APPENDIX E

Spotted Owl

Nesting, Roosting, Foraging Habitat

Field Verification
Page 2 of 12 Appendix E

Spotted Owl Nesting, Roosting, and Foraging (NRF) Habitat Field Verification

Methodology

Spotted Owl NRF Habitat verification was initiated in the fall of 2007. The mapped NRF habitat 

patches at the time were field-visited to determine if the stands contained the elements of NRF. 

According to the Programmatic BA. Features that support nesting and roosting habitat typically 

include a moderate to high canopy (60 to 90 percent); a multi-layered, multi-species canopy with 

large (> 30 inches diameter at breast height) overstory trees; a high incidence of large trees with 

various deformities (e.g., 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 owls to fly (Thomas et al. 1990). Foraging habitat 

generally consists of attributes similar to those in nesting and roosting habitat, but may not always 

support successfully nesting pairs (USDI 1992b). Dispersal habitat, at minimum, consists of stands 

with adequate tree size and canopy closure to provide protection from avian predators and at least 

minimal foraging opportunities: there may be variations over the owl’s range (e.g., drier sites in the 

east Cascades or northern California) (USDI FWS 1992b).”

Using the NRF descriptions as a guide, each mapped NRF patch was evaluated on the following 

bases: 

1. Was it multi-layered (yes/no). 

2. Average canopy closure (%). 

3. Average tree dbh (range in inches). 

4. Presence of >30”dbh trees, deformities, mistletoe for potential nest trees (yes/no). 

5. Amount and size of decadence (average diameter of downed logs, size and presence of 

snags/broken tree tops).

6. Understory brushy? (yes/no). 

7. Green limbs low to ground, small open areas on ground, or well-decayed logs for foraging? 

(yes/no). 

8. Would it provide NRF habitat or more likely foraging or dispersal habitat? 

Some examples of the NRF patches that were dropped include a single-storied stand with an average 

canopy closure of 25%, large ponderosa pine, high branches and high brush cover. An example of 

stand mapped as NRF but met criteria for foraging better was multi-storied, 40% canopy closure, 

average tree diameter was 15-28” with some 30+” dbh ponderosa pines, but these did not have large 

limbs or decay and limbs in the upper canopy. An example of stand that was retained as NRF was 

multi-storied, 50% canopy closure, contained Douglas-fir and ponderosa pine 12-48” dbh, contained 

decayed elements although many logs still firm, and brush level was low to moderate. If a mapped 

stand contained portions whereby the PCE may be met, the whole stand was retained for further 

analysis. This is to say, through the verification process if there was uncertainty whether or not to 

call a stand NRF, the process erred on the side of retaining it as NRF.

The following maps use the 2004 satellite vegetation database to give an overview of how 

some of the elements are distributed across the project area (blue or yellow outlined feature) 

and outside of the project area but within the general spotted owl survey area.
Appendix E Page 3 of 12

Map 1. This illustrates the distribution of large trees. The red, lavender, and purple areas reflect a 

multi-storied presence and an average tree diameter of 15-20”. Yellow areas are single-storied 

stands with an average tree diameter of 15-30”. The Sheridan Mt LSR is the hatched area, the NRF 

patches are outlined in black and the closest spotted owl home range (Three Trappers Buttes) is 

shown. The EXF project units are outlined in blue, and the green line shows the eastern edge of the 

Northwest Forest Plan boundary.
Page 4 of 12 Appendix E

Map 2. This illustrates the distribution of plant association groups. Orange areas reflect the 

ponderosa pine and ponderosa pine/lodgepole pine groups. Blue areas reflect associations with a fir 

component (ponderosa pine/Douglas-fir, white fir/Douglas-fir, Subalpine fir/white fir). Green areas 

reflect associations with mountain hemlock. Purple are areas dominated by lodgepole pine, and 

Dark Blue reflects more alpine associations of mountain hemlock with subalpine fir. The Sheridan 

Mt LSR is the hatched area; the NRF patches are outlined in black and the closest spotted owl home 

range (Three Trappers Buttes) is shown. The EXF project units are outlined in blue, and the green 

line shows the eastern edge of the Northwest Forest Plan boundary.
Appendix E Page 5 of 12

Map 3. This illustrates the canopy closure distribution. The lavender areas reflect an average of 55-

70% canopy closure; green equal 40-55% canopy closure; and yellow equals 70-100% canopy 

closure. The Sheridan Mt LSR is the hatched area, the NRF patches are outlined in black and the 

closest spotted owl home range (Three Trappers Buttes) is shown. The EXF project units are 

outlined in blue, and the green line shows the eastern edge of the Northwest Forest Plan boundary.
Page 6 of 12 Appendix E

The following “on-the-ground” figures illustrate the rationale discussed above:

Figure A1 represents the lower elevation portion of Unit 32. This portion had been mapped as NRF 

habitat but based on field reviews it is evident that it is dominated by ponderosa pine, heavy shrub 

cover and no evidence of large (>30” dbh) trees with decadence to provide for immediate nesting 

structure. Note: two other NRF patches within this unit were analyzed as NRF habitat.

Figure A1. Taken 16 June 2008. 
Appendix E Page 7 of 12

The following photos taken within Unit 23 illustrate the variability within a Unit and mapped NRF 

patch. This entire stand of mapped NRF was analyzed as NRF because of portions with a heavier fir 

dominance and fewer shrubs in the understory (Figures A2 and A3 ). Whereas, Figures A4 and A5 

illustrate the more open ponderosa pine dominance of some of the lower elevation pieces of this 

same NRF stand.

Figure A2. Taken 16 June 2008

Figure A3. Taken 28 October 2009. Note lack of brush, multi-story, ponderosa pine still 

dominates the large overstory.
Page 8 of 12 Appendix E

Figure A4. Taken 16 June 2008. The lower slope of the NRF patch in Unit 23. Note the singlestoried ponderosa pine; although the canopy closure if higher and there is a component of 

white fir. This illustrates the better quality foraging and dispersal habitat than perhaps the 

nesting components.

A5. Taken 16 June 2008. Again, the ponderosa pine dominance with heavy shrub understory.
Appendix E Page 9 of 12

Unit 11 is nearly completely overlain by a mapped NRF stand. The NRF mapped within this unit 

was particularly challenging to field verify because of the more variable nature within the Unit. 

Figures A6 and A7 were taken within portions of the NRF stand that contain many of the features 

that classify NRF (e.g. multi-story, multi-species in overstory, large downed wood); whereas Figures 

A8 and A9 that are part of the same NRF stand illustrate the opposite for nesting habitat (e.g. open 

canopy, heavy shrub cover, ponderosa pine dominance).

Figure A6. Taken 16 June 2008

Figure A7. Taken 16 July 2009.
Page 10 of 12 Appendix E

Figure A8. Taken 28 October 2009

Figure A9. Taken 16 June 2008.
Appendix E Page 11 of 12

Unit 12 also shared the same stand of mapped NRF as illustrated with Unit 11. This Unit 12 portion 

differs in that it is higher elevation and more consistently contains features that classify NRF habitat 

as shown in Figures A10-A12.

Figure A10. Taken 16 June 2008. Unit 12 NRF. Note the lack of ponderosa pine in overstory, 

multi-layered canopy, little to no brush cover.

Figure A11. Taken 16 July 2009. Unit 12 NRF. Note the decadence within ponderosa pine 

overstory and the dominance of fir in the overstory as well as the downed wood, multi-story 

and high canopy closure.
Page 12 of 12 Appendix E

Figure A12. Taken 16 July 2009. Unit 12 NRF illustrating a more open area with ponderosa 

pine and fir as the overstory , large down logs, and lack of brush cover.