period (temporal and spatial). Disturbance-only activities which may affect but are not likely to 

adversely affect spotted owls are consulted on separately under the Disturbance-Only BA and its 

accompanying LOC. This document includes only those disturbance-only activities which are not able 

to be conducted outside the disruption period (temporal and/or spatial) and therefore may affect and 

are likely to adversely affect spotted owls by disruption of breeding activities. 

General Effects to Critical Habitat and Late Successional Reserves – Disruption-only

Since no habitat would be modified, disruption-only activities have no effect on critical habitat or the 

function of late successional reserves.
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Project Effects – Disruption-Only Activities

No disruption-only activities are proposed in this consultation. 

The following treatments were considered as part of the above actions and are not standalone actions.

Post Harvest Burning: Treatment of harvest generated fuels can include grapple piling, hand piling 

and under burning. The loss of large woody debris would be minimized by prescribing broadcast and 

underburning during the spring or under “spring-like” conditions. Conditions are generally considered 

“spring-like” when the 1,000 hour fuels (> 3 inches in diameter) have fuel moistures of 25% or greater 

(VanDyne, pers. comm. 2011). Soil and duff moistures are damp, limiting duff consumption. Mortality 

of overstory trees would be low.

Prescribed burning prescriptions would ensure that coarse woody debris would be maintained after 

treatment in accordance with the NWFP and Forest or Land Use Plans. Therefore, the prey base 

dependent on large woody debris would not be significantly impacted. It is unlikely that nesting 

structure would be lost from prescribed burns conducted under “spring-like” conditions since moisture 

content of woody material is high and only the smaller diameter fuels burn readily. In addition, ground 

cover would come back within a season favoring native species.

Pile burning is most often conducted during the rainy season and piles are not located under nest 

trees. Standards for coarse woody debris would be maintained. Therefore, the addition of postharvest burning to the activities listed above would have discountable additional habitat modification 

beyond what is described under the appropriate activity above. Therefore, post-harvest burning would 

have no significant additional effect on the habitat of spotted owls.

Firewood cutting may occur at the landings of units or along roads, but no additional habitat within 

the treatment unit would be modified, other than that described under the appropriate activity above. 

Therefore, firewood cutting would have no significant additional effect on the habitat of spotted 

owls.

C. Direct and Indirect Effects of Disturbance to Spotted Owls

Disturbance from proposed actions conducted outside of the breeding period (between October 1 and 

February 28), or more than the disturbance distances from a spotted owl activity center or 

unsurveyed suitable habitat during any time of the year, or in surveyed unoccupied habitat during any 

time of the year, would have no effect on spotted owls.

About 6,092 acres of activities were evaluated as occurring within the disturbance distance of spotted

owls. (Appendix A, Table A-15). After this evaluation, no activities would occur within the disruption 

distance of spotted owls. All of the activities would be NLAA-outside disruption distance/time or 

no effect.

D. Effects to Areas of Concern

There are no Areas of Concern in the Action Area.

E. Recovery Action 32

Table A-17 in Appendix A identifies the projects in suitable habitat which meets the definition of 

Recovery Action (RA) 32 (USFWS 2011 pp. III-67). Two projects are proposed that have Fuel 

Treatment Activities in RA 32 habitat. Details follow below:
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Highway 46. The Detroit Ranger District is proposing to treat 35 acres of RA 32 habitat in LSR 

RO214 adjacent to residential areas and summer homes to reduce fuel risks. Treatments would be 

done by hand and consist of thinning and pruning trees less than 7” dbh and potentially burning or 

chipping some of the resulting fuels. The action would degrade the quality of the understory for 

spotted owl prey species somewhat but still maintain the habitat as nesting, roosting and foraging, 

post-treatment. The rationale for this project is to reduce fire risks in a residential interface area and

provide for greater safety of residents and fire fighters if a fire occurs in that area.

Three Sisters Risk Reduction Hazardous Fuels Treatment: The McKenzie River Ranger District is 

proposing fuels reduction treatment along about 52 miles of roads adjacent to the Three Sisters 

Wilderness Area. Treatments would cut and thin conifers and deciduous trees and shrubs leas than 

or equal to 10 inches dbh. Chipping, piling, and/or burning of slash would also occur. The treatment 

would cover about 1,205 acres. Up to 500 acres of the proposed units may contain RA 32 habitat, 

however a field determination has not yet been conducted and this may be a high estimate. The 

proposed activity would degrade the quality of the understory for spotted owl prey species along the 

portion of the stands within 150 feet of the roads but still maintain the overall habitat of the stand as 

nesting, roosting and foraging, post-treatment. It would not affect the functionality of any spotted owl 

territories. Treatments in RA 32 include 100 acres in LSR RO218 and overlap with critical habitat. 

The rationale for this project is to provide pre-established strategic suppression/containment areas 

adjacent to the roads to provide greater safety and ability to contain fires that may start within and 

adjacent to the Three Sisters Wilderness. To the degree that the roadside fire lines could contain a 

wildfire, the Fuel Treatment would protect RA 32 habitat and other spotted owl habitat from high 

intensity fire on the side of the road opposite the fire. 

F. Recovery Action 10

Recovery Action 10 of the Revised Recovery Plan for the Northern Spotted Owl states: “Conserve 

spotted owl sites and high value spotted owl habitat to provide additional demographic support to the 

spotted owl population” (USFWS 2011, p.III-43). An interagency team was to be created that would 

identify these areas and make recommendations for areas to conserve and manage. The intent of 

this action is to protect, enhance, and develop habitat in the quantity and distribution necessary to 

provide for the long-term recovery of spotted owls. In the interim period, while the team process is 

formalized and developed, the Recovery Plan recommends that that Federal land managers work 

with the Service to prioritize current and historic spotted owl nest sites for conservation and/or 

maintenance of existing levels of habitat. Both the reproductive status and the existing site condition 

are factors to consider in prioritization.

Evaluation of consistency with Recovery Action 10 begins with prioritization of known and historic 

sites, and high value and unsurveyed habitat (potential sites). Prioritization factors to consider are 

provided in the Recovery Plan (USFWS 2011, p. III-44). Appendix F describes the prioritization 

process used in this biological assessment.

Prioritization is intended to provide a “guide to evaluate the relative impacts of management actions, 

and conservation of sites that provide the most support to spotted owl demography” (USFWS 2011, 

p. III-44). It is also intended to “...minimize impacts to potential spotted owl sites” (USFWS 2011, p. 

III-45). 

In order to prioritize site conservation and habitat restoration, to analyze the effects of actions relative 

to RA10, and otherwise assess consistency with RA10, it was necessary to use the prioritization 

method described in Appendix E. This method incorporated RA10 considerations for site occupation, 

and pair and reproduction status, in combination with habitat conditions in the 0.5 mile Core Area and 

1.2 mile Provincial Home Range. 

The Recovery Plan discourages forest management actions that diminish the home range’s capacity 

to support spotted owl occupancy, survival and reproduction long-term, while recognizing that land 

managers have a variety of forest management obligations in addition to spotted owl considerations 

(USFWS 2011, p. III-45). Active forest management may be necessary to maintain or improve 

ecological conditions and the Recovery Plan supports projects that intend to provide long-term 

benefits to forest resiliency and restore natural forest dynamic processes. Such support is contingent 
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on projects that are implemented in a landscape context and use carefully applied prescriptions that 

promote long-term forest health. Examples of active management include: forest stand restoration, 

fire risk reduction, treatments of insect infestations and tree disease, and restoration of high-quality 

early seral habitat as described by Swanson et al. (2010:entire).

Effects to specific known and potential spotted owl sites

Adverse effects are due to removal of suitable habitat, disruption, and/or negative impacts to known 

or potential spotted owl nest patches. Adverse effects from spotted owl habitat removal are likely to 

result in injury by impacting spotted owl survival and/or reproduction by:

1. Reducing forage habitat below optimal levels,

2. Further reducing forage habitat that is currently below adequate levels, 

3. Impacting the nest patch, such as removing suitable or dispersal habitat, this may cause 

injury to the spotted owl.

Adverse effects from disruption are likely to result in harassment by impacting spotted owl survival 

and/or reproduction if the disturbance occurs within the disruption distance within one or more 

breeding seasons. Although harassment of breeding spotted owls is of short duration, especially 

compared to growing suitable habitat, the resulting adverse effects from disruption are additional 

adverse impacts to a spotted owl site that may have longer term adverse effects due to habitat 

changes. Adult spotted owls are expected to continue to survive with reduced reproduction or move 

to a new territory. Moving and searching for a new territory will potentially expose the adults to greater 

predation risk than a territorial spotted owl pair. Predation on spotted owls has not been directly 

observed, but is suspected by northern goshawks (Accipiter gentiles), cooper’s hawks (Accipiter 

cooperi), red-tailed hawks (Buteo jamaicensis), great horned owls (Bubo virginianus), and barred 

owls (Strix varia) (Courtney et al. 2004, page 2-8).

Detroit Ranger District

Highway 46: This large timber sale and restoration project in the Breitenbush 5thfield watershed 

would treat about 4,091 acres with a combination of Harvest Habitat Remove, Harvest Habitat 

Downgrade, Harvest Habitat Maintain, Harvest in Non-Habitat, Fuels Treatment, Special Habitat 

Restoration, Terrestrial Habitat Enhancement, and Road Construction. For territories that overlapped 

on treatments removing foraging habitat or that had treatments in NRF (only Fuel Treatments were in 

NRF), two years of surveys for spotted owls were conducted in during the period 2014-2016 (the 

south part of the project was added in 2015) within 1.2 miles of proposed units. Also surveys were 

conducted in parts of the project area from 2010-2012 as part of Portland General Electric’s Cascadia 

Crossing Project that was never implemented. Twenty eight current and historic owl territories 

overlap project activities. Treatments were specifically designed to maintain the functionality of all 

territories. No activities are proposed that would disrupt spotted owls.

No treatments are proposed in 300-meter nest patches.

Four territories (MSNO 0631, 0737, 3318, and 3344) have only activities proposed that maintain 

current habitat conditions and the territories are all above the 50% and 40% suitable habitat for Core 

Areas and general home ranges, respectively. The proposed project should therefore maintain the 

habitat functionality of these sites.

Eight territories have only activities proposed that maintain current habitat conditions but the Core 

Area is currently below the 50% suitable threshold and/or the general home range is below the 40% 

threshold. These sites are discussed as follows: 

1) MSNO 0732. The Core Area is at 62% suitable and the general home range is at 38%. The 

only activities proposed in the home range are 49 acres of Harvest Habitat Maintain and 28 

acres of huckleberry enhancement in dispersal habitat outside of the Core Area.
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2) MSNO 0795. The Core Area is at 38% suitable and the general home range is at 53%. The 

only activities proposed in the home range are 2 acres of Harvest Habitat Maintain in foraging 

habitat and 102 acres of Harvest Habitat Maintain in dispersal habitat outside of the Core 

Area.

3) MSNO 1349. The Core Area is at 49% suitable and the general home range is at 39%. The 

only activity proposed in the home range is 6 acres of Harvest Habitat Maintain in foraging 

habitat outside of the Core Area.

4) MSNO 3307. The Core Area is at 35% suitable and the general home range is at 36%. The 

only activity proposed in the home range is 70 acres of Harvest Habitat Maintain in dispersal 

habitat outside of the Core Area.

5) MSNO 3308. The Core Area is at 45% suitable and the general home range is at 41%. The 

only activities proposed in the home range are 15 acres of Harvest Habitat Maintain in 

dispersal habitat in the Core Area and 46 acres of Harvest Habitat Maintain in dispersal 

habitat in the general home range.

6) MSNO 3309. The Core Area is at 17% suitable and the general home range is at 17%. The 

only activity proposed in the home range is 16 acres of Harvest Habitat Maintain in dispersal 

habitat outside of the Core Area.

7) MSNO 3310. The Core Area is at 53% suitable and the general home range is at 39%. The 

only activities proposed in the home range are 1 acres of Harvest Habitat Maintain in 

dispersal habitat in the Core Area and 69 acres of Harvest Habitat Maintain in dispersal 

habitat in the general home range.

8) MSNO 3345. The Core Area is at 31% suitable and the general home range is at 34%. The 

activities proposed in the home range are 45 acres of Harvest Habitat Maintain in dispersal

habitat in the Core Area and 230 acres of Harvest Habitat Maintain in dispersal habitat in the 

general home range.

The project biologist reviewed the activities proposed in the home range of the above 8 owls and 

concluded that, because all activities maintain the functionality of the habitat and the amount of 

habitat, including dispersal habitat, that would not be treated, the proposed actions should maintain 

the current functionality of the territories.

Sixteen territories within the project area have some removal of dispersal and/or foraging habitat. The 

current condition of these territories and their RA 10 priority rank is shown in Table A18. The posttreatment habitat condition and a summary of effects to each site is given in Table A-19. Twelve sites 

(MSNO 0573, 0730, 0739, 0751, 0752, 0752a, 0991, 2110, 3305, 3317, 3854, and MTH#2) would all 

maintain suitable habitat in the Core Area and general home range above 50% and 40%, 

respectively. The project biologist concluded that the proposed project should therefore maintain the 

habitat functionality of these sites. Four territories in the project shown in Tables A-18 and A-19 are 

currently below the 50% suitable threshold and/or the general home range is below the 40% 

threshold. These four sites are discussed individually below. 

MSNO 1099 (RA 10 priority 4)

The activity center for MSNO 1099 is based on a 2010 nesting pair. Surveys have recently been 

conducted in 2010 and 2011. A pair was located in 2010 and a female was detected in 2011. 

Habitat levels for MSNO 1099 are currently below threshold levels within the 0.5 mile Core Area at 

39% suitable but above threshold levels within 1.2 mile home range at 50% (Table A-18). All of the 

proposed activities within this home range would maintain foraging habitat. No treatments would 

occur in the nest patch. Disturbance effect would be NLAA-outside disruption distance/time.

Within general home range, 9 acres of dispersal habitat would be removed for early seral gaps, 532 

acres of dispersal habitat would have Harvest Habitat Maintain, 4 acres of foraging habitat would 

have Harvest Habitat Maintain, and there would be Fuel Treatments that would maintain the habitat 

on 32, 33, and 48 acres of dispersal, foraging and NRF habitat, respectively. The percent suitable 

post-treatment would remain at 50% well above threshold levels.
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Within the Core Area, 9 acres of dispersal habitat would be removed for early seral gaps and 131

acres of dispersal habitat would have Harvest Habitat Maintain commercial thinning. The dispersal 

habitat that would be thinned is a 57-year old plantation. One hundred and six acres of dispersal 

habitat in the Core Area would not be treated. Post-treatment, the Core Area would consist of 39% 

suitable untreated, 19% dispersal untreated, 26% dispersal thinned and maintained, 2% dispersal 

removed, and 14% untreated non-habitat. 

The proposed action is not expected to significantly reduce the functionality of MSNO 1099 because 

suitable habitat would remain well above threshold levels in the general home range, no suitable 

habitat is removed, and only a small percentage of dispersal habitat would be removed in the Core 

Area.

MSNO 3336 (RA 10 priority 6)

The activity center for MSNO 3336 is based on a 2011 nesting pair. Surveys have recently been 

conducted in 2010 and 2011 with a pair located both years. 

Habitat levels for MSNO 3336 are currently below threshold levels within the 0.5 mile Core Area at 

40% suitable and within the 1.2 mile home range at 37% (Table A-18). No treatments would occur in 

the nest patch. Disturbance effect would be NLAA-outside disruption distance/time.

Within the Core Area, 14 acres of a total of 86 acres of dispersal habitat would have Harvest Habitat 

Maintain commercial thinning. No other treatments would occur. The dispersal habitat that would be 

thinned is expected to become suitable in about 36 years. Post-treatment, the Core Area would 

consist of 40% suitable untreated, 14% dispersal untreated, 3% dispersal thinned and maintained, 

and 43% untreated non-habitat. 

The general home range contains 1,080 acres of suitable and 1,033 acres of dispersal habitat. The 

majority of the dispersal habitat in the home range originated after a fire and has a year of origin 

about 1970 so in a little over 30 years it is expected to become foraging habitat. Within the general 

home range, 8 acres of dispersal habitat near the edge of the home range would be removed for 

sugar pine restoration, 174 acres of dispersal habitat would have Harvest Habitat Maintain thinning, 

and 3 acres of foraging habitat would have Harvest Habitat Maintain thinning. The percent suitable 

post-treatment would remain at 37% and 82% of the dispersal habitat in the home range would not be 

treated. 

The proposed action is not expected to significantly reduce the functionality of MSNO 3336 because 

suitable habitat would be maintained, 82% of the dispersal habitat would be left untreated, and only 8 

acres of dispersal habitat outside the Core Area would be removed.

MSNO 3349 (RA 10 priority 4)

The activity center for MSNO 3349 is based on a 1997 evening pair. This site was not surveyed 

because no suitable habitat was proposed for treatments in the territory. Consultation was based on 

the historic location.

Habitat levels for MSNO 3349 are currently below threshold levels within the 0.5 mile Core Area at 

31% suitable and within the 1.2 mile home range at 37% (Table A-18). No treatments would occur in 

the nest patch. Disturbance effect would be NLAA-outside disruption distance/time.

Within the Core Area, 26 acres of a total of 137 acres of dispersal habitat would have Harvest Habitat 

Maintain commercial thinning. No other treatments would occur. The dispersal habitats are 48 year 

old plantations. Post-treatment, the Core Area would consist of 34% suitable untreated, 22% 

dispersal untreated, 5% dispersal thinned and maintained, and 42% untreated non-habitat. 

The general home range contains 1,061 acres of suitable and 994 acres of dispersal habitat. The 

majority of the dispersal habitat in the home range is expected to become foraging habitat in about 32 

years. Within the general home range, 6 acres of dispersal habitat outside the Core Area would be 

removed for meadow restoration and 298 acres of dispersal habitat would have Harvest Habitat 

Maintain thinning. The percent suitable post-treatment would remain at 37% and 69% of the dispersal 

habitat in the home range would not be treated. 
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The proposed action is not expected to significantly reduce the functionality of MSNO 3349 because 

suitable habitat would be maintained, 69% of the dispersal habitat would be left untreated, and only 6

acres of dispersal habitat outside the Core Area would be removed.

MSNO 3876 (RA 10 priority 4)

The activity center for MSNO 3876 is based on a 1993 daytime pair. This site was not surveyed 

because no treatments would remove suitable habitat in the territory. Consultation was based on the 

historic location.

Habitat levels for MSNO 3876 are currently below threshold levels within the 0.5 mile Core Area at 

34% suitable and well below threshold levels within the 1.2 mile home range at 21% (Table A-18). No 

treatments would occur in the nest patch. Disturbance effect would be NLAA-outside disruption 

distance/time.

Within the Core Area, 51 acres of a total of 204 acres of dispersal habitat would have Harvest Habitat 

Maintain thinning and three acres would be removed for meadow restoration. No other treatments 

would occur. The dispersal habitats are plantations that range in age from 44-63 years old and are 

expected to become foraging habitat at about age 80. Post-treatment, the Core Area would consist of 

34% suitable untreated, 30% dispersal untreated, 10% dispersal thinned and maintained, 0.6% 

dispersal removed, and 26% untreated non-habitat. 

The general home range contains only 609 acres of suitable habitat and 966 acres of dispersal 

habitat. The dispersal habitat in the home range is similar to the Core Area described above. Within 

the general home range, 6 acres of dispersal habitat outside the Core Area would be removed for 

meadow restoration. Also in the general home range 3 acres of foraging habitat and 215 acres of 

dispersal habitat would have Harvest Habitat Maintain thinning. Post-treatment, the general home 

range would consist of about 21% suitable untreated, 0.1% suitable treated and maintained, 26% 

dispersal untreated, 7% dispersal thinned and maintained, 0.2% dispersal removed, and 46% 

untreated non-habitat. 

The proposed action is not expected to significantly reduce the functionality of MSNO 3876 because 

suitable habitat would be maintained, 77% of the dispersal habitat would be left untreated, and only 6 

acres of dispersal habitat would be removed.

In summary, the Highway 46 project is expected to maintain the current functionality of all 28 owl 

territories that overlap proposed activities.

Sweet Home Ranger District

Trout Creek: This timber sale and restoration project would treat about 1,171 acres with a 

combination of Harvest Habitat Remove, Harvest Habitat Downgrade, Harvest Habitat Maintain, 

Harvest in Non-Habitat, Special Habitat Restoration and Terrestrial Habitat Enhancement. Terrestrial 

Habitat Enhancement would underplant cedar in foraging habitat and would have no negative effects 

on owl nesting so will not be discussed further in this section. At least two years of surveys for 

spotted owls were conducted in all of the project area. Most were done in 2014 and 205, but some 

were done in 2015 and 2016 to cover new units that were added in 2015. Also one new territory was 

discovered in 2013 and monitored in 2014 and 2015. Nine current and historic owl territories overlap 

project activities. Treatments were specifically designed to maintain the existing functionality condition 

of all territories and many would have long-term beneficial effects. No activities are proposed that 

would disrupt spotted owls.

MSNOs 4094 and 0064 both are well above threshold levels for % suitable in the Core Area and 

general home ranges. The only treatment in these territories is 8 acres of Harvest Habitat Maintain to 

promote hardwoods in a plantation that is dispersal habitat (unit 72). This action would maintain the 

functionality of these home ranges. MSNOs 2963 and 2976 would only have treatments in nonhabitat that would not affect the functionality of the home ranges. 

The other five territories within the project area have some removal of dispersal and/or foraging 

habitat and/or activities in a nest patch. The current condition of these territories and their RA 10 
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priority rank is shown in Table A18. The post-treatment habitat condition and a summary of effects to 

each site is given in Table A-19. 

Three sites (MSNO 0687, 4460 and NEW13) would have a small amount of foraging habitat removed 

and/or downgraded outside the Core Area and would maintain suitable habitat in the Core Area and 

general home range above 50% and 40%, respectively. The project biologist concluded that the 

proposed project should therefore maintain the habitat functionality of these sites (Table A-19).

The two remaining territories shown in Tables A-18 and A-19 for this project are discussed 

individually below. 

MSNO 0661 (RA 10 priority 6)

The activity center for MSNO 0661 is based on a 1990 resident single. Surveys were conducted in 

2014 and 2015 and no spotted owls were detected. This site is in a peninsula of FS land surrounded 

by private forestry lands and is thought likely to be a non-functional site due to the poor habitat 

condition (34% suitable in the Core Area and 21% suitable in the general home range.

No treatments are proposed in suitable habitat in the home range. Five acres of Harvest Habitat 

Maintain thinning in dispersal habitat is proposed on the periphery of the 300-meter activity center. 

Eighteen and 45 acres of this treatment in dispersal habitat is proposed in the Core Area and general 

home range, respectively. In addition, 14 acres of Harvest Habitat Removal outside the Core Area is 

also proposed.

The treatments in the nest patch could harm nesting spotted owls by reducing cover near a nesting 

tree if nesting owls were present. Overall the treatment would maintain about 50% canopy cover in 

the stand and create 5 additional snags and downed trees/acre in the 5 acres of thinning in the nest 

patch. Cover treatment canopy is expected to be restored in about 7-10 years and the thinning 

treatments should improve spotted owl habitat long-term.

Because the site is thought to be unoccupied by spotted owls due to poor habitat conditions, no harm 

to spotted owls is expected from the treatment in the nest patch and in home range in general. 

Protocol surveys are being conducted in the territory in 2017 and would continue for at least 

five consecutive years or through project implementation, which ever came first. If spotted owls 

are detected, the treatment in the nest patch would be dropped.

MSNO 0688 (RA 10 priority 2)

The activity center for MSNO 0688 is based on a 1992 nesting pair. It was surveyed in 2014 and 

2015 and only barred owls were detected. Consultation was based on the historic location.

Habitat levels for MSNO 0688 are currently below threshold levels within both the 0.5 mile Core Area 

at 42% suitable and the 1.2 mile home range at 19% (Table A-18). About half the home range 

overlaps private timber lands and the site is considered marginal by the project biologist.

No treatments would occur in the nest patch. Within the Core Area, 12 acres of thinning would occur 

in non-habitat and 23 acres would occur in the general home range. The only treatment in owl habitat 

is 1.5 acres of foraging habitat that would be removed for early seral habitat creation. This loss of 

habitat on the very edge of the home range was considered a negligible impact to the current home 

range condition and would not affect the functionality of the home range. Thinning treatments would 

benefit the functionality of the site long-term by accelerating the development of non-habitat into 

dispersal and suitable habitat. 

In summary, the Trout Creek project is expected to maintain the current functionality of all 9 spotted 

owl territories that overlap proposed activities except for treatments in the nest patch of 0661 which is 

thought to be non-functional and unoccupied currently and will be monitored during implementation to 

verify lack of use.

McKenzie River Ranger District

Within this consultation, 4 projects may affect spotted owl sites on the McKenzie River Ranger 

District. These are discussed individually below.
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Park Thin: This timber sale project would treat about 85 acres with a combination of Harvest Habitat 

Remove and Harvest Habitat Downgrade in foraging habitat. No surveys were conducted for this 

project. The closest historic site is over 1.5 miles from the project area and no potential sites are 

expected to overlap the treatments because the area is highly fragmented with limited suitable 

habitat. Therefore, the project is not expected to affect the functionality of any spotted owl territories.

Q Thin: This timber sale project would treat about 70 acres with a combination of Harvest Habitat 

Remove, Harvest Habitat Downgrade, and Harvest Habitat Maintain. No activities are proposed that 

would disrupt spotted owls.

Two spotted owl sites overlap the treatment area and they are both annually surveyed as part of the 

HJA Demographic Study Area. The current condition of these territories and their RA 10 priority rank 

is shown in Table A18. The post-treatment habitat condition and a summary of effects to each site is 

given in Table A-19.

MSNOs 4085 was last found nesting in 1996, a pair was found in 2013, and an evening pair was 

detected in 2016. The territory is well above threshold levels for percent suitable in the Core Area 

and general home ranges. The only treatment in this territory would be 6 acres of Harvest Habitat 

Downgrade in foraging habitat outside the Core Area. This action would maintain the functionality of 

the home range as it would remain well above threshold levels for suitable habitat. 

MSNO 4488 has never had any documented nesting. The last detection occurred with an evening 

pair in 2005. There were also evening single detections in 2014, 2012, and 2006. There was an 

evening resident single detection in 2003 and 2004 and a pair in 1999. The territory is below 

threshold levels for percent suitable in the Core Area and general home ranges. The only treatment 

in this territory would be 21 acres of Harvest Habitat Downgrade in foraging habitat outside the Core 

Area. While suitable habitat acres within the 1.2 mile home range would fall further below 40%, the 

location of the proposed harvest unit is on the outer edge of the home range. A large parcel of about 

190 acres of cutover private land which is non-habitat lies between the core area and the outer home 

range and thus, it is unlikely that MSNO 4488 owls use the area of the proposed Q Thin harvest unit. 

The area of the unit has been annually surveyed to protocol with no responses. It is also a moderatehigher elevation habitat type in the true fir zone and less likely to be used. The habitat ranges from 

low quality suitable to dispersal. Therefore the proposed action should maintain the current 

functionality condition of the site. 

Lower South Fork McKenzie River Floodplain Restoration This floodplain restoration project 

would treat about 103 acres with Harvest Habitat Remove to collect trees for stream restoration. No 

activities are proposed that would disrupt spotted owls. 

Two spotted owl sites overlap the treatment area and they are both annually surveyed as part of the 

HJA Demographic Study Area. The current condition of these territories and their RA 10 priority rank 

is shown in Table A-18. The post-treatment habitat condition and a summary of effects to each site 

are given in Table A-19.

Both sites have been annually surveyed as part of the HJA Demographic Study Area since the late 

1980s. MSNO 2827 had a nesting pair in 2004, and also had 15 years of detections from 1988 to 

2011. Most recently, evening singles were found in 2009 and 2011 with no detections since 2011.

MSNO 2829 had a non-nesting pair in 1991 with no other detections in any other year. 

Both territory are well above threshold levels for percent suitable in the Core Area and general home 

ranges. The only treatment in the territories of MSNO 2827 and 2829 would be 53 and 51 acres, 

respectively, of foraging habitat removal outside the Core Area. The percent suitable in the home 

ranges post-treatment would be well above the 40% suitable threshold (at 59% and 65%) which is 

expected to maintain habitat to support the functionality of the home ranges.

Three Sisters Risk Reduction Hazardous Fuels Treatment This fuel reduction project would treat 

up to 1,205 acres of NRF with Fuel Treatment within 150 feet of roads. About 46 mile of roads would 

be treated on one side of the road and 6 miles would be treated on both sides of the road. The action 

would degrade but maintain the habitat. No treatments would occur in 300-meter known nest patches 
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or in 100-acre LSRs. Seasonal restrictions would be applied to activities near known nest patches to 

avoid disruptions of noise and smoke. 

About half the treatment area is surveyed annually as part of the HJA Demographic Study Area. 

Treatments in NRF habitat in the unsurveyed area would be surveyed for two consecutive years prior 

to any treatments and any nest patches found would be protected as described above.

Twenty two known spotted owl sites overlap the treatments of which 8 would have treatments in the 

Core Areas. Less than 10 acres would be treated in any Core Area and the habitat would be 

degraded but maintained (see Fuel Treatment Section for more discussion of this project). 

Because of the protective measures to avoid nest patches and disruption and to conduct surveys in 

unsurveyed habitat, and because the treatment would affect 10 acres or less in the Core Area and 

maintain the habitat, the project biologist concluded that the proposed project would not result in a 

loss of functionality to any spotted owl home range.

Middle Fork Ranger District

Within this consultation, 2 projects may affect spotted owl sites on the Middle Fork Ranger District. 

These are discussed individually below.

Bear Mountain Restoration: This restoration project would have Special Habitat Restoration on 

about 18 acres of NRF habitat and 200 acres on non-habitat. Seasonal restrictions from March 1 –

July 15 would be placed on all project activities. Protocol surveys are planned in the project area for 

2017 and 2018 as part of a larger landscape scale project. Seasonal restrictions could be waived if 

protocol surveys are completed and no disruption would occur.

Three known owl territories overlaps the proposed treatments. MSNO 1071 would only have a few 

acres of treatment in non-habitat on the periphery of the home range and would not be affected by 

the proposed project. The treatments would occur in the home range of MSNO 3073, but outside the 

nest patch. The treatments which would allow the fire to creep 100 feet into up to 18 acres of NRF 

habitat along the edge of the non-habitat meadows would maintain the NRF habitat and the 

functionality the home range. 

The third territory, MSNO 3081, would have treatments in non-habitat in the nest patch. MSNO 3081 

is a historic activity center based on a 1991 nighttime pair detection. No surveys have been 

conducted in recent years. The site currently has 53% and 64% suitable habitat in the Core Area and 

general home range, respectively (Table A-18). Up to 18 acres of meadow restoration treatment in 

non-habitat within the nest patch is proposed. Treatment in the nest patch would only consist of 

cutting and piling of trees 11” dbh or less in the meadow areas and invasive plant control. No burning 

would occur. The action would not affect any suitable or dispersal habitat in the nest patch but would 

delay the development of future owl habitat in meadow areas. Development of spotted owl habitat 

will take a long-time in these areas (assuming fire is excluded) because of the site conditions and 

they are unlikely to provide high quality late-successional habitat even without treatment.

The other effect to the territory of MSNO 3081 would be about 18 acres of underburning along the 

edge of NRF habitat adjacent of Unit 1 outside the nest patch. About half of these acres are in the 

Core Area. The underburning is expected to maintain the NRF habitat. Therefore the proposed 

action is not expected to harm the functionality of any spotted owl site.

Road 24 Reroute: This Road Construction activity would remove up to 6 acres of NRF habitat and 2 

acres of dispersal habitat to relocate a road away from a fish stream. The project occurs outside of 

known owl home ranges. Protocol surveys were conducted in suitable habitat within 1.2 miles of the 

project area in 2016 and no spotted owls were detected (barred owls were present). The second year 

of protocol surveys will be completed in 2017. If a new spotted owl nest patch is discovered during 

2017 surveys, seasonal restrictions may be implemented to avoid disruption and/or consultation may 

be reinitiated if located in project area. Spot checks would be completed in 2018-2019 as needed if 

implementation is delayed. Therefore this project is not expected to affect the functionality of any 

spotted owl home ranges.
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G. Special Management Considerations for Critical Habitat

Summary of special management considerations for critical habitat area discussed below.

West Cascades/Coast Ranges of Oregon and Washington

1. Conserve older stands that have occupied or high-value spotted owl habitat as described in 

RA 10 (includes all territories, occupied or not), and RA 32 (older, high quality, and more 

structurally complex stands that support spotted owl recovery). On Federal lands, this 

recommendation applies to all land-use allocations.

There are six projects in CH in this consultation. As described in the RA 10 section above 

and in Table A-19, none of the projects in CH are expected to result in a loss of viability to 

any spotted owl nest site. Many of the harvest treatments are expected to benefit spotted owl 

habitat in the long-term. The projects will therefore meet the intent of RA10 to conserve 

spotted owl sites. Other aspects of this management consideration is discussed by individual 

project below.

Highway 46: This large timber harvest and restoration project in the Breitenbush watershed 

was specifically designed to reduce impacts to older forest habitat, CH and spotted owl 

territories while meeting restoration needs. The only removal of suitable spotted owl habitat 

is 370 acres of foraging habitat in CH in matrix that is specific to sugar pine restoration, early 

seral habitat creation, meadow restoration and two acres of road rerouting to restore 

hydrologic functions. Most of the foraging habitat that would be treated is about 90 years of 

age and lacks stand structure.

The total LSR and CH acres in the project area are 27,452 comprising about 88% of the 

planning area. CH comprises 78% of the planning area. In LSR, only stands less than 80 

years old are proposed for thinning to comply with LSR management direction. Historically 

the Breitenbush watershed is estimated to have been about 60% in closed canopy late seral 

stands. About 48% of the watershed is currently closed canopy late seral. Most of these 

stands both in and out of CH would not be treated by this project. 

About 3,142 acres of Harvest Habitat Maintain commercial thinning is proposed that is 

expected to improved spotted owl habitat long-term, including 532 acres in foraging habitat, 

2,529 acres in dispersal habitat and 81 acres of non-habitat. About 2,643 of these acres are 

in CH, including 525 acres in foraging habitat.

The only treatment in NRF habitat in CH is 35 acres of Fuel Treatment that is also RA 32. 

Also 72 acres of NRF habitat that is not CH or RA 32 habitat would similarly be treated. This 

habitat is adjacent to a residential in-holding and would be treated to reduce fire risks and 

improve public and fire fighter safety in the event of a fire. The action would degrade but 

maintain the NRF and RA 32 habitat and is considered by the Forest Service to be a 

reasonable tradeoff balancing spotted owl critical habitat needs with public safety concerns.

This project meets the intent of this management consideration for CH.

Trout Creek: This timber harvest and restoration project has no treatments in NRF or RA 32 

habitat. The only treatment in LSR is 8 acres of thinning to promote the hardwood component

in an existing plantation that is considered non-habitat. Thinning in foraging, dispersal and 

non-habitat that maintain the habitat are expected to improve spotted owl habitat long-term.

Foraging habitat that would be treated are fire-regenerated stands about 117 to 141 years 

old. Within CH, 104 acres of foraging would be removed and 5 acres would be downgraded. 

The treatments in foraging habitat in CH include the 47-acre heavy thinning with a prescribed 

burn, 3 acres of oak restoration and 54 acres of hardwood fuel breaks. The five acres that 

would be downgraded is to promote the Forest plant of concern, tall bugbane.

This project meets the intent of this management consideration for CH.

Q Thin: This timber harvest project would remove 7 acres (for early seral gaps) and 

downgrade 36 acres of foraging habitat in AMA that is CH. The stand being treated is an 80-
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120 year old fire-regenerated stand and beginning to transition foraging habitat. Long-term,

the downgrade treatment which would maintain 40% canopy cover should improve suitable 

habitat. No RA32 stands or NRF habitat would be affected so impacts to older stands in CH 

are minimized.

Lower South Fork McKenzie River Floodplain Restoration: This stream restoration project 

would remove 53 acres of foraging habitat in CH to provide trees for down wood sources. 

The foraging stand being treated is 120-130 years old. No treatments would occur in NRF or 

RA 32 habitat or in LSRs. The foraging habitat that would be affected were extensively fieldreviewed during the fall of 2016. This field review resulted in two small 2-acre no-harvest 

skips that contain a concentration of larger legacy trees, as well as dropping of an additional 

area over a stream that contained RA 32 habitat. Because of the location of CH to the project 

area and the economic and logistic constraints with moving logs with intact root wads long 

distances, taking most of the logs from CH was thought necessary to make the project 

successful. The FS has worked to balance protection of older forest habitat for spotted owl 

with the importance of restoring the riparian area to enhance habitat for federally listed fish.

Three Sisters Risk Reduction Hazardous Fuels Treatment: The roadside Fuel Treatment 

project would maintain but degrade up to 1,205 acres of NRF habitat, including 880 acres in 

CH and up to 500 acres of RA 32 habitat. This is another project where the Forest Service is 

balancing the needs to better control fires that might burn out of the Three-Sisters Wilderness 

and reduce potential risks to public safety and fire fighters with the critical habitat needs of 

spotted owls. Limiting the treatments to the area within 150 of the road and protecting nest 

patches and 100-acre LSRs from the treatments would reduce the amount of older forest 

habitat affected. Approximately two slash piles/acre would be left for wildlife habitat which 

may provide cover for owl prey such as wood rats. Also 80-foot no-treatment buffers would 

be maintained along all Class 1 & 2 streams and 30-foot no-treatment buffers along Class 3 

and 4 streams and wetlands. Finally the treatments may help protect spotted owl habitat by 

being able to better control fires along the roadways. About 377 acres of the project in critical

habitat is in large LSRs. This fuel treatment along the edge of the road that would maintain 

trees larger than 10 inches dbh is consistent with the LSR assessment and other standards 

and guidelines for LSRs. 

Bear Mountain Meadow Restoration: This Special Habitat Restoration Project would have 

about 11 acres of underburning up to 100 feet into NRF habitat that is bordering meadow 

areas in CH. None of this stands are considered RA32 stands and the burning would 

maintain the function of the stands. Four acres of underburning that may occur in LSRs is 

consistent with the LSR Assessment and standards and guidelines for LSRs. 

This proposed action would be consistent with this management consideration for CH.

2. Management emphasis needs to be placed on meeting spotted owl recovery goals and longterm ecosystem restoration and conservation. When there is a conflict between these goals, 

actions that would disturb or remove the essential PBFs of spotted owl CH need to be 

minimized and reconciled with long-term ecosystem restoration goals.

All 6 projects in CH are specifically designed to avoid any short-term loss of functional 

spotted owl nesting territories. As discussed previously, 2,186 acres of Harvest Habitat 

Maintain in dispersal habitat and 525 acres in foraging critical habitat, that commercial thin

while maintaining the habitat, would improve the condition of the spotted owl habitat longterm. Similarly heavier thinning that temporarily removes dispersal habitat or downgrades 

foraging habitat may benefit spotted owl habitat in the long-term by promoting larger trees, 

greater canopy development, understory development, and horizontal and vertical diversity. 

These actions are consistent with this management consideration for CH for all these 

projects. Below is discussion of other ecosystem restoration tradeoffs with CH for the 

specific projects.

Highway 46: Several unique restoration needs influenced the treatments in CH for this 

project. The project area is near the northern extent of sugar pine which is rapidly declining 
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due to a reduction in fire. The District views the maintenance and enhancement of sugar 

pine in the limited areas it is found as an important restoration objective from the standpoint 

of biodiversity as well as long-term forest health in the face of climate change as this species 

should be resilient to climate warming at the northern extent of its range. Sugar pine 

restoration treatments were prescribed on 2 acres of non-habitat and 125 acres of dispersal 

habitat in CH. However, because of where it was found, 316 acres of roughly 90-year old 

stands in CH that are foraging habitat were prescribed for heavy thinning and shelterwood 

harvest that would remove suitable habitat for up to about 80 years. Because of the trees 

retained and the development of the sugar pine component on these warmer south-facing 

slopes, the stands should develop into high-quality spotted owl RA 32 habitat. All sugar pine 

treatments were done in areas that are not likely to affect the viability of any spotted owl nest 

sites in the short-term. That is how the District balanced the conflicting goals.

Less than 2% of the planning area is early seral, while historical levels were thought to have 

been about 9%. Also grass meadows habitat is limited and considered important to a wide 

range of species on the District. Therefore early seral habitat creation and meadow 

restoration are important ecological needs in the project area. 

The majority of the project area is critical habitat for spotted owls. All proposed early seral 

and gap creation is in CH and is divided about equally between dispersal and foraging 

habitat. CH was not avoided because the District and members of the public perceive a need 

to maintain some early seral across the landscape since that has been the historic pattern. 

While foraging habitat was not avoided, the areas treated are about 90-year old stands 

lacking structure that are considered lower quality foraging habitat. The main ways the 

issues of spotted owl habitat and restoration were reconciled is that no NRF or high-quality 

foraging habitat are proposed for early seral creation and only 44 acres of foraging habitat in 

CH are proposed for early seral and large gap treatment in the project area. Meadow 

restoration opportunities are limited to very specific sites and only 8 acres are proposed in 

foraging habitat that is CH. 

Restoration to enhance huckleberries and provide a limited amount of fish logs were 

designed to maintain the existing function of the habitat that was treated.

Trout Creek: This project has numerous restoration treatments in CH. Two hundred and forty 

six acres of underplanting cedar in fire-regenerated foraging habitat would be beneficial to 

spotted owl habitat in the long-term if successful. Five acres of foraging habitat would be 

downgraded to promote tall bug bane and 3 acres would be removed to promote oak and 

madrone. Because the acres of CH affected would be small and the sites are ecologically 

unique on the Sweet Home District, this was viewed by the FS as an acceptable tradeoff. 

The treatments in foraging habitat in CH include 54 acres of hardwood fuel breaks that would 

temporarily remove the habitat. The prescription is a unique attempt to provide fuel breaks 

along roads by encouraging alders and other deciduous trees. In the long-term, this may be 

more ecologically beneficial than traditional fuel breaks that periodically thin the conifers and 

remove the understory because the hardwoods would increase biodiversity and provide 

dispersal and foraging habitat for spotted owls. Also the fuel break treatment could have 

some beneficial effects to spotted owls by reducing the risk of fires spreading across the 

treated roadways. 

Except for one 47-acre treatment in foraging habitat in a 127 year-old stand, early seral 

habitat creation was prescribed in dispersal habitat to balance the needs to maintain and 

restore spotted owl habitat. The Harvest Habitat Remove treatment in foraging habitat 

prescribes 47 acres heavy thinning with a prescribed burn to create large numbers of snags 

and reduce the canopy to 15% cover to create high-quality early seral habitat. The total stand 

size is 112 acres with about 60% of the stand having no treatment thus resembling moderate 

severity patch burn. The purpose of this project is to create high quality early seral habitat 

with a large component of large snags to benefit avian and other species that prefer that type 

of habitat. Although only a portion of the unit is in CH, the BA is making a worst-case 

assumption that all the harvest and burning would occur in CH.
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Lower South Fork McKenzie River Floodplain Restoration: This project does not contribute to 

meeting spotted owl recovery goals, but is being proposed to restore river ecosystems for 

listed fish and other riparian species. Impacts to spotted owls are reduced by placing the tree 

removal where it will not harm owl sites and avoiding RA 32 habitat.

Three Sisters Risk Reduction Hazardous Fuels Treatment: This project does not contribute to 

meeting spotted owl recovery goals, but has been proposed to emphasize greater ability to 

control fires and improve fire fighter and public safety in the event of a wildfire. Treatments 

are designed to maintain spotted owl sites by avoiding nest patches, 100-acre LSRs and 

disruption to sites. Also the treatment would degrade but maintain the suitable and RA 32 

stands adjacent to the roads. The treatments could benefit CH by be able to control fires 

along the roads.

Bear Mountain Meadow Restoration: This project does not contribute to meeting spotted owl 

recovery goals, but has been proposed to restore meadow habitat that is not considered CH. 

Impacts to spotted owls are reduced by limiting treatments in units that overlap a nest patch 

to only cut and pile of conifer encroachment and weed treatment and by limiting treatments in 

owl habitat outside the nest patch to only low-intensity fire within 100 feet of the meadow 

edge that would maintain the functionality of the forested spotted owl habitat.

3. Continue to manage for large, continuous blocks of late-successional forest.

All projects in CH would continue to manage for late blocks of late-successional forest. 

Harvest treatments in LSR are all in stands less than 80 years of age and consistent with 

LSR standards and guidelines. No early seral habitat creation is proposed in LSR and 

harvest treatments would accelerate the development of late successional forest 

characteristics.

Fuel treatments and special habitat restoration in older LSR stands would all maintain the 

functionality of the habitat for spotted owls. Fuel treatments could help protect large blocks of 

late successional forest from stand-replacement fires.

The only project that would remove NRF habitat is 6 acres of road rerouting to protect 

riparian habitat in the Road 24 Reroute project that is outside of CH. The small acreage of 

habitat removed would have a minimal impact on continuity and connectivity of latesuccessional forest habitat.

4 In areas that are not currently late-seral forest or high-value habitat and where more 

traditional forest management might be conducted (e.g. Matrix), these activities should 

consider applying ecological forestry prescriptions. 

Bear Mountain Meadow Restoration, Three Sisters Risk Reduction Hazardous Fuels 

Treatment: N/A.

Highway 46: Thinning treatments in existing plantations of non-habitat and dispersal habitat 

would increase habitat diversity by variable density thinning, skips of up to 30% of the stand

and promotion of understory development. Portions of Riparian Reserves within the project 

area units consist of dense, overstocked, conifer-dominated stands with very little structural 

and species diversity and understory development. This lack of complexity and diversity is 

outside the natural range of variability and may be limiting nutrient cycling, deciduous organic 

matter input to waterbodies, and habitat for riparian-dependent wildlife. In overstocked, 

conifer-dominated portions lacking structural and species diversity, silvicultural tools to 

promote desired vegetation characteristics were considered to more quickly attain Aquatic 

Conservation Strategy Objectives. Thinning treatments to increase the shrub and deciduous 

components adjacent to streams in riparian reserves are proposed on about 814 acres. 

These treatments are expected to accelerate the development of late-seral habitat in the 

riparian reserves. 

Trout Creek: Treatments in the Trout Creek project units would result in the development of 

structural complexity and associated biological diversity through gap creation, dominant-treerelease gaps, and the planting of tree cohort focusing on drought- and fire-tolerant tree 
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110

species. No-harvest skips would provide areas where future snags would occur due to 

competition. Variable density thinning, releasing of hardwoods and under burning are also 

part of this project prescriptions. Snag and dead wood creation are part of prescription in one 

thinning unit and in regen harvest locations. If Knutson-Vandenberg Act (KV) funding is 

available, snags and dead wood would be created in additional thinning units. 

Q Thin: Q Thin would treat a mature stand between 80-120 years old that contain a mixture

of dispersal and foraging spotted owl habitat. The proposed harvest treatment includes two 

designated skips, one in the riparian area on the western edge, and an additional skip in a 

Class 4 stream headwaters area on the southeastern side of the unit. That area also contains 

a high number of larger overstory trees, and was dropped from the harvest unit boundary. 

The largest overstory conifers will not be removed, but rather left to benefit future stand 

development. At least 2 snags/acre and 2 downed trees in Decay Class 1 and 2/acre would 

be retained or created post-treatment if not present to benefit stand development. The 

thinning treatment is designed to improve long-term structural diversity in the stand. 

Lower South Fork McKenzie River Floodplain Restoration: The thinning treatment would

maintain an average stand canopy cover of 30 percent. This project would leave primarily the 

largest and healthiest trees with the largest crowns. Trees to be removed would range mostly 

within the 16-24 inch diameter range, although some may be larger. Understory treatments 

include removal of smaller tree size classes down to 7” diameter. Two 2-acre no-treatment 

skips are planned as part of this project. 

Snags would be felled if they pose a hazard to the thinning operation and would be left on 

site. Existing large down woody material will be maintained for habitat diversity, and full tree 

lengths would be retained as much as possible. The amount of down wood left would meet or 

exceed NWFP standards and guidelines of 240 lineal feet/acre. 

VII. Cumulative Effects

Cumulative effects are those effects of future State or private activities (not involving Federal 

activities) that are reasonably certain to occur within the action area of the Federal action subject to 

consultation (50 CFR 402.02 Definitions). A Memorandum to the Director of Fish and Wildlife Service, 

August 27, 1982, Cumulative Effects to be Considered Under Section 7 of the Endangered Species 

Act set forth the legal requirements for consideration by federal agencies of the cumulative effects. “A 

non-federal action is reasonably certain to occur if the action requires approval of a state or local 

resource or land use control agency and such agencies have approved the action, and the project is 

ready to proceed...these indicators must show more than the possibility that the non-federal project 

will occur; they must demonstrate with reasonable certainty that it will occur.”

Although the Willamette National Forest is lacking detailed information on spotted owls or spotted owl 

habitat for non-federal lands within the action area, non-federal lands within the Willamette National 

Forest boundaries usually only support marginal habitats, and do not notably contribute to the viability 

of the spotted owl. The Oregon Forest Practice Rules require protection of a 70-acre core area 

around active nest sites only, and do not provide any protection or conservation of other surrounding 

habitat. For a species that requires up to several thousand acres of habitat to persist, these rules 

allow for the progressive elimination of active spotted owl sites. Removal of large amounts of habitat 

around 70-acre cores will eventually render the core nest areas non-functional and displacement of 

spotted owls is the likely outcome. Non-federal timber lands, however, support some dispersal habitat 

for spotted owls and may contribute, at least temporarily (e.g., until the next harvest rotation) to the 

reproduction, health, and condition of spotted owls on adjacent Federal land. Habitat conditions on 

non-federal lands are not expected to improve significantly within the foreseeable future and, as a 

result, are not expected to contribute to the survival and recovery of the spotted owl.

The Level 1 Terrestrial Team is unaware of any proposed future State or private actions on nonFederal land within the action area.
Literature Cited LAA Biological Assessment- Willamette NF-FY 2018

111

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Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Appendix A. Summary Tables for Proposed Projects in this Consultation 

Willamette National Forest LAA Biological Assessment FY 2018
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

118

Table A- 1. Levels of treatment proposed by each administrative unit in this consultation.

Activity x Admin Unit (acres)

Activity Detroit RD Sweet Home 

RD

McKenzie 

River RD Middle Fork RD Grand Total

Fuels Treatment 198 1205 1403

Harvest Habitat Downgrade 88 114 202

Harvest Habitat Maintain 3061 395 27 3483

Harvest Habitat Remove 553 201 117 871

Harvest in Non-Habitat 107 181 288

Road Construction 2 8 10

Special Habitat Restoration 11 3 218 232

Terrestrial Habitat 

Enhancement 159 303 462

Grand Total 4091 1171 1463 226 6951

Activity in NSO Critical Habitat x Admin Unit (acres)

Activity Detroit RD Sweet Home 

RD

McKenzie 

River RD Middle Fork RD Grand Total

Fuels Treatment 126 880 1006

Harvest Habitat Downgrade 5 36 41

Harvest Habitat Maintain 2579 105 27 2711

Harvest Habitat Remove 530 137 66 733

Harvest in Non-Habitat 66 70 136

Road Construction 2 0 2

Special Habitat Restoration 8 3 114 125

Terrestrial Habitat 

Enhancement 114 246 360

Grand Total 3425 566 1009 114 5114
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

119

Table A- 2. Harvest Habitat Remove proposed in this consultation.

Ranger 

District/ 

Resource Area

Project Name Acres Land Use 

Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab ModEffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to 

CHU

Acres in 

RA 32 

Habitat

Detroit RD Highway 46 316 Matrix Foraging Habitat 

removed LAA NLAA WCS 3 316 LAA

Detroit RD Highway 46 148 Matrix Dispersal Habitat 

removed NLAA NLAA WCS 3 125 NLAA

Detroit RD Highway 46 15 Matrix Foraging Habitat 

removed LAA NLAA WCS 3 15 LAA

Detroit RD Highway 46 29 Matrix Dispersal Habitat 

removed NLAA NLAA WCS 3 29 NLAA

Detroit RD Highway 46 29 Matrix Foraging Habitat 

removed LAA NLAA WCS 3 29 LAA

Detroit RD Highway 46 16 Matrix Dispersal Habitat 

removed NLAA NLAA WCS 3 16 NLAA

Sweet Home 

RD Trout Creek 68 Matrix Foraging Habitat removed LAA NLAA WCS 3 47 LAA

Sweet Home 

RD Trout Creek 59 AMA Foraging Habitat removed LAA NLAA WCS 3 54 LAA

Sweet Home 

RD Trout Creek 60 Matrix Dispersal Habitat removed NLAA NLAA WCS 3 36 NLAA
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Ranger 

District/ 

Resource Area

Project Name Acres Land Use 

Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab ModEffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to 

CHU

Acres in 

RA 32 

Habitat

Sweet Home 

RD Trout Creek 14 AMA Dispersal Habitat removed NLAA NLAA

McKenzie River 

RD

Lower South Fork 

McKenzie River 

Floodplain 

Restoration-Wood 

Source Units 1-7 

(Cupola Unit)

53 Matrix Foraging Habitat 

removed LAA NE WCS 3 53 LAA

McKenzie River 

RD

Lower South Fork 

McKenzie River 

Floodplain 

Restoration-Wood 

Source Units 8-23, 

26-28

46 AMA Dispersal Habitat 

removed NLAA NE WCS 3 6 NLAA

McKenzie River 

RD

Lower South Fork 

McKenzie River 

Floodplain 

Restoration-Wood 

Source Units 24-

25

4 AMA Foraging Habitat 

removed LAA NE

McKenzie 

River RD Park Thin 7 AMA Foraging Habitat 

removed LAA NLAA

McKenzie 

River RD Q Thin 7 AMA Foraging Habitat 

removed LAA NE WCS 3 7 LAA

TOTAL 871 733 0
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Table A- 3. Harvest Habitat Downgrade proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project Name Acres Land Use 

Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab ModEffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to 

CHU

Acres 

in RA 

32 

Habitat

Sweet 

Home RD Trout Creek 83 Matrix Foraging downgraded to dispersal LAA NLAA

Sweet 

Home RD Trout Creek 5 AMA Foraging downgraded to dispersal LAA NLAA WCS 3 5 LAA

McKenzie 

River RD Park Thin 78 AMA Foraging downgraded to dispersal LAA NLAA

McKenzie 

River RD Q Thin 36 AMA Foraging downgraded to dispersal LAA NE WCS 3 36 LAA

TOTAL 202 41 0
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Table A- 4. Harvest Habitat Maintain proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project Name Acres Land Use 

Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab ModEffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to 

CHU

Acres in 

RA 32 

Habitat

Detroit RD Highway 46 530 Matrix Foraging Habitat 

maintained NLAA NLAA WCS 3 525 NLAA

Detroit RD Highway 46 2 LSR Foraging Habitat 

maintained NLAA NLAA

Detroit RD Highway 46 1859 Matrix Dispersal Habitat 

maintained NLAA NLAA WCS 3 1530 NLAA

Detroit RD Highway 46 670 LSR Dispersal Habitat 

maintained NLAA NLAA WCS 3 524 NLAA

Sweet 

Home RD Trout Creek 117 Matrix Dispersal Habitat maintained NLAA NLAA WCS 3 27 NLAA

Sweet 

Home RD Trout Creek 278 AMA Dispersal Habitat maintained NLAA NLAA WCS 3 78 NLAA

McKenzie 

River RD Q Thin 27 AMA Dispersal Habitat maintained NLAA NE WCS 3 27 NLAA

TOTAL 3483 2711 0
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Table A- 5. Fuels Treatment proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project 

Name Acres Land Use Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

EffectDisruption

2012 

CHU 

Subunit

CHU2012 

acres

Effect to 

2012 

CHU

Acres 

in RA 

32 

Habitat

Detroit RD Highway 

46 107 LSR NR(F) Habitat maintained NLAA NLAA WCS 3 35 NLAA 35

Detroit RD Highway 

46 63 Matrix Foraging Habitat maintained NLAA NLAA WCS 3 63 NLAA

Detroit RD Highway 

46 28 Matrix Dispersal Habitat maintained NLAA NLAA WCS 3 28 NLAA

McKenzie 

River RD

Three 

Sisters 

Risk 

Reduction 

HF 

Treatment

312 Matrix NR(F) Habitat 

maintained LAA NLAA WCS 4 81 LAA 50

McKenzie 

River RD

Three 

Sisters 

Risk 

Reduction 

HF 

Treatment

351 Admin 

withdrawn NR(F) Habitat maintained LAA NLAA WCS 4 345 LAA 250

McKenzie 

River RD

Three 

Sisters 

Risk 

Reduction 

HF 

Treatment

162 AMA NR(F) Habitat 

maintained LAA NLAA WCS 4 77 LAA 100

McKenzie 

River RD

Three 

Sisters 

Risk 

Reduction 

HF 

Treatment

380 LSR NR(F) Habitat 

maintained LAA NE WCS 4 377 LAA 100

TOTAL 1403 1006 535
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Table A- 6. Road Construction proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project 

Name Acres Land Use Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

EffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to CHU

Acres 

in RA 

32 

Habitat

Detroit 

RD Highway 46 2 Matrix Foraging Habitat removed LAA NLAA WCS 3 2 LAA

Middle 

Fork RD

Road 24 

Reroute 6 Matrix NR(F) Habitat removed LAA NLAA 0 NE

Middle 

Fork RD

Road 24 

Reroute 2 Matrix Dispersal Habitat removed NLAA NLAA 0 NE

TOTAL 10 2
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Table A- 7. Special Habitat Restoration proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project 

Name Acres Land Use Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

EffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to CHU

Acres 

in RA 

32 

Habitat

Detroit 

RD Highway 46 8 Matrix Foraging Habitat removed LAA NLAA WCS 3 8 LAA

Detroit 

RD Highway 46 3 Matrix Dispersal Habitat removed NLAA NLAA

Sweet 

Home RD Trout Creek 3 AMA Foraging Habitat removed LAA NE WCS 3 3 LAA

Middle 

Fork RD

Bear 

Mountain 

Meadow 

Restoration

186 Matrix Nonhabitat Non-habitat NE NLAA WCS 4 89 NE

Middle 

Fork RD

Bear 

Mountain 

Meadow 

Restoration

14 Admin 

withdrawn

Nonhabitat Non-habitat NE NLAA WCS 4 14 NE

Middle 

Fork RD

Bear 

Mountain 

Meadow 

Restoration

4

LSR100ac NR(F) Habitat 

maintained NLAA NLAA WCS 4 4 NLAA

Middle 

Fork RD

Bear 

Mountain 

Meadow 

Restoration

14 Matrix NR(F) Habitat 

maintained NLAA NLAA WCS 4 7 NLAA

TOTAL 232 125
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Table A- 8. Terrestrial Enhancement proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project 

Name Acres Land Use Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

EffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to CHU

Acres 

in RA 

32 

Habitat

Detroit 

RD Highway 46 30 Matrix Foraging Habitat maintained NLAA NLAA WCS 3 30 NLAA

Detroit RD Highway 46 80 Matrix Dispersal Habitat 

maintained NLAA NLAA WCS 3 80 NLAA

Detroit RD Highway 46 28 Matrix Dispersal Habitat 

maintained NLAA NLAA

Detroit RD Highway 46 17 Matrix Nonhabitat Non-habitat NE NLAA

Detroit RD Highway 46 4 Matrix Foraging Habitat 

maintained NLAA NLAA WCS 3 4 NLAA

Sweet 

Home RD Trout Creek 303 AMA Foraging Habitat maintained NLAA NE WCS 3 246 NLAA

TOTAL 462 360
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Table A- 9. Harvest in Non-Habitat proposed in this consultation.

Ranger 

District/ 

Resource 

Area

Project 

Name Acres Land Use Allocation

Current 

Habitat

Habitat 

Functionality 

Change

EffectHab 

Mod

EffectDisruptionCHU 

Subunit

CHU 

acres

Effect 

to CHU

Acres 

in RA 

32 

Habitat

Detroit 

RD Highway 46 2 Matrix Nonhabitat Non-habitat NE NLAA WCS 3 2 NLAA

Detroit 

RD Highway 46 24 Matrix Nonhabitat Non-habitat NE NLAA

Detroit 

RD Highway 46 81 Matrix Nonhabitat Non-habitat NE NLAA WCS 3 64 NLAA

Sweet 

Home RD Trout Creek 8 LSR Nonhabitat Non-habitat NE NLAA WCS 3 8 NLAA

Sweet 

Home RD Trout Creek 173 AMA Nonhabitat Non-habitat NE NLAA WCS 3 62 NLAA

TOTAL 288 136
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Table A- 10. Proposed acres of treatment in spotted owl suitable, dispersal and non-habitat.

Acres

Current Habitat Habitat Functionality Change AMA LSR1 Matrix

Admin 

Withdrawn

Congress 

Withdrawn Grand Total

Dispersal Habitat maintained4 305 670 2112 3087

Habitat removed2 60 258 318

Dispersal Total 365 670 2370 3405

Non-habitat Non-habitat 173 8 310 14 505

Non-habitat Total 173 8 310 14 505

Suitable NRF maintained4 162 491 326 351 1330

Foraging maintained4 303 2 627 932

NRF removed4 6 6

Foraging removed4 80 491 571

Foraging downgraded to dispersal3 119 83 202

NRF downgraded to dispersal3 0

Suitable Total 664 493 1533 351 3041

Grand Total 1202 1171 4213 365 6951

1

Includes associated Riparian Reserves and 100-acre LSRs

2 Habitat removed means to eliminate the functionality of this type of habitat (i.e., removal of suitable or dispersal habitat results in non-habitat after treatment).

3 Habitat downgraded means to change the functionality of the habitat from suitable to dispersal or NRF to foraging.

4 Habitat maintained means that current functionality of habitat is maintained (i.e., NRF (Nesting/Roasting/Foraging) habitat remains NRF, foraging remains foraging, and dispersal 

habitat continues to function as dispersal).
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Table A- 11. Proposed acres of treatment in spotted owl habitat and non-habitat by activity type and habitat functionality change.

Acres

Activity

Dispersal Non-habitat Suitable

Habitat Grand Total

maintained

Habitat 

removed Non-habitat Habitat maintained

Habitat 

removed

Suitable 

downgraded to 

dispersal

Fuels Treatment 28 1375 1403

Harvest Habitat Downgrade 202 202

Harvest Habitat Maintain 2951 532 3483

Harvest Habitat Remove 313 558 871

Harvest in Non-Habitat 288 288

Road Construction 2 8 10

Special Habitat Restoration 3 200 18 11 232

Terrestrial Enhancement 108 17 337 462

Grand Total 3087 318 505 2262 577 202 6951

Suitable Acres broken into NRF and foraging

Activity

Foraging* NRF*

Habitat Grand Total

maintained

Habitat 

removed

Foraging

downgraded to 

dispersal

Habitat 

maintained

Habitat 

removed

NRF 

downgraded to 

dispersal

Fuels Treatment 63 1312 1375

Harvest Habitat Downgrade 202 202

Harvest Habitat Maintain 532 532

Harvest Habitat Remove 558 558

Road Construction 2 6 8

Special Habitat Restoration 11 18 29

Terrestrial Enhancement 337 337

Grand Total 932 571 202 1330 6 0 3041

*Foraging and NRF acres comprise the total acres shown for suitable in the top part of the table.
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Table A- 12. Proposed acres of treatment activities in spotted owl critical habitat.

Critical Habitat Acres

Current Habitat Habitat Functionality Change AMA LSR1 Matrix

Admin 

Withdrawn

Congress 

Withdrawn Grand Total

Dispersal Habitat maintained4 105 524 1665 2294

Habitat removed2 6 206 212

Dispersal Total 111 524 1871 2506

Non-habitat Non-habitat 62 8 155 14 239

Non-habitat Total 62 8 155 14 239

Suitable NRF maintained4 77 416 88 345 926

Foraging maintained4 246 622 868

NRF removed4

Foraging removed4 64 470 534

Foraging downgraded to dispersal3 41 41

NRF downgraded to dispersal3

Suitable Total 428 416 1180 345 2369

Grand Total 601 948 3206 359 5114

1

Includes associated Riparian Reserves and 100-acre LSRs

2 Habitat removed means to eliminate the functionality of this type of habitat (i.e., removal of suitable or dispersal habitat results in non-habitat after treatment).

3 Habitat downgraded means to change the functionality of the habitat from suitable to dispersal or NRF to foraging.

4 Habitat maintained means that current functionality of habitat is maintained (i.e., NRF (Nesting/Roasting/Foraging) habitat remains NRF, foraging remains foraging, and dispersal 

habitat continues to function as dispersal).
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Table A- 13. Proposed acres of treatment in spotted owl critical habitat by activity type and habitat functionality change.

Critical Habitat Acres

Activity

Dispersal Non-habitat Suitable

Habitat Grand Total

maintained

Habitat 

removed Non-habitat Habitat maintained

Habitat 

removed

Suitable 

downgraded to 

dispersal

Fuels Treatment 28 978 1006

Harvest Habitat Downgrade 41 41

Harvest Habitat Maintain 2186 525 2711

Harvest Habitat Remove 212 521 733

Harvest in Non-Habitat 136 136

Road Construction 2 2

Special Habitat Restoration 103 11 11 125

Terrestrial Enhancement 80 280 360

Grand Total 2294 212 239 1794 534 41 5114

Suitable Acres in Critical Habitat broken into NRF and foraging

Activity

Foraging* NRF*

Habitat Grand Total

maintained

Habitat 

removed

Foraging

downgraded to 

dispersal

Habitat 

maintained

Habitat 

removed

NRF 

downgraded to 

dispersal

Fuels Treatment 63 915 978

Harvest Habitat Downgrade 41 41

Harvest Habitat Maintain 525 525

Harvest Habitat Remove 521 521

Road Construction 2 2

Special Habitat Restoration 11 11 22

Terrestrial Enhancement 280 280

Grand Total 868 534 41 926 0 0 2369

*Foraging and NRF acres comprise the total acres shown for suitable in the top part of the table.
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Table A- 14. Proposed habitat modification in spotted owl critical habitat subunits.

Activity in Critical Habitat Subunit (acres)

CHU Subunit / Activity

Dispersal Non-habitat Suitable

Habitat Grand Total

maintained

Habitat 

removed

Habitat 

maintained

Habitat 

maintained

Habitat 

removed

Suitable 

downgraded 

to dispersal

WCS 3

Fuels Treatment 28 98 126

Harvest Habitat Downgrade 41 41

Harvest Habitat Maintain 2186 525 2711

Harvest Habitat Remove 212 521 733

Harvest in Non-Habitat 136 136

Road Construction 2 2

Special Habitat Restoration 11 11

Terrestrial Enhancement 80 280 360

WCS 3 Total 2294 212 136 903 534 41 4120

WCS 4

Fuels Treatment 880 880

Special Habitat Restoration 103 11 114

WCS 4 Total 0 0 103 891 0 0 994

Grand Total 2294 212 239 1794 534 41 5114

Activity in Suitable Habitat in Critical Habitat broken into NRF and foraging (acres)

CHU Subunit / Activity

Foraging NRF

Habitat Grand Total

maintained

Habitat 

removed

Foraging 

downgraded to 

dispersal

Habitat 

maintained

Habitat 

removed

NRF

downgraded 

to dispersal

WCS 3

Fuels Treatment 63 35 98

Harvest Habitat Downgrade 41 41
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Harvest Habitat Maintain 525 525

Harvest Habitat Remove 521 521

Road Construction 2 2

Special Habitat Restoration 11 11

Terrestrial Enhancement 280 280

WCS 3 Total 868 534 41 35 0 0 1478

WCS 4

Fuels Treatment 880 880

Special Habitat Restoration 11 11

WCS 4 Total 0 0 0 891 0 0 891

Grand Total 868 534 41 926 0 0 2369
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Table A- 15. Effects to spotted owls by activity.

NSO Effect Habitat Modification Acres

Activity LAA NE NLAA Grand Total

Fuels Treatment 1205 198 1403

Harvest Habitat Downgrade 202 202

Harvest Habitat Maintain 3483 3483

Harvest Habitat Remove 558 313 871

Harvest in Non-habitat 288 288

Road Construction 8 2 10

Special Habitat Restoration 11 200 21 232

Terrestrial Habitat Enhancement 17 445 462

Grand Total 1984 505 4462 6951

NSO Effect Disturbance Acres

Activity NE NLAA LAA-disruption Grand Total

Fuels Treatment 380 1023 1403

Harvest Habitat Downgrade 36 166 202

Harvest Habitat Maintain 27 3456 3483

Harvest Habitat Remove 110 761 871

Harvest in Non-habitat 288 288

Road Construction 10 10

Special Habitat Restoration 3 229 232

Terrestrial Habitat Enhancement 303 159 462

Grand Total 859 6092 0 6951

NSO Effect Critical Habitat Acres

Activity LAA NE NLAA Grand Total

Fuels Treatment 880 126 1006

Harvest Habitat Downgrade 41 41

Harvest Habitat Maintain 2711 2711

Harvest Habitat Remove 521 212 733

Harvest in Non-habitat 136 136

Road Construction 2 2

Special Habitat Restoration 11 103 11 125

Terrestrial Habitat Enhancement 360 360

Grand Total 1455 103 3556 5114
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Table A- 16. Proposed projects in Late Successional Reserves.

LSR 

Number or 

category

Ranger District/ 

Resource Area Project Name Proposed Activity Current Habitat

Habitat 

Functionality 

Change

EffectHab Mod Acres

RO214 Detroit RD Highway 46 Harvest Habitat Maintain Foraging Habitat maintained NLAA 2

RO214 Detroit RD Highway 46 Harvest Habitat Maintain Dispersal Habitat maintained NLAA 670

RO214 Detroit RD Highway 46 Fuels Treatment NRF Habitat maintained NLAA 107

RO215 Sweet Home RD Trout Creek Harvest in Non-habitat Non-habitat Non-habitat NE 8

RO218 McKenzie River RD Three Sisters Risk Reduction HF 

Treatment Harvest Habitat Maintain NRF Habitat maintained LAA 380

LSR-100ac Middle Fork RD Bear Mountain Meadow Restoration Special Habitat 

Restoration NRF Habitat maintained NLAA 4

TOTAL 1171

Table A- 17. Proposed projects in RA 32 Habitat.

Acres in RA 32 Habitat

Ranger District Proposed Activity Project Name Acres in RA 32 Habitat

Detroit RD Fuels Treatment Highway 46 35

McKenzie River RD Fuels Treatment Three Sisters Risk Reduction HF Treatment 500

Grand Total 535
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Table A- 18. Environmental baseline of northern spotted owl sites with habitat removal or activities proposed in 300-meter nest patches. 

Ranger District Known Site ID Project Name LUA 

(Activity center)

2012 CH Subunit 

(Activity Center)

Core Area

Current Suitable 

Acres (% 

suitable)

Home Range

Current Suitable 

Acres (% 

suitable)

Recovery Action 

10 Priority Rank

Detroit RD 0573 Highway 46 Matrix WCS 3 276 (55%) 1402 (48%) 3

Detroit RD 0730 Highway 46 Matrix WCS 3 452 (90%) 2052 (71%) 3

Detroit RD 0739 Highway 46 LSR-100 acre WCS 3 263(52%) 2021 (70%) 3

Detroit RD 0751 Highway 46 LSR WCS 3 404 (81%) 1739 (60%) 3

Detroit RD 0752 Highway 46 Matrix WCS 3 359 (72%) 2049 (71%) 3

Detroit RD 0752a Highway 46 Matrix WCS 3 275(55%) 1762 (61%) 3

Detroit RD 0991 Highway 46 Matrix WCS 3 382 (76%) 1941 (67%) 1

Detroit RD 1099 Highway 46 Matrix WCS 3 194 (39%) 1447 (50%) 4

Detroit RD 2110 Highway 46 Matrix WCS 3 369 (74%) 1727 (60%) 3

Detroit RD 3305 Highway 46 LSR-100 acre WCS 3 471 (94%) 2023 (70%) 3

Detroit RD 3317 Highway 46 LSR-100 acre WCS 3 291 (58%) 1649 (57%) 3

Detroit RD 3336 Highway 46 Matrix WCS 3 202 (40 %) 1080 (37%) 3

Detroit RD 3349 Highway 46 Matrix 156 (31%) 1060 (37%) 4

Detroit RD 3854 Highway 46 LSR WCS 3 306 (61%) 1694 (59%) 5

Detroit RD 3876 Highway 46 LSR-100 acre 170 (34%) 609 (21%) 4

Detroit RD MTH#2 Highway 46 Matrix 249 (50%) 1667 (58%) 2
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Ranger District Known Site ID Project Name LUA 

(Activity center)

2012 CH Subunit 

(Activity Center)

Core Area

Current Suitable 

Acres (% 

suitable)

Home Range

Current Suitable 

Acres (% 

suitable)

Recovery Action 

10 Priority Rank

Sweet Home RD 0661 Trout Creek Administratively 

Withdrawn 172 (34%) 297 (21%)

Sweet Home RD 0687 Trout Creek LSR-100 acre WCS 3 431 (86%) 2316 (80%) 1

Sweet Home RD 0688 Trout Creek LSR-100 acre 210 (42%) 542 (19%)

Sweet Home RD 4460 Trout Creek AMA WCS 3 397 (79%) 1873 (65%) 1

Sweet Home RD NEW13 Trout Creek Matrix WCS 3 276 (55%) 1760 (61%) 1

McKenzie River RD 4085 Q Thin AMA WCS 3 276 (55%) 1423 (49%) 3

McKenzie River RD 4488 Q Thin LSR WCS 3 215 (43%) 1050 (36%) 4

McKenzie River RD 2827

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Administratively 

Withdrawn 273 (54%) 1757 (61%) 8

McKenzie River RD 2829

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

LSR-100 acre WCS 3 392 (78%) 1939 (67%) 8

Middle Fork RD 3081

Bear Mountain 

Meadow 

Restoration

Matrix WCS 4 269 (53%) 1865 (64%) 1
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138

Core areas and general home ranges with suitable habitat below threshold levels are underlined and highlighted in bold.

Table A- 19. Summary of effects to spotted owl sites with habitat removal or activities in the nest patch.

Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Detroit RD 0573 Highway 46 WCS 3 276 (55%) 1365 (47%)

37 acres of foraging habitat would be 

removed in the general home range 

outside the core area for sugar pine

restoration. The functionality of the site 

would be maintained due to suitable 

habitat remaining above threshold levels.

Detroit RD 0730 Highway 46 WCS 3 442 (88%) 2033 (70%)

10 and 19 acres of foraging habitat would 

be removed in the core area and general 

home range for meadow restoration, 

early seral gaps, and dominant tree 

release. The functionality of the site 

would be maintained due to suitable 

habitat remaining above threshold levels.

Detroit RD 0739 Highway 46 WCS 3 263 (52%) 1991 (69%)

30 acres of foraging habitat would be 

removed in the general home range 

outside the core area for sugar pine 

restoration. The functionality of the site 

would be maintained due to suitable 

habitat remaining above threshold levels.

Detroit RD 0751 Highway 46 WCS 3 404 (81%) 1739 (60%)

9 acres of dispersal habitat would be 

removed in the general home range 

outside the core area for early seral gaps. 

The functionality of the site would be 

maintained due to suitable habitat 

remaining above threshold levels.
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

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Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Detroit RD 0752 Highway 46 WCS 3 348 (69%) 2004 (69%)

11 and 45 acres of foraging habitat would 

be removed in the core area and general 

home range for sugar pine restoration. 

The functionality of the site would be 

maintained due to suitable habitat 

remaining above threshold levels.

Detroit RD 0752a Highway 46 WCS 3 275 (55%) 1717 (59%)

45 acres of foraging habitat would be 

removed in the general home range 

outside the core area for commercial 

thinning. The functionality of the site 

would be maintained due to suitable 

habitat remaining above threshold levels.

Detroit RD 0991 Highway 46 WCS 3 375 (75%) 1868 (65%)

7 and 73 acres of foraging habitat would 

be removed in the core area and general 

home range for sugar pine restoration, 

early seral creation, and road 

construction. The functionality of the site 

would be maintained due to suitable 

habitat remaining above threshold levels.

Detroit RD 1099 Highway 46 WCS 3 194 (39%) 1447 (50%)

9 acres of dispersal habitat would be 

removed in the core area and general 

home range for early seral gaps. All 

other actions would maintain the

functionality of the habitat and no 

suitable habitat would be treated in the 

core area so the project should have a 

negligible effect on the ability of site to 

support spotted owl reproduction. See 

RA 10 Section for further discussion. 
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Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Detroit RD 2110 Highway 46 WCS 3 360 (72%) 1710 (59%)

9 and 17 acres of foraging habitat would 

be removed in the core area and general 

home range for meadow restoration, 

early seral gaps, and sugar pine 

restoration. The functionality of the site 

would be maintained due to suitable 

habitat remaining above threshold levels.

Detroit RD 3305 Highway 46 WCS 3 436 (87%) 1906 (66%)

35 and 117 acres of foraging habitat 

would be removed in the core area and 

general home range for sugar pine 

restoration and early seral gaps. The 

functionality of the site would be 

maintained due to suitable habitat 

remaining above threshold levels.

Detroit RD 3317 Highway 46 WCS 3 290 (58%) 1628 (56%)

1 and 21 acres of foraging habitat would 

be removed in the core area and general 

home range for meadow restoration and

early seral gaps. The functionality of the 

site would be maintained due to suitable 

habitat remaining above threshold levels.
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Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Detroit RD 3336 Highway 46 WCS 3 202 (40%) 1080 (37%)

8 acres of dispersal habitat would be 

removed in the general home range 

outside of the core area for sugar pine 

restoration. All other actions would 

maintain the functionality of the habitat 

with only 3 acres of suitable (foraging) 

habitat affected by Harvest Habitat 

Maintain in the general home range 

outside of the Core Area. The project 

should have a negligible effect on the 

ability of site to support spotted owl 

reproduction. See RA 10 Section for 

further discussion. 

Detroit RD 3349 Highway 46 156 (31%) 1060 (37%)

6 acres of dispersal habitat would be 

removed in the general home range 

outside of the core area for meadow

restoration. All other actions would 

maintain the functionality of the habitat 

with no treatments is suitable habitat. 

The project should have a negligible 

effect on the ability of site to support 

spotted owl reproduction. See RA 10 

Section for further discussion. 

Detroit RD 3854 Highway 46 WCS 3 306 (61%) 1691 (58%)

3 acres of foraging habitat would be 

removed in the general home range 

outside the core area early seral gaps. 

The functionality of the site would be 

maintained due to suitable habitat 

remaining above threshold levels.
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

142

Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Detroit RD 3876 Highway 46 170 (34%) 609 (21%)

3 and 6 acres of dispersal habitat would 

be removed in the core area and general 

home range for meadow restoration. All 

other actions would maintain the 

functionality of the habitat with only 3 

acres of treatment in suitable habitat 

outside the core area. The project should 

have a negligible effect on the ability of 

site to support spotted owl reproduction. 

See RA 10 Section for further discussion. 

Detroit RD MTH #2 Highway 46 249 (50%) 1656 (57%)

11 acres of foraging habitat would be 

removed in the general home range 

outside the core area early seral gaps 

and meadow restoration. The 

functionality of the site would be 

maintained due to suitable habitat 

remaining at or above threshold levels.

Sweet Home RD 0661 Trout Creek 172 (34%) 297 (21%)

No treatments in suitable habitat. 14 

acres of dispersal would be removed 

outside the Core Area. 45 acres of 

dispersal would be thinned and 

maintained, five acres of which is in the 

nest patch. This site is thought to be 

nonfunctional due to the poor habitat 

condition and will be surveyed during 

implementation to verify lack of use so 

no harm to spotted owls is expected. 
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

143

Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Sweet Home RD 0687 Trout Creek WCS 3 431 (86%) 2311 (80%)

Five acres of foraging habitat would be 

downgraded outside the Core Area. The 

functionality of the site would be 

maintained due to suitable habitat being 

above threshold levels.

Sweet Home RD 0688 Trout Creek 210 (42%) 540 (19%)

1.5 acres of foraging habitat would be 

removed on the very edge of the home 

range for oak-savannah restoration. All 

other treatments would be in nonhabitat that would accelerate the 

development of owl habitat. The 

functionality of the current home range 

condition should be maintained due to 

the small amount of habitat affected

Sweet Home RD 4460 Trout Creek WCS 3 397 (79%) 1843 (64%)

Thirty acres of foraging habitat would be 

removed outside the Core Area. The 

functionality of the site would be 

maintained due to suitable habitat being 

above threshold levels.

Sweet Home RD NEW13 Trout Creek WCS 3 276 (55%) 1735 (60%)

Twenty five acres of foraging habitat 

would be removed or downgraded 

outside the Core Area. The functionality 

of the site would be maintained due to 

suitable habitat being above threshold 

levels.
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

144

Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

McKenzie River RD 4085 Q Thin WCS 3 276 (55%) 1417 (49%)

Six acres of foraging habitat would be 

downgraded outside the Core Area. The 

functionality of the site would be 

maintained due to suitable habitat being 

above threshold levels.

McKenzie River RD 4488 Q Thin WCS 3 215 (43%) 1029 (36%)

Twenty one acres of foraging habitat 

would be downgraded on the periphery 

of the 1.2 mile home range. The 

functionality of the site is unlikely to be 

affected because this habitat is 

separated from the Core Area by a parcel 

of private land that is non-habitat. See 

RA10 section for more discussion.

McKenzie River RD 2827

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

273 (54%) 1704 (59%)

Fifty three acres of foraging habitat 

would be removed outside the Core 

Area. The functionality of the site would 

be maintained due to suitable habitat 

being above threshold levels.

McKenzie River RD 2829

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

WCS 3 392 (78%) 1888 (65%)

Fifty one acres of foraging habitat would 

be removed outside the Core Area. The 

functionality of the site would be 

maintained due to suitable habitat being 

above threshold levels.
Appendix A. Summary Tables for Proposed Projects LAA Biological Assessment- Willamette NF-FY 2018

145

Ranger District Known Site ID Project Name 2012 CH Subunit 

(Activity Center)

Core Area

Post-treatment 

Suitable Acres (% 

suitable)

Home Range

Post-treatment

Suitable Acres (% 

suitable)

Summary of Effects to Spotted Owl 

Site

Middle Fork RD 3081

Bear Mountain 

Meadow 

Restoration

WCS 4 269 (53%) 1865 (64%)

Eighteen acres of meadow treatment in 

non-habitat in the nest patch is not 

expected to harm nesting. Up to 18 acre 

of underburning along the edge of NRF 

stands outside the nest patch should 

maintain the habitat and not affect the 

functionality of the home range. See RA 

10 Section for further discussion. 

Core areas and general home ranges with suitable habitat below threshold levels are underlined and highlighted in bold.
146

Appendix B. Willamette National Forest 

UNIT SPECIFIC DATA

LAA Biological Assessment FY 2018

Willamette Planning Province

.
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 147

Table B-1. Proposed projects for the Willamette National Forest during FY 2018 evaluated in this BA.

DETROIT RIVER RANGER DISTRICT Project Name Proposed Activity Acres

Land Use AllocationLSR Number or CategoryCurrent HabitatChangeHabitat Functionality Effect-Hab ModEffect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment AdverselyPotential Owl Sites 

Affected by 

Treatment(300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

Highway 46

Harvest 

Habitat 

Remove

316 Matrix Foragin

g

Habitat 

removed LAA NLAA WCS 3

316 LAA

0573, 

0730, 

0739, 

0752, 

0752

a, 

0991, 

2110, 

3305, 

3317

no

Highway 46

Harvest 

Habitat 

Remove

148 Matrix Dispers

al

Habitat 

removed NLAA NLAA WCS 3

125 NLAA

0730, 

0739, 

0752, 

0752

a, 

0991, 

2110, 

3305, 

3317, 

3336, 

MTH

#2

no

Highway 46

Harvest in 

Nonhabitat2 Matrix Nonhabitat Non-habitat NE NLAA WCS 

3

2 NLAA

0730, 

2110, 

3317, 

MTH

#2

no

Highway 46

Harvest 

Habitat 

Remove

15 Matrix Foragin

g

Habitat 

removed LAA NLAA WCS 3

15 LAA

0730, 

0991, 

2110, 

no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 148 Project Name Proposed Activity Acres Land Use Allocation LSR Number or Category Current Habitat Change Habitat Functionality Effect-Hab Mod

Effect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment AdverselyPotential Owl Sites 

Affected by 

Treatment(300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

3305, 

3354, 

MTH

#2

Highway 46

Harvest 

Habitat 

Remove

29 Matrix Dispers

al

Habitat 

removed NLAA NLAA WCS 3

29 NLAA

0730, 

0751, 

0752

a, 

0991, 

1099, 

2110, 

3305, 

3317, 

3336, 

3854

no

Highway 46

Harvest 

Habitat 

Remove

29 Matrix Foragin

g

Habitat 

removed LAA NLAA WCS 3

29 LAA

0573, 

0991, 

3305

no

Highway 46

Harvest 

Habitat 

Remove

16 Matrix Dispers

al

Habitat 

removed NLAA NLAA WCS 3

16 NLAA 3318, 

3854 no

Highway 46

Special 

Habitat 

Restoratio

n

8 Matrix Foragin

g

Habitat 

removed LAA NLAA WCS 3

8 LAA

0730, 

2110, 

3317, 

MTH

#2

no

Highway 46

Special 

Habitat 

Restoratio

n

3 Matrix Dispers

al

Habitat 

removed NLAA NLAA 3349, 3876 no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 149 Project Name Proposed Activity Acres Land Use Allocation LSR Number or Category Current Habitat Change Habitat Functionality Effect-Hab Mod

Effect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment AdverselyPotential Owl Sites 

Affected by 

Treatment(300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

Highway 46

Harvest in 

Nonhabitat24 Matrix Nonhabitat Non-habitat NE NLAA 3309 no

Highway 46

Road 

Constructi

on

2 Matrix Foragin

g

Habitat 

removed LAA NLAA WCS 3

2 LAA 991 no

Highway 46

Harvest 

Habitat 

Maintain

530 Matrix Foragin

g

Habitat 

maintained NLAA NLAA WCS 3

525 NLAA

0573, 

730, 

0752, 

0752

a, 

0991, 

1099, 

1349, 

2110, 

3305, 

3317, 

3854, 

MTH

#2

no

Highway 46

Harvest 

Habitat 

Maintain

2 LSR RO

214

Foragin

g

Habitat 

maintained NLAA NLAA 3854 no

Highway 46

Harvest 

Habitat 

Maintain

1859 Matrix Dispers

al

Habitat 

maintained NLAA NLAA WCS 3

1530 NLAA

0573, 

0730, 

0739, 

0751, 

0752, 

0752

a, 

0795, 

0991, 

no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 150 Project Name Proposed Activity Acres Land Use Allocation LSR Number or Category Current Habitat Change Habitat Functionality Effect-Hab Mod

Effect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment AdverselyPotential Owl Sites 

Affected by 

Treatment(300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

1099, 

2110, 

3305, 

3317, 

3318, 

3336, 

3349, 

3854, 

3876, 

MTH

#2

Highway 46

Harvest 

Habitat 

Maintain

670 LSR RO

214

Dispers

al

Habitat 

maintained NLAA NLAA WCS 3

524 NLAA

0573, 

631, 

0732, 

0737, 

0751, 

0795, 

1099, 

3307, 

3308, 

3309, 

3310, 

3318, 

3344, 

3345, 

3349, 

3854, 

3876

no

Highway 46

Harvest in 

Nonhabitat81 Matrix Nonhabitat Non-habitat NE NLAA WCS 

3

64 NLAA

0752, 

0752

a, 

3305, 

3317, 

3854

no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 151 Project Name Proposed Activity Acres Land Use Allocation LSR Number or Category Current Habitat Change Habitat Functionality 

Effect-Hab ModEffect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment AdverselyPotential Owl Sites 

Affected by 

Treatment(300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

Highway 46 Fuels 

Treatment 107 LSR RO214 NR(F) Habitat maintained NLAA NLAA WCS 3

35 NLAA

0751, 

1099, 

3854

no 35

Highway 46 Fuels 

Treatment 63 Matrix Foraging

Habitat 

maintained NLAA NLAA WCS 3

63 NLAA

0751, 

0991, 

1099, 

3854

no

Highway 46 Fuels 

Treatment 28 Matrix Dispersal

Habitat 

maintained NLAA NLAA WCS 3

28 NLAA

0751, 

1099, 

3854

no

Highway 46

Terrestrial 

Habitat 

Enhancem

ent

30 Matrix Foragin

g

Habitat 

maintained NLAA NLAA WCS 3

30 NLAA 3318 no

Highway 46

Terrestrial 

Habitat 

Enhanceme

nt

80 Matrix Dispersal Habitat 

maintained NLAA NLAA WCS 3

80 NLAA 3318 no

Highway 46

Terrestrial 

Habitat 

Enhanceme

nt

28 Matrix Dispersal Habitat 

maintained NLAA NLAA 732 no

Highway 46

Terrestrial 

Habitat 

Enhanceme

nt

17 Matrix Nonhabitat Non-habitat NE NLAA 732 no

Highway 46

Terrestrial 

Habitat 

Enhanceme

nt

4 Matrix Foraging Habitat 

maintained NLAA NLAA WCS 3

4 NLAA

0991, 

3317, 

3854

no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 152

SWEET HOME RANGER DISTRICT Project Name Proposed Activity

AcresLand Use AllocationLSR Number or CategoryCurrent HabitatChangeHabitat Functionality Effect-Hab ModEffect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment TreatmentAdversely Affected by Potential Owl Sites Activity in Nest Patch (300 meters) - yes/noAcres in RA 32 Habitat

Trout Creek

Harvest 

Habitat 

Remove

68 Matrix Foragin

g

Habitat 

removed LAA NLAA WCS 3

47 LAA

NEW

13, 

4460

no

Trout Creek

Harvest 

Habitat 

Remove

59 AMA Foragin

g

Habitat 

removed LAA NLAA WCS 3

54 LAA

NEW

13, 

4460

no

Trout Creek

Special 

Habitat 

Restoratio

n

3 AMA Foragin

g

Habitat 

removed LAA NE WCS 3

3 LAA

0687, 

0688, 

2963, 

4460

no

Trout Creek

Harvest in 

Nonhabitat8 LSR RO

215

Nonhabitat Non-habitat NE NLAA WCS 

3

8 NLAA 4094, 

0064 no

Trout Creek

Harvest 

Habitat 

Downgrad

e

83 Matrix Foragin

g

downgrade

d to 

dispersal

LAA NLAA NEW

13 no

Trout Creek

Harvest 

Habitat 

Downgrad

e

5 AMA Foragin

g

downgrade

d to 

dispersal

LAA NLAA WCS 

3

5 LAA 0687 no

Trout Creek

Harvest 

Habitat 

Remove

60 Matrix Dispers

al

Habitat 

removed NLAA NLAA WCS 3

36 NLAA NEW

13, no

Trout Creek

Harvest 

Habitat 

Remove

14 AMA Dispers

al

Habitat 

removed NLAA NLAA NEW13, 0661 no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 153 Project Name Proposed Activity Acres Land Use Allocation LSR Number or Category Current Habitat Change Habitat Functionality Effect-Hab Mod

Effect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment TreatmentAdversely Affected by Potential Owl Sites Activity in Nest Patch (300 meters) - yes/noAcres in RA 32 Habitat

Trout Creek

Terrestrial 

Habitat 

Enhancem

ent

303 AMA Foragin

g

Habitat 

maintained NLAA NE WCS 3

246 NLAA no

Trout Creek

Harvest 

Habitat 

Maintain

117 Matrix Dispers

al

Habitat 

maintained NLAA NLAA WCS 3

27 NLAA no

Trout Creek

Harvest 

Habitat 

Maintain

278 AMA Dispers

al

Habitat 

maintained NLAA NLAA WCS 3

78 NLAA yes

Trout Creek

Harvest in 

Nonhabitat173 AMA Nonhabitat Non-habitat NE NLAA WCS 

3

62 NLAA no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 154

MCKENZIE RIVER RANGER DISTRICT Project Name Proposed Activity Acres

Land Use AllocationLSR Number or CategoryCurrent HabitatChangeHabitat Functionality Effect-Hab ModEffect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by Known Owl Sites Adversely Affected by Treatment TreatmentAdversely Affected by Potential Owl Sites (300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Harvest 

Habitat 

Remove

53 Matrix Foragin

g

Habitat 

removed LAA NE WCS 3

53 LAA 2829, 

2827 no

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Harvest 

Habitat 

Remove

46 AMA Dispers

al

Habitat 

removed NLAA NE WCS 3

6 NLAA 0104, 

2836 no

Lower South Fork 

McKenzie River 

Floodplain 

Restoration

Harvest 

Habitat 

Remove

4 AMA Foragin

g

Habitat 

removed LAA NE no

Park Thin

Harvest 

Habitat 

Remove

7 AMA Foragin

g

Habitat 

removed LAA NLAA no

Park Thin

Harvest 

Habitat 

Downgrad

e

78 AMA Foragin

g

downgrade

d to 

dispersal

LAA NLAA no

Q Thin

Harvest 

Habitat 

Remove

7 AMA Foragin

g

Habitat 

removed LAA NE WCS 3

7 LAA 4085, 

4488 no

Q Thin

Harvest 

Habitat 

Downgrad

e

36 AMA Foragin

g

downgrade

d to 

dispersal

LAA NE WCS 

3

36 LAA 4085, 

4488 no

Q Thin

Harvest 

Habitat 

Maintain

27 AMA Dispers

al

Habitat 

maintained NLAA NE WCS 3

27 NLAA 4085, 

4488 no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 155 Project Name Proposed Activity Acres Land Use Allocation

LSR Number or CategoryCurrent HabitatChangeHabitat Functionality Effect-Hab ModEffect-DisruptionCHU SubunitCHU acresEffect to CHUTreatment (Adversely Affected by Known Owl Sites NOT Potential Owl Sites NOT TreatmentAdversely Affected by Known Owl Sites Adversely Affected by Treatment TreatmentAdversely Affected by Potential Owl Sites (300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

Three Sisters Risk 

Reduction HF 

Treatment

Fuels 

Treatment 312 Matrix NR(F) Habitat maintained LAA NLAA WCS 4

81 LAA 3024, 

2823 P215 no 50

Three Sisters Risk 

Reduction HF 

Treatment

Fuels 

Treatment 351

Admin 

withdraw

n

NR(F) Habitat 

maintained LAA NLAA WCS 4

345 LAA

2031, 

2418, 

1413, 

2497, 

2427, 

0866, 

3965, 

2785, 

0232

no 250

Three Sisters Risk 

Reduction HF 

Treatment

Fuels 

Treatment 162 AMA NR(F) Habitat maintained LAA NLAA WCS 4

77 LAA 2461, 

2433 no 100

Three Sisters Risk 

Reduction HF 

Treatment

Fuels 

Treatment 380 LSR RO 218 NR(F) Habitat maintained LAA NE WCS 4

377 LAA

2830, 

0850, 

0852, 

2950, 

2845, 

2952, 

0857, 

3023, 

0113

no 100
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

 156

MIDDLE FORK RANGER DISTRICT Project Name Proposed Activity

AcresLand Use AllocationLSR Number or CategoryCurrent HabitatChangeHabitat Functionality Effect-Hab ModEffect-DisruptionCHU SubunitCHU acresEffect to CHUKnown Owl Sites NOT Treatment (Adversely Affected by Potential Owl Sites NOT TreatmentAdversely Affected by AKnown Owl Sites 

dversely Affected by 

Treatment TreatmentAdversely Affected by Potential Owl Sites (300 meters) Activity in Nest Patch 

- yes/no

Acres in RA 32 Habitat

Bear Mountain 

Meadow 

Restoration

Special 

Habitat 

Restoratio

n

186 Matrix Nonhabitat Non-habitat NE NLAA WCS 

4

89 NE

3073, 

3081 yes

Bear Mountain 

Meadow 

Restoration

Special 

Habitat 

Restoratio

n

14

Admin 

withdraw

n

Nonhabitat Non-habitat NE NLAA WCS 

4

14 NE

3073, 

3081 yes

Bear Mountain 

Meadow 

Restoration

Special 

Habitat 

Restoratio

n

4

LSR100ac NR(F) Habitat 

maintained NLAA NLAA WCS 4

4 NLAA 3073, 

3081 no

Bear Mountain 

Meadow 

Restoration

Special 

Habitat 

Restoratio

n

14 Matrix NR(F) Habitat 

maintained NLAA NLAA WCS 4

7 NLAA 3073, 

3081 no

Road 24 Reroute

Road 

Constructi

on

6 Matrix NR(F) Habitat 

removed LAA NLAA 0 NE no

Road 24 Reroute

Road 

Constructi

on

2 Matrix Dispers

al

Habitat 

removed NLAA NLAA 0 NE no
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

157

Table B- 2. Status of the spotted owl and its habitat– Willamette NF.

WILLAMETTE NATIONAL FOREST Total Acres

Protected1 Unprotected2

Non Forest Service 

land within 

administrative unit 

boundary

Total 

Acres

% of 

Total Total Acres % of Total

Total 

Acres

% of 

Total

Acres within Boundary4 1,799,325 854,349 47% 944,9773 53% 111,3783 6%

Acres of Ownership5 1,687,947 854,349 51% 833,599 49%

Suitable Habitat – Capable 

Acres6 1,420,449 684,447 48% 735,613 52%

Suitable Habitat – Current Acres7 806,274 439,359 54% 366,916 46%

Known Spotted Owl Sites Number of 

Sites Protected % of Total Unprotected % of Total

Spotted Owl Sites8 621 449 72% 172 28%

Spotted Owl Sites with ≥ 50% 

suitable habitat in the core area 442 329 74% 113 26%

Spotted Owl Sites with ≥ 40% 

suitable habitat in the provincial 

home range

483 357 74% 126 26%

Spotted owl sites with ≥ 50% 

suitable habitat in the core area 

AND ≥ 40% suitable habitat in the 

provincial home range

415 310 75% 105 25%

1 Acres in this column are comprised of: Late Successional Reserves (LSR) and associated Riparian Reserves, 100-acre 

LSRs, Congressionally Withdrawn Areas.

2 Acres in this column are comprised of: Matrix, Adaptive Management Areas, and Administratively Withdrawn Areas 

including associated Riparian Reserves. Administratively Withdrawn Areas are included in the unprotected column 

because technically these areas are not designed to provide spotted owl habitat but rather to serve some other function 

such as “recreation and visual areas, back country, and other areas where management emphasis precludes scheduled 

timber harvest” (USDA, and USDI 1994a, p. A-4). The administrative land and resource management plan may protect 

and/or reduce the likelihood that spotted owl habitat located within Administratively Withdrawn Areas would be modified. 

3 Non-federal land is included in the Unprotected columns in this row only.

4 Acres in this row include both federal and non-federal lands within administrative boundaries. These acres are derived 

from corporate GIS data, which were last updated in 2013. All non-BLM or non-Forest Service acres are considered 

“unprotected.”

5 Acres shown in this row and all subsequent rows show only federal lands in the Willamette Planning Province.

6 Federal land that is capable of producing suitable spotted owl habitat, regardless of its current habitat.

7 Suitable habitat is defined as nesting, roosting, and foraging habitat.

8 Spotted owl sites represent pairs or resident singles 1990-2013. The Land Use Allocation of the site center determines 

whether it is shown in the protected or unprotected columns.

Data has been updated to reflect changes due to past harvest, land exchanges, GIS updates or new locations of spotted 

owl sites. 
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

158

Table B-3. Late-successional reserves and associated spotted owl habitat, Willamette NF –

2017.

LATE-SUCCESSIONAL 

RESERVE

TOTAL ACRES1 CAPABLE ACRES SUITABLE ACRES

% SUITABLE OF 

CAPABLE

RO2092 3,102 2,797 950 34%

RO213 57,167 55,218 36,460 66%

RO214 40,015 38,013 19,815 52%

RO215 27,822 25,558 16,610 65%

RO216 604 602 461 77%

RO217 9,860 9,372 8,057 86%

RO218 26,241 24,626 17,076 69%

RO219 66,023 65,344 35,855 55%

RO220 51,391 48,559 29,881 62%

RO221 16,612 15,965 10,313 65%

RO222 92,840 90,272 56,602 63%

TOTAL 319,677 376,326 232,080 62%

1

Includes only federal land within late successional reserves. Any overlapping wilderness acres have been removed 

from this table and are shown in the following table.

2 Opal Creek Wilderness is coincident with RO209 over a large portion of the LSR. In this table, Opal Creek 

Wilderness acres are not listed. See the following table for a combination of RO209 and Opal Creek Wilderness 

acres.

Table B-4. Late-successional reserves (LSRs)/wilderness complexes and associated spotted 

owl habitat, Willamette NF – 2017.

LSR / WILDERNESS COMPLEX TOTAL ACRES

CAPABLE 

ACRES

SUITABLE 

ACRES3

% SUITABLE 

OF CAPABLE

RO209/Opal Creek Wilderness 25,590 20,152 12,039 60%

RO213/Middle Santiam Wilderness 65,866 63,535 44,505 70%

RO214/Mt. Jefferson Wilderness 111,646 82,941 26,529 32%

RO215/Menagerie Wilderness 32,740 30,417 21,369 70%

RO218/Three Sisters Wilderness 212,972 159,769 97,019 61%

RO220/Waldo Lake Wilderness 85,540 79,409 55,338 70%

RO221/Diamond Peak Wilderness 35,548 31,045 24,723 80%

Mt. Washington Wilderness 40,223 17,033 3,994 23%

TOTAL 610,125 484,301 285,516 59%
Appendix B: Willamette National Forest LAA Biological Assessment- Willamette NF-FY 2018

159

Table B-5. Acres of critical habitat by subunit and habitat type on federal lands in the 

Willamette National Forest.

CRITICAL HABITAT 

SUBUNIT

SUITABLE HABITAT DISPERSAL HABITAT

NON-HABITAT (BUT 

FOREST CAPABLE)

Willamette National Forest

WCS-2 15 12 0

WCS-3 184,954 60,499 46,400

WCS-4 234,697 77,082 63,599

WCS-5 62 30 32

This table has been adjusted by previously consulted on actions that would remove suitable or 

dispersal habitat in 2012 critical habitat or actions that would downgrade suitable habitat to dispersal 

habitat in 2012 critical habitat.
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Owl Site Information and Narratives for Known Projects Proposed by the Willamette 

National Forest

Project narratives are included in this appendix for some projects to provide additional details about the project design 

than what was discussed in the text of this biological assessment. The project biologist has provided some initial effects 

analysis as a starting point for preparing the biological assessment. During the preparation of the BA and the consultation 

process, including the participation and feedback provided by the Level 1 Team members, effects assessments and 

determinations may have changed slightly and additional design criteria and mitigation measures may have been 

incorporated into the projects to reduce impacts to northern spotted owl. Refer to the text and tables in this BA for the 

final BA effects analysis for the proposed projects. For projects that do not have a project narrative, all the essential 

aspects of the projects are presented and discussed in the text of this document under the individual project discussions 

in the various effects sections.
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Project Narrative for Willamette Province FY2018 Biological Assessments

District/RA Project Name or Names6

BA 

(NLAA 

or 

LAA)

Cascades 

(East or 

West)

McKenzie River Lower South Fork McKenzie 

River Floodplain 

Enhancement – Wood 

Source Units

LAA West

Effects descriptions should include both beneficial and detrimental effects and their duration. This worksheet prompts for 

minimum information needed for activities and adversely affected spotted owl territories. Additional information may be 

required to adequately analyze the effects of an activity.

1. Description of the project.

Spotted owl consultation for this project is being proposed under ARBO II for the instream work, and the Level I 

programmatic consultation for the upland wood source units.

The harvest of 28 upland units is needed solely as a wood source for the Lower South Fork McKenzie River Floodplain 

Enhancement Project. Trees would be pushed over with heavy equipment to keep the root wad attached (which has more 

ecological value).

Suitable habitat treatments: This project would remove about 57 acres of suitable owl habitat with a post-treatment habitat 

type of non-habitat in stands are 120-130 years old. 53 acres would maintain a minimum canopy cover of 30%, contain five 

3-acre gaps, and two 2-acre unthinned skips which have concentrations of legacy trees. One of these skips is on the stand 

edge, and thus would not contribute to additional effects. Two additional small gaps of 2 acres in foraging habitat would be 

created adjacent to a road. Overall effects of this project are judged to be LAA. The amount of down wood left would meet 

or exceed Forest Plan standards and guidelines of 240 lineal feet or 2 down trees/acre. It is also expected that the unit 

would have at least one large snag/acre. Both designated skips contain large snags which are expected to be maintained. 

Since this activity would remove suitable habitat by removing it, Harvest – Habitat Remove may affect, and is likely to 

adversely affect spotted owls directly and indirectly by impairing the breeding or forage opportunities of resident spotted 

owls.

Dispersal habitat treatments: About 46 acres of dispersal habitat would be removed in scattered gaps ranging from 1-3 

acres in size in 60-80 year old stands that were recently thinned (Units 8-22). Three additional gaps (Units 26-28) in 

dispersal habitat are also planned for wood and helicopter staging areas.

Leave trees would be marked. Trees which show sign of insect or disease would be retained for natural snags or down 

wood. In addition, trees with crooked stems, forked tops, defects, or broken tops would be retained for wildlife habitat 

benefits. 

 
LAA Biological Assessment- Willamette NF-FY 2018

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Those snags that do not pose a safety concern would be retained to support habitat for the northern spotted owl preybase 

as well as primary cavity excavators. If falling is required, most snags will be left on site as downed wood if they do not 

pose a fire risk. Existing large down woody material will be maintained for habitat diversity, and full tree lengths will be 

retained as much as possible. 

The thinnings would not remove any existing downed wood from the stands or commercially harvest any existing snags. 

Snags that are hazards to the logging operations may be fallen and left on site, but the intent is to maintain existing snags 

where feasible. The amount of dead wood retained would meet Forest Plan standards and guidelines. Tree, shrub, and 

grass/forb forage planting or seeding may or may not occur in the gaps.

Following thinning and gap treatments, fuels may be treated to reduce wild fire risk by piling and burning, by limited 

broadcast burning, and by firewood sales. Fuel treatments are planned to protect all remaining live trees and snags.

We are describing the need for the entire project below as it relates to the need for a large wood source for river and 

floodplain placement. 

The purpose of the Lower South Fork McKenzie River Floodplain Enhancement project is to restore, to the extent 

practicable, the physical, chemical, and biological processes that maintain a healthy and resilient floodplain ecosystem. A 

well-functioning floodplain will provide diverse habitat for aquatic and terrestrial communities, including ESA-Threatened 

spring Chinook salmon and bull trout, Pacific lamprey and other native fishes, western pond turtle, amphibians, beaver, 

and waterfowl. Historically, the lower South Fork was a large alluvial valley with a complex network of side channels and 

frequently inundated floodplain. It was a depositional zone for much of the sediment, wood, and nutrients coming out of 

the South Fork drainage. As is typical of low gradient, alluvial valleys, this area was very biologically productive. According 

to 1937 surveys, the South Fork was the most important tributary for spring Chinook salmon spawning and the confluence 

area was known as a “bull trout paradise” that was intensively fished. 

Unfortunately, the South Fork has been significantly altered in the last century. Associated with construction of Cougar 

Dam in 1963 was straightening and channelization of the lower river with substantial amounts of levee, fill, and riprap 

material. In addition, large wood was removed from the river for timber and navigation purposes. These combined 

activities have limited the sediment and wood supply, altered the flow regime, reduced channel complexity, and restricted 

off-channel and floodplain connectivity. A recent habitat survey revealed very low pool habitat (12%) and wood 

abundance (<10 pieces/mile). The dominant substrate in both pools and riffles is cobble – too large for spawning. Fine 

sediment is no longer deposited onto floodplains, limiting nesting habitat for turtles. 

Recent studies indicate that stream biodiversity and productivity is greatest in streams that have a complex network of 

side channels (Cluer and Thorne 2013, Martens and Connolly 2014). Complex streams with a well-connected floodplain 

can be up to 250% more biologically productive than single thread channels (Bellmore et al. 2013). A review of projects 

designed to restore floodplain connectivity and side channel habitat increased salmon and trout production by 27-34% 

(Ogsten et al. 2014). By adding large wood to the Lower South Fork of the McKenzie River, we will be creating habitat 

features (pools, cover, gravel, side channels) that are important for native fish and wildlife.

This project proposes the following activities. Item 2 describes the need for large wood. 
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 Approximately 54 acres of levees (embankments built to prevent the overflow of a river), fill (material placed to dry 

out wetted areas), and riprap (material used to armor stream banks against scour and erosion) would be removed 

from stream banks and historic floodplains using heavy equipment. This material would be used to raise the 

elevation of the incised mainstem channel in order to restore flow to historic side channels and floodplain and to 

provide additional gravels and sediment to the system.

 Up to 4,000 pieces of large wood would be placed in stream channels and across adjacent floodplains. This wood 

would be sourced from 28 upland units totaling 105 acres, primarily from 2-3 acre gaps. Trees would be pushed 

over with heavy equipment to keep the root wad attached (which has more ecological value). 

 Up to three ponds would be enlarged and deepened using heavy equipment. They are currently shallow and 

ephemeral and expanding them will provide year-long benefits to Western pond turtles, waterfowl, and 

amphibians.

 Up to three culverts would be replaced and three road crossings would be removed to improve flow and aquatic 

organism passage.

 Approximately 3,100 linear feet of road would be decommissioned following access for the project

 All temporary roads and areas of disturbance would be fully rehabilitated and replanted with native vegetation.

o Will this treatment improve the overall quality of dispersal, forage or suitable habitat over time? 

The proposed treatments will result in a loss of foraging habitat that may last about 25 years in the 

thinned portion of units 1 and 2, and over 80 years in the 3-acre gaps. These gaps would retain all trees 

above 36 inches and under 18 inches since these diameters are not suitable for transport to the Lower 

South Fork McKenzie River project area. From a tree size standpoint, the thinning treatments may 

improve the growth response of the remaining trees in the thinned units 1 and 2. In these naturally 

regenerated stands, conifer trees would be removed across the 16-36” size class. Older fire regenerated 

stands, or mature stands, which are commonly associated with stands over 80 years of age show positive 

growth responses to thinning. Latham and Tappeiner (2002) showed that trees over 150 years old will 

respond to thinning with basal area growth “significantly greater ... for 15 to 63% of the trees.” Mature 

stands often have long term benefits of a variety of thinning densities which last 20-30 years (Latham and 

Tappeiner, 2002). Additionally 110-year old trees in heavy thinning stands showed a positive growth 

response which was “30 percent greater than that of the controls....” (Williamson, 1982).

It will take about 40 years for the created gaps to recover to dispersal habitat conditions for spotted owls. 

Thinned areas surrounding the gaps in units 1 and 2 are likely to recover to dispersal habitat within about 

15 years. The mix of gaps, surrounded by the thinned stand would take about 80 years to recover to 

foraging habitat conditions. At that time, the overall stand condition is likely to be improved over the 

current stand condition, since it would have improved vertical and horizontal diversity. 

The unharvested stands adjacent to the small gaps may show edge benefits with increased development 

of understory shrubs and forbs which have broad ecosystem benefits.

References:

Williamson, Richard L. 1982. Response to Commercial Thinning in a 110-year-old Douglas-Fir Stand. 

USDA Forest Service. Pacific Northwest Forest and Range Experiment Station. PNW-296.

Latham, P., and Tappeiner, J. 2002. Response of old-growth conifers to reduction in stand density in 

western Oregon forests. Tree Physiology 22:137-146.

Dispersal habitat conditions would not improve with the larger 3-acre gap treatments, however gap size in 

Critical Habitat is limited to 2 acres in size and these were located outside 0.5 mile nest core areas to 
LAA Biological Assessment- Willamette NF-FY 2018

164

reduce impacts. While there may be few or none as a result of the previous timber sale, any trees in 

these gaps under 14” diameter would be left. 

o Will the treatment accelerate or delay the development of late and old growth characteristics? 

o How long will it take for treated stands to develop into dispersal and suitable habitat with treatment 

compared to no-treatment? 

The 36 acres of thinned areas surrounding the gaps in units 1 and 2 may show slightly accelerated tree 

growth since there will be more open space to grow under the canopy, which will result in more rapid 

development of late and old growth characteristics. Thinning these stands to 30% canopy cover on average, 

would be expected to recover to 40% canopy cover and dispersal habitat conditions in 10 years. These 

areas would contain 60% canopy cover and suitable habitat characteristics in about 25 years. 

The four acres of gap creation in suitable habitat units 24 and 25 would delay the development of late and 

old growth characteristics by about 80 years. The remaining gaps in younger and recently harvested stands 

would delay the development of late and old growth characteristics by about 60-70 years.

o Additional rationale?

This project attempted to locate 4,000 pieces of large wood within an efficient distance to the South Fork 

McKenzie River Floodplain over a period of more than one year. The project being consulted on is an 

attempt to reduce effects of tree removal on the spotted owl and other resources by locating harvest units 

within the outer edges of known and surveyed home ranges, while still providing wood of adequate size 

and quantity for the project to provide the expected benefits to another listed species, Chinook salmon. 

The overall effects of this project are not beneficial to spotted owls.

2. Is the activity planned in any type of Late Successional Reserve (LSR)? 

☐ Yes ☒ No

3. Is the activity planned in Recovery Action 32 habitat?

☐ Yes ☒ No

4. Is the activity expected to disrupt owls, remove suitable or dispersal habitat, or have activities in a nest patch within a 

known or potential site territory?

☒ Yes ☐ No

If “yes”, spotted owl sites should also be entered into the NSO_sites spreadsheet whether the action is LAA or NLAA. 

If yes, complete the following.

 For all known or proposed owl sites that may be adversely affected, provide the following information.

o MSNO or other owl site identifier. 

2827, 2829

o Identify the priority of the owl site under RA 10. Use ranking 1-10 identified in new appendix.

8, 8
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165

o Describe the survey history regarding occupancy of the owl site (e.g., resident single, pair, unoccupied, 

unknown) and the nesting/reproductive status (e.g., nesting, non-nesting, unknown). Include when 

surveys were completed and if surveys were completed to protocol standards. If surveys have been 

recent, include the last five years. If surveys are historical (greater than 10 years ago), include the survey 

year that the activity center is based on. 

Both sites have been annually surveyed by the Oregon Cooperative Wildlife Research Unit since the late 

1980s. MSNO 2827 had a nesting pair in 2004, and also had 15 years of detections from 1988 to 2011. 

More recently, evening singles were found in 2009 and 2011. MSNO had a non-nesting pair in 1991 with 

no other detections in any other year. 

o Describe the site condition of the owl site.

 Nest Patch: Type of habitat, amount, and percentage within the nest patch both currently and 

after treatment.

No nest patch treatments are planned.

 Core Area: Amount and percentage of suitable habitat in the core area currently and after 

treatment.

No core area treatments are planned.

 Home Range: Amount and percentage of suitable habitat in the home range currently and after 

treatment.

MSNO 

2827

Current 

Acres/%

After 

Treatment 

Acres/%

Core 

Area 

Suitable 

Habitat

273/54% 273/54%

Home 

Range 

Suitable 

Habitat

1757/61% 1704/59%

MSNO 

2829

Current 

Acres/%

After 

Treatment 

Acres/%

Core 

Area 

Suitable 

Habitat

392/78% 392/78%

Home 

Range 

Suitable 

Habitat

1939/67% 1888/65%
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166

 If LAA effects are due to disruption, describe the source of disruption, time of year and how many seasons 

disruption is expected to occur.

None

 If LAA effects are due to general habitat modification (e.g., removal or downgrade of suitable habitat), 

describe the type of effects and their duration.

See above

 If LAA effects will occur to known or potential owl territories, describe these effects.

None, all territories will maintain suitable habitat levels above the thresholds.

o Explain the rationale for all LAA effects to the territory, including the potential for harm.

o Include any considerations relevant to the ability of a territory to provide for pair occupation and 

nesting/reproduction.

 For dispersal habitat removed, describe why the action is LAA or NLAA.

5. Is the activity planned in spotted owl critical habitat? 

☒ Yes ☐ No

If yes, complete the following:

 Describe the need and rationale for implementing the activity, and the specific treatments, in critical habitat.

The floodplain restoration project will occur on a large river with flows that could potentially reach up to 8,000cfs. 

Therefore, large whole trees will be essential to providing ballast and stability of logjams that are placed within the 

channel. We’ve searched extensively for potential wood source units with trees over 24”dbh, and the unit within 

Critical Habitat is the only large unit available, within a cost-efficient transport distance, that would provide enough 

large trees needed for the project as designed. Because it’s the only large unit, we need to maximize the number 

of trees taken from the unit.

 Describe the effects to critical habitat (NLAA, LAA or NE [if activity is disruption-only]).

Removal of suitable and dispesal habitat would modify spotted owl suitable habitat to the extent that it no longer 

serves the function of nesting, roosting and foraging. It may, however, continue to function as dispersal habitat. 

Since this activity would remove suitable and dispersal habitat, HH Remove may affect, and is likely to adversely 

affect spotted owl critical habitat either directly or indirectly by impairing the breeding, forage, or dispersal 

opportunities for resident spotted owls and reducing roosting opportunities for dispersing spotted owls. Effects to 

critical habitat from this project are expected to be LAA due to the removal of 53 acres of suitable owl habitat. 

 Address the effects of the activity(s) on PCEs (e.g., large trees, canopy complexity, snags and down logs; 

nesting, roosting, forage and dispersal habitats). Compare the effects of treatment vs. no treatment on PCE and 

habitat trajectories over a similar timeframe.

 PCE 1 is the forest types that support NSOs. This criterion was used to identify CH affected by the project. Because 

the tree removal would not result in a change in forest type, there is no effect to this PCE.
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167

 PCEs 2, 3, and 4 (nesting/roosting, foraging, and dispersal habitat) were specifically considered with respect to the 

proposed action to determine if they were removed, reduced, maintained or enhanced at a stand level. The 

assessment considered both short-term (0-15 years) and long-term (16-100 years) effects with respect to these 

PCEs. For early seral stands of capable (i.e. PCE 1) habitat that currently do not provide PCEs 2-4, the analysis 

of impacts had both a temporal scale (would the actions would delay or accelerate the development of the PCEs in 

the stand following treatment) and a qualitative scale (would the future habitat be better or worse with respect to 

the PCEs as a result of the treatment).

 The Lower South Fork McKenzie River Floodplain Enhancement Project would remove about 53 acres of suitable 

owl habitat, and 6 acres of dispersal habitat in critical habitat and thus affect PCEs 2, 3 and 4 at the stand scale. 

Tree removal would affect the spotted owl preybase, habitat capability and thus further reduce the local habitat 

quality for spotted owls. Dispersal habitat would not be present for about 10 years until the canopy recovers to 40%. 

With the thinning down to 30%, some of the remaining smaller trees would be released and thus their size and 

canopy complexity would be improved within several years. Some snags may be lost if they pose a hazard to the 

operation. Any impacts to PCEs 2, 3 and 4 should not be significant or adverse at the subunit CH scale.

 How long would the attainment of suitable habitat be delayed or accelerated by the activity? 

Suitable habitat attainment would be delayed by about 25 years as described above for units 1-7. In the 

remaining gaps totaling 6 acres, suitable habitat would recover in about 80 years. 

 Would there be sufficient suitable habitat in the immediate area after treatment to support a known or 

potential site? 

Two historically known sites have home ranges that overlap the 53 acres of suitable owl habitat that would be 

removed. While both sites have not had owls present for over 10 years and thus meet the definition of 

“unoccupied”, habitat levels are sufficient to support both sites.

 Discuss the effects of activities not located in critical habitat that may adversely affect owl territory(s) where 

the owl center is located in critical habitat.

Other project activities adjacent to the critical habitat are the proposed gaps in dispersal, however they are 

located outside the nest core of the nearest known owl site.

 Address special management considerations specific to the critical habitat unit.

WCS 3

West Cascades/Coast Ranges of Oregon and Washington

1. Conserve older stands that contain the conditions to support northern spotted owl occupancy or high-value 

northern spotted owl habitat as described in Recovery Actions 10 and 32 (USFWS 2011, pp. III-43, III-67). On 

Federal lands this recommendation applies to all land-use allocations (see also Thomas et al. 2006, pp. 284–

285). How does this activity meet this special management consideration?

Units 1-7 which contain suitable owl habitat were extensively field-reviewed during the fall of 2016. This field 

review resulted in two small 2-acre no-harvest skips that contain a concentration of larger legacy trees, as 

well as dropping of an additional area over a stream that contained RA32 habitat. 

2. Management emphasis needs to be placed on meeting northern spotted owl recovery goals and long-term 

ecosystem restoration and conservation. When there is a conflict between these goals, actions that would 
LAA Biological Assessment- Willamette NF-FY 2018

168

disturb or remove the essential physical or biological features of northern spotted owl critical habitat need to 

be minimized and reconciled with long-term ecosystem restoration goals. How does this activity meet this 

special management consideration?

This project would remove about 53 acres of suitable owl habitat and the final overstory canopy would be 

retained above 30%. Treatments would leave the largest trees intact, especially since their size limits 

transport as a wood source. In addition, most snags that do not pose a hazard to the operation would be 

retained. The understory stand structure would be diversified which could benefit the long-term stand 

structure.

3. Continue to manage for large, continuous blocks of late-successional forest. How does this activity meet this 

special management consideration?

No large, continuous blocks of late-successional forest would be removed with this project. 

4. In areas that are not currently late-seral forest or high-value habitat and where more traditional forest 

management might be conducted (e.g. matrix), these activities should consider applying ecological forestry 

prescriptions. Some examples that could be utilized include Franklin et al. (2002, pp. 417–421; 2007, entire), 

Kerr (2012), Drever et al. (2006, entire), Johnson and Franklin (2009, pp. 39–41), Swanson et al. (2010, 

entire), and others cited in the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011, pp. III-14, 

III-17 to III-19). Does the activity apply ecological forestry prescriptions?

☒ Yes ☐ No

If yes, describe what measures will be used (e.g., % skips, dead wood creation, leaving legacy features, 

releasing hardwoods, diversity thinning prescription, etc.). 

The thinning treatment will maintain an average stand canopy cover of 30 percent. This project will leave 

primarily the largest and healthiest trees with the largest crowns. Trees to be removed would range mostly 

within the 16-24 inch diameter range, although some may be larger. Understory treatments include removal 

of smaller tree size classes down to 7” diameter. 

Two 2-acre no-treatment skips are planned as part of this project. 

Snags will be felled if they pose a hazard to the thinning operation, and will be left on site. Existing large down 

woody material will be maintained for habitat diversity, and full tree lengths will be retained as much as 

possible. The amount of down wood left would meet or exceed Forest Plan standards and guidelines of 240 

lineal feet/acre. 

Project Narrative for Willamette Province FY2018 Biological Assessments

District/RA Project Name or Names7 BA 

(NLAA or LAA)

Cascades 

(East or West)

McKenzie River Ranger 

District

Park Thin LAA West

 
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169

1. Description of the project.

The McKenzie River Ranger District is proposing to treat approximately 85 acres in a stand that is 80-120 years old. 

Treatments would include 63 acres of commercial thinning, 3 gaps totalling 7 acres(THE GAPS WERE CHANGED TO 

HABITAT REMOVAL), and a 15 acre area that would be left unharvested as a skip to improve structural diversity. 

Thinning would primarily remove smaller, unhealthy trees that would be logged with skyline equipment. Gaps would 

increase diversity of shrub and forb habitat. 

The purpose of this project is to increase stand health and vigor; accelerate development of structural complexity, and 

provide wood products to the public. The area proposed for treatment is a fire-regenerated stand with Douglas-fir 

forming the primary overstory species with a minor component of western hemlock. The stand is currently in the 

beginning of the understory reinitiation stage of development (Oliver & Larson, 1996). There are approximately 126 

trees per acre, with an average diameter of 19.2 inches. This homogeneous stand is overstocked with declining vigor 

that leads to poor tree health, growth is severely limited, and competition mortality is ongoing. The stand is also at 

densities that limit the long-term survival and growth of understory regeneration, which limits the development of a 

more complex vertical canopy structure. The proposed project would release residual overstory and understory trees, 

increasing their growth, size, and vigor; increase overall stand health; accelerate the vertical structural complexity of the

stand and species diversification by releasing understory trees and plants; and do so while maintaining other existing 

structural and habitat components through the retention of existing snags and down wood, as well as some skipped, 

untreated areas over time.

Thinning treatments, totaling 63 acres will result in a stand with approximately 40 percent canopy cover and 55-65 

residual trees per acre. The project will primarily leave the biggest and healthiest trees with the largest crowns. The 

desired tree spacing in the thinning area will range between 18 to 36 feet, providing diversity in a more open 

environment to promote understory development by reducing competition for light, water, and soil nutrients. This 

project will accelerate development of larger conifer trees and meet all environmental requirements for soil, water, air, 

and wildlife habitat quality.

A minor (0-3/acre stand average) component of legacy trees and snags from the original stand may be present, but the 

thinnings would not harvest these features. The thinnings would not remove any existing downed wood from the stands 

or commercially harvest any existing snags. Snags that are hazards to the logging operations may be fallen and left on 

site, but the intent is to maintain existing snags where feasible. The amount of dead wood retained would meet Forest 

Plan standards and guidelines. A minimum of 40% canopy cover would remain in the stand, post-treatment. Gaps up to 

3-acres in size may be created in the stands while retaining the overall 40% canopy at the stand scale. Tree, shrub, and 

grass/forb forage planting or seeding may or may not occur in the gaps.

Unthinned skips may or may not be designed in the harvest units, depending on how the unit is drawn. In all layouts, 

unharvested areas are located for riparian buffers and to protect survey and manage species, special habitat areas, and 

other resource considerations. These may or may not be included in the units as unthinned skips, depending on whether 

the units are drawn to include or exclude these areas. In some projects, unthinned skips are also specifically designed to 

increase horizontal diversity beyond what would be achieved by buffers to protect other resources.

Some snag and downed logs may be created in or near the units after harvest. Because such treatments are usually 

done with KV or other funding sources that cannot be guaranteed at the time the treatments are being planned, snag 

and downed log creation is usually not a required design element of the treatment prescription unless it is needed to 
LAA Biological Assessment- Willamette NF-FY 2018

170

meet Plan Standards and Guidelines. Unless deadwood creation is a required element of the design criteria, it is not 

considered in the effects analysis. Nevertheless, a considerable amount of deadwood creation occurs post-treatment in 

HH Maintain treatments using KV and other funding sources. For Eugene BLM actions, snag and/or down log creation 

may or may not occur only within Riparian Reserves. No creation is planned in uplands on Eugene BLM.

Following thinning, fuels may be treated to reduce wild fire risk by piling and burning, by limited broadcast burning, and 

by firewood sales. If broadcast burning is used, an overstory mortality of up to 10% is acceptable and would create snag 

habitat. However, very few if any trees are generally killed as a result of broadcast burning. 

• Damage to residual trees, vegetation, and retained snags will be minimized when falling and yarding. 

• Snags will be retained when not a safety concern to support the prey of northern spotted owls and primary cavity 

excavators. If falling is required, they will be left on site as downed wood. The sale administrator should work with the 

purchaser to retain existing full tree lengths as much as possible.

• Existing large down woody material will be maintained for habitat diversity. 

• Gaps will retain two to three trees per acre in clumps or as individual trees to add diversity and provide for future 

recruitment of snags and down woody material.

• All off-road equipment will be cleaned to remove all dirt and debris prior to entering National Forest System Lands. 

Landings will not be placed in or adjacent to invasive plant infestations.

• Reduce treatment-created fuels or natural fuel accumulations through various methods such as hand and machine 

piling or pile burning to lessen the fire hazard. If slash piles are created, three to five piles per acre may be retained for 

wildlife benefit. If grapple piles are created, one pile will be left per every three acres.

• The stand contains a Class IV stream that will be protected with a no harvest buffer.

Associated activities would consist of road maintenance that includes rocking, brushing, blading, and rock compaction. 

Temporary road construction would not exceed 0.5 miles and there would be no permanent road construction, 

reconstruction, or culvert replacement. 

Fill in the items below.

 Describe the overall effects of the proposed project (NLAA/LAA). (Effects to LSR, RA32 habitat, critical habitat, 

and adverse effects to specific owl territories or sites are discussed below.)

Park Thin is a mature stand between 80-120 years old and is judged to contain a mix of dispersal and suitable 

spotted owl habitat. The aerial photo shows some areas that may be dispersal habitat, and a field review by the 

wildlife biologist has not yet been conducted. The forester who is proposing this project did not note any overstory 

legacy trees during the initial field assessment. If any large overstory trees are present, they would be left standing. 

 Compare effects of treatment vs. no treatment (Effects to LSRs, RA 32 habitat, owls subject to RA10, and effects 

to critical habitat are discussed below.)

o Will this treatment improve the overall quality of dispersal, forage or suitable habitat over time? 

The treatment will provide diversity in a more open environment to promote understory development, which 

will improve long-term stand structural diversity. The project will primarily leave the biggest and healthiest 

trees that possess the largest crowns. 

Will the treatment accelerate or delay the development of late and old growth characteristics? 
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171

The treatment may result in an increase in the rate of development of late successional characteristics.

o How long will it take for treated stands to develop into dispersal and suitable habitat with treatment 

compared to no-treatment? 

Because a minimum of a 40% canopy cover would be maintained, the stand would remain as dispersal 

habitat after treatment. With this level of canopy retention, it would be expected to again reach suitable 

habitat stand quality in about 15 years, and the overall stand structure is expected to improve, compared 

to no-treatment. 

0-

6.9” DBH

7-

16.9” DBH

17-

26.9” DBH

27-

32.9”DBH

33-

42.9”DBH

Total TPA

PSME 

Douglas-fir 

Trees/ Acre 54 46 57 15 5 177

TSHE

W. Hemlock

Trees/ Acre

31 1 2 0 0 34

TOTAL 85 47 59 15 5 211

o Additional rationale?

6. Is the activity planned in any type of Late Successional Reserve (LSR)? 

☐ Yes ☒ No

7. Is the activity planned in Recovery Action 32 habitat?

☐ Yes ☒ No

8. Is the activity expected to disrupt owls, remove suitable or dispersal habitat, or have activities in a nest patch within a 

known or potential site territory?

☒ Yes ☐ No

If “yes”, spotted owl sites should also be entered into the NSO_sites spreadsheet whether the action is LAA or NLAA. 

If yes, complete the following.

 For all known or proposed owl sites that may be adversely affected, provide the following information.

o MSNO or other owl site identifier. 

No spotted owl territories are known from the project area, and none are expected due to high habitat 

fragmentation. 

o Identify the priority of the owl site under RA 10. Use ranking 1-10 identified in new appendix.
LAA Biological Assessment- Willamette NF-FY 2018

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NA

o Describe the survey history regarding occupancy of the owl site (e.g., resident single, pair, unoccupied, 

unknown) and the nesting/reproductive status (e.g., nesting, non-nesting, unknown). Include when 

surveys were completed and if surveys were completed to protocol standards. If surveys have been 

recent, include the last five years. If surveys are historical (greater than 10 years ago), include the survey 

year that the activity center is based on. 

The project area has not been surveyed to protocol standards recently. While this area was surveyed in 

the late 1980s, no spotted owls have ever been documented in the project area. The nearest known owl 

location is a 1993 day resident single over 1.5 miles away.

o Describe the site condition of the owl site. 

 Nest Patch: Type of habitat, amount, and percentage within the nest patch both currently and 

after treatment.

 Core Area: Amount and percentage of suitable habitat in the core area currently and after 

treatment.

 Nest Patch: Amount and percentage of suitable habitat in the home range currently and after 

treatment.

 If LAA effects are due to disruption, describe the source of disruption, time of year and how many seasons 

disruption is expected to occur.

None

 If LAA effects are due to general habitat modification (e.g., removal or downgrade of suitable habitat), 

describe the type of effects and their duration.

Harvest – Habitat Downgrade of suitable and dispersal habitat thinning treatments may provide indirect beneficial 

effects to spotted owls because such treatments are expected to accelerate the growth of retained trees and could 

accelerate the rate at which some structural characteristics appear (e.g., large side limbs, greater crown ratios). 

While opening of the canopy may provide less suitable habitat conditions for the flying squirrel prey, leaving down 

wood and created piles would improve habitat conditions for other prey species such as woodrats. 

 If LAA effects will occur to known or potential owl territories, describe these effects.

o Explain the rationale for all LAA effects to the territory, including the potential for harm.

o Include any considerations relevant to the ability of a territory to provide for pair occupation and

nesting/reproduction.

 For dispersal habitat removed, describe why the action is LAA or NLAA.

9. Is the activity planned in spotted owl critical habitat? 
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☐ Yes ☒ No
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Project Narrative for Willamette Province FY2018 Biological Assessments

District/RA Project Name or Names8 BA 

(NLAA or LAA)

Cascades 

(East or West)

McKenzie River Ranger 

District

Q Thin LAA West

1. Description of the project. The McKenzie River Ranger District is proposing to treat approximately 90 acres in a 

stand that is 80-120 years old. Treatments would include 63 acres of commercial thinning, 7 acres of gaps(THE GAPS 

WERE CHANGED TO HABITAT REMOVAL),, and two no-harvest skips totalling 20 acres. Thinning would primarily 

remove smaller, unhealthy trees. The mix of skips, gaps, and thinning would increase overall structural diversity and also 

create small patches of increased shrub and forb diversity. 

The purpose of this project is to increase stand health and vigor; accelerate development of structural complexity, 

and provide wood products to the public. The area proposed for treatment is a fire-regenerated stand with 

Douglas-fir forming the primary overstory species with a minor component of western hemlock, Pacific silver fir, and 

Grand fir. The stand is currently in the beginning of the understory reinitiation stage of development (Oliver & 

Larson, 1996). There are approximately 137 trees per acre, with an average diameter of 20.4 inches. This 

homogeneous stand is overstocked with declining vigor that leads to poor tree health. the stand is currently at 

densities where stand health and vigor from a tree-perspective are in decline, growth is severely limited, and 

competition mortality is ongoing. The stand is also at densities that limit the long-term survival and growth of the

understory regeneration, which limits the development of a more complex vertical canopy structure. The proposed 

project would release residual overstory and understory trees, increasing their growth, size, and vigor; increase 

overall stand health; accelerate the vertical structural complexity of the stand and species diversification by 

releasing understory trees and plants; and do so while maintaining other existing structural and habitat components 

through the retention of existing snags and down wood, as well as some skipped, untreated areas over time.

Thinning treatments, totaling 63 acres will result in a stand with approximately 40 percent canopy cover and 55-65 

residual trees per acre. The project will primarily leave the biggest and healthiest trees with the largest crowns. The 

desired tree spacing in the thinning area will range between 18 to 36 feet, providing diversity in a more open 

environment to promote understory development by reducing competition for light, water, and soil nutrients. This

project will accelerate development of larger conifer trees and meet all environmental requirements for soil, water, 

air, and wildlife habitat quality.

• Temporary spurs shall be limited to no more than 1⁄2 mile in total length and use existing impacted areas wherever 

possible. Existing skid roads will be used as much as possible to minimize soil compaction. 

• Operations will be suspended if rainfall results in pooling or offsite movement of sediment. 

• Damage to residual trees, vegetation, and retained snags will be minimized when falling and yarding. 

• Snags will be retained when not a safety concern to support the prey of northern spotted owls and primary cavity 

excavators. If falling is required, they will be left on site as downed wood. The sale administrator should work with 

the purchaser to retain existing full tree lengths as much as possible.

• Existing large down woody material will be maintained for habitat diversity. 

 
LAA Biological Assessment- Willamette NF-FY 2018

175

• Gaps will retain two to three trees per acre in clumps or as individual trees to add diversity and provide for future 

recruitment of snags and down woody material.

• All off-road equipment will be cleaned to remove all dirt and debris prior to entering National Forest System 

Lands. Landings will not be placed in or adjacent to invasive plant infestations.

• Reduce treatment-created fuels or natural fuel accumulations through various methods such as hand and 

machine piling or pile burning to lessen the fire hazard. If slash piles are created, three to five piles per acre may be 

retained for wildlife benefit. If grapple piles are created, one pile will be left per every three acres.

Associated activities would consist of road maintenance that includes rocking, brushing, blading, and rock 

compaction. Temporary road construction would not exceed 0.5 miles and there would be no permanent road 

construction, reconstruction, or culvert replacement.

Q Project Trees per Acre by Species

 0-

6.9” DBH

7-16.9”DBH 17-

26.9”DBH

27-

32.9”DBH

33-

42.9”DBH

Total TPA

PSME

Douglas-fir 

Trees/ Acre

36 33 56 10 4 139

TSHE

W. Hemlock 

Trees/ Acre

18 0 2 3 0 23

ARGR

Grand fir 

Trees/ Acre

9 0 0 0 0 9

ABAM

Pac Silver fir 

Trees/ Acre

55 19 10 0 0 84

TOTAL 118 52 68 13 4 255

Q Thin is proposed in a stand that contains a mix of low quality foraging and dispersal habitat at a moderately high 

elevation of about 4,000 feet. About 27 acres in the stand center was thinned in 1989 with the Three Bears sale and 

currently consists of dispersal habitat with a more open canopy than the rest of the stand. The remaining 43 acres 

proposed for harvest qualify as low quality foraging habitat. A minor (0-3/acre stand average) component of legacy 

trees and snags from the original stand is present, but the thinning would not harvest these features. The thinning 

would not remove any existing downed wood from the stands or commercially harvest any existing snags. Snags that 

are hazards to the logging operations may be fallen and left on site, but the intent is to maintain existing snags where 

feasible. The amount of dead wood retained would meet Forest Plan standards and guidelines. Post-treatment, the 

thinned stand would have at least two snags and two trees per acre of large down wood of the average stand 

diameter left, counted as full tree lengths, all in decay classes 1-2. If these are not present post-treatment, 

enhancement treatments are recommended. A minimum of 40% canopy cover would remain in the stand, posttreatment. Gaps up to 3-acres in size (no more than 7 acres total) may be created in the stand while retaining the 

overall 40% canopy at the stand scale. Tree, shrub, and grass/forb forage planting or seeding may or may not occur 

in the gaps.

Snags and downed logs may be created in or near the units after harvest. Because such treatments are usually done 

with KV or other funding sources that cannot be guaranteed at the time the treatments are being planned. 
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176

Nevertheless, a considerable amount of deadwood creation occurs post-treatment using KV and other funding 

sources. 

Following thinning, fuels may be treated to reduce wild fire risk by piling and burning, by limited broadcast burning, 

and by firewood sales. While the post-harvest slash treatments are not yet known, if broadcast burning is used, a 

limited amount of overstory stand mortality may occur and is desireable from a wildlife perspective. Large snags will 

be protected during burning operations.

Fill in the items below.

 Describe the overall effects of the proposed project (NLAA/LAA). (Effects to LSR, RA32 habitat, critical habitat, 

and adverse effects to specific owl territories or sites are discussed below.)

Q Thin is a mature stand between 80-120 years old and is judged to contain a mix of dispersal and suitable spotted 

owl habitat. The project would not remove the largest overstory trees, and would release the understory trees. This 

project would thin suitable owl habitat and thus, downgrade suitable owl habitat to dispersal habitat. These effects 

are LAA – Likely to Adversely Affect. 

 Compare effects of treatment vs. no treatment (Effects to LSRs, RA 32 habitat, owls subject to RA10, and effects 

to critical habitat are discussed below.)

o Will this treatment improve the overall quality of dispersal, forage or suitable habitat over time? 

The treatment will provide diversity in a more open environment to promote understory development, which 

will improve long-term stand structural diversity. The project will primarily leave the biggest and healthiest 

trees that possess the largest crowns. 

o Will the treatment accelerate or delay the development of late and old growth characteristics? 

The treatment may result in an increase in the rate of development of late successional characteristics.

o How long will it take for treated stands to develop into dispersal and suitable habitat with treatment 

compared to no-treatment? 

Because a minimum of a 40% canopy cover would be maintained, the stand would remain as dispersal 

habitat after treatment. With this level of canopy retention, it would be expected to again reach suitable 

habitat stand quality in about 15 years, and the overall stand structure is expected to improve, compared 

to no-treatment. 

o Additional rationale?

10. Is the activity planned in any type of Late Successional Reserve (LSR)? 

☐ Yes ☒ No

11. Is the activity planned in Recovery Action 32 habitat?

☐ Yes ☒ No

12. Is the activity expected to disrupt owls, remove suitable or dispersal habitat, or have activities in a nest patch within a 

known or potential site territory?

☒ Yes ☐ No

If “yes”, spotted owl sites should also be entered into the NSO_sites spreadsheet whether the action is LAA or NLAA. 

If yes, complete the following.
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177

 For all known or proposed owl sites that may be adversely affected, provide the following information.

o MSNO or other owl site identifier. Identify the priority of the owl site under RA 10. Use ranking 1-10 

identified in new appendix.

MSNO 4085 - 3

MSNO 4488 - 4

o Describe the survey history regarding occupancy of the owl site (e.g., resident single, pair, unoccupied, 

unknown) and the nesting/reproductive status (e.g., nesting, non-nesting, unknown). Include when 

surveys were completed and if surveys were completed to protocol standards. If surveys have been 

recent, include the last five years. If surveys are historical (greater than 10 years ago), include the survey 

year that the activity center is based on. 

MSNO 4085 was last found nesting in 1996, a pair was found in 2013, and an evening pair was detected 

in 2016. Other previous owl detections for this site included a 1993 day resident single, 1994 evening 

pair, and a 1998 evening single. This site is annually monitored by the Oregon Cooperative Wildlife 

Research Unit.

MSNO 4488 appears to have never nested and the last detection occurred with an evening pair in 2005. 

There were also evening single detections in 2014, 2012, and 2006. There was an evening resident 

single detection in 2003 and 2004; and a pair in 1999. This site is annually monitored by the Oregon 

Cooperative Wildlife Research Unit.

o Describe the site condition of the owl site.

 Nest Patch, Core Area, and Home Range: Type of habitat, amount, and percentage within the 

nest patch both currently and after treatment.

MSNO 4085 Current 

Acres/%

After Treatment 

Acres/%

Nest Patch 

Suitable 

Habitat

41/59% 41/59%

Core Area 

Suitable 

Habitat

276/55% 276/55%

Home Range 

Suitable 

Habitat

1423/49% 1417/49%

MSNO 4488 Current 

Acres/%

After Treatment 

Acres/%

Nest Patch 

Suitable 

Habitat

30/43% 30/43%
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178

Core Area 

Suitable 

Habitat

215/43% 215/43%

Home Range 

Suitable 

Habitat

1050/36% 1029/36%

 If LAA effects are due to disruption, describe the source of disruption, time of year and how many seasons 

disruption is expected to occur.

 If LAA effects are due to general habitat modification (e.g., removal or downgrade of suitable habitat), 

describe the type of effects and their duration.

Harvest – Habitat Downgrade of suitable and dispersal habitat thinning treatments may provide indirect 

beneficial effects to spotted owls because such treatments are expected to accelerate the growth of 

retained trees and could accelerate the rate at which some structural characteristics appear (e.g., large 

side limbs, greater crown ratios). While opening of the canopy may provide less suitable habitat conditions 

for their primary prey species, the flying squirrel, leaving down wood and created piles would improve 

habitat conditions for other prey species such as woodrats. 

 If LAA effects will occur to known or potential owl territories, describe these effects.

o Explain the rationale for all LAA effects to the territory, including the potential for harm.

Suitable habitat acres would remain above the threshold within the 0.5 mile core areas and the home range 

of MSNO 4085. However, home range suitable habitat acres for MSNO 4488 are already below threshold 

levels at 1,050 acres. The Q Thin project is not expected to harm this territory because of the large block 

of ~190 acres of non-habitat on private land that lies between the nest core and the outer perimeter of the 

home range where the Q Thin unit is located. About 21 acres of foraging habitat within this home range are 

proposed for thinning, and 40% canopy cover would remain. It is very unlikely that the owl or owls at that 

site use this habitat. Thinning the Q Thin unit is not expected to harm the territory of MSNO 4488. 

Harvest – Habitat Downgrade would modify spotted owl suitable habitat to the extent that it no longer serves 

the function of nesting, roosting and foraging. It may, however, continue to function as dispersal habitat.

Since this activity would remove suitable habitat by downgrading it to dispersal, Harvest – Habitat 

Downgrade may affect, and is likely to adversely affect spotted owls directly and indirectly by impairing the 

breeding or forage opportunities of resident spotted owls.

o Include any considerations relevant to the ability of a territory to provide for pair occupation and 

nesting/reproduction.

The current condition of the Q Thin proposed treatment stand is that it contains a mix of dispersal and 

suitable habitat that does not have nesting potential. Downgrade of suitable habitat would modify spotted 

owl suitable habitat to the extent that it no longer serves the function of foraging. It may, however, continue 

to function as dispersal habitat. Since this activity would remove suitable habitat by downgrading it to 

dispersal, HH Downgrade may affect, and is likely to adversely affect spotted owl habitat either directly or 

indirectly by impairing the breeding or forage opportunities for resident spotted owls and reducing roosting 

opportunities for dispersing spotted owls.

 For dispersal habitat removed, describe why the action is LAA or NLAA.
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179

No dispersal habitat would be removed.

13. Is the activity planned in spotted owl critical habitat? 

☒ Yes ☐ No

If yes, complete the following:

 Describe the need and rationale for implementing the activity, and the specific treatments, in critical habitat.

The project would accelerate development of larger conifer trees and bigger crowns, and improve structural 

habitat diversity in a younger mature stand under 120 years of age.

 Describe the effects to critical habitat (NLAA, LAA or NE [if activity is disruption-only]).

Thinning the 70 acres in the Q Thin stand would downgrade the 43 acres of 80-120 year old foraging habitat that 

is not suitable for nesting. Effects to critical and spotted owl habitat would be LAA for general habitat modification 

of suitable habitat, NE for disturbance, and LAA to critical habitat.

 Address the effects of the activity(s) on PCEs (e.g., large trees, canopy complexity, snags and down logs; 

nesting, roosting, forage and dispersal habitats). Compare the effects of treatment vs. no treatment on PCE and 

habitat trajectories over a similar timeframe.

Without treatment, the project biologist estimated the stands would continue to slowly develop into higher quality 

suitable foraging habitat (PCE 3) over the next 40 years and improve even more over time. Those areas with 

dispersal habitat would develop into low quality suitable habitat in the next 20 years. With treatment, the suitable 

habitat would be downgraded to dispersal habitat and recover to suitable habitat after ~15 years, at which time the 

habitat quality would be improved as discussed above. Due to the short-term effects to suitable habitat for about 15 

years, the project biologist identified this potential effect as likely to adversely affect critical habitat. In the longerterm, the thinning should create more vegetation layers, larger-sized trees, and greater canopy development 

compared to no-treatment which would benefit PCE 3. Snag and down wood habitat levels may be improved with 

this project if they do not currently meet Northwest Forest Plan levels and funding is available. Within CH, large 

snags should be present at a minimum of 3/acre within 0.5 mile owl core areas, and 2/acre in treated suitable 

habitat. Down wood levels should be present at 3 and 2 trees/acre, respectively, and created if they are not present. 

A delay of foraging habitat on ~43 acres of CH will not affect the future functionality of any owl sites. Suitable habitat 

is currently above threshold levels within one of the known owl home ranges, and the other owl home range area 

that the Q Thin unit is within, is unlikely to be used due to the ~190 acre patch of private land with non-habitat that 

is located between the Q Thin unit and the nest core. 

The treatments would downgrade about 43 acres of suitable habitat in critical habitat for about 15 years. To assess 

the effects to this temporary loss of suitable habitat on owl dispersal in the area, the project wildlife biologist 

evaluated the amount of dispersal and suitable habitat (since both habitats provide for dispersal) within 0.5 miles of 

the treatment units. A landscape photo shows good north-south suitable and contiguous habitat corridors, as well 

as a broad east-west corridor both to the north and the south of the Q Thin unit. These corridors are expected to 

continue to provide dispersal habitat without adversely impacting owl dispersal at this localized scale. No breaks 

in any existing corridor of forested habitat are expected to occur as a result of the proposed Q Thin treatment. 

Sufficient dispersal habitat would be maintained to provide for the life-history needs for dispersal for any spotted 

owls using this area. Therefore the action is not expected to adversely affect dispersal habitat (PCE 4) in critical 

habitat. 

 How long would the attainment of suitable habitat be delayed or accelerated by the activity? 

The treatments would not delay and could accelerate the development of PCE 2 (nesting/roosting habitat). Because 

the treatments are expected to increase diameter, crown radius, and crown ratio of individual trees, they are 

expected to improve the quality of PCE 2 in the long term and may be beneficial to PCE 2. Some of the created 

slash piles would be retained, which would benefit the woodrat preybase of spotted owls. There is also an 

opportunity to enhance snag and large down wood habitat which would further improve habitat quality.
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180

 Would there be sufficient suitable habitat in the immediate area after treatment to support a known or 

potential site? 

Yes, see above discussion.

 Discuss the effects of activities not located in critical habitat that may adversely affect owl territory(s) where 

the owl center is located in critical habitat.

Both owl activity centers, most of the home range areas as well as the Q Thin proposed unit are located in 

critical habitat. 

 Address special management considerations specific to the critical habitat unit.

Subunit WCS 3 has about 319,736 acres, and is expected to function primarily for demographic support to the 

overall spotted owl population, as well as north-south connectivity between subunits. Since the proposed thinning 

would temporarily downgrade low quality suitable owl habitat on a landscape that shows adequate north-south 

connectivity based on a visual examination of an aerial photo, overall effects to the critical habitat unit connectivity 

are judged to be NLAA.

West Cascades/Coast Ranges of Oregon and Washington

1. Conserve older stands that contain the conditions to support northern spotted owl occupancy or high-value 

northern spotted owl habitat as described in Recovery Actions 10 and 32 (USFWS 2011, pp. III-43, III-67). On 

Federal lands this recommendation applies to all land-use allocations (see also Thomas et al. 2006, pp. 284–

285). How does this activity meet this special management consideration?

No RA32 habitat would be modified.

2. Management emphasis needs to be placed on meeting northern spotted owl recovery goals and long-term 

ecosystem restoration and conservation. When there is a conflict between these goals, actions that would 

disturb or remove the essential physical or biological features of northern spotted owl critical habitat need to 

be minimized and reconciled with long-term ecosystem restoration goals. How does this activity meet this 

special management consideration?

The proposed Q Thin project has been designed to thin with a “light touch” treatment that would maintain a 

stand average of 40% canopy post treatment. The thinning treatment would improve stand structure and tree 

growth rates as described above and may provide benefits to the functions of critical habitat after 15 and 

more years. 

3. Continue to manage for large, continuous blocks of late-successional forest. How does this activity meet this 

special management consideration?

Maintaining a 40% canopy to the south of a large patch of private land that is non-habitat, and in between 

three known home ranges will maintain the habitat functions of the large, continuous block of 80-120 year old 

forest. These habitat qualities would be improved in the future after about 15 years, as discussed above.

4. In areas that are not currently late-seral forest or high-value habitat and where more traditional forest 

management might be conducted (e.g. matrix), these activities should consider applying ecological forestry 

prescriptions. Some examples that could be utilized include Franklin et al. (2002, pp. 417–421; 2007, entire), 

Kerr (2012), Drever et al. (2006, entire), Johnson and Franklin (2009, pp. 39–41), Swanson et al. (2010, 
LAA Biological Assessment- Willamette NF-FY 2018

181

entire), and others cited in the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011, pp. III-14, 

III-17 to III-19). Does the activity apply ecological forestry prescriptions?

☒ Yes ☐ No

If yes, describe what measures will be used (e.g., % skips, dead wood creation, leaving legacy features, 

releasing hardwoods, diversity thinning prescription, etc.). 

The Q Thin project includes two designated skips, one in the riparian area on the western edge, and an 

additional skip in a Class 4 stream headwaters area on the southeastern side of the unit. That area also 

contains a high number of larger overstory trees, and was dropped from the harvest unit boundary. The 

largest overstory conifers will not be removed, but rather left to benefit future stand development. The creation 

of snags and large down wood if it is not already present at the levels discussed above, would further benefit 

future stand development.
182

 

Appendix C. Potential Spotted Owl Site 

Considerations 

LAA Biological Assessment FY 2018

Willamette National Forests
Appendix C: Potential Spotted Owl Site Considerations 

183

Scientific Basis for Potential Spotted Owl Sites

Since the complete range-wide population surveys for the spotted owls are not available, it is a 

well-established analytical approach to analyze the effects of proposed activities on the spotted 

owl based on the extent, duration and timing of habitat-altering activities. 

The amount of forest habitat likely to be used by spotted owls is based on the known range of 

habitat conditions used by spotted owls for nesting, roosting, and foraging (Thomas et al. 1990; 

Courtney et al. 2004). In addition, the basis for finding that a proposed action is likely to 

significantly impair the breeding, feeding, sheltering and/or dispersal of affected spotted owls 

relies on the scientifically-recognized range of habitat conditions that are known to adequately 

provide for spotted owl life history requirements. 

Spotted owls exhibit consistent patterns of habitat association, and these patterns provide the 

foundation for assessing the potential effects caused by land management activities. In the 1990 

Conservation Strategy for the Northern Spotted Owl, the Interagency Scientific Committee 

(Thomas et al. 1990) stated that:

“With the exception of recent studies in the coastal redwoods of California, all studies of 

habitat use suggest that old-growth forests are superior habitat for northern spotted owls. 

Throughout their range and across all seasons, spotted owls consistently concentrated 

their foraging and roosting in old-growth or mixed-age stands of mature and old-growth 

trees....Structural components that distinguish superior spotted owl habitat in 

Washington, Oregon, and northwestern California include: a multilayered, multispecies 

canopy dominated by large (>30 inches dbh) conifer overstory trees, and an understory 

of shade-tolerant conifers or hardwoods; a moderate to high (60-80 percent) canopy 

closure; substantial decadence in the form of large, live coniferous trees with deformitiessuch as cavities, broken tops, and dwarf mistletoe infections; numerous large snags; 

ground cover characterized by large accumulations of logs and other woody debris; and a 

canopy that is open enough to allow owls to fly within and beneath it.”

Fifteen years later, the conclusions of the Interagency Scientific Committee were echoed in the 

Scientific Evaluation of the Status of the Northern Spotted Owl (Courtney et al. 2004), which 

found that the habitat attributes identified by Thomas et al. (1990) remain important components 

of spotted owl habitat. Notably, positive relationships were found with the aforementioned 

attributes whether the samples of spotted owl and random locations were within old-growth forest, 

non-old growth forest on National Parks, public or private land. In 2011, the Revised Recovery 

Plan for the Northern Spotted Owl (USFWS 2011) again reiterated the association of spotted owls 

with older forest conditions, stating: “Spotted owls generally rely on older forested habitats 

(Carroll and Johnson 2008) because such forests contain the structures and characteristics 

required for nesting, roosting, and foraging (NRF).”

Spatial Use of Forest Landscapes

A major advance in our understanding of spotted owl habitat relationships from Thomas et al. 

(1990) to the present is that we now have a much better understanding of the spatial scale of 

habitat selection (Hunter et al. 1995, Meyer et al. 1998, Zabel et al. 2003, Weins et al. 2014) and 

the relationships of habitat to spotted owl fitness (Franklin et al. 2000, Olson et al. 2004, Dugger 

et al. 2005, Weins et al. 2014). Generally, guidance for management activities addressing 

territorial organisms is spatially explicit and such activities are applied to an area corresponding to 

the movements and activity patterns of the individuals occupying the territory or territories. 

Spotted owls are territorial predators that range widely in search of food but are ‘anchored’ during 

the breeding season to a nest site (Rosenberg and McKelvey 1999). That is, spotted owls are 

central-place foragers. Foraging close to the nest reduces travel time and energetic expenditures 

of adults and also increases the ability of the adults to remain nearby and protect their young. 

Several studies have shown that the selection of nest sites by spotted owls is related to the 

amount of older forest habitat at multiple spatial scales (Ripple et al. 1991, Ripple et al. 1997, 

Swindle et al. 1999, and Perkins 2000). Based on this research, evaluations of spotted owl use of 
Appendix C: Potential Spotted Owl Site Considerations 

184

an area appear to be most meaningful at two spatial scales: 1) the home range and 2) the core 

area. Habitat selection at a larger home range scale is likely dependent on habitat selection at the 

smaller core area (Johnson 1980 for hierarchy of habitat selection).

The home range is the “area traversed by the individual in its normal activities of food gathering, 

mating, and caring for young” (Burt 1943:351). Within home ranges, areas receiving concentrated 

use, typically surrounding the nest site and favored foraging areas, are called core areas 

(Bingham and Noon 1997). Establishing the exact spatial extent of a spotted owl’s home range 

and core area based on relative use within a home range typically requires use of radio-telemetry. 

Because of the intensity and high cost of radio-telemetry, action agencies are generally not able 

to conduct this type of study for specific projects. Therefore, for purposes of assessing a project’s 

potential impacts to the spotted owl, circles centered on spotted owl nest sites or activity centers 

that approximate the median core areas and home range areas of spotted owls monitored in 

previous radio telemetry studies (see home range estimates in Thomas et al. 1990 and reaffirmed 

in Courtney et al. 2004) will be used unless more specific information is available. 

These circles serve as proxies for the area where the amount and configuration of habitat has 

been shown to affect occupancy, survival, reproduction, and related fitness. Local data from the 

HJ Andrews demography study and other local information from the Willamette Province were 

used to determine home range and core area configurations to evaluate effects to spotted owls in 

this consultation. 

Resources such as food availability as well as breeding and resting sites can be distributed in 

patches on heterogeneous landscapes, such as those prevalent throughout the Northwest Forest 

Plan (NWFP) provinces. In such landscapes, animals are likely to disproportionately use areas 

that contain relatively higher densities of important resources (Powell 2000), with concentrated 

use close to their nests. These disproportionately used areas are referred to as “core areas” 

(Bingham and Noon 1997). Thomas et al. (1990) found that amounts of suitable habitat within 0.7 

miles (986 acres) of spotted owl activity centers were important to spotted owl life history 

functions, and the amount of suitable habitat around nest sites was significantly greater than the 

amount of suitable spotted owl habitat in random circles. The findings of Thomas et al. (1990) 

illustrate the importance of the amount of suitable habitat within a spotted owl territory to support 

the life history requirements of the spotted owl. The results of subsequent studies (see below) 

also indicated that a 0.5-mile radius circular area encompassing 500 acres around spotted owl 

activity centers is likely a more appropriate scale at which to evaluate the amounts of suitable 

habitat required by breeding spotted owls (USFWS 2009 and USFWS 2011 Appendix C). These 

studies relied on three primary sources of information to support the 500-acre core area size: (1) 

the distribution of locations of radio-telemetered spotted owls; (2) the territorial spacing patterns 

of spotted owls; and (3) the results of studies comparing relative habitat selection by spotted owls 

at different scales.

The Willamette Planning Province Level 1 team uses circles as surrogates for approximating 

spotted owl home range and core areas to inform impacts to the species. It is recognized that 

spotted owls may adjust the shape of their home ranges to encompass as much older forest 

habitat as possible (Carey et al. 1992). As such, the use of circles may not exactly overlap with 

actual areas used by spotted owls. The latter may be defined by other factors such as 

topographic features (e.g., drainages), abundance and availability of prey species, and the 

distribution and/or abundance of competitors and predators (Anthony and Wagner 1998; 

Courtney et al. 2004). However, the practice of using circles has a biological basis (Lehmkuhl and 

Raphael 1993), and has been utilized by many researchers to provide a uniform method for 

quantifying (comparing/contrasting) spotted owl habitat (Thomas et al. 1990; Ripple et al. 1991; 

Lehmkuhl and Raphael 1993; Ripple et al. 1997; Swindle et al. 1999; Perkins 2000; Franklin et al. 

2000; Olson et al. 2004; Dugger et al. 2005, and summary in Courtney et al. 2004). The use of 

circles also seems appropriate for species, like the spotted owl, characterized as a central place 

species. 

The following estimates by NWFP Province help inform a spotted owl spatial analysis for Oregon: 

Coast Ranges Province = 4,524 acres or a circle with a 1.5-mile radius; West Cascades Province 
Appendix C: Potential Spotted Owl Site Considerations 

185

= 2,895 acres or a circle with a 1.2-mile radius; and the Klamath Province = 3,398 acres or a 

circle with a 1.3- mile radius. Within a home range, the smaller core-use area estimate of 500 

acres or a circle with a 0.5 mile radius inform the spotted owl core-use area analysis for each of 

the aforementioned provinces (Thomas et al. 1990; USFWS 1992; Carey et al. 1992; Anthony 

and Wagner 1998; Irwin et al. 2000; Courtney et al. 2004; Glenn et al. 2004; UFWS 2011). In 

general for analysis purposes, the core-use/home range area circle(s) will be centered on a 

spotted owl activity center that represents the area that spotted owls are likely to use for nesting 

and foraging in any given year. Where available, local information on home range and core use 

areas is used, recognizing that circles are rough proxies and their value is that the amount and 

configuration of habitat within those radii has been shown to affect occupancy, survival, 

reproduction, and related fitness.

Habitat Availability in Core Areas and Home Ranges

Core Area

The best available information to date indicates that spotted owl survival and fitness are positively 

correlated with large patch sizes of older forest or large forest patches containing a high 

proportion of older forest (Franklin et al. 2000, Olson et al. 2004 and Dugger et al. 2005, Weins et 

al. 2014). Habitat-based fitness, or habitat fitness potential (HFP), is the “fitness conferred on an 

individual occupying a territory of certain habitat characteristics” (Franklin et al. 2000). HFP is a 

function of both the survival and reproduction of individuals within a given territory. For example, 

the datasets analyzed by Franklin et al. (2000) were re-analyzed to evaluate the relationship 

between HFP and the simple proportion of older forest within spotted owl core areas. The results 

of that analysis (USFWS 2007, pp. 134-136), indicate a quadratic relationship between spotted 

owl HFP and older forest conditions, with optimum HFP occurring when 53 percent of the 

estimated core area consisted of older forest (Franklin et al. 2000). More than half (55 percent) of 

the high-quality1 spotted owl territories had core areas comprised of 50 to 65 percent older forest. 

In a similar study in southern Oregon, Dugger et al. (2005) found that spotted owl HFP was 

positively related to the proportion of older forest in the core area, although the strength of the

relationship decreases with increased proportions. Roughly 72 percent of core areas with a HFP 

greater than 1.0 had more than 50 percent older forest, whereas core areas with a HFP of less 

than 1.0 never contained more than 50 percent older forest. 

Mean percent cover of old forest within spotted owl core areas in southwest Oregon and 

northwest California have varied widely among studies (about 35 to 60 percent) (Hunter et al. 

1995; Ripple et al. 1997; Gutiérrez et al.. 1998; Meyer et al. 1998; Franklin et al. 2000; Dugger et 

al. 2005). It is difficult to assess how much of this variation was due to differences in ecological 

setting, spatial scale, habitat classification, and individual variation among owls. Nonetheless, the 

central tendency of these results was roughly 50-60 percent older forest habitat within spotted owl 

core areas. 

Home Range 

Bart (1995) evaluated the suggestion in the 1992 draft recovery plan for the spotted owl (USFWS 

1992) that at least 40 percent of the estimated home range be retained as suitable habitat. Using 

demographic data from throughout the spotted owl’s range, including Oregon, Bart (1995) 

calculated that spotted owl populations are stable when the average proportion of nesting, 

roosting and forage2 habitat in the home range is 30 to 50 percent. In the Oregon Coast Ranges, 

Olson et al. (2004) found that spotted owl occupancy was positively correlated with the amount of 

mid and late-seral forest. Spotted owl demography and the presence of spotted owls appear to be 

positively associated with an intermediate amount of horizontal heterogeneity in forest habitat at 

the home range scale (Schilling et al. 2013). Findings reported in more recent papers (see 

 

1 HFP greater than 1

2 Nesting, roosting, forage habitat is called “suitable” habitat in this document.
Appendix C: Potential Spotted Owl Site Considerations 

186

USFWS 2009) have been consistent with those of Bart (1995). Weins et al. (2014) found a 

positive relationship between the six month survival rate of spotted owls and the percent of older 

forest in the individual home range.

Site Occupancy

Habitat-based assessments and/or modeling have been used in various studies to estimate the 

presence (occupancy) of breeding spotted owls. These tools are important for evaluating the 

species-habitat relationships. Bart (1995) reported that occupied spotted owl core areas 

contained at least 30 to 50 percent mature and old growth forest. Spotted owl demographic 

performance, particularly occupancy, increases with increasing amounts of suitable habitat in the 

core area. Meyer et al. (1998) examined landscape indices associated with spotted owl sites 

versus random plots on BLM lands throughout Oregon. Across provinces, landscape indices 

highly correlated with the probability of spotted owl occupancy included 30 percent or more older 

forest within the 500 acres surrounding the site3 and that site occupancy decreased following the 

harvest of suitable habitat in the vicinity of the core area. In their northwest California study area, 

Zabel et al. (2003) found that the highest probability of spotted owl occupancy occurred when the 

core area was comprised of 69 percent nesting/roosting habitat. Stepping up to the larger home 

range scale, Thomas et al. (1990), Bart and Forsman (1992), Bart (1995), Olson et al. 2004, and 

Dugger et al. (2005) suggest that when spotted owl home ranges included less than 40 to 60 

percent nesting, roosting and forage habitat, they were more likely to have lower occupancy and 

fitness. 

Many different combinations of forest habitat structure and amount at various spatial scales may 

support viable spotted owl territories sufficient for the survival and reproduction of individual owls. 

Despite consistent patterns of habitat selection by spotted owls, structural conditions of forest 

habitats occupied by spotted owls are highly variable. However, overall, the best available 

information suggests that: (1) the probability of spotted owls occupying a given patch of forest 

habitat increases when core areas contain a range of forest habitat conditions that support the 

essential life history requirements of individual spotted owls; and (2) the survival and fitness of 

spotted owls are positively correlated with larger patch sizes of older forest or larger patches of 

forest habitat with a high proportion of older forest (Franklin et al. 2000; Olson et al. 2005; Dugger 

et al. 2005).

Spotted Owl Habitat at Known and Potential Site Scales

This consultation uses the areas of home range, core area, and nest patch depicted in Table F-1 

to determine effects of activities to known sites and to delineate and determine effects within 

potential sites. 

As shown in Table F-1, this consultation uses the established 1.2 mile radius home range (also 

referred to as provincial home range), 0.5 mile radius core area, and 300 meter nest patch 

distances appropriate within the Willamette Planning Province. Known sites are also referred to 

as “spotted owl sites” in this document. The described analytical process, including all effects 

determinations, was developed to assess the effects of proposed federal actions in the Willamette 

Planning Province evaluated in this document. This consultation is not intended to represent 

mandatory guidance or be applicable to other planning provinces or future consultations.

Table F- 1. Size of home range, core area and estimated nest patch in the Willamette 

Planning Province

Province Median Home Range 

Radius and Area

Mean Core Area 

Radius and Area

Estimated Nest Patch 

Radius and Area

 

3 This predictive value decreased with increasing distance from the site.
Appendix C: Potential Spotted Owl Site Considerations 

187

Willamette Planning 

Province

Oregon Cascades

1.2 miles ≈ 2,895 

acres

(Forsman et al. 1984 

pp. 18 & 20; Meslow 

and Miller, 1989, p. 2;

Thomas et al. 1990 p. 

194, Table I1; USDA & 

USDI, 1994, p.12)

0.5 mile = 500 acres

Swindle et al. 1999;

Irwin et al. 2000, 2005

300 meters = 70 acres

Swindle et al. 1999;

Perkins et al. 2000

40% = 1,158 acres 50% = 250 acres 100% = 70 acres

Home Range (1.2 mile radius or about 2,895 acres)

The home range represents a minimum area for spotted owls to carry out all life history needs, 

particularly during the nesting season. The home range for Willamette Planning Province has 

been described in Forsman et al, 1984, pp. 18 & 20; Meslow and Miller, 1989, p. 2; Thomas et al. 

1990 p. 194; USDA & USDI, 1994, p.12. This is supported by later researchers such as Wiens et 

al. (2014). The home range surrounds the nest patch and core area and, barring more site 

specific information (e.g., habitat type and orientation), was delineated using a 1.2 mile radius 

circle.

Core Area (0.5 mile radius or 503 acres)

The core area represents the area most heavily used during the nesting season for nesting, 

foraging and rearing young. Bingham & Noon (1997) defined the core area as that portion of a 

spotted owl home range that received disproportionately high use for nesting, roosting and 

access to prey. Although Courtney et al. (2004:5-5) observed that core area sizes varied greatly 

among spotted owls, Bingham & Noon (1997), Wagner & Anthony (1999), Franklin et al. (2000) 

and Irwin et al. (2000) collectively suggested a core area of about 500 acres. The core area 

surrounds a nest patch and is located in the best available habitat that is likely to support 

concentrated use for nesting, roosting and rearing of young during the nesting season. Barring 

more site specific information (e.g., habitat type and orientation), this area was delineated using a 

0.5 mile radius circle.

Nest Patch (300 meters or 70 acres)

The nest patch represents an area where a spotted owl would be likely to select a nest tree or 

trees. This is based on habitat usage of spotted owls within the Central Cascades Study Area, 

located on the Willamette National Forest. Nest patch size has been shown to be an important 

attribute for site selection by spotted owls. More specifically, models developed by Swindle et al. 

(1997) and Perkins (2000) showed that the 200-300 meter radius (sometimes greater) 

encompassing approximately 75 acres around a Nest Patch is important to spotted owls. Having 

as much of the 300 meter radius in suitable habitat was critical to nest position on the landscape. 

Miller (1989) found that, on average, the extent of forested area used by juvenile spotted owls 

prior to dispersal averaged approximately 70 acres.

Meyer et al. (1998) found that old-growth patch size (i.e., larger patches) was strongly related to 

spotted owl site selection in Oregon. In reviewing the results of Table 5-2 (Courtney et al. 2004), it 

appears that spotted owls select nest sites on the landscape to maximize the amount of older 

forest habitat near the nest (USFWS, 2005).

Known site centers and corresponding nest patches are based on nest trees or pair activity 

centers. Potential site centers and nest patches are located in the best available habitat likely to 

facilitate spotted owl nesting by providing suitable nest trees and forage habitat for rearing of 

young immediately after leaving the nest tree. Potential site center locations considered the 

typical nearest neighbor distance (see Table 2) to nearby known and potential sites, and 

avoidance of barred owl “core use areas,” when this information was available. Barring more site 
Appendix C: Potential Spotted Owl Site Considerations 

188

specific information, (e.g., habitat type and orientation), this area was delineated using a 300 

meter radius circle.

Potential Site (1.2 miles or about 2,895 acres)

This consultation uses the term “potential sites” to describe areas equivalent to the home range 

for known sites that support breeding spotted owls based on habitat conditions, but where 

surveys are nonexistent, outdated or otherwise insufficient to establish known sites. Potential 

sites are an analytical concept to address “potential spotted owl sites” and, when applicable, 

“unsurveyed habitat” used in the Revised Recovery Plan for the Northern Spotted Owl (U.S. Fish 

and Wildlife Service, 2011; “Recovery Plan”). The Recovery Plan excerpts below reflect an 

approach to define and manage for potentially occupied areas outside of known sites as part of 

the spotted owl recovery strategy.

“In unsurveyed spotted owl habitat, the agencies and the Service should work 

cooperatively through the Endangered Species Act consultation process to minimize 

impacts to potential spotted owl sites” (p. III-45);

“There is a wide breadth of spotted owl occupancy data throughout the species’ range. 

Where spotted owl occupancy data are unavailable (e.g., unsurveyed habitat), land 

managers have a variety of tools to assist in determining where likely occupied habitat is 

and how to implement this recovery action, including assumption of occupancy (a 

common practice during section 7 consultation), surveys, spotted owl modeling results, 

forest stand data, etc.” (p. III-46);

“Spotted Owl Site: Any location where territorial spotted owls are known to be present, 

were historically present, or may be present in unsurveyed habitat. Spotted owl sites can 

be identified through surveys where spotted owls were detected (USFWS 2010). In cases 

where survey data are unavailable, spotted owl sites can be identified by 1) conducting 

surveys, or 2) using a modeling approach that uses habitat and landscape characteristics 

to identify areas with a high probability of being occupied by spotted owls.”(p. G-4).

Potential Site Delineation

Potential sites could support breeding spotted owl pairs and management of such areas is 

recommended in the Recovery Plan. Therefore, this consultation recognizes the need for the 

delineation and analysis of potential sites to determine the effects of proposed activities. Potential 

site delineation is based on guidance in the Recovery Plan, decades of knowledge acquired from 

spotted owl surveys, and the best commercial and scientific information available. Spotted owl 

habitat associations and habitat requirements for reproduction were considered. Collectively, this 

information constitutes a synthesis of the best available science that was used to develop the 

general analytical framework described below.

Assessment of habitat within the home range, core area, and nest patch scales considered 

habitat quality, amount, orientation, contiguity and interior forest conditions, as well as specific 

spotted owl life history needs within each of these three scales (e.g., nest patches contain known 

or potential suitable nest trees). This information was used to evaluate and determine if an area 

possessed the characteristics that could support spotted owls. Habitat age and function was 

assessed by unit biologists using a variety of best available information such as agency forest 

operations inventory data, MaxEnt modeling, Lidar or other suitable aerial imagery or modeling. 

When necessary, field examination was also conducted to accurately evaluate habitat type. In all 

cases, area-specific conditions were assessed and the best available information was utilized in 

delineating a potential site. Survey data, when available, also provided known or probable 

locations of spotted owls within known or potential sites.

A general outline of the process used follows:

1. Geographic areas beyond 1.2 miles from known or potential site centers were identified. 

This value represents the median distance between known sites within the Central 

Cascades Demographic Study Area, commonly called the “nearest neighbor” distance. 
Appendix C: Potential Spotted Owl Site Considerations 

189

2. Within such areas, spotted owl habitat was identified and mapped. It was then 

determined if there was sufficient habitat quality, amount and spatial orientation to identify 

a potential site center. A consideration was that amount and quality of habitat present 

should be able to support a resident pair. Potential sites should also be able to support 

reproductive resident pairs. Ideally these areas would be close to or above thresholds 

which the literature indicates is necessary for successful reproduction (suitable habitat of 

approximately 40% or more in the home range and 50% or more in the core area with 

adequate habitat in the nest patch to support a nesting pair). Where available, site 

specific data were used to adjust these thresholds to more closely reflect actual 

conditions on the ground in the localized area. Local survey data were also used to 

establish or refine potential site locations. Based on local conditions, potential sites were 

delineated in some situations where habitat may be below the previously described 

thresholds. For example, where survey data indicated that owls could be residing in the 

area, or where nearby known sites occupied by spotted owls exhibited similar type, 

quality and quantity of habitat.

3. Proposed management activity locations were examined to see if they would be within 

the home range of an existing known or potential site. If so, effects were determined 

based on the general analytical framework described in this consultation.

Potential site center locations considered the typical nearest neighbor distance to nearby known 

and potential sites and avoidance of barred owl core use areas, if known. The “nearest neighbor” 

distance of 1.2 miles was used as a minimum spacing between new potential sites and nearby 

known or potential sites. 

Potential site centers and their nest patches were located in the best available habitat likely to 

facilitate spotted owl nesting by providing suitable nest trees and forage habitat for rearing of 

young immediately after leaving the nest tree. Barring more site specific information, (e.g., habitat 

type and orientation), the nest patch was delineated using a 300 meter radius circle. Potential site 

core areas were located in the best available habitat likely to support concentrated use for 

nesting, roosting and rearing of young during the entire nesting season. Barring more site specific 

information (e.g., habitat type and orientation), this area was delineated using a 0.5 mile radius 

circle.
Appendix C: Potential Spotted Owl Site Considerations 

190

Literature Cited in Appendix C

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Miller Mountain Study Area: Identification and evaluation of northern spotted owl habitat in 

managed forests of southwest Oregon and the development of silvicultural systems for 

managing such habitat. Draft Progress Report. Oregon Cooperative Wildlife Research Unit, 

Oregon State University, Corvallis, OR.

Bart, J. 1995. Amount of Suitable Habitat and Viability of Northern Spotted Owls. Conservation 

Biology 9(4):943-946.

Bart, J. and E.D. Forsman. 1990. Surveys of northern spotted owls on public lands. Ohio 

Cooperative Research Unit, Dept. of Zoology. Ohio State University, Columbus, OH. Also, 

For. Serv., Forestry Sciences Laboratory, Olympia, WA.

Bart, J. and E.D. Forsman. 1992. Dependence of northern spotted owls, Strix occidentalis 

caurina, on old-growth forests in the western United States. Biological Conservation 62(2):95-

100.

Bingham, B. and B.R. Noon. 1997. Mitigation of habitat take: Application to habitat conservation 

planning. Conservation Biology 11(1):127-139.

Burt, W.H. 1943. Territoriality and home range concepts as applied to mammals. Journal of 

Mammalogy 24:346-352.

Carey, A.B., S.P. Horton, and B.L. Biswell. 1992. Northern spotted owls: influence of prey base 

and landscape character. Ecological Monographs 62(2):223-250. 

Carroll, Carlos and Devin S. Johnson. 2008. The importance of being spatial (and reserved):

assessing northern spotted owl habitat relationships with hierarchical Bayesian models. 

Conservation Biology, Volume 22, No. 4, 1026–1036. 2008 Society for Conservation Biology.

Courtney, S.P., J.A. Blakesley, R.E. Bigley, M.L. Cody, J.P. Dumbacher, R.C. Fleischer, A.B. 

Franklin, J.F. Franklin, R.J. Gutiérrez, J.M. Marzluff, L. Sztukowski. 2004. Scientific 

evaluation of the status of the northern spotted owl. Sustainable Ecosystems Institute. 

Portland, Oregon. September 2004

Davis, R.J., tech. coord. 2011. Northwest Forest Plan-status and trends of northern spotted owl 

populations and habitats from 1994 to 2008. Gen. Tech. Rep. PNW-GTR-850. Portland, OR: 

U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 216 pp.

Dugger, K. M., F. Wagner, R. G. Anthony, and G. S. Olson. 2005. The relationship between 

habitat characteristics and demographic performance of northern spotted owls in southern 

Oregon. The Condor. 107:863-878.

Forsman, E.D., T.J. Kaminiski, J.C. Lewis, K.J. Maurice, and S.G. Sovern. 2005. Home range 

and habitat use of northern spotted owls on the Olympic Peninsula, Washington. J. Raptor 

Research 39(4):365-377.

Franklin, A.B., D.R. Anderson, R.J. Gutiérrez, and K.P. Burnham. 2000. Climate, habitat quality, 

and fitness in northern spotted owl populations in northwestern California. Ecological

Monographs 70(4):539-590.

Glenn, E.M., M.C. Hansen, R.G. Anthony. 2004. Spotted owl home-range and habitat use in 

young forests of western Oregon. J. Wildl. Man. 68(1):33-50.

Gutiérrez, R.J., J.E. Hunter, G. Chávez-León, and J. Price. 1998. Characteristics of spotted owl 

habitat in landscapes disturbed by timber harvest in northwestern California. Journal of 

Raptor Research 32(2):104-110.

Hunter, J.E., R.J. Gutiérrez, and A.B. Franklin. 1995. Habitat configuration around spotted owl 

sites in northwestern California. The Condor 97(3):684-693.
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Irwin, L. L., D. F. Rock, and G. P. Miller. 2000. Stand structures used by northern spotted owls in 

managed forests. Journal of Raptor Research. 34(3):175-186.

Irwin, L. L., D. Rock, and S. Rock. 2005. Adaptive management monitoring of spotted owls. 

Annual National Council for Air and Stream Improvement progress report. Unpubl.

Johnson, D.H. 1980. The Comparison of usage and availability measurements for evaluation 

resource preference. Ecology 61:65-71.

Lehmkuhl, John F and Martin G. Raphael. 1993. Habitat pattern around northern spotted owl 

location on the Olympic Peninsula, Washington. Journal of Wildlife Management 57(2):302-

315.

Lint, J. et al. 2005. DRAFT. Northwest Forest Plan – The first ten years (1994-2003): Status and 

trend of northern spotted owl populations and habitat. PNW Station Edit Draft (Lint, Technical 

Coordinator, 2005). USDA Forest Service, PNW Research Station, PNW-GTR-2005. Draft. 

Portland, OR 230pp.

Meslow, E. C. and G. S. Miller. 1989 unpubl. The ecology of spotted owls on the Willamette 

National Forest: Supplement to 1989 annual report (spotted owl demography and habitat use 

segments, 1 September 1988 – 31 August 1989). Oregon Cooperative Wildlife Research 

Unit, Oregon State University, Corvallis. 16 pp.

Meyer, J.S., L.L. Irwin, and M.S. Boyce. 1998. Influence of habitat abundance and fragmentation 

on northern spotted owls in western Oregon. Wildlife Monog. No. 139.

Miller, G.S. 1989. Dispersal of juvenile spotted owls in western Oregon. M.S. Thesis. Oregon 

State University, Corvallis, Oregon.

Olson, G.S., E.M. Glenn, R.G. Anthony, E.D. Forsman, J.A. Reid, P.J. Loschl, and W.J. Ripple. 

2004. Modeling demographic performance of northern spotted owls relative to forest habitat 

in Oregon. Journal of Wildlife Management 68(4):1039-1053. 

Olson, G.S., R.G. Anthony, E.D. Forsman, S.H. Ackers, P.J. Loschl, J.A. Reid, K.M Dugger, E.M. 

Glenn, and W.J. Ripple. 2005. Modeling of site occupancy dynamics for northern spotted 

owls, with emphasis on the effects of barred owls. Journal of Wildlife Management 69(3):918-

932. 

Perkins, J.P. 2000. Land cover at northern spotted owl nest and non-nest sites, east-central coast 

ranges, Oregon. M.S. thesis. Department of Forest Resources, Oregon State University, 

Corvallis, OR.

Powell, R.A. 2000. Animal home ranges and territories and home range estimators. Pp. 65-110 In 

L. Boitani and T.K. Fuller (eds.), Research techniques in animal ecology: controversies and 

consequences. Columbia University Press, New York.

Ripple, W.J., D.H. Johnson, K.T. Hershey, and E.C. Meslow. 1991. Old-growth and mature 

forests near spotted owl nests in western Oregon. J. Wildlife Management 55(2):316-318.

Ripple, W.J., P.D. Lattin, K.T. Hershey, F.F. Wagner, and E.C. Meslow. 1997. Landscape 

composition and pattern around northern spotted owl nest sites in southwest Oregon. Journal 

of Wildlife Management 61(1):151-158.

Rosenberg, D.K. and K.S. McKelvey. 1999. Estimation of habitat selection for central-place 

foraging animals. J. Wildlife Management 63(3):1028-1038

Schilling, J.W., K.M. Dugger, and R.G. Anthony. 2013. Survival and home range size of northern 

spotted owls in southwest Oregon. Journal of Raptor Research. 47(1):1-4.

Swindle, K.A., W.J. Ripple, E.C. Meslow, and D.J. Schafer. 1999. Old-forest distribution around 

spotted owl nests in the central Cascade Mountains, Oregon. J. Wildlife Management 

63(4):1212-1221. 
Appendix C: Potential Spotted Owl Site Considerations 

192

Thomas, J.W., E.D. Forsman, J.B. Lint, E.C. Meslow, B.R. Noon and J. Verner. 1990. A 

conservation strategy for the northern spotted owl: Report of the Interagency Scientific 

Committee to address the conservation of the northern spotted owl. USDA Forest Service; 

USDI Bureau of Land Management, Fish and Wildlife Service, National park Service. 427 pp. 

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and Wildlife Service). 1994. Section 7 consultation guidance for the forest ecosystem plan. 

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USFWS (U.S. Fish and Wildlife Service). 2005. Draft (November 2005): The USFWS 40% rule 

based on the current science on the northern spotted owl; an update. U.S. Fish and Wildlife 

Service, Portland, Oregon. 8 pp.

USFWS (U.S. Fish and Wildlife Service). 2007. Draft recovery plan for the northern spotted owl, 

Strix occidentalis caurina: Merged Options 1 and 2. Portland, Oregon. 170 pp.

USFWS (U.S. Fish and Wildlife Service). 2009. Regulatory and scientific basis for the U.S. Fish 

and Wildlife Service guidance for evaluation of take for northern spotted owls on private 

timberlands in California’s northern interior region.

USFWS (U.S. Fish and Wildlife Service). 2010a. Draft protocol for surveying proposed 

management activities that may impact northern spotted owls. Portland, Oregon.

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owl (Strix occidentalis caurina). U.S. Fish and Wildlife Service, Portland, Oregon. Svi + 258 

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Wagner, F.F. and R.G. Anthony. 1999. Reanalysis of northern spotted owl habitat use on the 

Miller Mountain study area. A report for the Research Project: Identification and evaluation of 

northern spotted owl habitat in managed forests of southwest Oregon and the development of 

silvicultural systems for managing such habitat. Oregon Cooperative Wildlife Research Unit, 

Depar. Fisheries and Wildlife, Oregon State Univ. Corvallis, OR.

Wiens, J.D., R. G. Anthony, and E. D. Forsman. 2014. Competitive interactions and resource 

partitioning between northern spotted owls and barred owls in western Oregon. Wildlife 

Monographs No. 185. 50 pp.

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Applications 13(4):1027-1040.
193

Appendix D. Northern Spotted Owl Status of the 

Species and Range-wide Baseline. 

Prepared by USFWS, June 2017
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 194

Northern Spotted Owl--Status of the Species

Legal Status

The northern spotted owl was listed as threatened on June 26, 1990 due to widespread loss and 

adverse modification of suitable habitat across the owl’s entire range and the inadequacy of 

existing regulatory mechanisms to conserve the owl (USDI FWS 1990a, p. 26114). Listing 

priority numbers are assigned on a scale of 1C (highest) to 18 (lowest). The “C” reflects conflict 

with development, construction, or other economic activity (USDI FWS 1983, p. 43104). The 

northern spotted owl was originally listed with a recovery priority number of 3C, but that number 

was changed to 6C in 2004 during the 5-year review of the species (USDI FWS 2004, p. 55). 

This number reflects a high degree of threat, a low potential for recovery, and the owl’s 

taxonomic status as a subspecies (USDI FWS 1983, p. 51895). The most recent five year status 

review was completed on September 29, 2011, and did not propose changes to the listing status 

or introduce any new threats (USDI FWS 2011). In 2012, the Service was petitioned to uplist 

the northern spotted owl from threatened to endangered status under the Endangered Species 

Act. In April 2015, the Service determined that petition presented substantial information 

indicating that the listing may be warranted due to a number of listing factors (USDI FWS 2015 

80 FR pp.19259-19263). The species’ status report is currently under review.

Life History

Taxonomy

The northern spotted owl is one of three subspecies of spotted owls currently recognized by the 

American Ornithologists’ Union. The taxonomic separation of these three subspecies is 

supported by genetic (Barrowclough and Gutiérrez 1990, pp.741-742; Barrowclough et al. 1999, 

p. 928; Haig et al. 2004, p. 1354), morphological (Gutiérrez et al. 1995, p. 2), and biogeographic 

information (Barrowclough and Gutiérrez 1990, p.741-742). The distribution of the Mexican 

subspecies (S. o. lucida) is separate from those of the northern and California (S. o. occidentalis) 

subspecies (Gutiérrez et al. 1995, p.2). Recent studies analyzing mitochondrial DNA sequences 

(Haig et al. 2004, p. 1354; Chi et al. 2004, p. 3; Barrowclough et al. 2005, p. 1117) and 

microsatellites (Henke et al., unpubl. data, p. 15) confirmed the validity of the current subspecies 

designations for northern and California spotted owls. The narrow hybrid zone between these 

two subspecies, which is located in the southern Cascades and northern Sierra Nevada, appears 

to be stable (Barrowclough et al. 2005, p. 1116).

Funk et al. (2008, pp. 1-11) tested the validity of the three current recognized subspecies of 

spotted owls and found them to be valid. During this genetics study, bi-directional hybridization 

and dispersal between northern spotted owls and California spotted owls centered in southern 

Oregon and northern California was discovered. In addition, a discovery of intro-regression of 

Mexican spotted owls into the northernmost parts of the northern spotted owl populations in 

Washington was made, indicating long-distance dispersal of Mexican spotted owls into the 

northern spotted owl range (Funk et al. 2008, pp. 1-11). Some hybridization of northern spotted 

owls with barred owls has been recorded (Hamer et al. 1994, pp. 487-491; Dark et al. 1998, pp. 

50-56; Kelly 2001, pp. 33, 38). 

Physical Description

The northern spotted owl is a medium-sized owl and is the largest of the three subspecies of 

spotted owls (Gutiérrez et al. 1995, p. 2). It is approximately 46 to 48 centimeters (18 inches to 

19 inches) long and the sexes are dimorphic, with males averaging about 13 percent smaller than 
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females. The mean mass of 971 males taken during 1,108 captures was 580.4 grams (1.28 

pounds) (out of a range 430.0 to 690.0 grams) (0.95 pound to 1.52 pounds), and the mean mass 

of 874 females taken during 1,016 captures was 664.5 grams (1.46 pounds) (out of a range 490.0 

to 885.0 grams) (1.1 pounds to 1.95 pounds) (P. Loschl and E. Forsman, pers. comm. cited in 

USDI FWS 2011, p. A-1). The northern spotted owl is dark brown with a barred tail and white 

spots on its head and breast, and it has dark brown eyes surrounded by prominent facial disks. 

Four age classes can be distinguished on the basis of plumage characteristics (Forsman 1981; 

Moen et al. 1991, p. 493). The northern spotted owl superficially resembles the barred owl, a 

species with which it occasionally hybridizes (Kelly and Forsman 2004, p. 807). Hybrids exhibit 

physical and vocal characteristics of both species (Hamer et al. 1994, p. 488).

Current and Historical Range 

The current range of the spotted owl extends from southwest British Columbia through the 

Cascade Mountains, coastal ranges, and intervening forested lands in Washington, Oregon, and 

California, as far south as Marin County (USDI FWS 1990a, p. 26115). The range of the spotted 

owl is partitioned into 12 physiographic provinces (see Figure A-1) based on recognized 

landscape subdivisions exhibiting different physical and environmental features (USDI FWS 

2011, p. III-1; Thomas et al. 1993). These provinces are distributed across the species’ range as 

follows: 

 Four provinces in Washington: Eastern Washington Cascades, Olympic Peninsula, 

Western Washington Cascades, Western Washington Lowlands

 Five provinces in Oregon: Oregon Coast Range, Willamette Valley, Western Oregon 

Cascades, Eastern Oregon Cascades, Oregon Klamath 

 Three provinces in California: California Coast, California Klamath, California Cascades

The spotted owl is extirpated or uncommon in certain areas such as southwestern Washington 

and British Columbia. Timber harvest activities have eliminated, reduced or fragmented spotted 

owl habitat sufficiently to decrease overall population densities across its range, particularly 

within the coastal provinces where habitat reduction has been concentrated (USDI FWS 2011, 

pp. B-1 to B-4; Thomas and Raphael 1993). 

Behavior

Northern spotted owls are primarily nocturnal (Forsman et al. 1984, pp. 51-52) and spend 

virtually their entire lives beneath the forest canopy (Courtney et al. 2004, p. 2-5). They are 

adapted to maneuverability beneath the forest canopy rather than strong, sustained flight 

(Gutiérrez et al. 1995, p. 9). They forage between dusk and dawn and sleep during the day with 

peak activity occurring during the two hours after sunset and the two hours prior to sunrise 
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Figure A-1. Physiographic Provinces within the range of the northern spotted owl in the 

United States (from USDI FWS 2011, A-3)

(Gutiérrez et al. 1995, p. 5; Delaney et al. 1999, p. 44). They will sometimes take advantage of 

vulnerable prey near their roosts during the day (Layman 1991, pp. 138-140; Sovern et al. 1994, 

p. 202).

Northern spotted owls seek sheltered roosts to avoid inclement weather, summer heat, and 

predation (Forsman 1975, pp. 105-106; Barrows and Barrows 1978; Barrows 1981; Forsman et 
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al. 1984, pp. 29-30). Northern spotted owls become stressed at temperatures above 28°C, but 

there is no evidence to indicate that they have been directly killed by temperature because of 

their ability to thermoregulate by seeking out shady roosts in the forest understory on hot days 

(Barrows and Barrows 1978; Forsman et al. 1984, pp. 29-30, 54; Weathers et al. 2001, pp. 678, 

684). During warm weather, spotted owls seek roosts in shady recesses of understory trees and 

occasionally will even roost on the ground (Barrows and Barrows 1978, pp. 3, 7-8; Barrows 

1981, pp. 302-306, 308; Forsman et al. 1984, pp. 29-30, 54; Gutiérrez et al. 1995, p. 7). Glenn et 

al. (2010, p. 2549) found that population growth was negatively associated with hot summer 

temperatures at their southernmost study area in the southern Oregon Cascades, indicating that 

warm temperatures may still have an effect on the species. Both adults and juveniles have been 

observed drinking water, primarily during the summer, which is thought to be associated with 

thermoregulation (Gutiérrez et al. 1995, p. 7).

Spotted owls are territorial; however, home ranges of adjacent pairs overlap (Forsman et al. 

1984, p. 22; Solis and Gutiérrez 1990, p. 746) suggesting that the area defended is smaller than 

the area used for foraging. They will actively defend their nests and young from predators 

(Forsman 1975, p. 15; Gutiérrez et al. 1995, p. 11). Territorial defense is primarily effected by 

hooting, barking and whistle type calls. Some spotted owls are not territorial but either remain as 

residents within the territory of a pair or move among territories (Gutiérrez 1996, p. 4). These 

birds are referred to as “floaters.” Floaters have special significance in spotted owl populations 

because they may buffer the territorial population from decline (Franklin 1992, p. 822). Little is 

known about floaters other than that they exist and typically do not respond to calls as vigorously 

as territorial birds (Gutiérrez 1996, p. 4).

Spotted owls are monogamous and usually form long-term pair bonds. “Divorces” occur but are 

relatively uncommon. There are no known examples of polygyny in this owl, although 

associations of three or more birds have been reported (Gutiérrez et al. 1995, p. 10).

Habitat Relationships

Home Range and Core Areas 

Spotted owls are territorial raptors that range widely in search of prey but are ‘anchored’ during 

the breeding season to a nest site (central-place forager). Evaluations of spotted owl habitat are 

usually conducted at two spatial scales; the home range and core areas. The home range is the 

“area traversed by the individual in its normal activities of food gathering, mating, and caring for 

young” (Burt 1943:351, cited in USDI FWS 2009). Within home ranges, areas receiving 

concentrated use, typically surrounding the nest site and favored foraging areas, are called core 

areas. Because the size and pattern of spotted owl’s space use are typically unknown, estimates 

of use areas are derived from radio-telemetry studies. Results from Bingham and Noon (1997) 

showed that spotted owls typically used 20-21 percent of their home range as core use area 

habitat, which generally included 60-70 percent of the sites within their home range used during 

the breeding season. As central place foragers, nesting spotted owls are likely very sensitive to 

activities that occur within their core use areas and especially their nest patch (Swindle et al. 

1997, Miller et al. 1989, and Meyer et al. 1998).

The habitat composition within cores and annual home ranges has been found to be directly 

correlated with demographic response such as occupancy, reproductive success, survival, and 

fitness. Meyer et al. (1998) examined landscape indices associated with spotted owl sites versus 

random plots on BLM lands throughout Oregon. Across provinces, landscape indices highly 

correlated with the probability of spotted owl occupancy included the percent older forest (30 
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percent) within the 500 acres (analogous to a core-use area) surrounding the site. Zabel et al. 

(2003, abstract, p. 1033) found the best-fitting model for owl occupancy predictions in northwest 

California was at the 200-ha (500 acre) scale. Their model found a pseudo-threshold relationship 

to nesting and roosting habitat (meaning once the quantity of the habitat metric reached some 

‘‘threshold’’ level the probability of occupancy did not increase or decrease substantially with 

more habitat) and a quadratic relationship to foraging habitat. Bart (1995) found that core areas 

should contain 30-50 percent mature and old growth forest. Results from Thomas et al. (1990), 

Bart and Forsman (1992) Bart (1995) and Dugger et al (2005) suggest that when spotted owl 

home ranges have less than 40 to 60 percent nesting/roosting/foraging (NRF), they were more 

likely to have lower occupancy and fitness. Olson et al. (2005) found similar results on their 

Oregon Coast Ranges study area. 

As further described in the 2009 FWS Guidelines (USDI FWS 2009, “Guidelines”), the 

probability of occupancy is increased when core areas contain a range of habitat conditions 

suitable for use by spotted owls, and the survival and fitness of spotted owls is positively 

correlated with larger patch sizes or proportion of older forests (Franklin et al. 2000, Dugger et 

al. 2005). The Guidelines express “the strongest type of information relevant to the evaluation of 

take relates to the fitness of spotted owls to characteristics of their habitat.” Depending on the 

availability of habitat, fitness may be compromised when additional habitat degradation or losses 

occur. The final evaluation of incidental take is both a quantitative and qualitative analysis of 

the actual amount and distribution of habitat available to the spotted owl when compared to the 

effects of the proposed action and site specific conditions. 

Recently developed habitat-fitness and landscape models have demonstrated the importance of 

having sufficient amounts of NRF habitat within core use areas to adequately provide for spotted 

owl survival and reproduction along with access to prey. For example, Franklin et al. (2000) 

found that the proportion of good habitat was around 60 percent to lesser quality habitat for owl 

core use areas in northwest California. In a recently published study of spotted owls in the 

Oregon Klamath Province, survival was negatively correlated with forest fragmentation 

(Schilling et al. 2013). 

Home-range sizes vary geographically, generally increasing from south to north, which is likely 

a response to differences in habitat quality (USDI FWS 1990a, p. 26117). Estimates of median 

size of their annual home range (the area traversed by an individual or pair during their normal 

activities (Thomas and Raphael 1993, pp. IX-15)) vary by province and range from 2,955 acres 

in the Oregon Cascades (Thomas et al. 1990, p. 194) to 14,211 acres on the Olympic Peninsula 

(USDI FWS 1994, p. 3). Zabel et al. (1995, p. 436) showed that these provincial home ranges 

are larger where flying squirrels are the predominant prey and smaller where wood rats are the 

predominant prey. Home ranges of adjacent pairs overlap (Forsman et al. 1984, p. 22; Solis and 

Gutiérrez 1990, p. 746), suggesting that the defended area is smaller than the area used for 

foraging. Spotted owl core areas vary in size geographically and provide habitat elements that 

are important for the reproductive efficacy of the territory, such as the nest tree, roost sites and 

foraging areas (Bingham and Noon 1997, p. 134). Some studies have found that spotted owls 

use smaller home ranges during the breeding season and often dramatically increase their home 

range size during fall and winter (Forsman et al. 1984, pp. 21-22; Sisco 1990, p. iii). In Southern 

Oregon, one study found that home range and core areas remained essentially the same between 

seasons, concluding that perhaps this was due to the quality of available habitat (Shilling et al. 

2013). 

Although differences exist in natural stand characteristics that influence home range size, habitat 
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loss and forest fragmentation effectively reduce habitat quality in the home range. A reduction 

in the amount of suitable habitat reduces spotted owl abundance and nesting success (Bart and 

Forsman 1992, pp. 98-99; Bart 1995, p. 944).

Habitat Use and Selection

Forsman et al. (1984, pp.15-16) reported that spotted owls have been observed in the following 

forest types: Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), grand 

fir (Abies grandis), white fir (Abies concolor), ponderosa pine (Pinus ponderosa), Shasta red fir 

(Abies magnifica shastensis), mixed evergreen, mixed conifer hardwood (Klamath montane), and 

redwood (Sequoia sempervirens). The upper elevation limit at which spotted owls occur 

corresponds to the transition to subalpine forest, which is characterized by relatively simple 

structure and severe winter weather (Forsman 1975, p. 27; Forsman et al. 1984, pp. 15-16).

Spotted owls generally rely on older forested habitats because such forests contain the structures 

and characteristics required for nesting, roosting, and foraging. Features that support nesting and 

roosting typically include a moderate to high canopy closure (60 to 80 percent); a multi-layered, 

multi-species canopy with large overstory trees (with diameter at breast height [dbh] of greater 

than 30 inches); a high incidence of large trees with various deformities (large cavities, broken 

tops, mistletoe infections, and other evidence of decadence); large snags; large accumulations of 

fallen trees and other woody debris on the ground; and sufficient open space below the canopy 

for spotted owls to fly (Thomas et al. 1990, p. 19). Weathers et al. 2001, (p. 686) found the 

spotted owl association with structurally complex habitats containing high canopy closure was in 

part due to their intolerance of high temperatures. Complex vertically structured habitat such as 

mature and old-growth forests habitats contain sufficient cover to provides protection from 

predators (Franklin et al. 2000, p. 578-579).

Spotted owls nest almost exclusively in trees. Like roosts, nest sites are found in forests having 

complex structure dominated by large diameter trees and high canopy closure (Forsman et al. 

1984, p. 30; Hershey et al. 1998, p. 1402, LaHaye et al. 1997, p. 46-48). Even in forests that 

have been previously logged, spotted owls select forests having a structure (i.e., larger trees, 

greater canopy closure) different than forests generally available to them (Folliard 1993, p. 40; 

Buchanan et al. 1995, p. 304-305; Hershey et al. 1998, p. 1406-1407). In eastern Washington, 

spotted owl nest sites were found to have canopies of dominant and/or codominant and 

intermediate trees that were farther aboveground, more 35-60-cm (14-24 in)-dbh Douglas-fir 

(Pseudotsuga menzies/, greater basal area of Douglas-fir trees, more 61-84-cm (24-33.5 in) dbh 

ponderosa pine (Pinus ponderosa) trees, more live tree basal and more basal area of Class IV 

snags (broken snags with no branches and little bark).

Roost sites selected by spotted owls have more complex vegetation structure than forests 

generally available to them (Barrows and Barrows 1978, p. 2-3; Forsman et al. 1984, pp. 29-30; 

Solis and Gutiérrez 1990, pp. 742-743, 747). These habitats are usually multi-layered forests 

having high canopy closure and large diameter trees in the overstory. 

Foraging habitat is the most variable of all habitats used by territorial spotted owls (Thomas et al. 

1990; USDI FWS 2011, p. G-2). Descriptions of foraging habitat have ranged from complex 

structure (Solis and Gutiérrez 1990, pp. 742-744) to a broader range of forests with lower canopy 

closure and smaller trees than forests containing nests or roosts (Gutiérrez 1996, p. 3-5). 

Foraging habitat for northern spotted owls provides a food supply for survival and reproduction. 

Foraging activity is positively associated with tree height diversity (North et al. 1999, p. 524), 

canopy closure and woody debris (Irwin et al. 2000, p. 180; Courtney et al. 2004, pp. 5-15), snag 
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volume, density of snags greater than 20 in (50 cm) dbh (North et al. 1999, p. 524; Irwin et al. 

2000, pp. 179-180; Courtney et al. 2004, pp. 5-15), density of trees greater than or equal to 31 in 

(80 cm) dbh (North et al. 1999, p. 524), volume of woody debris (Irwin et al. 2000, pp. 179-180), 

and young forests with some structural characteristics of old forests (Carey et al.1992, pp. 245-

247; Irwin et al. 2000, pp. 178-179). Northern spotted owls select old forests for foraging in 

greater proportion than their availability at the landscape scale (Carey et al. 1992, pp. 236-237; 

Carey and Peeler 1995, p. 235; Forsman et al. 2004, pp. 372-373), but will forage in younger 

stands with high prey densities and access to prey (Carey et al. 1992, p. 247; Rosenberg and 

Anthony 1992, p. 165; Thome et al. 1999, pp. 56-57). 

Dispersal habitat is essential to maintaining stable populations by filling territorial vacancies 

when resident northern spotted owls die or leave their territories, and to providing adequate gene 

flow across the range of the species. Dispersal habitat, at a minimum, consists of stands with 

adequate tree size and canopy closure to provide protection from avian predators and at least 

minimal foraging opportunities (USDI FWS 2011, p. G-1). Dispersal habitat may include 

younger and less diverse forest stands than foraging habitat, such as even-aged, pole-sized 

stands, but such stands should contain some roosting structures and foraging habitat to allow for 

temporary resting and feeding for dispersing juveniles (USDI FWS 2011, p. G-1). . In a study 

of the natal dispersal of northern spotted owls, Sovern and others (2015, pp. 257-260) found the 

majority of roosts were in forested habitats with at least some large (>50 cm or about 19 inches 

dbh) trees and they selected stands with high canopy cover (>70 percent) at the landscape scale. 

These authors suggested the concept of ‘dispersal’ habitat as a lower quality type of habitat may 

be inappropriate. Forsman et al. (2002, p. 22) found that spotted owls could disperse through 

highly fragmented forest landscapes. However, the stand-level and landscape-level attributes of 

forests needed to facilitate successful dispersal have not been thoroughly evaluated (Buchanan 

2004, p. 1341).

Spotted owls may be found in younger forest stands that have the structural characteristics of 

older forests or retained structural elements from the previous forest. In redwood forests and 

mixed conifer-hardwood forests along the coast of northwestern California, considerable 

numbers of spotted owls also occur in younger forest stands, particularly in areas where 

hardwoods provide a multi-layered structure at an early age (Thomas et al. 1990, p. 158; Diller 

and Thome 1999, p. 275). In mixed conifer forests in the eastern Cascades in Washington, 27 

percent of nest sites were in old-growth forests, 57 percent were in the understory reinitiation 

phase of stand development, and 17 percent were in the stem exclusion phase (Buchanan et al.

1995, p. 304). In the western Cascades of Oregon, 50 percent of spotted owl nests were in lateseral/old-growth stands (greater than 80 years old), and none were found in stands of less than 40 

years old (Irwin et al. 2000, p. 41). 

In the Western Washington Cascades, spotted owls roosted in mature forests dominated by trees 

greater than 50 centimeters (19.7 inches) dbh with greater than 60 percent canopy closure more 

often than expected for roosting during the non-breeding season. Spotted owls also used young 

forest (trees of 20 to 50 centimeters (7.9 inches to 19.7 inches) dbh with greater than 60 percent 

canopy closure) less often than expected based on this habitat’s availability (Herter et al. 2002, p. 

441). 

In the Coast Ranges, Western Oregon Cascades and the Olympic Peninsula, radio-marked 

spotted owls selected for old-growth and mature forests for foraging and roosting and used 

young forests less than predicted based on availability (Forsman et al. 1984, pp. 24-25; Carey et 

al. 1990, pp. 14-15; Thomas et al. 1990; Forsman et al. 2005, pp. 372-373). Glenn et al. (2004,
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pp. 46-47) studied spotted owls in young forests in western Oregon and found little preference 

among age classes of young forest.

Habitat use is influenced by prey availability. Ward (1990, p. 62) found that spotted owls 

foraged in areas with lower variance in prey densities (that is, where the occurrence of prey was 

more predictable) within older forests and near ecotones of old forest and brush seral stages. 

Zabel et al. (1995, p. 436) showed that spotted owl home ranges are larger where flying squirrels 

(Glaucomys sabrinus) are the predominant prey and smaller where wood rats (Neotoma spp.) are 

the predominant prey. The availability or abundance of prey can in turn influence reproductive 

success (Rosenburg et al. 2003, pp. 1720-1723). 

The availability and distribution of habitats are important considerations. Landscape-level 

analyses in portions of Oregon Coast and California Klamath provinces suggest that a mosaic of 

late-successional habitat interspersed with other seral conditions may benefit spotted owls more 

than large, homogeneous expanses of older forests (Zabel et al. 2003, p. 1038; Franklin et al.

2000, pp. 573-579; Meyer et al. 1998, p. 43). In Oregon Klamath and Western Oregon Cascade 

provinces, Dugger et al. (2005, p. 876) found that apparent survival and reproduction was 

positively associated with the proportion of older forest near the territory center (within 730 

meters) (2,395 feet). Survival decreased dramatically when the amount of non-habitat (nonforest areas, sapling stands, etc.) exceeded approximately 50 percent of the home range (Dugger 

et al. 2005, pp. 873-874). The authors concluded that they found no support for either a positive 

or negative direct effect of intermediate-aged forest—that is, all forest stages between sapling 

and mature, with total canopy cover greater than 40 percent—on either the survival or 

reproduction of spotted owls. It is unknown how these results were affected by the low habitat 

fitness potential in their study area, which Dugger et al. (2005, p. 876) stated was generally much 

lower than those in Franklin et al. (2000) and Olson et al. (2004), and the low reproductive rate 

and survival in their study area, which they reported were generally lower than those studied by 

Anthony et al. (2006). Olson et al. (2004, pp. 1050-1051) found that reproductive rates 

fluctuated biennially and were positively related to the amount of edge between late-seral and 

mid-seral forests and other habitat classes in the central Oregon Coast Range. Olson et al. (2004, 

pp. 1049-1050) concluded that their results indicate that while mid-seral and late-seral forests are 

important to spotted owls, a mixture of these forest types with younger forest and non-forest may 

be best for spotted owl survival and reproduction in their study area. In a large-scale 

demography modeling study, Forsman et al. (2011, pp. 1-2) found a positive correlation between 

the amount of suitable habitat and recruitment of young.

Reproductive Biology

The spotted owl is relatively long-lived, has a long reproductive life span, invests significantly in 

parental care, and exhibits high adult survivorship relative to other North American owls 

(Forsman et al. 1984; Gutiérrez et al. 1995, p. 5). Spotted owls are sexually mature at 1 year of 

age, but rarely breed until they are 2 to 5 years of age (Miller et al. 1985, p. 93; Franklin 1992, p. 

821; Forsman et al. 2002, p. 17). Breeding females lay one to four eggs per clutch, with the 

average clutch size being two eggs; however, most spotted owl pairs do not nest every year, nor 

are nesting pairs successful every year (USDI FWS 1990b; Forsman et al. 1984, pp. 32-34; 

Anthony et al. 2006, p. 28), and re-nesting after a failed nesting attempt is rare (Gutiérrez 1996, 

p. 4). The small clutch size, temporal variability in nesting success, and delayed onset of 

breeding all contribute to the relatively low fecundity of this species (Gutiérrez 1996, p. 4). 
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Courtship behavior usually begins in February or March, and females typically lay eggs in late 

March or April. The timing of nesting and fledging varies with latitude and elevation (Forsman 

et al. 1984, p. 32). After they leave the nest in late May or June, juvenile spotted owls depend on 

their parents until they are able to fly and hunt on their own. Parental care continues after 

fledging into September (USDI FWS 1990a; Forsman et al. 1984, p. 38). During the first few 

weeks after the young leave the nest, the adults often roost with them during the day. By late 

summer, the adults are rarely found roosting with their young and usually only visit the juveniles 

to feed them at night (Forsman et al. 1984, p. 38). Telemetry and genetic studies indicate that 

close inbreeding between siblings or parents and their offspring is rare (Haig et al. 2001, p. 35; 

Forsman et al. 2002, p. 18). Hybridization of northern spotted owls with California spotted owls 

and barred owls has been confirmed through genetic research (Hamer et al. 1994, pp. 487-492; 

Gutiérrez et al. 1995, pp. 2-3; Dark et al. 1998, p. 52; Kelly 2001, pp. 33-35; Funk et al. 2008, 

pp. 161-171). 

Dispersal Biology

Natal dispersal of spotted owls typically occurs in September and October with a few individuals 

dispersing in November and December (Miller et al. 1997; Forsman et al. 2002, p. 13). Natal 

dispersal occurs in stages, with juveniles settling in temporary home ranges between bouts of 

dispersal (Forsman et al. 2002, pp. 13-14; Miller et al. 1997, p. 143). The median natal dispersal 

distance is about 10 miles for males and 15.5 miles for females (Forsman et al. 2002, p. 16). 

Dispersing juvenile spotted owls experience high mortality rates, exceeding 70 percent in some 

studies (USDI FWS 1990a; Miller 1989, pp. 32-41). Known or suspected causes of mortality 

during dispersal include starvation, predation, and accidents (Miller 1989, pp. 41-44; USDI FWS 

1990a; Forsman et al. 2002, pp. 18-19). Parasitic infection may contribute to these causes of 

mortality, but the relationship between parasite loads and survival is poorly understood (Hoberg 

et al. 1989, p. 247; Gutiérrez 1989, pp. 616-617; Forsman et al. 2002, pp. 18-19). Successful 

dispersal of juvenile spotted owls may depend on their ability to locate unoccupied suitable 

habitat in close proximity to other occupied sites (LaHaye et al. 2001, pp. 697-698).

There is little evidence that small openings in forest habitat influence the dispersal of spotted 

owls, but large, non-forested valleys such as the Willamette Valley apparently are barriers to 

both natal and breeding dispersal (Forsman et al. 2002, p. 22). The degree to which water 

bodies, such as the Columbia River and Puget Sound, function as barriers to dispersal is unclear, 

although radio telemetry data indicate that spotted owls move around large water bodies rather 

than cross them (Forsman et al. 2002, p. 22). Analysis of the genetic structure of spotted owl 

populations suggests that gene flow may have been adequate between the Olympic Mountains 

and the Washington Cascades, and between the Olympic Mountains and the Oregon Coast Range 

(Haig et al. 2001, p. 35).

Breeding dispersal occurs among a small proportion of adult spotted owls; these movements 

were more frequent among females and unmated individuals (Forsman et al. 2002, pp. 20-21). 

Breeding dispersal distances were shorter than natal dispersal distances and also are apparently 

random in direction (Forsman et al. 2002, pp. 21-22). In California spotted owls, a similar 

subspecies, the probability for dispersal was higher in younger owls, single owls, paired owls 

that lost mates, owls at low quality sites, and owls that failed to reproduce in the preceding year 

(Blakesley et al. 2006, p.77). Both males and females dispersed at near equal distances 

(Blakesley et al. 2006, p. 76). In 72 percent of observed cases of dispersal, dispersal resulted in 

increased habitat quality (Blakesley et al. 2006, p. 77).
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Dispersal can also be described as having two phases: transience and colonization (Courtney et al 

2004, p. 5-13). Fragmented forest landscapes are more likely to be used by owls in the 

transience phase as a means to move rapidly between denser forest areas (Courtney et al 2004, p. 

5-13; USDI FWS 2012a, p. 14086). Movements through mature and old growth forests occur 

during the colonization phase when birds are looking to become established in an area (Miller et 

al 1997, p. 144; Courtney et al 2004, p. 5-13). Transient dispersers use a wider variety of forest 

conditions for movements than colonizing dispersers, who require habitats resembling 

nesting/roosting/foraging habitats used by breeding birds (USDI FWS 2012a, p. 14086). 

Dispersal success is likely highest in mature and old growth forest stands where there is more 

likely to be adequate cover and food supply (USDI FWS 2012a, p. 14086). 

Food Habits

Spotted owls are mostly nocturnal, although they also forage opportunistically during the day 

(Forsman et al. 1984, p. 51; 2004, pp. 222-223; Sovern et al. 1994, p. 202). The composition of 

the spotted owl’s diet varies geographically and by forest type. Generally, flying squirrels 

(Glaucomys sabrinus) are the most prominent prey for spotted owls in Douglas-fir and western 

hemlock (Tsuga heterophylla) forests (Forsman et al. 1984, pp. 40-41) in Washington and 

Oregon, while dusky-footed wood rats (Neotoma fuscipes) are a major part of the diet in the 

Oregon Klamath, California Klamath, and California Coastal provinces (Forsman et al. 1984, pp. 

40-42; 2004, p. 218; Ward et al. 1998, p. 84; Hamer et al. 2001, p. 224). Depending on location, 

other important prey include deer mice (Peromyscus maniculatus), tree voles (Arborimus 

longicaudus, A. pomo), red-backed voles (Clethrionomys spp.), gophers (Thomomys spp.), 

snowshoe hare (Lepus americanus), bushy-tailed wood rats (Neotoma cinerea), birds, and 

insects, although these species comprise a small portion of the spotted owl diet (Forsman et al. 

1984, pp. 40-43; 2004, p. 218; Ward et al. 1998; p. 84; Hamer et al. 2001, p.224). 

Other prey species such as the red tree vole (Arborimus longicaudus), red-backed voles 

(Clethrionomys gapperi), mice, rabbits and hares, birds, and insects) may be seasonally or 

locally important (reviewed by Courtney et al. 2004, pp. 4-27). For example, Rosenberg et al. 

(2003, p. 1720) showed a strong correlation between annual reproductive success of spotted owls 

(number of young per territory) and abundance of deer mice (Peromyscus maniculatus) (r2 = 

0.68), despite the fact they only made up 1.6±0.5 percent of the biomass consumed. However, it 

is unclear if the causative factor behind this correlation was prey abundance or a synergistic 

response to weather (Rosenberg et al. 2003, p. 1723). Ward (1990, p. 55) also noted that mice 

were more abundant in areas selected for foraging by owls. Nonetheless, spotted owls deliver 

larger prey to the nest and eat smaller food items to reduce foraging energy costs; therefore, the 

importance of smaller prey items, like Peromyscus, in the spotted owl diet should not be 

underestimated (Forsman et al. 2001, p. 148; 2004, pp. 218-219). In the southern portion of their 

range, where woodrats are a major component of their diet, northern spotted owls are more likely 

to use a variety of stands, including younger stands, brushy openings in older stands, and edges 

between forest types in response to higher prey density in some of these areas (Forsman et al. 

1984, pp. 24-29). 

Population Dynamics

The northern spotted owl is relatively long-lived, has a long reproductive life span, invests 

significantly in parental care, and exhibits high adult survivorship relative to other North 

American owls (Forsman et al. 1984; Gutiérrez et al. 1995, p. 5). The spotted owl’s long 

reproductive life span allows for some eventual recruitment of offspring, even if recruitment 
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does not occur each year (Franklin et al. 2000, p. 576). 

Annual variation in population parameters for spotted owls has been linked to environmental 

influences at various life history stages (Franklin et al. 2000, p. 581). In coniferous forests, mean 

fledgling production of the California spotted owl (Strix occidentalis occidentalis), a closely 

related subspecies, was higher when minimum spring temperatures were higher (North et al. 

2000, p. 805), a relationship that may be a function of increased prey availability. Across their 

range, spotted owls have previously shown an unexplained pattern of alternating years of high 

and low reproduction, with highest reproduction occurring during even-numbered years (e.g., 

Franklin et al. 1999, p. 1). Annual variation in breeding may be related to weather (i.e., 

temperature and precipitation) (Wagner et al. 1996, p. 74; Zabel et al. 1996, p.81 In: Forsman et 

al. 1996) and fluctuation in prey abundance (Zabel et al. 1996, pp.437-438). 

A variety of factors may regulate spotted owl population levels. These factors may be densitydependent (e.g., habitat quality, habitat abundance) or density-independent (e.g., climate). 

Interactions may occur among factors. For example, as habitat quality decreases, densityindependent factors may have more influence on survival and reproduction, which tends to 

increase variation in the rate of growth (Franklin et al. 2000, pp. 581-582). Specifically, weather 

could have increased negative effects on spotted owl fitness for those owls occurring in relatively 

lower quality habitat (Franklin et al. 2000, pp. 581-582). A consequence of this pattern is that at 

some point, lower habitat quality may cause the population to be unregulated (have negative 

growth) and decline to extinction (Franklin et al. 2000, p. 583). Recent findings of the northern 

spotted owl meta-analysis suggest that competition with barred owls is an important stressor of 

spotted owl populations, but habitat availability and climatic patterns also appear to influence 

survival, occupancy, recruitment, and, to a lesser extent, fecundity (Dugger et al. 2016, entire). 

Authors noted variable annual rates of decline across the range, but the CleElum study area in 

Washington and the control area in Green Diamond study area in northern California showed the 

highest annual rates of population decline (Dugger et al. 2016, pp.70-71; further detail provided 

in Barred Owls section below). Rangewide, the weighted mean estimated population was 

determined to decline 3.8 percent per year (Dugger et al. 2016, p. 71).

Olson et al. (2005, pp. 930-931) used open population modeling of site occupancy that 

incorporated imperfect and variable detectability of spotted owls and allowed modeling of 

temporal variation in site occupancy, extinction, and colonization probabilities (at the site scale). 

The authors found that visit detection probabilities average less than 0.70 and were highly 

variable among study years and among their three study areas in Oregon. Pair site occupancy 

probabilities declined greatly on one study area and slightly on the other two areas. However, 

for all owls, including singles and pairs, site occupancy was mostly stable through time. Barred 

owl presence had a negative effect on these parameters (see barred owl discussion in the New 

Threats section below). However, there was enough temporal and spatial variability in detection 

rates to indicate that more visits would be needed in some years and in some areas, especially if 

establishing pair occupancy was the primary goal. 

Threats 

The spotted owl was listed as threatened throughout its range “due to loss and adverse 

modification of suitable habitat as a result of timber harvesting and exacerbated by catastrophic 

events such as fire, volcanic eruption, and wind storms” (USDI FWS 1990a, p. 26114). More 

specifically, threats to the spotted owl included low populations, declining populations, limited 

habitat, declining habitat, inadequate distribution of habitat or populations, isolation of 
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provinces, predation and competition, lack of coordinated conservation measures, and 

vulnerability to natural disturbance (USDI FWS 1992a, pp. 33-41). These threats were 

characterized for each province as severe, moderate, low, or unknown (USDI FWS 1992a, pp. 

33-41). Declining habitat was recognized as a severe or moderate threat to the spotted owl 

throughout its range, isolation of populations was identified as a severe or moderate threat in 11 

provinces, and a decline in population was a severe or moderate threat in 10 provinces. 

Together, these three factors represented the greatest concerns about rangewide conservation of 

the spotted owl. Limited habitat was considered a severe or moderate threat in nine provinces, 

and low populations were a severe or moderate concern in eight provinces, suggesting that these 

factors were also a concern throughout the majority of the spotted owl’s range. Vulnerability to 

natural disturbances was rated as low in five provinces. 

The degree to which predation and competition might pose a threat to the spotted owl was 

unknown in more provinces than any of the other threats, indicating a need for additional 

information. Few empirical studies exist to confirm that habitat fragmentation contributes to 

increased levels of predation on spotted owls (Courtney et al. 2004, pp. 11-8 to 11-9). However, 

great horned owls (Bubo virginianus), an effective predator on spotted owls, are closely 

associated with fragmented forests, openings, and clearcuts (Johnson 1992, p. 84; Laidig and 

Dobkin 1995, p. 155). As mature forests are harvested, great horned owls may colonize 

fragmented forests, thereby increasing spotted owl vulnerability to predation.

The Service conducted a 5-year review of the spotted owl in 1994 (USDI FWS 2004), for which 

the Service prepared a scientific evaluation of the status of the spotted owl (Courtney et al. 

2004). An analysis was conducted assessing how the threats described in 1990 might have 

changed by 2004. Some of the key threats identified in 2004 were:

 “Although we are certain that current harvest effects are reduced, and that past harvest is 

also probably having a reduced effect now as compared to 1990, we are still unable to 

fully evaluate the current levels of threat posed by harvest because of the potential for lag 

effects...In their questionnaire responses...6 of 8 panel member identified past habitat 

loss due to timber harvest as a current threat, but only 4 viewed current harvest as a 

present threat” (Courtney and Gutiérrez 2004, pp.11-7).

 “Currently the primary source of habitat loss is catastrophic wildfire, although the total 

amount of habitat affected by wildfires has been small (a total of 2.3 percent of the rangewide habitat base over a 10-year period)” (Courtney and Gutiérrez 2004, pp.11-8).

 “Although the panel had strong differences of opinion on the conclusiveness of some of 

the evidence suggesting [barred owl] displacement of [spotted owls], and the mechanisms 

by which this might be occurring, there was no disagreement that [barred owls] 

represented an operational threat. In the questionnaire, all 8 panel members identified 

[barred owls] as a current threat, and also expressed concern about future trends in 

[barred owl] populations” (Courtney and Gutiérrez 2004, pp. 11-8).

Threats, as identified in the 2011 Revised Recovery Plan for the Northern Spotted Owl, continue 

to emphasize that habitat loss and barred owls are the main threats to northern spotted owl 

recovery (USDI FWS 2011, Appendix A), and that effects of high severity wildfires pose 

concern for habitat conservation in some portions of the range (Davis et al. 2016, p. 38).

Barred Owls (Strix varia)
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Barred owls currently appear to be the primary threat to northern spotted owls. With its recent 

expansion to as far south as Marin County, California (Gutiérrez et al. 2004, pp. 7-12 to 7-13; 

Steger et al. 2006, p.226), the barred owl’s range now completely overlaps that of the northern 

spotted owl. Evidence that barred owls are occurring in higher densities than spotted owls in 

many parts of the range (3–8 barred owl territories/northern spotted owl; Hamer et al. 2007; 

Singleton et al. 2010; Wiens et al. 2011, 2014), and, to a lesser extent, northern California 

spotted owls (Diller et al. 2016, Dugger et al. 2016). In a recent study, the highest densities 

found were in the Oregon Coast Range, with up to 20 barred owls per spotted owl territory 

reported (Wiens et al. 2017, p. 12). 

The two species of owls share similar habitats and are likely competing for food resources 

(Hamer et al. 2001, p. 226, Gutiérrez et al. 2007, p. 187; Livezey and Fleming 2007, p. 319, 

Weins et al., 2014, pp. 24 and 33). Hamer found a strong diet overlap (76 percent) between 

northern spotted and barred owl diets (pp. 221, 226). Barred owl diets are more diverse than 

northern spotted owl diets and include species associated with riparian and other moist habitats 

(e.g. fish, invertebrates, frogs, and crayfish), along with more terrestrial and diurnal species 

(Smith et al. 1983; Hamer et al. 2001; Gronau 2005, Weins et al., 2014, p. 24). Even though 

barred owls may be taking northern spotted owls’ primary prey only as a generalist, northern 

spotted owls may be affected by a sufficient reduction in the density of these prey items due to 

barred owls, leading to a depletion of prey to the extent that the northern spotted owl cannot find 

an adequate amount of food to sustain maintenance or reproduction (Gutiérrez et al. 2007, p. 

187; Livezey and Fleming 2007, p. 319). These impacts are likely to have direct and indirect 

effects on ecosystem processes (Holm et al. 2017, p. 618)

In addition to completion for prey, barred owls are competing for habitats (Hamer et al. 1989, 

p.55; Dunbar et al. 1991, p. 467; Herter and Hicks 2000, p. 285; Pearson and Livezey 2003, p. 

274; Weins et al., 2014, pp. 24 and 33). Barred owls were initially thought to be more closely 

associated with early successional forests than spotted owls, based on studies conducted on the 

west slope of the Cascades in Washington (Hamer et al 1989, p. 34; Iverson 1993, p.39). 

However, more recent studies conducted in the Pacific Northwest show that barred owls 

frequently use mature and old-growth forests (Pearson and Livezey 2003, p. 270; Gremel 2005, 

Schmidt 2006, p. 1; Singleton et al. 2010, pp. 290-292). In the fire prone forests of eastern 

Washington, a telemetry study conducted on barred and spotted owls showed that barred owl 

home ranges were located on lower slopes or valley bottoms, in closed canopy, mature, Douglasfir forest, while spotted owl sites were located on mid-elevation areas with southern or western 

exposure, characterized by closed canopy, mature, ponderosa pine or Douglas-fir forest 

(Singleton et al. 2005, p. 1).

In addition to resource competition, barred owls have been documented to physically attack 

spotted owls (Pearson and Livezey 2003, p. 274), and circumstantial evidence strongly indicated 

that a barred owl killed a spotted owl (Leskiw and Gutiérrez 1998, p. 226). 

There is consensus in the literature on the negative influence barred owls are having on northern 

spotted owl site occupancy, fecundity, reproduction, apparent survival, and detectability, and that 

data indicates that over the last ten-fifteen years, they are contributing to declines in spotted owl 

populations (Olson et al. 2005, p. 924; Forsman et al. 2011, pp. 69-70), Dugger et al. 2011, pp. 

2463-2467; Dugger et al. 2016, pp. 70-96). As barred owls have expanded, the occupancy of 

historical spotted owl territories appears to be declining. Over ten years ago, site occupancy of 

spotted owls in Washington and Oregon was significantly lower (p < 0.001) after barred owls 

were detected within 0.8 kilometer (0.5 miles) of the territory center but was “only marginally 
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lower” (p = 0.06) if barred owls were located more than 0.8 kilometer (0.5 miles) from the 

spotted owl territory center (Kelly et al. 2003, p. 51). Pearson and Livezey (2003, p. 271) found 

that there were significantly more barred owl site-centers in unoccupied spotted owl circles than 

occupied spotted owl circles (centered on historical spotted owl site-centers) with radii of 0.8 

kilometer (0.5 miles) (p = 0.001), 1.6 kilometer (1 mile) (p = 0.049), and 2.9 kilometer (1.8 

miles) (p = 0.005) in Gifford Pinchot National Forest. In Olympic National Park, Gremel (2005, 

p. 11) found a significant decline (p = 0.01) in spotted owl pair occupancy at sites where barred 

owls had been detected, while pair occupancy remained stable at spotted owl sites without barred 

owls. Olson et al. (2005, p. 928) found that the annual probability that a spotted owl territory 

would be occupied by a pair of spotted owls after barred owls were detected at the site declined 

by 5 percent in the HJ Andrews study area, 12 percent in the Coast Range study area, and 15 

percent in the Tyee study area. In contrast, Bailey et al. (2009, p. 2983), when using a twospecies occupancy model, showed no evidence that barred owls excluded northern spotted owls 

from territories in Oregon. More recently, results from a barred owl and northern spotted owl 

radio-telemetry study in Washington reported two northern spotted owls fleeing their territories 

and traveling six and 15 miles, believed to be as a result of frequent direct encounters with barred 

owls; both northern spotted owls were subsequently found dead (Irwin et al. 2010, p. 3-4). 

Preliminary findings from an ongoing barred owl experimental control/treatment study, spotted 

owl pair occupancy was low, has declined in control sites; while (with the exception of one year 

in one study area), the occupancy by barred owls has increased (Wiens et al. 2017, tables 1 and 

2). Authors also report that the probability of use by barred owls within 500 acre hexagons 

(1,235 acres) in the Oregon Coast Ranges study area was high in the two years of the study in the 

control area (>0.920) (p. 16). 

Numerous studies suggest that barred owls are negatively affecting spotted owl survival and 

reproduction. Anthony et al. (2006, p. 32) found significant evidence for negative effects of 

barred owls on apparent survival of spotted owls in two of 14 study areas (Olympic and 

Wenatchee). They attributed the equivocal results for most of their study areas to the coarse 

nature of their barred owl covariate. Dugger et al. (2011, pp. 2463-2467) described synergistic 

effects associated with territory composition and presence of barred owls; some northern spotted 

owl pairs retained their territories and continued to survive and successfully reproduce during 

their study even when barred owls were present, but the effects of reduced old growth forest in 

the core habitat areas were compounded when barred owls were present - extinction rates of 

northern spotted owl territories nearly tripled when barred owls were detected. Yackulic and 

others documented similar findings; the effects of interspecific competition were likely to 

negatively affect spotted owls, both through its immediate effects on local extinction and by 

indirectly lowering colonization (Yackulic et al., 2014, pp. 271-273). 

Most recently, apparent survival and local extinction rates were the key vital rates associated 

with barred owl presence in spotted owl populations (Dugger et al., 2016, p. 93-98). Dugger et 

al. (2016, pp. 98-99) suggested that barred owl densities may now be high enough across the 

range of the northern spotted owl that, despite the continued management and conservation of 

suitable owl habitat on Federal lands (Davis et al. 2011, 2015), the long-term prognosis for the 

persistence of northern spotted owls may be in question without additional management 

intervention. For example, Dugger et al. (2016) found that the removal of barred owls in the 

Green Diamond study area in northern California had rapid, positive effects on northern spotted 

owl survival and rates of population change, suggesting that, along with habitat conservation and 

management, barred owl removal may be able to slow or reverse northern spotted owl population 

declines on at least a localized scale (Diller et al. 2016). 
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Olson et al. (2004, p. 1048) found that the presence of barred owls had a significant negative 

effect on the reproduction of spotted owls in the central Coast Range of Oregon (in the Roseburg 

study area). The conclusion that barred owls had no significant effect on the reproduction of 

spotted owls in one study (Iverson 2004, p. 89) was unfounded because of small sample sizes 

(Livezey 2005, p. 102). It is likely that all of the above analyses underestimated the effects of 

barred owls on the reproduction of spotted owls because spotted owls often cannot be relocated 

after they are displaced by barred owls (E. Forsman, pers. comm., cited in USDI FWS 2011, p. 

B-11). Anthony et al. (2006, p. 32) found significant evidence for negative effects of barred 

owls on apparent survival of spotted owls in two of 14 study areas (Olympic and Wenatchee). 

They attributed the equivocal results for most of their study areas to the coarse nature of their 

barred owl covariate. Dugger et al. (2011, pp. 2463-2467) confirmed the synergistic effects of 

barred owls and territory habitat characteristics on extinction and colonization rates of territories 

by northern spotted owls. Extinction rates of northern spotted owl territories nearly tripled when 

barred owls were detected (Dugger et al. 2011, p. 2464). The recent meta-analysis suggested 

weak relationships between fecundity and barred owls across all study areas; however, declines 

in the number of occupied spotted owl sites contributed to declines in the total number of young 

produced per study area (Dugger et al. 2016 p. 96).

Monitoring and management of northern spotted owls has become more complicated due to their 

possible reduced detectability when barred owls are present (Kelly et al. 2003, pp. 51-52; 

Courtney et al. 2004, p. 7-16 ; Olson et al. 2005, p. 929; Crozier et al. 2006, p.766-767). 

Evidence that northern spotted owls were responding less frequently during surveys led the 

Service and its many research partners to update the northern spotted owl survey protocol (USDI 

FWS 2012b). The recent changes to the northern spotted owl survey protocol were based on the 

probability of detecting northern spotted owls when barred owls are present (See USDI FWS 

Memorandum, revised January 9, 2012, “Northern Spotted Owl Survey Protocol” and attached 

“Protocol for Surveying Proposed Management Activities That May Impact Northern Spotted 

Owls” for guidance and methodology). 

In an analysis of more than 9,000 banded spotted owls throughout their range, only 47 hybrids 

were detected (Kelly and Forsman 2004, p. 807). Consequently, hybridization with the barred 

owl is considered to be “an interesting biological phenomenon that is probably inconsequential, 

compared with the real threat—direct competition between the two species for food and space” 

(Kelly and Forsman 2004, p. 808). 

There is no evidence that the increasing trend in barred owls has stabilized in any portion of the 

spotted owl’s range in the western United States, and “there are no grounds for optimistic views 

suggesting that barred owl impacts on northern spotted owls have been already fully realized” 

(Gutiérrez et al. 2004, pp. 7-38). To date, this situation does not appear to have changed. 

Wildfire 

At the time of listing there was recognition that large-scale wildfire posed a threat to the spotted 

owl and its habitat (USDI FWS 1990a, p. 26183). New information suggests fire may be more 

of a threat than previously thought. In 2005 the overall total amount of habitat affected by 

wildfires was been relatively small (Lint 2005, p. v) but since then, there have been significant 

losses of nesting/roosting habitats reported, particularly in the reserved land allocations of the 

Klamath Province and parts of the Oregon Cascades (Davis et al. 2011, pp. 43-48; Davis et al. 

2016, tables 5 and 7). Table A-2 below also summarizes habitat lost from natural disturbances, 

the majority of which has resulted from high severity fires. Silvicultural management of forest 
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fuels are currently being implemented throughout the spotted owl’s range, in an attempt to 

reduce the levels of fuels that have accumulated during nearly 100 years of effective fire 

suppression; however, the ability to protect spotted owl habitat and viable populations of spotted 

owls from large fires through risk-reduction endeavors is uncertain (Courtney et al. 2004, pp. 12-

11). The NWFP recognized wildfire as an inherent part of managing spotted owl habitat in 

certain portions of the range. The distribution and size of reserve blocks as part of the NWFP 

design may help mitigate the risks associated with large-scale fire (Lint 2005, p. 77).

Studies indicate that the effects of wildfire on spotted owls and their habitat are variable, 

depending on fire intensity, severity, and size. Within the fire-adapted forests of the spotted 

owl’s range, spotted owls likely have adapted to withstand fires of variable sizes and severities. 

However, fire is often considered a primary threat to spotted owls because of its potential to alter 

habitat rapidly (Bond et al. 2009, p. 1116) and is a major cause of habitat loss on Federal lands 

(Courtney et al. 2004, executive summary; Davis et al. 2011, pp. 43-48; Davis et al. 2016, tables 

5 and 7). 

Research results on spotted owl use of burned landscapes and their demographic variables 

following fires at localized scales has yielded variable results that were influenced by small 

sample sizes, varying impacts to habitat, existing forest management practices, the condition of 

pre- and post-fire landscapes, and the status of spotted owls that previously occupied the sites 

(Elliott 1985; Gaines et al. 1995, King et al. 1998; Bond et al. 2002; Jenness et al. 2004; Clark 

2007; Seamans and Gutierrez 2007; Bond et al. 2009; Clark et al. 2011; Roberts et al. 2011; 

Clark et al. 2013; Comfort 2014; Lee and Bond 2015a; Lee and Bond 2015b; Bond et al. 2016; 

and Jones et al., 2016). Bond and others (2002) examined the demography of the three spotted 

owl subspecies after wildfires, in which wildfire burned through spotted owl nest and roost sites 

in varying degrees of severity. Post-fire demography parameters for the three subspecies were 

similar or better than long-term demographic parameters for each of the three subspecies in those 

same areas (Bond et al. 2002, p. 1025-1026). In a preliminary study conducted by Anthony and 

Andrews (2004, p. 8) in the Oregon Klamath Province, their sample of spotted owls appeared to 

be using a variety of habitats within the area of the Timbered Rock fire, including areas where 

burning had been moderate. Site fidelity can influence spotted owl use of burned areas that were 

previously suitable (Clark 2007, Bond et al. 2009, Lee et al. 2012). Also, the amount, extent, 

and location of high severity fires appear to be strong influences on spotted owl occupancy. One 

year following the extensive King Fire in the Sierra Nevada Mountains, Jones and others (2016) 

documented strong negative California spotted owl population impacts, with declines in 

occupancy and reproduction associated with severely burned sites; the probability of site 

extinction in that study was seven times higher one year after the fire where more than 50 

percent of the site (approximately 0.7 mile radius area) burned at high severity (75–100 percent 

canopy mortality) (p. 303-304). 

In southwest Oregon, lower occupancy and survival rates of spotted owl were found in burned 

areas compared to unburned, but the results were confounded by prior management and post-fire 

harvest (Clark 2007, Clark et al. 2011, Lee et al. 2012, Clark et al. 2013). Available data on the 

direct mortality of spotted owls from fire is limited. In one study, mortality was assumed to have 

occurred at one site, and spotted owls were present at only one of the six sites 1 year after a fire 

(Gaines et al. 1997, p. 126). In 1994, two wildfires burned in the Yakama Indian Reservation in 

Washington’s eastern Cascades, affecting the home ranges of two radio-tagged spotted owls 

(King et al. 1998, pp. 2-3). No direct mortality of spotted owls was observed, even though thick 

smoke covered several spotted owl site-centers for a week. Although the amount of home ranges 
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burned was not quantified, spotted owls were observed using areas that burned at low and 

medium intensities. More research is needed to understand further the relationship between fire 

and spotted owl habitat use. Overall, we can conclude that fires are a change agent for northern 

spotted owl habitat, but there are still many unknowns regarding how much fire benefits or 

adversely affects northern spotted owl habitat (USDI FWS 2011, p. III-31).

West Nile Virus

West Nile virus (WNV), caused by a virus in the family Flaviviridae, has killed millions of wild 

birds in North America since it arrived in 1999 (McLean et al. 2001; Caffrey 2003; Caffrey and 

Peterson 2003, pp. 7-8; Marra et al. 2004, p. 393). Mosquitoes are the primary carriers (vectors) 

of the virus that causes encephalitis in humans, horses, and birds. Mammalian prey may also 

play a role in spreading WNV among predators, like spotted owls. Owls and other predators of 

mice can contract the disease by eating infected prey (Garmendia et al. 2000, p. 3111; Komar et 

al. 2001). One captive spotted owl in Ontario, Canada, is known to have contracted WNV and 

died.

Human activities and landscape physiography appear to influence the occurrence of WNV 

(Dobson and Foufopoulos 2001, p. 1004; Gibbs et al. 2006, p. 80). Mountainous terrain 

typically associated with northern spotted owls may limit the widespread occurrence of WNV. 

The effect of how WNV will ultimately affect spotted owl populations is unknown but localized 

populations could be adversely affected (Blakesley and others 2004, in Courtney et al. 2004, p. 

8-25-8-31). Susceptibility to infection and the mortality rates of infected individuals vary among 

bird species (Blakesley et al. 2004, pp. 8-33), but most owls appear to be quite susceptible. For 

example, breeding Eastern screech owls (Megascops asio) in Ohio experienced 100 percent 

mortality (T. Grubb pers. comm. in Blakesley et al. 2004, pp. 8-33). Barred owls, in contrast, 

showed lower susceptibility (B. Hunter pers. comm. in Blakesley et al. 2004, pp. 8-34). Some 

level of innate resistance may occur (Fitzgerald et al. 2003), which could explain observations in 

several species of markedly lower mortality in the second year of exposure to WNV (Caffrey and 

Peterson 2003). Wild birds also develop resistance to WNV through immune responses (Deubel 

et al. 2001). The effects of WNV on bird populations at a regional scale have not been large, 

even for susceptible species (Caffrey and Peterson 2003), perhaps due to the short-term and 

patchy distribution of mortality (K. McGowan, pers. comm., cited in Courtney et al. 2004) or 

annual changes in vector abundance and distribution. Findings from a modeling effort 

identifying likely sources of vectors and potential hosts suggest that populations of northern 

spotted owls in the coastal mountains of northwestern California are at the greatest risk of 

exposure to WNV, and that owls in the Cascade Mountains of California are at moderate risk of 

exposure (Boyce et al 2004, cited in Blakesley et al. 2004).

Blakesley et al. (2004, pp. 8-35) offer competing propositions for the likely outcome of spotted 

owl populations being infected by WNV. One scenario is that spotted owls can tolerate severe, 

short-term population reductions due to WNV, because spotted owl populations are widely 

distributed and number in the several hundreds to thousands. An alternative scenario is that 

WNV will cause unsustainable mortality, due to the frequency and/or magnitude of infection, 

thereby resulting in long-term population declines and extirpation from parts of the spotted owl’s 

current range. Thus far, no mortality in wild, northern spotted owls has been recorded; however, 

WNV is a potential threat of uncertain magnitude and effect (Blakesley et al. 2004, pp. 8-34). 

Sudden Oak Death 

Sudden oak death was not listed as particular threat at the time of listing but was recognized as a 
Appendix D. Northern Spotted Owl Rangewide Baseline

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potential threat to the spotted owl after it was discovered in Oregon (Courtney et al. 2004, USDI 

Fish and Wildlife 2011). This disease is caused by the fungus-like pathogen, Phytopthora 

ramorum that was recently introduced from Europe and is rapidly spreading as it is capable of 

infecting over 100 species of trees and shrubs (APHIS 2011, in Peterson et al. 2015, p. 937) . 

The disease has been found in several different forest types and at elevations from sea level to 

over 800 m and is now known to extend over 650 km from south of Big Sur, California to Curry 

County, Oregon (Rizzo and Garbelotto 2003, p. 198). In some areas it has reached epidemic 

proportions in oak (Quercus spp.) and tanoak (Lithocarpus densiflorus) forests along 

approximately 300 kilometers (186 miles) of the central and northern California coast (Rizzo et 

al. 2002, p. 733). Near Brookings, Oregon it has killed tanoak and causing dieback of closely 

associated wild rhododendron (Rhododendron spp.) and evergreen huckleberry (Vaccinium 

ovatum) (Goheen et al. 2002, p. 441), common components of spotted owl habitat. Despite 

treatments of infected sites that remove all infected trees and shrubs as well as those occurring 

within a 300 foot buffer, occurrences of infected sites have increased since 2001 (Peterson et al. 

2015, p. 937). The majority of infected sites in Oregon are concentrated in the Chetco River 

drainage, but it has been located as far north as Cape Sebastian (Peterson et al. 2015, p. 238). 

The spores from this pathogen are transmitted through the coastal fog and rain or through 

contaminated surfaces. During a study completed between 2001 and 2003 in California, onethird to one-half of the hiker’s present in the study area carried infected soil on their shoes 

(Davidson et al. 2005, p. 587), creating the potential for rapid spread of the disease. Sudden oak 

death poses a threat of uncertain proportion because of its potential impact on forest dynamics 

and alteration of key prey and spotted owl habitat components (e.g., hardwood trees, forest 

structure and nest tree mortality); especially in the southern portion of the spotted owl’s range 

(Courtney et al. 2004, pp. 6-26 through 6-27, 11-8). Eradication treatments themselves have the 

potential to remove habitat at the stand level as all hardwoods and shrubs identified as carriers 

are removed. Because of the coastal influence on this pathogen, sudden oak death is not likely to 

be of consequence rangewide, but could compound existing stressors in coastal provinces of the 

spotted owl range.

Inbreeding Depression, Genetic Isolation, and Reduced Genetic Diversity 

Inbreeding and other genetic problems due to small population sizes were not considered an 

imminent threat to the spotted owl at the time of listing. Earlier studies showed no indication of 

reduced genetic variation and past bottlenecks in Washington, Oregon, or California 

(Barrowclough et al. 1999, p. 922; Haig et al. 2004, p. 36). A more recent study however, 

reported a significant bottleneck influence in the Washington Cascades, an area known to be 

experiencing a significant population decline, and that other areas with significant population 

bottlenecks were correlated with declines in population growth rate (Funk et al. 2010, as 

reviewed in Haig et al. 2015, p. 187). Canadian populations may be more adversely affected by 

issues related to small population size including inbreeding depression, genetic isolation, and 

reduced genetic diversity (Courtney et al. 2004, pp. 11-9). A 2004 study (Harestad et al. 2004, p. 

13) indicates that the Canadian breeding population was estimated to be less than 33 pairs and 

annual population decline may be as high as 35 percent. In 2007, a recommendation was made 

by the Spotted Owl Population Enhancement Team to remove northern spotted owls from the 

wild in British Columbia (USDI FWS 2012a, p. 14078). This recommendation resulted in the 

eventual capture of the remaining 16 wild northern spotted owls in British Columbia for a 

captive breeding program (USDI FWS 2012a, p. 14078). Low and persistently declining 

populations throughout the northern portion of the species range (see “Population Trends” 

below) may be at increased risk of losing genetic diversity.
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Hybridization of northern spotted owls with California spotted owls, Mexican spotted owls, and 

barred owls has been confirmed through genetic research (Funk et al. 2008, p. 1; Hamer et al. 

1994, p. 487; Gutiérrez et al. 1995, p. 3; Dark et al. 1998, p. 50; Kelly 2001, pp. 33-35). 

Climate Change 

Global climate change has the potential to produce entirely new environmental conditions, 

making predictions about future ecological consequences a more daunting challenge. Recent 

forecasts indicate that climate change will have long-term and variable impacts on forest habitat 

at local and regional scales. Locally, this could involve shifts in tree species composition that 

influence habitat suitability. Regionally, there could be losses of habitat availability caused by 

advances or retreats of entire vegetative communities, and perhaps prey communities as well. 

These changes combined with effects from past management practices is currently influencing 

current forest ecosystem processes and dynamics by increasing the frequency and magnitude of 

wildfires, insect outbreaks, drought, and disease (USDI FWS 2011, pp. III-5 - III-11). In the 

Pacific Northwest, mean annual temperatures rose 0.8o C (1.5o F) in the 20th century and are 

expected to continue to warm from 0.1oto 0.6o C (0.2oto 1o F) per decade (Mote and Salathe 

2010, p. 29). Climate change models generally predict warmer, wetter winters and hotter, drier 

summers and increased frequency of extreme weather events in the Pacific Northwest (Salathe et 

al. 2010, pp. 72-73). 

Glenn et al. (2010, p.2551) noted that the potential consequences of global climate change on 

Pacific Northwest forests remain somewhat unclear, though there is potential for changes in 

forest composition and disturbance patterns that could affect northern spotted owl populations. 

Most models predict warmer, wetter winters and hotter, drier summers for the Pacific Northwest 

in the first half of the 21st century (Mote et al., 2008, Mote et al. 2014, p. 489). This may result in 

a change in species composition or reduction in the acreage of existing low-elevation forests. 

The general predicted trend in North American forests is declining occupancy by conifers and 

displacement by hardwoods. Both the frequency and intensity of wildfires and insect outbreaks 

are expected to increase over the next century in the Pacific Northwest (Littell et al. 2010, p. 

130). One of the largest projected effects on Pacific Northwest forests is likely to come from an 

increase in fire frequency, duration, and severity. Westerling et al. (2006, pp. 940-941) analyzed 

wildfires and found that since the mid-1980s, wildfire frequency in western forests has nearly 

quadrupled compared to the average of the period from 1970-1986. The total area burned is 

more than 6.5 times the previous level and the average length of the fire season during 1987-

2003 was 78 days longer compared to 1978-1986 (Westerling et al. 2006, p. 941). The area 

burned annually by wildfires in the Pacific Northwest is expected to double or triple by the 2080s 

(Littell et al. 2010, p. 140). Wildfires are now the primary cause of spotted owl habitat loss on 

Federal lands, with about 505,800 acres of nesting/roosting habitat loss attributed to wildfires 

from 1993 to 2012 (Davis et al. 2016, table 7, p. 22).

In its review of the status of the northern spotted owl in California (CDFW 2016, p. 153-155), 

the California Department of Fish and Wildlife (CDFW) evaluated the possible effects of climate 

change upon northern spotted owl and the forested habitats on which it depends. In general, 

CDFW (2016, p. 153-155) determined that climate change is occurring within the northern 

spotted owl’s entire range, including California, with many climate projections forecasting 

steady changes in the future. They reported that climate change studies predict future conditions 

that may negatively impact northern spotted owls, such as wet and cold springs, more frequent 

and severe summer heat waves, decreased fog along the coast, shifts in forest species 

composition, and increased frequency of severe wildfire events. However, CDFW (2016, p. 153-
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 213

155) also reported that in some instances predicted future conditions, such as increased 

frequency of low to moderate severity fires and expansion of suitable owl habitat forest types, 

may be favorable to the northern spotted owl in the long-term. They further reported that in 

California, current rates of temperature and precipitation change predict hotter and drier 

conditions in some areas of the northern spotted owl’s range, and wetter colder conditions in 

other areas of the range. They looked at past precipitation and temperature trends, and reported 

that drying trends across most of the northern spotted owl’s range in California, coupled with 

warmer winters and cooler summers in the interior and cooler winters and warmer summers 

along the coast, may play a role in both owl and prey population dynamics. CDFW (2016, p. 

153-155) recommended that further research is necessary to understand how climate change may 

be affecting northern spotted owls in California and throughout its range.

Potential changes in temperature and precipitation have important implications for spotted owl 

reproduction and survival. Wet, cold weather during the winter or nesting season, particularly 

the early nesting season, has been shown to negatively affect spotted owl reproduction (Olson et 

al. 2004, p. 1039, Dugger et al. 2005, p. 863), survival (Franklin et al. 2000 pp. 576-577, Olson 

et al. 2004, p. 1039, Glenn et al. 2011, p. 1279), and recruitment (Glenn et al. 2010, pp.2446-

2547). Cold, wet weather may reduce reproduction and/or survival during the breeding season 

due to declines or decreased activity in small mammal populations so that less food is available 

during reproduction when metabolic demands are high (Glenn et al. 2011, pp. 1288-1289). Cold, 

wet nesting seasons may increase the mortality of nestlings due to chilling and reduce the 

number of young fledged per pair per year (Franklin et al. 2000, p.557, Glenn et al. 2011, p. 

1286). Most recently, the relationships between spotted owl populations and climate was 

complex and variable, but rangewide, Dugger and others (2016, page 98) suggested that survival 

increased when winters were warmer and drier. This may become a factor in population 

numbers in the future; given climate change predictions for the Pacific Northwest include 

warmer, wetter winters.

Drought or hot temperatures during the summer have also been linked to reduced spotted owl 

recruitment (Glenn et al. 2010, p. 2549). Drier, warmer summers and drought conditions during 

the growing season strongly influence primary production in forests, food availability, and the 

population sizes of small mammals that spotted owls prey upon (Glenn et al. 2010, p. 2549). 

Various types of changes in climate can have direct or indirect effects on species. These effects 

may be positive, neutral, or negative and they may change over time, depending on the species 

and other relevant considerations, such as the effects of interactions of climate with other 

variables (e.g., habitat fragmentation) (IPCC 2007, pp. 8–14, 18–19). For the more central 

portion of the northern spotted owl’s range such as the location of the action area, climate 

models have provided a series of projections. For example, annual temperatures are likely to 

increase up to 3 degrees in the next couple of decades. Total precipitation may remain roughly 

similar to historic levels but likely increasing in the fall and winter months. Rising temperatures 

will cause snow to turn to rain in the lower elevations. As a result, the area is likely to 

experience more severe storm events, variable weather, higher and flashier winter and spring 

runoff events and increased flooding. Reduced snowpack and soil moisture along with hotter 

temperatures and longer fire seasons likely will increase significantly (Doppelt et al. 2008). 

While a change in forest composition or extent is likely as a result of climate change, the rate of 

that change is uncertain. In forests with long-lived dominant tree species, mature individuals can 

survive these stresses, so direct effects of climate on forest composition and structure would 

most likely occur over a longer time scale (100 to 500 years) in some areas than disturbances 
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such as wildfire or insect outbreaks (25 to 100 years) (McKenzie et al. 2009). The presence of 

high-quality habitat may buffer the negative effects of cold, wet, springs and winters on survival 

of spotted owls as well as ameliorate the effects of heat. This habitat might help maintain a 

stable prey base, thereby reducing the cost of foraging during the breeding season when 

energetic needs are high (Franklin et al. 2000).

Although the scientific literature has explored the link between climate change and the invasion 

by barred owls, changing climate alone is unlikely to have caused the invasion (Livezey 2009). 

In general, climate change can increase the success of introduced or invasive species in 

colonizing new territory. Invasive animal species are more likely to be generalists, such as the 

barred owl, than specialist, such as the spotted owl and adapt more successfully to a new climate 

than natives. 

In summary, effects of climate change may vary across the range, but is likely to exacerbate 

some existing threats to the spotted owl such as the projected potential for increased habitat loss 

from drought-related fire, tree mortality, insects and disease, as well as affecting reproduction 

and survival during years of extreme weather. 

Exposure to Toxicants

Toxicants were not identified as a threat when the northern spotted owl was listed, but a growing 

body of information suggests exposure to anti-coagulant rodenticides, fertilizers, other 

contaminants, as well as other factors associated with marijuana cultivation represent a growing 

concern for northern spotted owls. Recent accounts show that the scope and scale of exposure 

from illegal cultivation is increasing on federal and non-federal ownerships; these threats extend 

northern spotted owls and many other wildlife species and the resources they depend upon 

(Thompson et al. 2013, entire, Gabriel et al. 2013, entire; Wengert et al. 2015, p. 8; CDFW 2016 

pp. 176-177, CEPA 2017b, p.1; Gabriel et al. 2017a and 2017b; Higley et al. 2017 (abstracts). 

Known grow sites have been found to intersect with both subspecies of spotted owl ranges 

throughout California. On Forest Service lands in 2014, more than 620,000 marijuana plants on 

about 1,500 ac (607 ha) were removed from 167 different sites; about 90 percent of which were 

in California (US Senate press release 2015). Over 600 trespass grow sites were reported on 

mixed California ownerships in 2010 (Wengert et al. 2015, p. 8). Increases in mortalities from 

and exposure to pesticides in fishers in the Sierras and Northern California indicate that toxicants 

from marijuana cultivation suggest increasing trends (Gabriel et al. 2015, pp. 5-8, 14, Gabriel et 

al. 2017a). 

Illegal cultivation is a serious issue in the Klamath Physiographic Province, an area recognized 

as an important area for northern spotted owl populations (Schumaker et al. 2014). One 

cultivation site within a known northern spotted owl nest stand on the Rogue River/Siskiyou 

National Forest contained over 50 pounds of rodenticide (D. Clayton, pers. comm. 2017). In 

Southwestern Oregon in Jackson and Josephine Counties alone, a multi-agency Drug Task force 

reported a total of 100 illegal marijuana cultivation sites containing approximately 294,090 

plants between 2005-2014 (R.Caruthers, pers.comm.). Many of these sites were located within 

known spotted owl home ranges, cores, or nest stands (D. Clayton pers. comm. 2017). 

Known exposure and recent data on impacts to barred owls suggest serious implications for 

northern spotted owls. In Hoopa Tribal lands in northwestern California, of 176 barred owls 

tested for exposure to anticoagulant rodenticides, 65 percent tested positive for one or more 

second generation ARs; many of these were collected from known spotted owl home ranges 
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(Higley et al. 2017). From another data set in northwestern California, barred owls collected 

from 37 historical northern spotted owl territories have been tested for ARs (Gabriel et al. 2017, 

in review). In Oregon, 40 percent of barred owls sampled (n=10) tested positive for rodenticides.

Disturbance 

Northern spotted owls may also respond physiologically to a disturbance without exhibiting a 

significant behavioral response. In response to environmental stressors, vertebrates secrete stress 

hormones called corticosteroids (Campbell 1990, p. 925). Although these hormones are essential 

for survival, extended periods with elevated stress hormone levels may have negative effects on 

reproductive function, disease resistance, or physical condition (Carsia and Harvey 2000, pp. 

517-518; Saplosky et al. 2000, p. 1). In avian species, the secretion of corticosterone is the 

primary non-specific stress response (Carsia and Harvey 2000, p. 517). The quantity of this 

hormone in feces can be used as a measure of physiological stress (Wasser et al. 1997, p. 1019). 

Recent studies of fecal corticosterone levels of northern spotted owls indicate that low intensity 

noise of short duration and minimal repetition does not elicit a physiological stress response 

(Tempel and Gutiérrez 2003, p. 698; Tempel and Gutiérrez 2004, p. 538). However, prolonged 

activities, such as those associated with timber harvest, may increase fecal corticosterone levels 

depending on their proximity to northern spotted owl core areas (Wasser et al. 1997, p.1021; 

Tempel and Gutiérrez 2004, p. 544).

The effects of noise on spotted owls are largely unknown, and whether noise is a concern has 

been a controversial issue. The effect of noise on birds is extremely difficult to determine due to 

the inability of most studies to quantify one or more of the following variables: 1) timing of the 

disturbance in relation to nesting chronology; 2) type, frequency, and proximity of human 

disturbance; 3) clutch size; 4) health of individual birds; 5) food supply; and 6) outcome of 

previous interactions between birds and humans (Knight and Skagan 1988, pp. 355-358). 

Additional factors that confound the issue of disturbance include the individual bird’s tolerance 

level, ambient sound levels, physical parameters of sound, and how it reacts with topographic 

characteristics and vegetation, and differences in how species perceive noise. 

Information specific to behavioral responses of spotted owls to disturbance is limited, research 

indicates that recreational activity can cause Mexican spotted owls (S. o. lucida) to vacate 

otherwise suitable habitat (Swarthout and Steidl 2001, p. 314) and helicopter overflights can 

reduce prey delivery rates to nests (Delaney et al. 1999, p. 70). Additional effects from 

disturbance, including altered foraging behavior and decreases in nest attendance and 

reproductive success, have been reported for other raptors (White and Thurow 1985, p. 14; 

Andersen et al. 1989, p. 296; McGarigal et al. 1991, p. 5). 

Although it has not been conclusively demonstrated, it is anticipated that nesting spotted owls 

may be disturbed by heat and smoke as a result of burning activities during the breeding season.

Conservation Needs of the Spotted Owl

Based on the above assessment of threats, the spotted owl has the following habitat-specific and 

habitat-independent conservation (i.e., survival and recovery) needs: 

Habitat-specific Needs

1. Large blocks of habitat capable of supporting clusters or local population centers of 

spotted owls (e.g., 15 to 20 breeding pairs) throughout the owl’s range;

2. Suitable habitat conditions and spacing between local spotted owl populations throughout 
Appendix D. Northern Spotted Owl Rangewide Baseline

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its range that facilitate survival and movement;

3. Suitable habitat distributed across a variety of ecological conditions within the northern 

spotted owl’s range to reduce risk of local or widespread extirpation;

4. A coordinated, adaptive management effort to reduce the loss of habitat due to 

catastrophic wildfire throughout the spotted owl’s range, and a monitoring program to clarify 

whether these risk reduction methods are effective and to determine how owls use habitat treated 

to reduce fuels; and

5. In areas of significant population decline, sustain the full range of survival and recovery 

options for this species in light of significant uncertainty. 

Habitat-independent Needs

1. A coordinated research and adaptive management effort to better understand and manage 

competitive interactions between spotted and barred owls; and

2. Monitoring to understand better the risk that WNV and sudden oak death pose to spotted 

owls and, for WNV, research into methods that may reduce the likelihood or severity of 

outbreaks in spotted owl populations.

Conservation Strategy

Since 1990, various efforts have addressed the conservation needs of the spotted owl and 

attempted to formulate conservation strategies based upon these needs. These efforts began with 

the ISC’s Conservation Strategy (Thomas et al. 1990); they continued with the designation of 

critical habitat (USDI FWS 1992b), the Draft Recovery Plan (USDI FWS 1992a), and the 

Scientific Analysis Team report (Thomas et al. 1993), report of the Forest Ecosystem 

Management Assessment Team (Thomas and Raphael 1993); and they culminated with the 

NWFP (USDA FS/USDI BLM 1994a). Recently, the management strategy for portions of 

Bureau of Land Management lands in Oregon (2.5 million acres) was modified and is no longer 

following all measures described in the NWFP (USDI BLM 2016a). In comparison to the 

NWFP land use allocations, the Late-Successional Reserve (LSR) designs of the revised 

Resource Management Plans (RMPs) make similar contributions to the development and spacing 

of the large habitat blocks needed for northern spotted owl conservation. The RMPs includes 

approximately 177,000 more acres (71,629 ha) of LSR and Riparian Reserves than in the NWFP. 

These land use allocations represent 36 and 27 percent of the RMP lands, respectively, and will 

be managed for the retention and development of large trees and complex forests across the RMP 

landscape (USDI FWS 2016a, Table 1, p. 9). Two additional key provisions differ from 

previous strategies, including a mitigation that the BLM would participate in, cooperate with, 

and provide support for an interagency program for barred owl management to implement 

Recovery Action 30 when the Service determines the best manner in which barred owl 

management can contribute to the recovery of the northern spotted owl. Also, timber sales that 

would cause the incidental take of northern spotted owls from timber harvest would not be 

authorized until implementation of a barred owl management program has begun (USDI BLM 

2016b, p. xxxiii). Overall fundamentals of these large-scale conservation strategies have been 

based upon the reserve design principles first articulated in the ISC’s report, which are 

summarized as follows: 

 Species that are well distributed across their range are less prone to extinction than 

species confined to small portions of their range.

 Large blocks of habitat, containing multiple pairs of the species, are superior to small 
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blocks of habitat with only one to a few pairs.

 Blocks of habitat that are close together are better than blocks far apart.

 Habitat that occurs in contiguous blocks is better than habitat that is more fragmented.

 Habitat between blocks is more effective as dispersal habitat if it resembles suitable 

habitat. 

Federal Contribution to Recovery

Since it was signed on April 13, 1994, the NWFP has guided the management of Federal forest 

lands within the range of the spotted owl (USDA FS/USDI BLM 1994a, 1994b). The NWFP 

was designed to protect large blocks of old growth forest and provide habitat for species that 

depend on those forests including the spotted owl, as well as to produce a predictable and 

sustainable level of timber sales. The NWFP included land use allocations which would provide 

for population clusters of northern spotted owls (i.e., demographic support) and maintain 

connectivity between population clusters. Certain land use allocations in the plan contribute to 

supporting population clusters: LSRs, Managed Late-successional Areas, and Congressionally 

Reserved areas. Riparian Reserves, Adaptive Management Areas, and Administratively 

Withdrawn areas can provide both demographic support and connectivity/dispersal between the 

larger blocks, but were not necessarily designed for that purpose. Matrix areas were to support 

timber production while also retaining biological legacy components important to old-growth 

obligate species (in 100-acre owl cores, 15 percent late-successional provision, etc. (USDA 

FS/USDI BLM 1994a, USDI FWS 1994) which would persist into future managed timber 

stands. 

The NWFP with its rangewide system of LSRs was based on work completed by three previous 

studies (Thomas et. al. 2006): the 1990 Interagency Scientific Committee (ISC) Report (Thomas 

et. al. 1990), the 1991 report for the Conservation of Late-successional Forests and Aquatic 

Ecosystems (Johnson et. al. 1991), and the 1993 report of the Scientific Assessment Team 

(Thomas et. al. 1993). 

The Forest Ecosystem Management Assessment Team and the NWFP predicted, based on expert 

opinion, the spotted owl population would decline in the Matrix land use allocation over time, 

while the population would stabilize and eventually increase within LSRs as habitat conditions 

improved over the next 50 to 100 years (Thomas and Raphael 1993, p. II-31; USDA FS/USDI 

BLM 1994a, 1994b, p. 3&4-229). The results of the first decade of monitoring, Lint (2005, p. 

18) did not yield conclusions whether implementation of the NWFP would reverse the spotted 

owl’s declining population trend because not enough time had passed to provide the necessary 

measure of certainty. However, the results from the first decade of monitoring did not provide 

any reason to depart from the objective of habitat maintenance and restoration as described in the 

NWFP (Lint 2005, p. 18; Noon and Blakesley 2006, p. 288). Other stressors that occur in 

suitable habitat, such as the range expansion of the barred owl (already in action) and infection 

with WNV (which may or may not occur) may complicate the conservation of the spotted owl. 

Recent reports about the status of the spotted owl offer few management recommendations to 

deal with these emerging threats. 

On June 28, 2011, the Service published the Revised Recovery Plan for the Northern Spotted 

Owl (USDI FWS 2011). The recovery plan identifies threats from competition with barred owls, 

ongoing loss of northern spotted owl habitat as a result of timber harvest, loss or modification of 

northern spotted owl habitat from uncharacteristic wildfire, and loss of amount and distribution 

of northern spotted owl habitat as a result of past activities and disturbances (USDI FWS 2011, 
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p. II-2 and Appendix A). To address these threats, the current recovery strategy identifies five 

main steps: 1) development of a rangewide habitat modeling framework; 2) barred owl 

management; 3) monitoring and research; 4) adaptive management; and 5) habitat conservation 

and active forest restoration (USDI FWS 2011, p. II-2). The recovery plan lists recovery actions 

that address each of these items, some of which were retained from the 2008 recovery plan 

(USDI FWS 2008). The Managed Owl Conservation Areas and Conservation Support Areas 

recommended in the 2008 recovery plan are not a part of the recovery strategy outlined in the 

Revised Recovery Plan. The Service completed a rangewide, multi-step habitat modeling 

process to help evaluate and inform management decisions and critical habitat development 

(USDI FWS 2011, Appendix C).

The Revised Recovery Plan recommended implementing a robust monitoring and research 

program for the spotted owl. The recovery plan encourages these efforts by laying out the 

following primary elements to evaluate progress toward meeting recovery criteria: monitoring 

spotted owl population trends, comprehensive barred owl research and monitoring, continued 

habitat monitoring; inventory of spotted owl distribution, and; explicit consideration for climate 

change mitigation goals consistent with recovery actions (USDI FWS 2011, p. II-5). The 

Revised Recovery Plan also strongly encourages land managers to be aggressive in the 

implementation of recovery actions, including strategies that include active forest management. 

In other words, land managers should not be so conservative that, to avoid risk, they forego 

actions that are necessary to conserve the forest ecosystems that are necessary to the long-term 

conservation of the spotted owl. But they should also not be so aggressive that they subject 

spotted owls and their habitat to treatments where the long-term benefits do not clearly outweigh 

the short-term risks. Finding the appropriate balance to this dichotomy will remain an ongoing 

challenge for all who are engaged in spotted owl conservation (USDI FWS 2011, p. II-12). The 

Revised Recovery Plan estimates that recovery of the spotted owl could be achieved in 

approximately 30 years (USDI FWS 2011, p. II-3). The Revised Recovery Plan and the critical 

habitat designation build on the NWFP and recommends continued implementation of the NWFP 

and its standards and guides (USDI FWS 2011, p. I-1). 

Spotted Owl Recovery Units 

The 2011 Final Revised Recovery Plan for the Northern Spotted Owl determined that the 12 

existing physiographic provinces meet the criteria for use as recovery units (USDI FWS 2011, p. 

III 1-2). Recovery criteria, as described in the 2011 Final Revised Recovery Plan (p. 11-3), are 

measurable and achievable goals that are believed to result through implementation of the 

recovery actions described in the recovery plan. Achievement of the recovery criteria will take 

time and are intended to be measured over the life of the plan, not on a short-term basis. The 

criteria are the same for all 12 identified recovery units. The four recovery criterion are: 1) 

stable population trend, 2) adequate population distribution, 3) continued maintenance and 

recruitment of northern spotted owl habitat, and 4) post-delisting monitoring (USDI FWS 2011, 

p III-3). 

Conservation Efforts on Non-Federal Lands

In the report from the Interagency Scientific Committee (Thomas et al. 1990, p. 3, p. 272), the 

draft recovery plan (USDI FWS 1992b), and the report from the Forest Ecosystem Management 

Assessment Team (Thomas and Raphael 1993, p. IV-189), it was noted that limited Federal 

ownership in some areas constrained the ability to form a network of old-forest reserves to meet 

the conservation needs of the spotted owl. In these areas in particular, non-Federal lands would 
Appendix D. Northern Spotted Owl Rangewide Baseline

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be important to the rangewide goal of achieving conservation and recovery of the spotted owl. 

The Service’s primary expectations for private lands are for their contributions to demographic 

support (pair or cluster protection) to Federal lands, or their connectivity with Federal lands. In 

addition, timber harvest within each state is governed by rules that provide protection of spotted 

owls or their habitat to varying degrees. 

There are 17 current and ongoing conservation plans (CPs) including Habitat Conservation Plans 

(HCPs) and Safe Harbor Agreements (SHAs) that have incidental take permits issued for 

northern spotted owls—eight in Washington, three in Oregon, and six in California (USDI FWS 

2011, p. A-15). The CPs range in size from 76 acres to more than 1.8 million acres, although not 

all acres are included in the mitigation for northern spotted owls. In total, the CPs cover 

approximately 3 million acres (9.4 percent) of the 32 million acres of non-Federal forest lands in 

the range of the northern spotted owl. The period of time that the HCPs will be in place ranges 

from 20 to 100 years. While each CP is unique, there are several general approaches to 

mitigation of incidental take: 

 Reserves of various sizes, some associated with adjacent Federal reserves

 Forest harvest that maintains or develops nesting habitat

 Forest harvest that maintains or develops foraging habitat

 Forest management that maintains or develops dispersal habitat

 Deferral of harvest near specific sites

Washington. Timber harvest on State lands in Washington is guided by a number of State laws 

and policies. The Washington State Environmental Policy Act (SEPA) requires analysis of 

environmental impacts and consideration of reasonable alternatives for actions proposed by the 

State. State timber harvest activities must also comply with the State Forest Practices Act 

(Chapter 76.09 RCW), which regulates all forest management activities in Washington. In 1996, 

the State Forest Practices Board adopted rules (Washington Forest Practices Board 1996) that 

would contribute to conserving the spotted owl and its habitat on non-Federal lands. Adoption of 

the rules was based in part on recommendations from a Science Advisory Group that identified 

important non-Federal lands and recommended roles for those lands in spotted owl conservation 

(Hanson et al. 1993, pp. 11-15; Buchanan et al. 1994, p. ii). The 1996 rules identified 10 

landscapes, or Spotted Owl Special Emphasis Areas (SOSEAs) where owl protections on 

nonfederal lands would be emphasized. The 1996 rule package was developed by a stakeholder 

policy group and then reviewed and approved by the Forest Practices Board (Buchanan and 

Swedeen 2005, p. 9). The Forest Practices Board in Washington has a long-standing relationship 

with the Service and collaborates extensively on owl conservation. The Service provided 

extensive technical assistance in the development of the Board's existing owl rules. The Board 

was recognized in the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011a) for 

its ongoing owl conservation efforts in Recovery Action 18 encouraged to continue to use its 

existing processes "to identify areas on non-federal lands in Washington that can make strategic 

contributions to northern spotted owl conservation over time. 

The Forest Practices Rules for northern spotted owls can be described as containing three basic 

types of provisions: 1) regulations that apply outside SOSEAs, 2) a circle-based protection 

scheme for northern spotted owl sites inside SOSEAs, and 3) landscape-level planning options 

for inside SOSEAs. Forest Practices Rules outside the SOSEAs are designed to protect the 

immediate vicinity of northern spotted owl site centers during the nesting season (March 1 to 

August 31). During the nesting season, the best 70 ac (28 ha) of habitat around the site center is 

protected from harvest. Outside the nesting season there are no owl-related protections that 
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 220

constrain harvest of suitable northern spotted owl habitat in spotted owl management circles 

(Buchanan and Swedeen 2005, p 14).

Early spotted owl-related HCPs in Washington generally were intended to provide demographic 

or connectivity support (USDI FWS 1992b, p. 272). Currently, seven HCPs are in effect, 

totaling about 2.1 million acres in addition to 108,000 acres in two SHAs (USDI FWS ECOS 

Database June 19, 2017). Some of these CPs focus on providing nesting/roosting habitat 

throughout the area or in strategic locations; while others focus on providing connectivity 

through foraging habitat and/or dispersal habitat. One long term habitat management agreement 

covering 13,000 acres in which authorization of take was provided through an incidental take 

statement (section 7) associated with a Federal land exchange (USDI FWS 2011, p. A-15).

Oregon. Timber harvest on non-federal lands in Oregon is guided by the Forest Practices Act 

and Forest Practices Rules (Oregon Department of Forestry [ODF] 2014). The Oregon Forest 

Practices Act provides for protection of 70-acre core areas around sites occupied by an adult pair 

of spotted owls capable of breeding (as determined by recent protocol surveys), but it does not 

provide for protection of spotted owl habitat beyond these areas. In general, no large-scale 

spotted owl habitat protection strategy or mechanism currently exists for non-Federal lands in 

Oregon. 

State forests however are directed toward more of a multiple use objective and are managed to 

achieve “greatest permanent value,” considering economics, environmental, and cultural goals. 

Each State Forest has a Forest Management Plan that seeks to implement these ideals. 

Ultimately, the State’s goal is to produce timber revenue and also provide for a range of habitats 

across ownerships. Specific policies and procedures have been adopted on State lands to protect 

and conserve the northern spotted owl and its habitat. The State Forests Division has an 

extensive survey program across all districts as part of annual harvest planning (approximately 

$1.4 million spent in 2016) and conducts density surveys on two districts. Division policy 

directs districts to avoid any harvest activity which results in less than 40 percent suitable habitat 

within the provincial home range of an owl or pair. Thirty percent of Oregon State forests must 

be managed for “complex forest structures” and late seral tree species, for the benefit of a 

number of wildlife species. The locations of these managed lands are based in part on locations 

of northern spotted owl nest sites. Within these areas, a variety of treatments are employed to 

promote complex habitat and species diversity. Two spotted owl-related HCPs currently in 

effect cover more than 210,000 acres of non-Federal lands. In addition, six SHAs covering about 

1.9 million acres are currently in effect. 

California. The California State Forest Practice Rules, which govern timber harvest on private 

lands, require landowners to conduct spotted owl surveys for actions proposed in suitable habitat 

and to require specified habitat retention requirements around nest sites, core areas, and home 

ranges (California Department of Forestry and Fire Protection [CAL FIRE] 2017, pp. 114-117). 

Under the Forest Practice Rules, timber harvest plans cannot be approved if they are determined 

to likely result in incidental take of federally listed species, unless landowners are covered by an 

HCP or SHA. 

In 2016, the northern spotted owl was listed as an endangered species under the California 

Endangered Species Act (CESA). The incidental take of state-listed species is prohibited under 

the California Code of Regulations (783-783.8) and the California Fish and Game Code 2080 

(CDFW 2016)., unless the take is authorized by a Federal incidental take permit (CAL FIRE

2017, page .31). Currently CAL FIRE is responsible for those determinations unless Service 
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 221

technical assistance is specifically requested. While this regulatory framework conserves 

northern spotted owl habitat and minimizes or avoids the likelihood of takes, there are situations 

where timber harvesting may occur outside of the THP review process (Emergency and 

Exemption Notices as specifically described in the CFPRs Sections 1038 and 1052). In these 

cases some timber operations are permitted by CAL FIRE without fully evaluating the potential 

impacts to northern spotted owl. In the California Cascades and Klamath Provinces, three 

industrial timberland owners or management companies operate under spotted owl management 

plans that have been reviewed by the U.S. Fish and Wildlife Service or CAL FIRE and that 

outline basic measures for spotted owl protection specific to their ownership, in accordance with 

state forest practice rules, and other state and Federal laws. In coastal California, two industrial 

timberland owners currently manage under provisions of Habitat Conservation Plans (HCPs) and 

two Safe Harbor Agreements (SHAs) that authorize the incidental take of spotted owls. The 

HCPs and SHAs cover about 601,000 acres of non-Federal lands. Implementation of these plans 

is intended to provide for spotted owl demographic and connectivity support to NWFP lands 

(USDI FWS 2011, p. A-16). 

Rangewide Environmental Baseline

The environmental baseline of the species incorporates the effects of all past human activities 

and natural events that led to the present-day status of the species and its habitat, including all 

previously consulted on effects (USDI FWS/USDC NMFS 1998, pp. 4-19). 

Habitat Trends

The Service has used information provided by the USFS, BLM, and National Park Service to 

update the habitat baseline conditions by tracking relative habitat changes over time on Federal 

lands for northern spotted owls on several occasions, since the northern spotted owl was listed in 

1990 (USDA FS/USDI BLM 1994b, USDI FWS 2001, Lint 2005, Davis et al. 2011, Davis et al. 

2016). These NWFP monitoring reports assess the status and trends of spotted owl habitat across 

22.1 million acres of federally administered forest lands in addition to 23.8 million acres of 

nonfederal forest lands within the range in the United States. The estimate of 7.4 million acres 

used for the NWFP in 1994 (USDA FS/USDI BLM 1994b) was believed to be representative of 

the general amount of northern spotted owl habitat on NWFP lands at that time. These periodic 

rangewide evaluations of northern spotted owl habitat (Lint et al. 2005, Davis et al. 2011, Davis 

et al. 2016) are used to determine if the rate of potential change to northern spotted owl habitat 

has been consistent with changes in amount of habitat anticipated under the NWFP and described 

in the Final Supplemental Environmental Impact Statement (FSEIS; USFS and USDI 1994b).

Each analysis has used more up-to-date and higher quality data than the previous analyses and 

new analytical methods have been incorporated over time. While this improved the overall 

quality of the information provided, it also means that individual reports should not be compared 

directly without fully understanding the processes used to develop the results. 

Trends for suitable habitat are largely declining rangewide, with rates of loss varying by 

province and land allocation. Approximately 9,089,700 acres of spotted owl nesting/roosting 

habitat existed on Federal lands and 3,436,000 acres existed on non-federal lands at the 

beginning of the NWFP in 1994/1996 Davis and others (2016, pp.23-24). Two decades into the 

NWFP, Davis and others (2016, tables 6 and 7, pp. 21-22) reported a gross loss of about 650,200 

acres of nesting/roosting habitat, representing about 7.2 percent of what was present in 

1994/1996. Most of the losses (73 percent) occurred within the federally reserved LUAs, or a 

loss of about 7.5 percent of the habitat reserved by the NWFP; the majority of these losses were 
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 222

due to high severity fires within the Klamath Physiographic Provinces. 

Some recruitment of nesting/roosting habitat was noted (Davis et al. 2016, p. 24). The 

recruitment of habitat in non-reserved areas led to a net increase in nesting/roosting habitat of 4.3 

percent since 1993. Most of the gains occurred in the moister physiographic provinces (e.g., 

Coast Ranges and Western Cascades) however, there was also a large gain (13.5 percent) in the 

Oregon Eastern Cascades. Authors noted that habitat recruitment estimates have a higher level 

of uncertainty than estimates of habitat loss for reasons detailed in the NWFP 15-year monitoring 

report (Davis et al. 2011, pgs. 48 and 49). Although the spatial resolution of this new habitat 

map currently makes it unsuitable for tracking habitat effects at the scale of individual projects, 

the Service has evaluated the map for use in tracking provincial and rangewide habitat trends and 

now considers these data as the best available information on the distribution and abundance of 

extant spotted owl habitat within its range as of 2012 for Oregon and Washington, and 

California, when the base imagery was collected. 

The Service also considers habitat effects that are documented through the section 7 consultation 

process since 1994. The analytical framework of these consultations focuses on the reserve and 

connectivity goals established by the NWFP land-use allocations (USDA FS/USDI BLM 1994a), 

with effects expressed in terms of changes in suitable northern spotted owl habitat within those 

land-use allocations. 

In February 2013, the Service adopted the 2006/07 satellite imagery data on spotted owl habitat 

as the new rangewide habitat baseline for Federal lands which effectively resets the timeframe 

for establishing changes in the distribution and abundance of spotted owl habitat. These data 

were refreshed in May of 2017 to reflect the 2012 remotely-sensed layer utilized in Davis et al., 

2016. Until these data are refreshed, the assessment of local, provincial and rangewide spotted 

owl habitat status in this and future Opinions as well as Biological Assessments will rely on 

these habitat data associated with 2012 imagery to characterize changes in the status of spotted

owl habitat. 

Service’s Consultation Database

To update information considered in 2001 (USDI FWS 2001), the Service designed the 

Consultation Effects Tracking System database in 2002, which recorded impacts to northern 

spotted owls and their habitat at different spatial and temporal scales. In 2011, the Service 

replaced the Consultation Effects Tracking System with the Consulted on Effects Database 

located in the Service’s Environmental Conservation Online System (ECOS). The ECOS 

Database corrected technical issues with the Consultation Effects Tracking System. Data are 

currently entered into the ECOS Database under various categories including; land management 

agency, land-use allocation, physiographic province, and type of habitat affected. 

Rangewide Consultation Effects: 1994 to May 16, 2017

Between 1994 and May 16, 2017, the Service has consulted on the proposed removal/downgrade 

of approximately 212,940 acres of federal nesting/roosting habitats (Table A-1) or about 2.4 

percent of the 9.09 million acres of northern spotted owl nesting/roosting habitat estimated by 

Davis et al. (2016) to have occurred on Federal lands in 1994. These changes in suitable 

northern spotted owl habitat are consistent with the expectations for implementation of the 

NWFP, which anticipated a rate of habitat harvested at 2.5 percent per decade (USDA FS/USDI 

BLM 1994a). 

The Service also tracks habitat changes on non-NWFP lands through consultations for long-term 
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 223

Habitat Conservation Plans, Safe Harbor Agreements, or Tribal Forest Management Plans. 

Consultations conducted since 1994 have documented the eventual combined reduction of about 

453,790 acres of habitat on non-NWFP lands. Most of these losses have yet to be realized 

because they are part of long-term management plans.
Appendix D. Northern Spotted Owl Rangewide Baseline

Willamette Planning Province 224

Table A-1: Rangewide summary of effects to northern spotted owl nesting/roosting habitat1

(acres) documented through ESA section 7 consultations or technical assistance reports; 

1994 to Present. May 16 11:33:42 MDT 2017

Land Ownership

Consulted On

Habitat Changes2

Other Habitat 

Changes3

Removed/

Downgraded

Maintained/

Improved

Removed/

Downgraded

Maintained/

Improved

USFS, BLM, and NPS 212,941 565,037 276,009 97,181

Bureau of Indian Affairs / Tribes 114,099 28,372 2,398 0

Habitat Conservation Plans/Safe 

Harbor Agreements 339,692 14,539 N/A N/A

Other Federal, State, County, 

Private Lands 68,813 28,447 2,392 0

Total Changes 735,545 636,395 280,799 97,181

Notes:

1. Northern spotted owl suitable habitat includes nesting/roosting habitat, and foraging habitat. 

Nesting/roosting habitat supports all life-history functions for spotted owls including foraging, and is 

sometimes referred to as nesting, roosting, and foraging habitat (NRF). Foraging-only habitat is a separate 

category that can include more open and fragmented forests, and does not provide structures for 

nesting/roosting. Habitat effects summarized in this table are all classified as impacts to nesting/roosting 

habitats. Impacts to foraging-only habitat are tracked separately. 

2. Includes effects documented through ESA section 7 consultations for the period from 1994 to 6/26/2001 

(USFWS 2001) and all subsequent effects reported in the USFWS Tracking and Integrated Logging System 

- Northern Spotted Owl Consultation Effects Database (web application and database). 

3. Includes effects to spotted owl nesting/roosting habitat documented through technical assistance reports 

resulting from wildfires and other natural causes, private timber harvest, and/or land exchanges not 

associated with ESA section 7 consultations. 
Appendix D: Northern Spotted Owl Rangewide Baseline

225

Table A-2. Summary of northern spotted owl nesting/roosting1 habitat (acres) removed 

or downgraded as documented through ESA section 7 consultations on Federal lands. 

Environmental baseline and summary of effects by state, province, and land use 

function from 2012 to present. Tue May 16 11:37:48 MDT 

2017

State Physiographic

Province2

Evaluation Baseline (2012)3

Nesting/Roosting Habitat Removed/Downgraded4

% 

Provincial

Baseline

Affected

% 

Rangewide

Effects

Land Management 

Effects

Habitat Loss from 

Natural Events Total NR 

removed/ 

downgra

ded NR Acres in 

Reserves

NR 

Acres in 

NonReserves

Total NR 

Acres

Reserve

s

5

NonReserv

es6

Total Reserv

es

NonReserv

es

Total

WA Eastern 

Cascades 554,786 224,876 779,662 276 2 278 3,895 0 3,895 4,173 0.54 5.62

Olympic 

Peninsula 554,786 224,876 779,662 0 0 0 0 0 0 0 0 0

Western 

Cascades 957,314 212,325 1,169,639 15 46 61 0 0 0 61 0.01 0.08

Western 

Lowlands 12,964 3 12,967 0 0 0 0 0 0 0 0 0

OR Cascades 

East 206,719 133,080 339,799 945 2,393 3,338 0 453 453 3,791 1.12 5.11

Cascades 

West 1,425,026 949,045 2,374,071 639 6,781 7,420 761 1,775 2,536 9,956 0.42 13.41

Coast 

Range 468,575 38,898 507,473 567 1,112 1,679 0 0 0 1,679 0.33 2.26

Klamath 

Mountain

s

706,840 227,726 934,566 1,692 3,536 5,228 5,736 3,891 9,627 14,855 1.59 20.01

Willamette 

Valley 3,688 3,938 7,626 0 0 0 0 0 0 0 0 0

CA Cascades 120,067 89,316 209,383 0 67 67 0 0 0 67 0.03 0.09

Coast 113,857 9,999 123,856 0 0 0 0 2,193 2,193 2,193 1.77 2.95

Klamath 1,143,050 622,027 1,765,077 242 418 660 15,528 21,277 36,805 37,465 2.12 50.46

Total 6,267,672 2,736,109 9,003,781 4,376 14,355 18,731 25,920 29,589 55,509 74,240 0.82 100

Notes:

1. Northern spotted owl suitable habitat includes nesting/roosting habitat, and foraging habitat. 

Nesting/roosting habitat supports all life-history functions for spotted owls including foraging, and is 

sometimes referred to as nesting, roosting, and foraging habitat (NRF). Foraging-only habitat is a 

separate category that can include more open and fragmented forests, and does not provide structures 

for nesting/roosting. Habitat effects summarized in this table are all classified as impacts to 

nesting/roosting habitat. Impacts to foraging-only habitat are tracked separately. 
Appendix D: Northern Spotted Owl Rangewide Baseline

226

2. Defined in the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011) as Recovery 

Units as depicted on page A-3. 

3. Spotted owl nesting/roosting (NR) habitat on Federal lands (includes USFS, BLM, NPS, DoD, 

USFWS ) based on GIS data developed for the Northwest Forest Plan 20-year monitoring report for 

northern spotted owl habitat as reported by Davis et al. 2016 (PNW-GTR-929). Nesting/roosting 

habitat acres are approximate values based on 2012 satellite imagery. Values reported here may vary 

slightly from values reported in PNW-GTR-929.

4. Estimated nesting/roosting habitat removed or downgraded from land management (e.g., timber sales) 

or natural events (e.g., wildfires) as documented through section 7 consultation or technical assistance. 

Effects reported here include acres removed or downgraded from 2012 to present. 

5. Reserve land use allocations intended to provide spotted owl demographic support include LateSuccessional Reserves identified in the Northwest Forest Plan on National Forests, designated 

Wilderness, and other Congressionally-reserved lands. Reserves on BLM lands in western Oregon 

managed under the 2016 revised Land and Resource Management Plans include Late-Successional 

Reserves, Congressionally-reserved lands, National Landscape Conservation System lands, and some 

District Designated Reserves (e.g., Areas of Critical Environmental Concern). 

6. Non-reserve lands intended to provide spotted owl dispersal connectivity between reserves include 

USFS and BLM designations for timber production (matrix and harvest land base designations), 

Adaptive Management Areas, and other non-reserved land use designations. 

Since 2012, the acres reported as removed/downgraded varied in origin and by province. 

Rangewide, of the total Federal acres consulted on for ‘Habitat Removed/Downgraded’, 

approximately 18,730 acres or 0.2 percent of 9,003,780 million acres of northern spotted owl 

nesting/roosting (NR) habitat occurred as a result of land management activities; whereas 

considerably more (55,510 acres, or about 0.6 percent of total NR habitat) were reported as 

lost from natural events (Table A-2). The West Cascades and Oregon Klamath provinces 

have the highest reported reductions due to management (combined 12,650 ac or 68 percent 

of total land management effects and 0.14 percent of total 9,003,780 NR acres). The 

California Klamath province reports the largest losses from natural events with about 36,800 

acres (about 66 percent of rangewide losses from natural disturbances and 0.4 percent of total 

NR acres), followed by the Oregon Klamath and West Cascades (reductions of about 9,630 

acres 2,535 acres, respectively). Also almost twice as much habitat has been removed from 

high severity fires in reserves (areas where habitat was expected to contribute to long-term 

conservation) than has been removed from land management actions in non-reserves (areas 

expected to experience more habitat loss). Combining causes of habitat reductions, the 

California and Oregon Klamath provinces overall report the highest losses, represented by 

about 50 percent and 20 percent of the total rangewide effects.

Recently, the Service modified the database input to account for effects to the habitats that 

could be used as foraging, but that lack the age or structural characteristics of habitats used 

for nesting and roosting (NR). This distinction may not be made in all consultations. These 

data represent effects as reported in individual consultations and likely do not represent the 

entirety of impacts to foraging habitat within critical habitat since 2012. For many projects, 

affected foraging likely is captured within the “NR” acres as foraging habitat was lumped 

into “nesting/roosting/foraging habitat” at the time of consultation. As reported, almost all of 

the losses to foraging habitat occurred in the California Klamath province (17,038 acres of 

18,134 acres reported). Table A-3 summarizes the acres of foraging habitat removed or 

downgraded. 
Appendix D: Northern Spotted Owl Rangewide Baseline

227

Table A-3. Summary of northern spotted owl foraging habitat1(acres) removed or 

downgraded as documented through ESA section 7 consultations on Federal lands. 

Summary of effects by state, province, and land use function from 2012 to present. Tue 

May 16 11:37:48 MDT 

State Physiographic

Province2

Foraging Habitat Removed/Downgraded3

Land Management Effects

Habitat Loss from Natural 

Events Total Foraging 

Habitat

removed/ 

Reserves downgraded 4 NonReserves5 Total Reserves NonReserves Total

WA Eastern Cascades 0 0 0 0 0 0 0

Olympic 

Peninsula 0 0 0 0 0 0 0

Western 

Cascades 0 0 0 0 0 0 0

Western 

Lowlands 0 0 0 0 0 0 0

OR Cascades East 0 0 0 0 62 62 62

Cascades West 0 481 481 0 0 0 481

Coast Range 0 1,772 1,772 0 0 0 1,772

Klamath 

Mountains 0 1,586 1,586 0 0 0 1,586

Willamette 

Valley 0 0 0 0 0 0 0

CA Cascades 473 179 652 0 0 0 652

Coast 0 1 1 0 1,034 1,034 1,035

Klamath 1,454 286 1,740 8,558 8,480 17,038 18,778

Total 1,927 4,305 6,232 8,558 9,576 18,134 24,366

Notes:

1. Northern spotted owl suitable habitat includes nesting/roosting habitat, and foraging habitat. 

Nesting/roosting habitat supports all life-history functions for spotted owls including foraging, and is 

sometimes referred to as nesting, roosting, and foraging habitat (NRF). Foraging-only habitat is a 

separate category that can include more open and fragmented forests, and does not provide structures 

for nesting/roosting. Habitat effects summarized in this table are all classified as impacts to 

nesting/roosting habitat. Impacts to foraging-only habitat are tracked separately. 

2. Defined in the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011) as Recovery 

Units as depicted on page A-3. 

3. Spotted owl nesting/roosting (NR) habitat on Federal lands (includes USFS, BLM, NPS, DoD, 

USFWS ) based on GIS data developed for the Northwest Forest Plan 20-year monitoring report for 
Appendix D: Northern Spotted Owl Rangewide Baseline

228

northern spotted owl habitat as reported by Davis et al. 2016 (PNW-GTR-929). Nesting/roosting 

habitat acres are approximate values based on 2012 satellite imagery. Values reported here may vary 

slightly from values reported in PNW-GTR-929. Estimated nesting/roosting habitat removed or 

downgraded from land management (e.g., timber sales) or natural events (e.g., wildfires) as 

documented through section 7 consultation or technical assistance. Effects reported here include acres 

removed or downgraded from 2012 to present. 

4. Reserve land use allocations intended to provide spotted owl demographic support include LateSuccessional Reserves identified in the Northwest Forest Plan on National Forests, designated 

Wilderness, and other Congressionally-reserved lands. Reserves on BLM lands in western Oregon 

managed under the 2016 revised Land and Resource Management Plans include Late-Successional 

Reserves, Congressionally-reserved lands, National Landscape Conservation System lands, and some 

District Designated Reserves (e.g., Areas of Critical Environmental Concern). 

5. Non-reserve lands intended to provide spotted owl dispersal connectivity between reserves include 

USFS and BLM designations for timber production (matrix and harvest land base designations), 

Adaptive Management Areas, and other non-reserved land use designations. 

Other Past Habitat Trend Assessments 

In 2005, the Washington Department of Wildlife released the report, “An Assessment of 

Spotted Owl Habitat on Non-Federal Lands in Washington between 1996 and 2004” (Pierce 

et al. 2005). This study estimates the amount of spotted owl habitat in 2004 on lands affected 

by state and private forest practices. The study area is a subset of the total Washington forest 

practice lands, and statistically-based estimates of existing habitat and habitat loss due to fire 

and timber harvest are provided. In the 3.2-million acre study area, Pierce et al. (2005) 

estimated there was 816,000 acres of suitable spotted owl habitat in 2004, or about 25 

percent of their study area. Based on their results, Pierce et al. (2005) estimated there were 

less than 2.8 million acres of spotted owl habitat in Washington on all ownerships in 2004. 

Most of the suitable owl habitat in 2004 (56%) occurred on Federal lands, and lesser amounts 

were present on state-local lands (21%), private lands (22%) and tribal lands (1%). Most of 

the harvested spotted owl habitat was on private (77%) and state-local (15%) lands. A total 

of 172,000 acres of timber harvest occurred in the 3.2 million-acre study area, including 

harvest of 56,400 acres of suitable spotted owl habitat. This represented a loss of about 6 

percent of the owl habitat in the study area distributed across all ownerships (Pierce et al. 

2005). Approximately 77 percent of the harvested habitat occurred on private lands and 

about 15 percent occurred on State lands. Pierce and others (2005) also evaluated suitable 

habitat levels in 450 spotted owl management circles (based on the provincial annual median 

spotted owl home range). Across their study area, they found that owl circles averaged about 

26 percent suitable habitat in the circle across all landscapes. Values in the study ranged 

from an average of 7 percent in southwest Washington to an average of 31 percent in the east 

Cascades, suggesting that many owl territories in Washington are significantly below the 40 

percent suitable habitat threshold used by the State as a viability indicator for spotted owl 

territories (Pierce et al. 2005).

Moeur et al. 2005 estimated an increase of approximately 1.25 to 1.5 million acres of 

medium and large older forest (greater than 20 inches dbh, single and multi-storied canopies) 

on Federal lands in the NWFP area between 1994 and 2003. The increase occurred primarily 

in the lower end of the diameter range for older forest. In the greater than 30 inch dbh size 

class, the net area increased by only an estimated 102,000 to 127,000 acres (Moeur et al. 

2005). The estimates were based on change-detection layers for losses due to harvest and 

fire and re-measured inventory plot data for increases due to ingrowth. Transition into and 
Appendix D: Northern Spotted Owl Rangewide Baseline

229

out of medium and large older forest over the 10-year period was extrapolated from 

inventory plot data on a subpopulation of Forest Service land types and applied to all Federal 

lands. Because size class and general canopy layer descriptions do not necessarily account 

for the complex forest structure often associated with northern spotted owl habitat, the 

significance of these acres to northern spotted owl conservation remains unknown.

Population Trends 

There are no estimates of the historical population size and distribution of spotted owls, 

although they are believed to have inhabited most old-growth forests throughout the Pacific 

Northwest prior to modern settlement (mid-1800s), including northwestern California (USDI 

FWS 1989, pp. 2-17). 

The current range of the spotted owl extends from southwest British Columbia through the 

Cascade Mountains, coastal ranges, and intervening forested lands in Washington, Oregon, 

and California, as far south as Marin County (USDI FWS 1990a, p. 26114). The range of the 

spotted owl is partitioned into 12 physiographic provinces (Figure A-1) based on recognized 

landscape subdivisions exhibiting different physical and environmental features (USDI FWS 

1992a, p. 31). The spotted owl has become rare in certain areas, such as British Columbia, 

southwestern Washington, and the northern coastal ranges of Oregon.

Because the existing survey coverage and effort are insufficient to produce reliable 

rangewide estimates of population size, demographic data are used to evaluate trends in 

spotted owl populations. Analysis of demographic data can provide an estimate of the finite 

rate of population change (λ), which provides information on the direction and magnitude of 

population change. A λ of 1.0 indicates a stationary population, meaning the population is 

neither increasing nor decreasing. A λ of less than 1.0 indicates a decreasing population, and 

a λ of greater than 1.0 indicates a growing population. Demographic data, derived from 

studies initiated as early as 1985, have been analyzed periodically to estimate trends in the 

populations of the spotted owl (Anderson and Burnham 1992; Burnham et al. 1994; Forsman 

et al. 1996; Anthony et al. 2006; Forsman et al. 2011; Dugger et al. 2016). 

The most recent meta-analysis (Dugger et al. 2016) found continued declines in virtually all 

demographic parameters evaluated (Table A-4). Estimates of annual rates of population 

change, occupancy rates, and realized population change showed continuing declines across 

the range, and that the annual rate of decline was increasing in many areas, including 

southern Oregon and northern California. With the exception of treatment areas the Green 

Diamond Study Area (GDR-T) where removal of barred owls was initiated in 2009, Dugger 

et al. (2016, p. 70) reported that the populations in all study areas were declining, including 

those study areas that had been relatively stable in earlier analyses. Notably, the rate of 

realized population change for northern spotted owls in Cle Elum and the Olympic Peninsula 

demographic study areas in Washington showed a 60-70 percent decline over the past two 

decades. Lower rates were observed in the Oregon and California study areas where the 

realized rate of population change has shown a decline of 31-64 percent over the past two 

decades; the confidence intervals for some of the estimates of rate of population change 

slightly overlap zero, the results indicated a significant negative time trend at seven of the 

eleven study areas (Dugger et al. 2016, p. 70). These findings indicate that these populations 

are declining over time and the rate of decline is increasing. 

The probability of occupancy has declined in all three states over the past two decades. 
Appendix D: Northern Spotted Owl Rangewide Baseline

230

Dugger et al. (2016, pp. 73-74); reported that occupancy rates in Washington declined from a 

range of 56 to100 percent in 1995, to a range of 11 to 26 percent in 2013. During this same 

time period, occupancy rates in Oregon declined from a range of 61 to 88 percent in 1995, to 

a range of 28 to 48 percent in 2013. In California, occupancy rates declined from a range of 

approximately 42 to 92 percent in 1993, to a range of 38 to 55 percent in 2013. This 2016 

analysis was the first rangewide assessment of northern spotted owl population status to 

include estimates of occupancy dynamics (i.e. proportion of northern spotted owl territories 

occupied by a resident single or pair in a given year compared to the total number of 

territories surveyed), which revealed that territory occupancy of northern spotted owls has 

declined substantially in all 11 study areas since the early 1990s. The lowest occupancy rates 

were observed in 2013 (the final year included in this study) in the Oregon Coast Ranges 

Study Area (28 percent) and at the 3 study areas in Washington (Olympic, Cle Elum, 

Rainier). 

Two methods of estimating populations have been described - records of known sites and 

population modeling. As of July 1, 1994, there were 5,431 known site-centers of spotted owl 

pairs or resident singles: 851 sites (16 percent) in Washington, 2,893 sites (53 percent) in 

Oregon, and 1,687 sites (31 percent) in California (USDI FWS 1995, p. 9495). The actual 

number of currently occupied spotted owl locations across the range is unknown because 

many areas remain unsurveyed (USDI FWS 2011, p. A-2). In addition, many historical sites 

are no longer occupied because spotted owls have been displaced by barred owls, timber 

harvest, or severe fires, and it is possible that some new sites have been established due to 

reduced timber harvest on Federal lands since 1994. The totals above represent the 

cumulative number of locations recorded in the three states, not population estimates. 

Estimated populations were modeled during the 2012 critical habitat designation which 

projected a steady-state rangewide population size of roughly 3,400 female northern spotted 

owls. Population sizes varied regionally from low in the north, especially the northwest (e.g., 

about 100 in the North Coast Olympics and West Cascades North modeling regions), to high 

in parts of southern Oregon and northern California (e.g. about 750 each in the Inner 

California Coast, Klamath East, Klamath West, Redwood Coast, and West Cascades South 

modeling regions) (Dunk et al., 2012, p. 64). These estimates likely over represent the 

numbers of females as this modeling effort does not reflect rates of declines from 2008 -

2011 (as described in Dugger et al. 2016). Additionally, the actual number of currently 

occupied spotted owl locations across the range is unknown because many areas remain unsurveyed (USFWS 2011b, p. A-2) and many historical sites are no longer occupied because 

spotted owls have been displaced by barred owls, timber harvest, or severe fires. Other 

factors such as impacts of illegal marijuana grows have likely negatively affected localized 

spotted owl populations (Gabriel pers. comm. 2017; Gabriel et al. 2017a, 2017b, Higley et al. 

2017). Another unmeasured factor might include the possibility that some new sites have 

been established due to reduced timber harvest on Federal lands since 1994.
Appendix D: Northern Spotted Owl Rangewide Baseline

231

Table A-4. Summary of most recent spotted owl population trends from in 

demographic study areas in Washington, Oregon, and California 1985-2013 (Derived 

from Dugger et al. 2016, Tables 2, 4 and 25). 

Study Area a

Fecundity Apparent Survival Occupancy Rates Lamda

Mean 

Lamda

% Pop Size

Washington

CLE Declining Declining Declining No trend 0.916 –77%

RAI No trend Declining Declining No trend 0.953 –61%

OLY No trend No trend Declining No trend 0.961 –59%

Oregon

COA Declining No trend Declining Declining 0.949 –64%

HJA Declining Declining Declining Declining 0.965 –47%

TYE Declining Declining Declining Declining 0.976 –31%

KLA Declining No trend Declining Declining 0.972 –34%

CAS No trend Declining Declining No trend 0.963 –44%

California

NWC Declining Declining Declining Declining 0.970 –55%

HUP Declining Declining Declining Declining 0.977 –32%

GDR-CB Declining Declining Declining Declining 0.988 –31%

GDR-TB Declining Declining Declining Declining 0.961 –26%

GDR-CA ** ** Declining ** 0.878 –41%

GDR-TA   N/A c**  1.030 –9%

c Data used for occupancy modeling in the GDR study area excluded treatment areas after Barred Owl 

removals began in 2009.

** Too few years since Barred Owl removal to evaluate a trend.

In the northern-most portion of the range in British Columbia, few spotted owls are 

remaining. Chutter et al. (2004, p. v) suggested immediate action was required to improve the 

likelihood of recovering the spotted owl population in British Columbia. In 2007, personnel 

in British Columbia captured and brought into captivity the remaining 16 known wild spotted 

owls (USDI FWS 2011, p. A-6). Prior to initiating the captive-breeding program, the 

population of spotted owls in Canada was declining by as much as 10.4 percent per year 

(Chutter et al. 2004, p. v). As of 2016, this program was comprised of 17 spotted owls, eight 

of which were born in captivity. One chick was successfully hatched in 2017 (British 

Columbia 2017). The program is targeted produce annually up to 20 captive-born owls ready 

for release back into the wild until the population reaches 200; the first year of release 

expected to occur in the spring of 2018. The amount of previous interaction between spotted 

owls in Canada and the United States is unknown.

Status of Spotted Owl Critical Habitat

Legal Status
Appendix D: Northern Spotted Owl Rangewide Baseline

232

The final rule designating critical habitat for the northern spotted owl was published on 

December 4, 2012 (USDI FWS 2012a), and became effective on January 3, 2013. Critical 

habitat for the northern spotted owl now includes approximately 9,577,969 acres in 11 units 

and 60 subunits in California, Oregon, and Washington.

Designation of critical habitat serves to identify those lands that are necessary for the 

conservation and recovery of the listed species. In this case, the Service’s primary objective 

in designating critical habitat was to identify capable and existing essential northern spotted 

owl habitat and highlight specific areas where management of the northern spotted owl and 

its habitat should be given highest priority. The expectation of critical habitat is to 

ameliorate habitat-based threats. The recovery of the northern spotted owl requires habitat 

conservation in concert with the implementation of recovery actions that address other, nonhabitat-based threats to the species, including the barred owl (USDI FWS 2012a, p. 71879). 

The conservation role of northern spotted owl critical habitat is to “adequately support the 

life-history needs of the species to the extent that well-distributed and inter-connected 

northern spotted owl nesting populations are likely to persist within properly functioning 

ecosystems at the critical habitat unit and range-wide scales” (USDI FWS 2012a, p. 71938). 

The specific conservation roles of the subunits included in the action area are described 

below in the Environmental Baseline. 

Physical or Biological Features and Primary Constituent Elements

When designating critical habitat, the Service considers “the physical or biological features 

[PBFs] essential to the conservation of the species and which may require special 

management considerations or protection” (50 CFR §424.12; USDI FWS 2012a, p. 71897). 

“These include, but are not limited to: (1) space for individual and population growth and for 

normal behavior; (2) food, water, air, light, minerals, or other nutritional or physiological 

requirements; (3) cover or shelter; (4) sites for breeding, reproduction, or rearing (or 

development) of offspring; and (5) habitats that are protected from disturbance or are 

representative of the historical, geographical, and ecological distributions of a species” 

(USDI FWS 2012a, p. 71897). The final critical habitat rule states that “for the northern 

spotted owl, the physical or biological features essential to the conservation of the species are 

forested areas that are used or likely to be used for nesting, roosting, foraging, or dispersing” 

(USDI FWS 2012a, p. 71897). The final critical habitat rule for the northern spotted owl 

provides an in-depth discussion of the PBFs, which may be referenced for further detail 

(USDI FWS 2012a, pp. 71897-71906).

The final rule for critical habitat defines the primary constituent elements (PCEs) as the 

specific elements of the PBFs that are considered essential to the conservation of the northern 

spotted owl and are those elements that make areas suitable as nesting, roosting, foraging, 

and dispersal habitat (USDI FWS 2012a, p. 71904). The PCEs should be arranged spatially 

such that it is favorable to the persistence of populations, survival, and reproductive success 

of resident pairs, and survival of dispersing individuals until they are able to recruit into a 

breeding population (USDI FWS 2012a, p. 71904). Within areas essential for the 

conservation and recovery of the northern spotted owl, the Service has determined that the 

PCEs are:
Appendix D: Northern Spotted Owl Rangewide Baseline

233

i) Forest types that may be in early-, mid-, or late-seral stages and that support the 

northern spotted owl across its geographic range;

ii) Habitat that provides for nesting and roosting;

iii) Habitat that provides for foraging;

iv) Habitat to support the transience and colonization phases of dispersal, which in all 

cases would optimally be composed of nesting, roosting, or foraging habitat (PCEs 2 

or 3), but which may also be composed of other forest types that occur between larger 

blocks of nesting, roosting, or foraging habitat (USDI FWS 2012, pp. 72051-72052).

In 2016, the Service returned to the use of statutory reference of PBFs rather than PCEs when 

evaluating and discussing the availability and function of, as well as the effects to the 

attributes of critical habitat in the adverse modification analysis (USDI FWS 2016b). Some 

critical habitat subunits may contain all of the PBFs and support multiple life history 

requirements of the northern spotted owl, while some subunits may contain only those PBFs 

necessary to support the species particular use of that habitat. All of the areas designated as 

critical habitat, however, do contain PCE 1, forest type. As described in the final rule, PCE 1 

always occurs in concert with at least one other PCE (PCE 2, 3, or 4; USDI FWS 2012a, p. 

72051). Northern spotted owl critical habitat does not include meadows, grasslands, oak 

woodlands, aspen woodlands, or manmade structures and the land upon which they are 

located (USDI FWS 2012a, p. 71918).

PCE 1: Forest Types

The primary forest types that support the northern spotted owl are: Sitka spruce, western 

hemlock, mixed conifer, mixed evergreen, grand fir, Pacific silver fir, Douglas-fir, white fir, 

Shasta red fir, redwood/Douglas-fir, and moister ponderosa pine (USDI FWS 2012a, p. 

72051).

PCE 2: Nesting and Roosting Habitat

Nesting and roosting habitat habitats provide structural features for nesting, protection from 

adverse weather conditions, and cover to reduce predation risk for adults and young. Unlike 

foraging habitat, structural conditions of nesting roosting habitats do not vary much across 

the range. The final rule describes characteristics associated with nesting and roosting 

habitats sufficient for foraging by territorial pairs, moderate to high canopy cover (60 to 

over 80 percent), multilayered and multispecies canopies with large overstory trees (20 to 30 

inches dbh), basal area greater than 240 square feet per acre, high diversity of tree diameters, 

high incidence of large live trees with various deformities (e.g., large cavities, broken tops, 

mistletoe infections, and other evidence of decadence), large snags and large accumulations 

of woody debris on the ground, and sufficient open space beneath the canopy for flight 

(USDI FWS 2012a, p. 72051). Nesting and roosting habitats will also function as foraging 

and dispersal habitat (FWS 2012a, p. 71884). 

PCE 3: Foraging Habitat 

Foraging habitat varies across the range, depending upon ecological conditions and disturbance 

regimes that influence vegetation structure and prey species distributions. Across most of the 

owl’s range, nesting and roosting habitat is also foraging habitat, but in some regions 

(particularly in the southern portion of the range) northern spotted owls may additionally use 

other habitat types for foraging as well (differences in foraging habitats between ecological 

provinces are discussed below). 
Appendix D: Northern Spotted Owl Rangewide Baseline

234

PCE 4: Dispersal Habitat

Northern spotted owl dispersal habitat is habitat that supports the transience and colonization 

phases of owl dispersal, and in all cases would optimally be composed of nesting, roosting, 

or foraging habitat (PCE 2 or 3), but which may also be composed of other forest types that 

occur between larger blocks of northern spotted owl nesting, roosting, or foraging habitat. In 

cases where nesting, roosting, or foraging habitats are insufficient to provide for dispersing 

or nonbreeding owls, the specific dispersal PCEs are: habitat supporting transience phase of 

dispersal (protection from avian predators, minimal foraging opportunities, younger and less 

diverse forests that provide some roosting structures and foraging opportunities) and habitat 

supporting the colonization phase of dispersal (nesting, roosting, and foraging habitat but in 

smaller amounts than needed to support a nesting pair) (USDI FWS 2012a, p. 72052). 

Zones of Habitat Associations used by Northern Spotted Owls

Differences in patterns of habitat associations used by the northern spotted owl across its 

range suggest four different broad zones of habitat use, which we characterize as the (1) West 

Cascades/Coast Ranges of Oregon and Washington, (2) East Cascades, (3) Klamath and 

Northern California Interior Coast Ranges, and (4) Redwood Coast (Figure A-2). We 

configured these zones based on a qualitative assessment of similarity among ecological 

conditions and habitat associations within the 11 different regions analyzed during the critical 

habitat designation process (see USDI FWS 2012a). These four zones capture the range in 

variation of some of the PBFs essential to the conservation of the northern spotted owl. 

Habitat modeling indicates that vegetation structure has a dominant influence on owl 

population performance, with habitat pattern and topography also contributing. High canopy 

cover, high density of large trees, high numbers of sub-canopy vegetation layers, and low to 

moderate slope positions are all important features. Summarized below are the PBFs for 

each of these four zones, emphasizing zone-specific features that are distinctive within the 

context of general patterns that apply across the entire range of the northern spotted owl.

West Cascades/ Coast Range of Oregon and Washington - This zone includes five regions 

west of the Cascade crest in Washington and Oregon (Western Cascades North, Central and 

South; North Coast Ranges and Olympic Peninsula; and Oregon Coast Ranges; USDI FWS 

2011, p. C–13). Climate in this zone is characterized by high rainfall and cool to moderate 

temperatures. Variation in elevation between valley bottoms and ridges is relatively low in 

the Coast Ranges, creating conditions favorable for development of contiguous forests. In 

contrast, the Olympic and Cascade ranges have greater topographic variation with many 

high-elevation areas supporting permanent snowfields and glaciers. Douglas-fir and western 

hemlock dominate forests used by northern spotted owls in this zone. Root diseases and 

wind-throw are important natural disturbance mechanisms that form gaps in forested areas. 

Flying squirrels (Glaucomys sabrinus) are the dominant prey, with voles and mice also 

representing important items in the northern spotted owl’s diet.
Appendix D: Northern Spotted Owl Rangewide Baseline

235

Figure A-1. Regions and zones of habitat associations used by northern spotted owls in Washington, 

Oregon, and California.

West Cascade/Coast Ranges of Oregon and Washington - Nesting habitat in this zone is 

mostly limited to areas with large trees with defects such as mistletoe brooms, cavities, or 

broken tops. The subset of foraging habitat that is not nesting/roosting habitat generally had 

slightly lower values than nesting habitat for canopy cover, tree size and density, and canopy 

layering. Prey species (primarily the northern flying squirrel) in this zone are associated with 

mature to late-successional forests, resulting in small differences between nesting, roosting, 

and foraging habitats.

East Cascades -This zone includes the Eastern Cascades North and Eastern Cascades South 

regions (USDI FWS 2011, p. C–13). This zone is characterized by a continental climate 

(cold, snowy winters and dry summers) and a high frequency of natural disturbance due to 

fires and outbreaks of forest insects and pathogens. Flying squirrels are the dominant prey 

species, but the diet of northern spotted owls in this zone also includes relatively large 

proportions of bushy-tailed woodrats (Neotoma cinerea), snowshoe hare (Lepus americanus), 

pika (Ochotona princeps), and mice (Microtus spp. (Forsman et al. 2001, pp. 144–145).

Our modeling indicates that habitat associations in this zone do not show a pattern of 

dominant influence by one or a few variables (USDI FWS 2011, Appendix C). Instead, 

habitat association models for this zone included a large number of variables, each making a 

relatively modest contribution (20 percent or less) to the predictive ability of the model. The 

features that were most useful in predicting northern spotted owl habitat quality were 
Appendix D: Northern Spotted Owl Rangewide Baseline

236

vegetation structure and composition, and topography, especially slope position in the north. 

Other efforts to model habitat associations in this zone have yielded similar results (e.g., 

Garm et al. 2010, pp. 2048–2050; Loehle et al. 2011, pp. 25–28).

Relative to other portions of the northern spotted owls’ range, nesting and roosting habitat in 

this zone includes relatively younger and smaller trees, likely reflecting the common usage of 

dwarf mistletoe (Arceuthobium douglasii) brooms (dense growths) as nesting platforms 

(especially in the north). Forest composition that includes high proportions of Douglas-fir is 

also associated with this nesting structure. Additional foraging habitat in this zone generally 

resembles nesting and roosting habitat, with reduced canopy cover and tree size, and reduced 

canopy layering. High prey diversity suggests relatively diverse foraging habitats are used. 

Topographic position was an important variable, particularly in the north, possibly reflecting 

competition from barred owls (Singleton et al. 2010, pp. 289, 292). Barred owls, which have 

been present for over 30 years in the northern portions of this zone, preferentially occupy 

valley-bottom habitats, possibly compelling northern spotted owls to establish territories on 

less productive, mid-slope locations (Singleton et al. 2010, pp. 289, 292).

Klamath and Northern California Interior Coast Ranges - This zone includes the Klamath 

West, Klamath East, and Interior California Coast regions (USDI FWS 2011, p. C–13). This 

region in southwestern Oregon and northwestern California is characterized by very high 

climatic and vegetative diversity resulting from steep gradients of elevation, dissected 

topography, and large differences in moisture from west to east. Summer temperatures are 

high, and northern spotted owls occur at elevations up to 5,800 feet. The western portions of 

this zone support a diverse mix of mesic forest communities interspersed with drier forest 

types. Forests of mixed conifers and evergreen hardwoods are typical of the zone. The 

eastern portions of this zone have a Mediterranean climate with increased occurrence of the 

ponderosa pine. Douglas-fir/dwarf mistletoe is rarely used for nesting platforms in the 

western part of the northern spotted owl’s range, but is commonly used in the east.

The prey base for northern spotted owls in this zone is correspondingly diverse, but 

dominated by dusky-footed woodrats, bushy-tailed woodrats, and flying squirrels. Northern 

spotted owls have been well studied in the western Klamath portion of this zone (Forsman et 

al. 2004, p. 217), but relatively little is known about northern spotted owl habitat use in the 

eastern portion and the California Interior Coast Range portion of the zone.

Our habitat association models for this zone suggest that vegetation structure and topographic 

features are nearly equally important in influencing owl population performance, particularly 

in the Klamath. High canopy cover, high levels of canopy layering, and the presence of very 

large dominant trees were all important features of nesting and roosting habitat. Compared 

to other zones, additional foraging habitat for this zone showed greater divergence from 

nesting habitat, with much lower canopy cover and tree size. Low to intermediate slope 

positions were strongly favored. In the eastern Klamath, the presence of Douglas-fir was an 

important compositional variable in our habitat model (USDI FWS 2011, Appendix C).

Redwood Zone - This zone is confined to the northern California coast, and is represented by 

the Redwood Coast region (USDI FWS 2011, p. C–13). It is characterized by a maritime 

climate with moderate temperatures and generally mesic conditions. Near the coast, frequent 

fog delivers consistent moisture during the summer. Terrain is typically low-lying (0 to 

3,000 feet). Forest communities are dominated by redwood, Douglas-fir–tanoak 
Appendix D: Northern Spotted Owl Rangewide Baseline

237

(Lithocarpus densiflorus) forest, coast live oak (Quercus agrifolia), and tanoak series. 

Dusky footed woodrats are the dominant prey items for northern spotted owls in this zone.

Habitat association models for this zone diverged strongly from models for other zones. 

Topographic variables (slope position and curvature) had a dominant influence with 

vegetation structure having a secondary role. Low position on slopes was strongly favored, 

along with concave landforms.

Several studies of northern spotted owl habitat relationships suggest that stump-sprouting and 

rapid growth of redwood trees, combined with high availability of woodrats in patchy, 

intensively managed forests, enables northern spotted owls to occupy a wide range of 

vegetation conditions within the redwood zone. Rapid growth rates enable young stands to 

develop structural characteristics typical of older stands in other regions. Thus, relatively 

small patches of large remnant trees can also provide nesting habitat structure in this zone.

Climate Change and Range-wide Spotted Owl Critical Habitat

There is growing evidence that recent climate change has impacted a wide range of 

ecological systems (Stenseth et al. 2002, entire; Walther et al. 2002, entire; Ådahl et al. 2006, 

entire; Karl et al. 2009, entire; Moritz et al. 2012, entire; Westerling et al. 2011, p. S459; 

Marlon et al. 2012, p. E541). Climate change, combined with effects from past management 

practices, is exacerbating changes in forest ecosystem processes and dynamics to a greater 

degree than originally anticipated under the NWFP. Environmental variation affects all 

wildlife populations; however, climate change presents new challenges as systems may 

change beyond historical ranges of variability. In some areas, changes in weather and 

climate may result in major shifts in vegetation communities that can persist in particular 

regions. (See expanded discussion in environmental baseline section above).

Climate change will present unique challenges to the future of northern spotted owl 

populations and their habitats. Northern spotted owl distributions (Carroll 2010, entire) and 

population dynamics (Franklin et al. 2000, entire; Glenn et al. 2010, entire; Glenn et al. 

2011a, entire) may be directly influenced by changes in temperature and precipitation. In 

addition, changes in forest composition and structure as well as prey species distributions and 

abundance resulting from climate change may impact availability of habitat across the 

historical range of the subspecies. The 2011 Northern Spotted Owl Revised Recovery Plan 

provides a detailed discussion of the possible environmental impacts to the habitat of the 

northern spotted owl from the projected effects of climate change (USDI FWS 2011, pp. III-5 

to III-11).

Because both northern spotted owl population dynamics and forest conditions are likely to be 

influenced by large-scale changes in climate in the future, we have attempted to account for 

these influences in our designation of critical habitat by recognizing that forest composition 

may change beyond the range of historical variation, and that climate changes may have 

unpredictable consequences for both Pacific Northwest forests and northern spotted owls. 

Our critical habitat designation also recognizes that forest management practices that 

promote ecosystem health under changing climate conditions will be important for northern 

spotted owl conservation.

Current Condition of Range-Wide Critical Habitat
Appendix D: Northern Spotted Owl Rangewide Baseline

238

The current condition of critical habitat incorporates the effects of all past human activities 

and natural events that led to the present-day status of the habitat (USDI FWS/USDC NMFS 

1998, pg. 4-19). With the revision of spotted owl critical habitat, the rangewide condition 

has been “reset” as of December 4, 2012. 

The Service updated the ECOS database to reflect the 2006/2007 habitat baseline developed 

for the NWFP 15-year monitoring report (Davis et al. 2011, Appendix D, Table D). 

Additional updates were made in May of 2017 to reflect imagery utilized in the 20-year 

NWFP monitoring report (Davis et al. 2016). The Service’s ECOS database indicates that as 

of May 16, 2017, approximately 4.89 million acres nesting/roosting (NR) habitat occur 

within the rangewide 9.577 million acres of spotted owl critical habitat (Table A-5). Since 

the imagery date of 2012, an estimated 25,350 acres of NR habitat in critical habitat have 

been removed or downgraded range-wide (about .26 percent of the available 

nesting/roosting). The majority of these impacts originated in the Washington East 

Cascades, Oregon West Cascades and the Oregon and California Klamath Physiographic 

Provinces. Rangewide, about 15,080 acres were associated with natural disturbances, and 

about 10,300 were associated with land management actions. Over half of the total losses 

(about 14,500 acres) occurred in land use allocations under the NWFP that were intended to 

emphasize maintenance of spotted owl habitat values (i.e., late-successional reserves). The 

losses of NR habitat in the Oregon Klamath Province (where the action area occurs) 

represent about 21.6 percent of rangewide losses (about 5,500 of 25,350 acres). Over 6,000 

acres of NR losses were reported for the California Klamath; 5,200 of which were in reserved 

land allocations. These losses in the California and Klamath Provinces resulted primarily 

from effects of high severity fires in 2013 and 2014 in Southern Oregon and Northern 

California. 
Appendix D: Northern Spotted Owl Rangewide Baseline

239

Table A-5. Designated northern spotted owl critical habitat. Summary of northern 

spotted owl nesting/roosting1 habitat (acres) removed or downgraded as documented 

through ESA section 7 consultations. Summary of effects by state, province, and land 

use function from 2012 to present. Tue May 16 

11:47:11 MDT 2017

Physiographic

Province2

Evaluation Baseline

Nesting/Roosting Habitat Removed/Downgraded5

% 

Provincial

Baseline

Affected

% 

Range

-wide

Effect

s

Land Management Effects Habitat Loss

from Natural Events

Total NR 

Acres 

Removed

Total 

Designated 

Critical 

Habitat 

Acres3

Nesting/Roos

ting Acres4 Reserves6

NonReserves

7

Total Reserves NonReserves Total

WA Eastern 

Cascades 1,022,960 467,221 265 2 267 3,895 0 3,895 4,162 0.89 16.42

Olympic 

Peninsula 507,165 211,373 0 0 0 0 0 0 0 0.00 0.00

Western 

Cascades 1,387,567 606,093 15 43 58 0 0 0 58 0.01 0.23

OR Cascades 

East 529,652 187,798 893 1,460 2,353 0 0 0 2,353 1.25 9.28

Cascades 

West 1,965,407 1,255,027 596 3,103 3,699 662 0 662 4,361 0.35 17.20

Coast 

Range 1,151,874 483,846 1 695 696 0 0 0 696 0.14 2.75

Klamath 

Mountains 911,681 542,119 1,324 1,152 2,476 1,476 1,535 3,011 5,487 1.01 21.64

CA Cascades 243,205 97,248 0 67 67 0 0 0 67 0.07 0.26

Coast 149,044 94,033 0 0 0 0 2,018 2,018 2,018 2.15 7.96

Klamath 1,708,787 945,505 242 412 654 5,192 303 5,495 6,149 0.65 24.26

Total 9,577,342 4,890,263 3,336 6,934 10,270 11,225 3,856 15,08

1

25,351 0.26% 100%

Notes:

1. Northern spotted owl suitable habitat includes nesting/roosting habitat, and foraging-only habitat. 

Nesting/roosting habitat supports all life-history functions for spotted owls including foraging, and is 

sometimes referred to as nesting, roosting, and foraging habitat. Foraging-only habitat is a separate 

category that can include more open and fragmented forests, and does not provide structures for 

nesting/roosting. Habitat effects summarized in this table are all classified as impacts to 

nesting/roosting habitats. Impacts to foraging-only habitat are tracked separately. 

2. Defined in the Revised Recovery Plan for the Northern Spotted Owl (USFWS 2011) as Recovery 

Units as depicted on page A-3. 

3. Northern spotted owl critical habitat as designated December 4, 2012 (77 FR 71876). Total designated 

critical habitat acres listed here (9,577,342 acres) are derived from GIS data, and vary slightly from the 

total acres (9,577,969 acres) listed in the Federal Register (-627 acres). 
Appendix D: Northern Spotted Owl Rangewide Baseline

240

4. Spotted owl nesting/roosting (NR) habitat based on GIS data developed for the Northwest Forest Plan 

20-year monitoring report by Davis et al. 2016 (PNW-GTR-929). NR habitat acres are approximate 

values based on 2012 satellite imagery. 

5. Estimated nesting/roosting habitat removed or downgraded from land management (e.g., timber sales) 

or natural events (e.g., wildfires) as documented through section 7 consultation or technical assistance. 

Effects reported here include acres removed or downgraded from 2012 to present. 

6. Reserve land use allocations intended to provide spotted owl demographic support include LateSuccessional Reserves identified in the Northwest Forest Plan on National Forests, designated 

Wilderness, and other Congressionally-reserved lands. Reserves on BLM lands in western Oregon 

managed under the 2016 revised Land and Resource Management Plans include Late-Successional 

Reserves, Congressionally-reserved lands, National Landscape Conservation System lands, and some 

District Designated Reserves (e.g., Areas of Critical Environmental Concern). 

7. Non-reserve lands intended to provide spotted owl dispersal connectivity between reserves include 

USFS and BLM designations for timber production (matrix and harvest land base designations), 

Adaptive Management Areas, and other non-reserved land use designations. 

Recently, the Service modified the ECOS database input to account for effects to the habitats 

that could be used as foraging, but that lack the age or structural characteristics of habitats 

used for nesting and roosting. This distinction may not be made in all consultations. These 

data represent effects as reported in individual consultations and likely do not represent the 

entirety of impacts to foraging habitat within critical habitat since 2012. For many projects, 

affected foraging likely is captured within the NR acres as foraging habitat was lumped into 

“nesting/roosting/foraging habitat” at the time of consultation. Trends to date mirror impacts 

reported by Davis et al. 2016, where habitat reductions are disproportionally affecting 

reserved lands and the Oregon and Klamath Province (Table A-6). 

Table A-6: Designated northern spotted owl critical habitat. Summary of northern 

spotted owl foraging habitat1(acres) removed or downgraded as documented through 

ESA section 7 consultations. Summary of effects by state, province, and land use 

function from 2012 to present. Tue May 16 

11:50:46 MDT 2017

Physiographic

Province2

Foraging Habitat Removed/Downgraded4

Total 

Designated

Critical 

Habitat

Acres3

Land Management Effects Habitat Loss

from Natural Events

Total 

Foraging 

Habitat

removed/ 

downgraded Reserves5 NonReserves6 Total Reserves5 NonReserves6 Total

WA Eastern 

Cascades 1,022,960 0 0 0 0 0 0 0

Olympic 

Peninsula 507,165 0 0 0 0 0 0 0

Western 

Cascades 1,387,567 0 0 0 0 0 0 0

OR Cascades 

East 529,652 0 0 0 0 0 0 0
Appendix D: Northern Spotted Owl Rangewide Baseline

241

Physiographic

Province2

Foraging Habitat Removed/Downgraded4

Total 

Designated

Critical 

Habitat

Acres3

Land Management Effects Habitat Loss

from Natural Events

Total 

Foraging 

Habitat

removed/ 

downgraded Reserves5 NonReserves6 Total Reserves5 NonReserves6 Total

Cascades 

West 1,965,407 0 63 63 0 0 0 63

Coast Range 1,151,874 0 441 441 0 0 0 441

Klamath 

Mountains 911,681 0 736 736 0 0 0 736

CA Cascades 243,205 0 60 60 0 0 0 60

Coast 149,044 0 1 1 0 870 870 871

Klamath 1,708,787 1,449 272 1,721 5,996 259 6,255 7,976

Total 9,577,342 1,449 1,573 3,022 5,996 1,129 7,125 10,147
Appendix D: Northern Spotted Owl Rangewide Baseline

242

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data.
261

Appendix E. Recovery Action 10 

Priority Site Ranking 

LAA Biological Assessment FY 2018

Willamette National Forests
Appendix E: RA 10

262

Background and Need

The Revised Northern Spotted Owl Recovery Plan (the recovery plan) of June 28, 2011 contains 

33 recovery actions to promote recovery of the Northern spotted owl; one of which is Recovery 

Action 10 (RA10).

Recovery Action 10 – Conserve spotted owl sites and high value spotted owl habitat to 

provide additional demographic support to the spotted owl population. (recovery plan, p. III43).

This recovery action recommends conservation and restoration priorities for known and potential 

sites, and high value habitat based on considerations of site occupation and reproduction status, 

plus habitat conditions within the core area and provincial range. “The intent of this recovery 

action is to protect, enhance and develop habitat in the quantity and distribution necessary to 

provide for the long-term recovery of spotted owls” (p. III-44).

Recovery Action 10 (RA 10) recommends: “For Federal lands, create an interagency scientific 

team to use the latest and best available habitat modeling information and other data to identify 

these high value areas [high-value habitat and potential sites in unsurveyed habitat]. This team 

will make recommendations for areas to conserve and manage...” (p. III-42). 

The recovery plan further recommends interim guidance to be applied to achieve the intent of 

RA10 until such interagency teams are convened and further guidance provided. “When planning 

management activities, Federal and no-federal managers should work with the Service to 

prioritize known and historic spotted owl sites for conservation and/or maintenance of existing 

levels of habitat.” (p. III-44). “In unsurveyed spotted owl habitat, the agencies and the Service 

should work cooperatively through the Endangered Species Act consultation process to minimize 

impacts to potential spotted owl sites” (recovery plan, p. III-45)

RA 10 prioritization process used in this BA

Prioritization is intended to provide a “guide to evaluate the relative impacts of management 

actions, and conservation of sites that provide the most support to spotted owl demography” 

(recovery plan, p. III-44). In order to prioritize site conservation and habitat restoration, to analyze 

the effects of actions relative to RA10, and otherwise assess consistency with RA10, it was 

necessary to prioritize known and potential sites (unsurveyed suitable habitat). The prioritization 

method used in this BA incorporates RA10 considerations for site occupation, pair and 

reproduction status, in combination with habitat conditions in the 0.5 mile Core Area and 1.2 mile 

Provincial Home Range. 

The use of these prioritizations is solely to assess and describe actions relative to RA10. There is 

no change to other existing standards of the BA, including effects determinations based on two 

consecutive years of protocol surveys indicating a site to be “temporarily unoccupied”. The 

prioritization does not imply that any site, or unsurveyed habitat, is not providing current or future 

value for spotted owl recovery. Survey data have shown that unoccupied sites may be reoccupied 

at any time, if habitat is sufficient. The prioritization method incorporated the concept of historic 

sites without the need to define them specifically. 

The definition of a Potential Site is more fully described in Appendix E of this BA. Table F-2 

describes and defines the terminology used in the RA10 prioritization approach in this BA. A few 

of these terms are further discussed below.

“Occupation Status” indicates whether or not owls were present at a site in a given year and 

their pair status. If owls were present, occupation status was categorized as either a single 

individual or a pair. If owls were absent, occupation status was categorized as “Unoccupied” or 

“Unknown”. A Yearly Site Status of Unoccupied was derived only when a 6-visit valid Protocol 

Visit regime (or another survey methodology approved by the USFWS) was conducted and no 

owls were detected. Yearly Site Status was assessed as “Unknown” when no owls were 

detected but survey protocol methods were not used to verify occupancy status.
Appendix E: RA 10

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“Reproduction Status” indicates whether or not a spotted owl pair attempted to nest at site in a 

given year. Annual outcomes are categorized as “Nesting” or “Unknown”. (NOTE: some protocols 

describe methods to confirm “Non-Nesting” in a given year, versus an assumption of Unknown).

Occupation and Reproduction status outcomes may vary slightly from accepted survey or 

monitoring protocol status determinations. Any differences were solely to apply a simplified 

approach to prioritizing and managing for sites consistent with RA10. Definitions are not intended 

to alter other existing survey or monitoring protocol status definitions used for other purposes.

“Protocol Visits (or Surveys)” were defined as survey (or monitoring) visits to a site that 

covered an appropriate amount of site area and were consistent with the timing, spacing and 

methods as described in an accepted survey protocol (or other survey regime approved by the 

USFWS).

A “Survey Year” was one comprised of the proper amount of Protocol Visits to arrive at a Yearly 

Site Status. This appendix is based on the 6-visit recommendation found in the USFWS survey 

protocol. With approval of the USFWS, other survey/monitoring protocols that require fewer visits 

may be used (e.g. Demography Study Area 3-visit protocols for sites therein). The concept of 

Protocol Visits and a valid Survey Year become most important when determining whether a site 

was unoccupied in a given year, and ultimately its RA10 Priority number.

“Yearly Site Status”: This was assessed by using survey results to determine known 

occupation, pair, and reproductive status at a site in a given year; including surveys determining a 

status of “Unoccupied”. When site surveys were not conducted, or were not completed to 

recommended protocol standards (method, timing, amount, area covered), and status 

determinations were not made; the Yearly Site Status was determined to be Unknown (see both 

“General” and “Historic Status” processes for incorporating Yearly Status results into a RA10 

Priority in the complete, or partial, absence of surveys accompanied by lack of status 

determinations).

“RA10 Priority”: The RA10 Priority is a summarization of previous Yearly Site Status results (or 

lack of) over multiple years. This represents a relative priority for conservation and restoration 

among all sites in a local field unit. 

The lower the RA10 Priority number, the higher the priority for conservation that maintains site 

capability for pair occupation and reproduction as recommended in RA10. For example, RA10 

Priority number 1 sites are those most valuable to conserve consistent with RA10. 

Conversely, the higher the RA10 Priority number for a site, the lower its priority for conservation 

and the higher its priority for restoration treatments if unoccupied (e.g. thinning harvest). For 

example, RA10 Priority number 10 sites are the lowest priority for conserve in accord with RA10.

Within this Appendix, it is important to note any distinctions between same or similar terms that 

may have different definitions for Yearly Site Status versus RA10 Priority (e.g., Unoccupied 

status).

Processes to Determine the RA10 Priority:

General Process (sites with recent surveys):

The prioritization process used the following hierarchical considerations: recent survey 

information, historic survey information, and unsurveyed potential sites (in that order). For sites 

with recent surveys, the Yearly Site Status was compiled for the 5 most recent Survey Years 

within the last 10 calendar years. The ‘’highest” Yearly Site Status was used to derive the RA10 

Priority. Status hierarchy from highest to lowest was as follows: nesting pair, non-nesting pair, 

single, and unoccupied. The highest status was then combined with habitat conditions in the core 

area and provincial home range to determine a final RA10 Priority. Years without valid protocol 

surveys and no owl detections (non-Survey Years) were not incorporated into RA10 priorities. 

The RA10 Priority criteria are summarized in Table F-1. A RA10 Priority status of “Unoccupied” 

was determined when there were at least 5 Survey Years with a Yearly Site Status of Unoccupied 

within the last 10 calendar year; and this status occurred in the previous 3 consecutive calendar 
Appendix E: RA 10

264

years. If this condition was not met, the Historic Status Process below was used to determine the 

RA10 Priority.

Historic Status Process (sites without a sufficient number or type of recent 

surveys):

Historic Sites with no Survey Years in the last 10 calendar years: If any of the following situations 

applied to a site, one of two Historic Status Processes described below was used to determine 

RA10 Priority:

 No surveys were conducted at the site; and/or

 Conducted surveys were non-protocol due to being inconsistent or incomplete with 

regards to methods, timing, amount or area covered and no spotted owls were detected 

(i.e., no valid Survey Years); and/or

 Valid surveys were done which resulted in an Unoccupied status; but this status was not 

achieved at least 5 times in the last 10 years and for the 3 consecutive previous years.

1) Under the above scenario, if a known site had habitat above both the 50/40% thresholds in the 

core area and provincial home range respectively, the site was given a RA10 Priority of 1-Known 

Site with Reproductive Pair and Habitat Above Both Thresholds. These unsurveyed sites were 

assessed a priority number the same as those with known reproductive pairs found by survey. 

This logic is consistent with the common consultation assumption that unsurveyed suitable 

habitat is occupied and accommodates RA10 objectives of conserving habitat that could 

reasonably be expected to support reproductive pairs. 

2) Under the same above scenario, if a known site had habitat below one or both of the 50/40% 

thresholds in the core area and provincial home range respectively, the highest occupation and 

reproduction status since 1990 was used to determine the RA10 Priority.

Older sites without recent survey data: Some known sites have not been surveyed since 1990. For 

known sites with no valid Survey Years, and no indication of spotted owl presence after 1989, local 

biologists decided how to assign a RA10 Priority based on current habitat and survey history. If 

these types of known sites have ample habitat to support resident spotted owls, they were 

considered relevant to species recovery and RA10 direction, and therefore at least as important as 

Potential Sites with regards to RA10 Priority. Future survey of these sites would ensure the best 

available information is used to determine their RA10 Priority. 

Sites with spotted owl presence and incomplete survey data: When non-protocol surveys 

indicated owl presence at a site, but did not fully determine occupation or reproduction status; the 

local field unit biologists decided how to use this information to assess the Yearly Site Status 

and/or RA10 Priority. 

As example: Two surveys occurred over a minority portion of a known site area and only a single 

owl was detected. Depending on the amount and location of the area covered by surveys, habitat, 

recent site status and activity areas, and other local knowledge, the local biologist may have 

assumed a status ‘’higher than’’ a single owl for the RA10 Priority.

Example Scenarios for Determining RA10 Priority:

Example 1: A known site with 5 valid Survey Years in the last 7 calendar years and spotted owls 

detected. RA10 Priority assessed using the General Process:

A known site, with habitat below both of the 50/40% thresholds in the core area and 

provincial home range respectively, had 5 valid Survey Years within the last 7 calendar years. 

Surveys resulted in: a nesting pair once, a non-nesting pair once, a single owl once, and a 

status of Unoccupied twice. No surveys occurred in 2 of the calendar years. Under this 

scenario, the highest occupation and reproduction status within the last seven calendar years 

is used to determine the RA10 Priority. This resulted in a RA10 Priority of 2 (regardless of 

what year the nesting pair was detected or what years surveys did not occur) (see Table H1).
Appendix E: RA 10

265

Example 2: A known site with valid Survey Years and no spotted owls detected. RA10 Priority 

assessed using the General Process:

A known site, with habitat above both of the 50/40% thresholds in the core area and 

provincial home range respectively, had 5 consecutive Survey Years with no owls detected. 

The site was given a RA10 Priority of 8 (see Table H- 1).

Example 3: A known site without recent Survey Years (incomplete or no surveys) and no owl 

detections. RA10 Priority is assessed using the Historic Status Process:

A known site with habitat below both the 50/40% thresholds in core area and provincial home 

range respectively, received sporadic and incomplete surveys over the last 10 calendar 

years. Within the last 10 calendar years, the site was fully surveyed to protocol and had a 

status of Unoccupied in 2 non-consecutive years; no owls were detected during partial 

surveys (amount and/or area covered) that occurred in 5 years; and no surveys occurred in 3 

years. Since, within the last 10 calendar years, no owls were detected, and there was an 

insufficient amount and timing of visits to result in a status of Unoccupied, the highest status 

of “single owl” from historic 1999 surveys was used to determine the RA10 Priority (see Table 

H- 1).
Appendix E: RA 10

266

Table H- 1. Recovery Action 10: Current status and site prioritization used in this BA.

RA10 

Priority

Relative Priority for 

Conservation

Site Occupation and 

Reproduction Status

Habitat Conditions 

(above both thresholds; 

OR below 1 or both 

thresholds)

1

Highest KS with Reproductive Pair or 

Any Unsurveyed1 Known Site 

>= 50% CA & 

>= 40% PHR

2

KS with Reproductive Pair or 

Unsurveyed Known Site with 

Reproductive Pair

< 50% CA &/or

< 40% PHR

3 KS with Pair >= 50% CA & 

>= 40% PHR

4

KS with Pair or 

Unsurveyed Known Site with Pair

< 50% CA &/or

< 40% PHR

5 KS with Single >= 50% CA &

>= 40% PHR

6

KS with Single or 

Unsurveyed Known Site with Single

< 50% CA &/or

< 40% PHR

7 Any Unsurveyed PS2 Any2

8 KS/PS Unoccupied >= 50% CA & 

>= 40% PHR

9 KS/PS Unoccupied < 50% CA &/or

< 40% PHR

10 Lowest TS Any

Abbreviations & Definitions (see Table F-2 for full terminology definitions)

RA10 Recovery Action 10 of the Revised Northern Spotted Owl Recovery Plan (2011).

KS Known Site, including historic sites (any definition).

PS Potential Site

TS Temporary Site (See term definitions in separate table. A site with spotted owl detections that 

does not warrant establishment of a known site).

CA Core Area of 0.5 mile

PHR Provincial Home Range( or Home Range) of 1.2 mile

RA10 Priority Recovery Action 10 Spotted Owl Site Relative Priority

1

Unsurveyed Sites means Territories with less than 5 protocol Survey Years in the last 10 calendar year period. “Unsurveyed” 

conditions could arise from various combinations of sites with zero surveys or incomplete non-protocol surveys without owl 

detections (i.e., no valid Survey Years).

2

A Potential Site as defined in Appendix E of this BA. Based on local field unit knowledge, potential sites may have habitat slightly 

below 50/40% thresholds in the core area and provincial home range respectively and still provide for spotted owl pair occupation. 

When habitat amounts are below amounts to provide for pair occupation, the concept of a potential site is no longer valid because it 

would not provide for spotted owl pair occupation. If spotted owls are detected in a potential site, the site immediately becomes a 

temporary or known site for the purposes of RA10 prioritization.
Appendix E: RA 10

267

Table H- 2. Terminology and Concepts used in Recovery Action 10 prioritization in this 

BA.

Term Definition

Core Area Area defined by a 0.5 mile radius around a site center.

Habitat 

Conditions

For RA10 Priority, habitats were categorized as one of two conditions: 1) Habitat 

equal to, or above, both of the 50/40% thresholds in the core area and provincial 

home range respectively; or 2) Habitat below one or both of these thresholds at 

the same scales.

Historic Status 

Process 

(for RA10 

Prioritization)

RA10 Prioritization process used when there were less than 5 valid Survey Years 

within the last 10 calendar years, and no spotted owls were detected. This 

includes scenarios without a sufficient number and arrangement of surveys to 

determine a site to be “Unoccupied”. RA10 Priority outcomes using this process 

were either 1) The highest Yearly Status since 1990 was used to determine RA10 

Priority when habitat is below one or both of the 50/40% thresholds in the core

area and provincial home range respectively; OR 2) the site was assumed to be 

occupied by a reproductive pair when habitat is above both of the 50/40% 

thresholds in the core area and provincial home range respectively. 

Known Site A site with a permanent state-issued Master Site Number (or other identifier), 

including "historic sites" (any definition). 

No-Survey 

Year

Any year (1) without surveys, or (2) Where no owls were detected, but only partial 

or incomplete surveys were done with regard to protocol methods for amount, 

timing, and area covered.

Occupation 

and

Reproduction

Status

Yearly Site Status indicating whether a site had a Single spotted owl, a spotted owl 

Pair, was Unoccupied (valid protocol methods and no owls detected), or status 

was Unknown (no owls detected, but valid protocol method amounts or coverage 

not implemented). 

Pair

A Yearly Site Status outcome when surveys (or other information) indicated a 

spotted owl pair was present (at least one time) and non-nesting in a given year 

(or nest status was unknown).

A RA10 Priority that included a spotted owl Pair was assigned when a pair was 

present at a site at least 1 time in the previous 5 Survey Years during that last 10 

year period (with no indication of a nest attempt); or as a result of using the 

Historic Status Process.

Potential 

Site

A Potential Site as defined in Appendix E of this BA. Based on local field unit 

knowledge, Potential sites may have habitat slightly below 50/40% thresholds in 

the core area and home range and still provide for spotted owl pair occupation. 

When habitat amounts are below amounts to provide for pair occupation, the 

concept of a Potential Site is no longer valid. If spotted owls are detected in a 

Potential Site, the site immediately becomes a Temporary or Known Site for the 

purposes of RA10 evaluation.

Process 

(for RA10 

Prioritization)

RA10 Prioritization process used when ample valid Survey Years (amount or 

results) occurred in the last 10 calendar years, including a sufficient number of 

protocol surveys to determine a site to be “Unoccupied”. The highest Yearly Status 

from recent surveys was used to determine RA10 Priority.
Appendix E: RA 10

268

Term Definition

Protocol 

Visit(s)

Survey (or monitoring) visit regime for a site with the appropriate amount, timing 

and spacing of visits for a year based on accepted survey protocols. This appendix 

is based on the 6-visit protocol methodology found in the USFWS protocol. With 

approval of the USFWS, other survey/monitoring protocols that require fewer 

visits may be used (e.g., Demography Study Area protocols for sites therein may 

require only 3 visits).

Provincial 

Home Range 

(or Home 

Range)

Area defined by a 1.2 mile radius around a site center. 

RA10 Priority

A prioritization of spotted owl sites following direction established by Recovery 

Action 10. The higher the priority (lower the number) the more the site is 

expected to contribute to spotted owl demographic support. Priority was based on 

various combinations of Yearly Site Status or Historic Status, and habitat 

conditions.

Reproductive 

Pair

A Yearly Site Status outcome when surveys (or other information) indicated a 

spotted owl pair attempted to nest at a site in a given year. Status options for 

reproduction were “nesting” or “unknown” (non-nesting was used when methods 

are in accord with protocols methods that specify how to “confirm’’ non-nesting).

A RA10 Priority that included a spotted owl Reproductive Pair was assigned when 

a nesting pair was present at a site at least 1 time in the previous 5 Survey Years 

during the last 10 year period; or as a result of using the Historic Status Process.

Single

A Yearly Site Status outcome when surveys (or other information) indicated a 

spotted owl single individual was present (at least one time) and not paired in a 

given year.

A RA10 Priority that included a spotted owl Single was assigned when a single 

individual was present at a site at least 1 time in the previous 5 Survey Years 

during that last 10 year period (with no indication of pair presence); or as a result 

of using the Historic Status Process.

Survey Year

Any year where: (1) a survey protocol was implemented to determine a site to be 

Unoccupied; or (2) Surveys (or other information) indicating a positive occupation 

and/or nesting status (i.e., owls were detected). Note that occupation and 

reproductive status can be confirmed in fewer than 6 survey visits.

Temporary Site

An area where spotted owls have been detected, but the number and/or timing of 

detections over 1 or more years does not warrant establishment of a Known Site. 

If spotted owls are detected for the first time in an area (or the first time after 

many years of no detections/surveys), Temporary Sites are usually treated as 

Known Sites until the site status is determined (often within the following year).
Appendix E: RA 10

269

Term Definition

Unknown

A Yearly Site Status of “Unknown” occurred when a site was not surveyed in a 

given year; or surveys were not consistent with protocol methods (for method, 

amount, timing and spacing) and no owls were detected. 

When owls were not detected in the last 5 Survey Years and the site status was 

unknown (based on a lack of surveys and/or protocol status determinations within 

the last 10 calendar years), one of the 2 Historic Site Processes was used to 

determine the RA10 Priority. NOTE: When non-protocol surveys indicated owl 

presence at a site, but did not fully determine occupation or reproduction status; 

the local field unit biologists decided how to use this information to assess the 

Yearly Site Status and/or RA10 Priority.

Unoccupied

A Yearly Site Status of Unoccupied was determined during a valid Survey (using 

Protocol visits for area covered, amount, timing and spacing of visits) that resulted 

in no owl detections.

A RA 10 Priority that included a status of Unoccupied was assigned when there 

were at least 5 valid Survey Years in the last 10 calendar years, including 3 

consecutive previous calendar years, all with a Yearly Site Status of Unoccupied.

Yearly Site 

Status

Annual site status based on survey results (or lack thereof) and a combination of 

Occupation and Reproduction status.
270

Appendix F. Acronyms 

LAA Biological Assessment FY 2018

Willamette National Forest
Appendix F. Acronyms 

271

Acronym Name

ACEC Area of Critical Environmental Concern (BLM Land Use designation. 

Considered Administratively Withdrawn for the purposes of this BA)

AMA Adaptive Management Area

BA Biological Assessment

BLM United States Department of Interior, Bureau of Land Management

BO Biological Opinion

CA Core Area (often a 0.5 mile radius circle around a spotted owl activity 

center)

CH/CHU Critical Habitat/Critical Habitat Unit

CSA Conservation Support Areas (Recovery Plan)

dbh Diameter Breast Height (measurement of tree diameter at approximately 4 

feet from ground on the uphill side of the trunk)

DTR Danger Tree Removal

EIS Environmental Impact Statement

ERFO Emergency Relief for Federally Owned [Roads]

ESA Endangered Species Act

FS, USFS United States Department of Agriculture, Forest Service

FSR Forest Service Road

FWS, USFWS United States Department of Interior, Fish and Wildlife Service

GIS Geographic Information System

HHD Harvest – Habitat Downgraded

HHM Harvest – Habitat Maintain

HHR Harvest – Habitat Remove

ICS Incident Command System

ITR Individual Tree Removal

LOC Letter of Concurrence

LSR Late Successional Reserve

MA-LAA, LAA May affect, likely to adversely affect

MA-NLAA, NLAA May affect, not likely to adversely affect
Appendix F. Acronyms 

272

Acronym Name

MOCA Managed Owl Conservation Areas (Recovery Plan)

MVUM Motor Vehicle Use Map (Forest Service) Indicates roads that are open to 

public use.

NE No effect

NEPA National Environmental Policy Act

NF National Forest

NP Nest Patch (often a 300 meter circle around a spotted owl activity center)

NRF Nesting, roosting, foraging [habitat for spotted owls]

NSO Northern spotted owl(s)

NWFP Northwest Forest Plan

PBF Physical and Biological Features

PCE Primary Constituent Elements

PCT Pre-commercial Thinning or Stand Density Management

PHR Provincial Home Range (often a 1.2 mile radius circle around a spotted owl 

activity center)

PRMP Proposed Resource Management Plan (BLM for western Oregon)

RA Resource Area (United States Department of Interior, Bureau of Land 

Management)

RA10 Recovery Action 10 (Revised Recovery Plan, NSO, 2011)

RA32 Recovery Action 32 (Revised Recovery Plan, NSO, 2011)

RD Ranger District (United States Department of Agriculture, Forest Service)

ROD Record of Decision (NEPA)

ROW Right of Way (Road Construction)

RR Riparian Reserve

USDA United States Department of Agriculture

USDI United States Department of Interior

USFS, FS United States Department of Agriculture, Forest Service

USFWS, FWS United States Department of Interior, Fish and Wildlife Service

WUI Wildland Urban Interface
Appendix F. Acronyms 

273