United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

General Technical

Report RMRS-GTR-22

February 1999

The Northern Goshawk in

Utah: Habitat Assessment

and Management

Recommendations

Russell T. Graham

Ronald L. Rodriguez

Kathleen M. Paulin

Rodney L. Player

Arlene P. Heap

Richard Williams
Rocky Mountain Research Station

324 25th Street

Ogden, UT 84401

The Authors ___________________

Russell T. Graham is a Research Forester with the Rocky

Mountain Research Station’s Forestry Sciences Laboratory in Moscow, ID. He holds a B.S. degree in forestry, an

M.S. degree in forestry, and a Ph. D. degree in forestry.

Ronald L. Rodriguezis the Wildlife Program Leader on the

Dixie and Fishlake National Forests in Cedar City, UT. He

holds a B.S. degree in wildlife and range management, and

an M.S. degree in wildlife and range management.

Kathleen M. Paulin is a Wildlife Biologist on the Ashley

National Forest in Vernal, UT. She holds a B.S. degree in

biology, and an M.S. degree in wildlife ecology.

Rodney L. Playeris a Wildlife Biologist on the Manti-La Sal

National Forest in Price, UT. He holds a B.S. degree in

range management, and an M.S. degree in range and

wildlife relationships.

Arlene P. Heapis the GIS Laboratory Manager on the Dixie

National Forest in Cedar City, UT.

Richard Williams is a Wildlife Biologist on the WasatchCache National Forest in Salt Lake City, UT. He holds a

B.S. degree in wildlife management.

Acknowledgments _____________

This assessment was successfully completed, thanks

to the contribution and help of many people from throughout the State of Utah. Hugh Thompson, the Forest

Supervisor of the Dixie National Forest, provided support

and encouragement and, more importantly, he set priorities that facilitated the assembling of the team to complete the project. The wildlife biologists from several

different agencies that helped with the project deserve a

special thanks. The details of a project of this size always

take more time than anticipated. Mark Madsen spent

many days working with maps and data that were the

heart of the project and we thank him for his effort. We

thank Nancy Brunswick, Theresa Rigby, and Angela

Dudley who were invaluable in helping us assemble the

multitude of tables used. Also we thank Theresa Jain for

her invaluable help in completing the final draft, and the

Publishing Services staff of the Rocky Mountain Research Station, and in particular, technical publication

editor B. Shimon Schwarzschild for his editing suggestions. And last, but not least, we thank our families.

Without their support and understanding we could not

have endured the long hours and days away from home.

Abstract ____________________________________________

Graham, Russell T.; Rodriguez, Ronald L.; Paulin, Kathleen M.; Player, Rodney L.; Heap, Arlene P.;

Williams, Richard. 1999. The northern goshawk in Utah: habitat assessment and management

recommendations. Gen. Tech. Rep. RMRS-GTR-22. Ogden, UT: U.S. Department of Agriculture,

Forest Service, Rocky Mountain Research Station. 48 p.

This assessment describes northern goshawk (Accipiter gentilis) habitat in the State of Utah. Because

of fire exclusion, insect and disease epidemics, timber harvest, livestock grazing, or a combination of

these factors the forests and woodlands of Utah have changed drastically since the early 1900’s. Forests

are now dominated by mid- and late successional species (Douglas-fir, white fir, and subalpine fir) rather

than the early successional species (lodgepole and ponderosa pine). Along with these changes came

suspected declines in goshawk populations. Goshawk habitat in Utah was assessed using potential

vegetation types, current vegetation types, and expert knowledge. Subalpine fir (17 percent) and quaking

aspen (10 percent) potential vegetation types were the most common forest types in the State. Nearly

95 percent of the subalpine fir potential vegetation type was rated as high or medium for nesting habitat,

while nearly 90 percent of the quaking aspen potential vegetation type was rated as high or medium for

nesting. Similarly, combining nesting and foraging preferences 70 percent of the subalpine fir potential

vegetation type is rated as either high value or optimum habitat. In addition, throughout Utah all of the high

value habitats are well connected. The present conditions of the forests and woodlands of Utah are prone

to insect and disease epidemics in addition to the risk of stand replacing fires. To ensure the goshawk’s

continued existence in Utah will require the restoration of these degraded habitats and the protection of

native processes.
Contents______________________

Page

Executive Summary ...................................................i

Issue ...................................................................... i

Questions............................................................... i

Northern Goshawk and Its Habitat........................ ii

Habitat Assessment .............................................. ii

Recommendations ................................................v

Assessment Questions ........................................ vi

Introduction .............................................................. 1

Background .............................................................. 2

General Taxonomy and Distribution .................... 2

Historical Distribution in Utah............................... 2

Characteristics of Occupied Habitats in Utah ...... 2

Nesting Habitat ................................................. 2

Nest Site Characteristics .................................. 3

Foraging Habitat ............................................... 5

Nonbreeding Season Habitat ........................... 6

Factors Influencing the Species........................... 7

History of Goshawk Conservation Efforts ......... 7

Livestock Grazing ............................................. 7

Fire Suppression .............................................. 8

Timber Harvest ................................................. 8

Insect and Disease Outbreaks ......................... 8

Competition, Predation, and Disease ............... 9

Status and Distribution of Habitat in Utah ................ 9

Habitat Assessment ............................................. 9

Potential Vegetation Type Descriptions ............. 10

White Fir ......................................................... 10

Subalpine Fir .................................................. 11

Lodgepole Pine............................................... 11

Engelmann Spruce ......................................... 11

Ponderosa Pine .............................................. 12

Douglas-fir ...................................................... 12

Quaking Aspen ............................................... 12

Pinyon/Juniper ................................................ 12

Delineation of Potential Vegetation Types ......... 13

Current Habitat .................................................. 13

Page

Habitat Valuation Process ................................. 15

Nesting Habitat .................................................. 15

Foraging Habitat ................................................ 18

Combined Habitat Rankings .............................. 20

Habitat Connectivity ........................................... 24

Trends and Risks to Habitat ................................... 26

Natural Threats .................................................. 26

White Fir ......................................................... 26

Subalpine Fir .................................................. 26

Lodgepole Pine............................................... 30

Engelmann Spruce ......................................... 30

Ponderosa Pine .............................................. 30

Quaking Aspen ............................................... 31

Douglas-fir ...................................................... 31

Pinyon/Juniper ................................................ 31

Administrative Threats ....................................... 32

Threats From Management Activities ................ 32

Recommendations ................................................. 38

State of Utah Recommendations ....................... 38

Nest Sites ....................................................... 39

Foraging Areas and General Home Range .... 39

Potential Vegetation Type Recommendations .... 39

Subalpine Fir .................................................. 39

Lodgepole Pine............................................... 39

Engelmann Spruce ......................................... 40

Ponderosa Pine .............................................. 40

Quaking Aspen ............................................... 40

Douglas-fir ...................................................... 40

White Fir ......................................................... 40

Pinyon/Juniper ................................................ 41

Assessment Questions .......................................... 41

References ............................................................. 42

Appendix A ............................................................. 47

Northern Goshawk Interagency

Technical Team.............................................. 47

Northern Goshawk Technical Contributors ........ 47

List of Reviewers ............................................... 48

i

Executive Summary

This assessment describes northern goshawk

(Accipiter gentilis) habitat in the State of Utah. It can

be used in both regional and sub-regional level

planning. At these levels, this assessment should

(1) provide information on the location and connectivity of habitat that can be used to make more

informed decisions for managing both public and

private lands; and (2) complement other regional

assessments such as the Interior Columbia Basin

(Quigley and others 1996) or the USDA Forest

Service Intermountain Region’s Proper Functioning

Condition assessment (USDA Forest Service 1997).

At the local level (forest level and lower) this

assessment outlines a process that should be used

to describe goshawk habitat, proper functioning

condition, or other forest or woodland characteristics of interest. At this level, fine resolution data

should be used to describe these characteristics,

and this assessment can be used to provide context. In addition, at this level, the management

recommendations for the northern goshawk in the

Southwestern United States (Reynolds and other

1992) should be used to help prepare site prescription. Data in this assessment are too coarse for

making site specific prescriptions and should only

be used to provide context and describe processes

when used at these levels. In addition, this assessment does not prescribe implementation methods.

It describes desired conditions, with managers needing to decide how and if they will be used. This

assessment describes goshawk habitat and does

not describe goshawk demographics, nor does it

directly address goshawk population viability.

Issue __________________________

Changes in forest structure, large tree removal,

and other forest developments singly or in combination may negatively affect northern goshawk populations (Crocker-Bedford 1990). These changes in

habitat could be associated with timber harvest,

changes in fire regimes, insect and disease epidemics, or with livestock grazing or all these

activities. Perhaps one of the greatest impacts on

habitat loss is the lack of fire within the ecosystem.

Successful fire exclusion, by altering native successional pathways, has dramatically altered forested

ecosystems exemplified by ingrowth of shadetolerant tree species throughout Utah. With these

changes in habitat came suspected declines in

goshawk populations in much of the Southwestern

United States (Bloom and others 1986; Herron and

others 1985; Kennedy 1989). Because of these

suspected declines in goshawk population in July

1991, the USDI Fish and Wildlife Service announced

a 90 day finding for a petition to list the northern

goshawk in Utah, Colorado, New Mexico, and Arizona as endangered and to include critical habitat

(USDI Fish and Wildlife Service 1997). Since this

petition’s acceptance, the USDI Fish and Wildlife

Service determined that listing the northern goshawk as endangered was not warranted. Through

court action in 1992 and 1997, the USDI Fish and

Wildlife Service was ordered to revisit its decision,

and ordered the agency to address the status of the

goshawk in the Western United States.

Questions______________________

To address the issue of declining goshawk habitat

in Utah, the technical team, in consultation with

forest managers, developed the following questions to guide the assessment:

1. Is there adequate nesting habitat available?

2. Is there adequate foraging habitat available?

3. Are northern goshawks able to move freely

between habitat patches?

4. Is the population viable at the State level?

5. Where is the high value habitat?

6. How are current management policies affecting goshawks?

7. What are the important habitat trends and their

implications for goshawks:

This assessment will attempt to address these

questions.
ii

Northern Goshawk and Its

Habitat ________________________

Distribution of the goshawk is Holarctic with three

recognized subspecies breeding in North America:

the northern goshawk (A.g. atricapillus), Queen

Charlotte (A.g. laingi ), and the Apache (A.g. apache)

(USDI Fish and Wildlife Service 1997). The northern

goshawk—hereafter referred to for the sake of

brevity as “goshawk”—is the largest and most widespread of the three subspecies of the genus Accipiter in North America. The goshawk lives in a variety

of forest cover types throughout the State of Utah

ranging from the subalpine environments typified by

Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) to pinyon/juniper (Pinus

edulis/Juniperus osteosperma) woodlands bordering the grass and shrub lands. The forests in which

goshawks forage and nest have been impacted by

effective wildfire suppression throughout the West

(Dieterich 1983; Keane and others 1990; McCune

1983; Stein 1988; Weaver 1961). Large numbers of

seedlings and saplings in many forests have created “ladder” fuels that carry fires from the surface

into the crowns (Madany and West 1980). This

condition combined with a build-up of surface fuels,

produces severe and intense crown fires.

Habitat Assessment _____________

This assessment describes goshawk habitat for

the State of Utah, the area in which recommendations and inferences as to the status of goshawk

habitat were requested by the involved and cooperating parties. To understand the processes influencing goshawk habitat in Utah, and to disclose

more immediate threats and risks to goshawk habitat in the State, a smaller geographic area was

required. This geographic unit needed to provide

interpretive power and be spatially explicit across

the forest and woodlands of Utah, independent of

ownership or administrative boundary. The geographic unit that was chosen was defined by potential vegetation. This classification system integrates

a variety of physical and biological components

including climate, soils, geology, and vegetation.

For the assessment of goshawk habitat in Utah, we

chose eight potential vegetation types.

Potential vegetation types were not delineated for

Utah. Therefore, using Geospatial Analysis Processes data to identify patches of vegetation, 1,112

vegetative polygons of the forest and woodlands of

Utah were identified. To each of these polygons, the

potential vegetation type was assigned using inventory plot data points located near or in the polygon,

and by local knowledge supplied by resource managers familiar with the area (table E1). Inventory

points were random plots sampled by the Forest

Inventory and Analysis (FIA) group of the Rocky

Mountain Research Station. To each of the potential vegetation type polygons current vegetation

was determined using a combination of potential

vegetation type, Geospatial Analysis Processes, and

FIA data along with expert knowledge (table E1).

Each vegetative polygon is the State was evaluated by wildlife biologists, as to their value for

goshawk foraging and nesting. Each polygon was

rated as high, medium, or low quality in four categories: goshawk nesting habitat, small to mediumsized mammal habitat, woodpecker habitat, and

habitat for other medium-sized birds. These ratings

were used to produce a combined goshawk rating

for each of the polygons in the State. Areas were

rated as high value habitat if they were rated high for

nesting as also rated high for at least one prey

group. This combined habitat rating would include

areas where populations of one or two of the prey

groups are expected to be abundant.

Habitat is connected and available to goshawks if

it is accessible from existing population centers. If

every patch can be reached and subsequently

occupied, then all areas could be considered connected. Connectivity has positive implications for

population viability because it allows individuals to

emigrate to new areas with their current habitat

declines in value. Connected habitat patches ensures that individuals will be available to re-colonize

habitats or emigrate to new breeding territories

throughout the State.

Although goshawks are clearly capable of traveling long distances to find suitable habitat, information available indicates that 20 to 60 mile movements are typical. Therefore, a maximum distance

of 60 miles between patches of high value habitat

would represent a conservative method of defining

connectivity. This definition ensures that goshawks

will be able to disperse freely throughout the State,

always finding high value habitat (map E1).

The forests and woodlands of Utah are dominated

by late seral species (table E2). Depending on the

potential vegetation type, white fir (Abies concolor),

subalpine fir (Abies lasiocarpa), Douglas-fir

(Pseudotsuga menziesii), pinyon pine, and juniper

often dominate the forests. In addition, most forests
iii

Table E1—Proportion of the forests and woodlands in Utah in each potential vegetation type and

the proportion of the forests and woodlands in Utah currently in different current cover

types.

Potential vegetation typea Current cover typeb

Percent Percent

White fir 7 White fir 6

Subalpine fir 17 Subalpine fir 8

Pinyon/juniper 50 Pinyon/juniper 51

Lodgepole pine 1 Lodgepole pine 2

Engelmann spruce 1 Lodgepole pine/quaking aspen 2

Ponderosa pine 5 Engelmann spruce 2

Quaking aspen 10 Engelmann spruce /subalpine fir 2

Douglas-fir 9 Engelmann spruce/lodgepole pine 4

Ponderosa pine 4

Cottonwood 1

Quaking aspen 9

Douglas-fir 2

Douglas-fir/quaking aspen 6

Gambel oak/big tooth maple 1

aPotential vegetation type: Defined as a classification system that integrates a variety of physical and

biological components including climate, soil, geology and vegetation. These are identified by species

indicative of similar conditions (Hann and other 1997)

White fir = Abies concolor

Subalpine fir = Abies Lasiocarpa

Lodgepole pine = Pinus contorta

Engelmann spruce = Picea engelmannii

Ponderosa pine = Pinus ponderosa

Quaking aspen = Populus tremuloides

Douglas-fir = Pseudotsuga menziesii

Pinyon/juniper = Pinus edulis/Juniperus oesteosperma bCover type: Defined as a plurality of one species or a mixture of two or more species in a particular forest

or stand.

Cottonwood = Populus spp.

Gambel oak = Quercus gambelii

Big tooth maple = Acer grandidentatum

contain many seedlings and saplings, creating dense

forests prone to insect, disease, and stand replacing fires. Ponderosa pine (Pinus ponderosa), quaking aspen (Populus tremuloides) and lodgepole

pine (Pinus contorta), which are early and mid-seral

species in most potential vegetation types, are often

poorly represented. Moveover, quaking aspen is

one of the most important cover types supporting

goshawks in Utah. Forests dominated by late seral

species in general are more unstable in both the

short- and long-term than forests dominated by

early and mid-seral species. In addition to being

unstable and at risk to stand replacing fires because

of dense stands with many canopy layers, these

same conditions make them undesirable for both

nesting and foraging by goshawks.

No other potential vegetation type is so dominated

by late seral species as pinyon/juniper (table E2).

With this condition and the indeterminate successional pathways present, the short-term prognosis

for the type is a continued dominance of pinyon and

juniper. Throughout the State, attempts to convert

stands to early and mid-seral stages have had

limited success. The introduction of exotics (cheat

grass, Bromus tectorum) also changes successional pathways and alters fire regimes.

Owners or administrators of the forests and woodlands of Utah include these entities: the USDI National Park Service, USDI Bureau of Land Management, USDA Forest Service, private, State of Utah

and Native Americans. By far, the USDA Forest

Service administers the majority of the forests and

woodlands in Utah. Also, these lands contain the

majority of the high and medium valued nesting

habitat, and the majority of the high value combined

foraging and nesting habitat.

The USDA Forest Service manages lands for a

variety of objectives ranging from intensive forest

management to recreation. Range management is

emphasized on 17 to 23 percent of the forest and
iv

Map E1—Connectivity of high value habitat patches (Lands considered high value for nesting and high value for

at least one of the prey groups—mammals, woodpeckers, or other birds—were considered high value) showing

connections. High value habitat was considered connected if an adjacent patch was within 60 miles.
v

woodlands, and timber is emphasized on up to 58

percent, depending on the potential vegetation type.

Also, much of the lands in which range is emphasized are rated high or medium for nesting (table

E3). In terms of overall habitat, 34 percent of the

lands with a range emphasis were rated as high

value habitat and 43 percent of the mixed use areas

were rated as high quality habitat (table E3). These

management directions can decrease prey habitat

by removing cover and food for prey species. Also,

indirectly, they can interfere with fire regimes and

native forest succession. Depending on the intensity and duration, grazing could be detrimental to

goshawk habitat and to quaking aspen stands.

Recommendations ______________

The forest and woodlands of Utah providing goshawk habitat are diverse in species composition

and structure. The history of land-use in Utah is

highly variable, ranging from domestic livestock

grazing to tourism and snow skiing. With these land

uses came the desire to protect forests and woodlands from fire. Effective fire exclusion began in the

mid-1900’s. As a result, the forests and woodlands

of Utah are now dominated by dense stands of late

seral species, which are prone to epidemics of

diseases and insects and stand replacing fires.

Table E2—Proportion of each potential vegetation type currently in various forest cover types.

Potential vegetation typea

White Subalpine Lodgepole Engelmann Ponderosa Pinyon/ Quaking DouglasCurrent coverb fir fir pine spruce pine juniper aspen fir

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Percent - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

White fir 84 2 ------

Subalpine fir 1 45 - 2 6 - 3 2

Pinyon/juniper - - - - - 99 - -

Lodgepole pine - - 14 2 - - - 16

Lodgepole pine/

quaking aspen - 3 51 12 - - 2 -

Engelmann spruce - 12 1 18 ----

Engelmann spruce/

subalpine fir - 8 - 49 ----

Engelmann spruce/

lodgepole pine - 20 6 14 ----

Engelmann spruce/

Douglas-fir - - - - - -2 -

Ponderosa pine 1 1 - 1 84 - 1 2

Cottonwood - - 2 - - 1 - -

Quaking aspen 2 4 11 2 9 - 84 -

Douglas-fir 3 3 2 - - - - 18

Douglas-fir/ponderosa

pine/quaking aspen/

lodgepole pine 1 - 13 -----

Douglas-fir/subalpine fir - - - - - -1 -

Quaking aspen/

subalpine fir - - - - - -1 -

Douglas-fir/quaking aspen - - - - - - - 61

Gambel oak - 1 - - - -42

Gambel oak/

big tooth maple 10 -------

Gambel oak/quaking aspen - - - - - -3 -

aSee table E1 for potential vegetation descriptions.

bSee table E1 for current vegetation descritions.
vi

The conservation of the northern goshawk will

require the restoration and protection of degraded

habitats and native processes. The following recommendations describe actions aimed at sustaining habitat for the goshawk and selected prey in the

forests and woodlands of Utah. The applicability for

meeting these recommendations is the responsibility of the specific land owner or administrator. Because these recommendations are directed at habitat and native processes, they will also benefit a

myriad of other plant and animal species.

• Increase early and mid-seral species using

mechanical means or fire or both.

• Evaluate activities near the edges of high value

habitat as to how they may impact the connectivity of habitat, irrespective of ownership.

• Increase the numbers and distribution of large

trees in the landscape.

• Maintain large trees in nest sites.

• Develop properly functioning systems at both

the regional and landscape level.

• Ensure that in lodgepole stands a seed source

is present when applying treatments.

• Recognize that long persistent quaking aspen

can successfully regenerate under an existing

canopy.

• Recognize that the successional pathways of

pinyon/juniper potential vegetation types are

indeterminate, and in general most of the conditions after disturbance are less stable than the

present late seral condition.

Assessment Questions __________

1. Is there adequate nesting habitat available?

Presently there appears to be adequate nesting

habitat in Utah to maintain a breeding population of

goshawks.

2. Is there adequate foraging habitat available?

Based on prey habitat, it appears that foraging

habitat is presently available throughout the State.

3. Are northern goshawks able to move freely

among all available habitat patches?

Yes, goshawks appear to be able to move freely

among habitat patches throughout Utah.

4. Is the population viable at the State level?

This assessment cannot answer the question of

population viability directly because there are inadequate demographic data available. In general,

existing habitat appears to be capable of supporting

a viable population of goshawks at the State spatial

scale. However, even though high quality habitat

Table E3—Proportion of management area categories rated as high, medium and low nesting habitat

and the proportion of each management category rated as high for combined nesting and

foraging.

Management area Nesting habitat Combined habitat

categorya High Medium Low High

- - - - - - - - - - - - - - - - - - - Percent - - - - - - - - - - - - - - - - -

Wilderness 33 50 16 23

Administrative areas 41 42 19 31

Mixed use 53 26 21 43

Recreation emphasis 66 7 27 10

Timber emphasis 47 49 5 39

Range emphasis 48 41 11 34

Private interface 50 32 18 41

Special Use 75 17 7 67

General direction (Dixie) 24 24 52 20

aManagement categories (USDA Forest Service 1998):

Wilderness—designated and proposed wilderness areas.

Administrative areas—variety of areas, from guard stations to municipal watersheds; usually in small parcels.

Mixed uses—currently achieving a variety of management goals, no change desired.

Recreation emphasis—concentrated recreation use and development.

Timber emphasis—provide opportunities for commodity production within ecological constraints.

Range emphasis—provide opportunities for livestock grazing within ecological constraints.

Private land interface—lands influenced by nearby private lands and managed cooperatively to meet resource

objectives.

Special uses—activities conducted under special use permits, such as mining and summer homes, and administrative

sites such as guard stations or municipal watersheds.

General direction (Dixie)—management for a variety of resource conditions based on local objectives and priorities.
vii

does not appear to be lacking, Statewide, habitat

deficiencies may be present at the local level.

5. Where is the high value habitat?

High value habitat is distributed throughout the

State (map E1).

6. How are current management policies affecting northern goshawks?

Current management policies are affecting northern goshawks in a variety of ways. On USDA Forest

Service administered lands, 20 percent of the high

value habitat is being managed with a timber emphasis, 35 percent with mixed uses, and 27 percent

with a range emphasis. Each of these management

categories allows for activities that either can degrade or improve goshawk habitat. Information in

this assessment does not reveal any substantial

deficiencies in habitat quality in any management

category. There are two possible explanations for

these results: (1) management activities are having

no negative effect on goshawk habitat, or (2) management activities are having some negative effects on goshawk habitat, but the effects are not

detectable at either scale used in this assessment.

We currently have no data available to determine

which is true. Current management policies have

the potential to degrade habitat if any one activity is

over-applied or mis-applied. Thus current management policies provide for a wide range of implementation options, with a correspondingly wide range of

possible effects on goshawk habitat. The critical

decisions are those being made on individual project

level analyses, because this is where managers

can use the best available information in ensure that

projects are providing for goshawk habitat needs.

7. What are the important habitat trends and

their implications for goshawks?

The most obvious trend in Utah forests and woodlands is the lack of early and mid-seral species in all

of the potential vegetation types. If forest management stresses proper functioning conditions, the

importance of large trees, maintaining native processes, using adaptive management, and recognizing the role of fire, the habitat outlook could be

favorable for the goshawk and its prey. Urbanization and more intensive uses of the forests by

humans could degrade goshawk habitat, especially

on private lands. This trend could also affect the

connectivity of the habitat across the State.

USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 1

Introduction ____________________

This habitat assessment and the management recommendations for the northern goshawk (Accipter

gentilis) are an interagency effort applicable for the

State of Utah. This document is a cooperative effort by

the Utah Division of Wildlife Resources, USDA Forest

Service, USDI Fish and Wildlife Service, USDI Bureau of Land Management, and USDI National Park

Service (appendix A). It will describe habitat and develop recommendations to provide for long-term sustainable goshawk habitat throughout Utah. In addition, this effort will provide consistency in management

of goshawk habitat. This should reduce threats to

the species or its habitat and lower the priority for its

listing as a threatened or endangered species by the

USDI Fish and Wildlife Service in the future.

Changes in forest structure, especially large tree

removal, and other forest management activities singly or in combination may negatively affect goshawk

populations (Crocker-Bedford 1990). These changes in

habitat are associated with some or all of the following:

timber harvest, fire (wild or prescribed), insect and

disease epidemics, and livestock grazing. Perhaps one

of the greatest influences on habitat is fire exclusion

from forest and woodland ecosystems. Successful fire

exclusion has altered native successional pathways,

resulting in ingrowth of shade-tolerant tree species

throughout Utah. With these changes in habitat came

suspected declines in goshawk populations in much of

the Western United States (Bloom and others 1986;

Herron and others 1985; Kennedy 1989).

In July 1991, the USDI Fish and Wildlife Service

announced a 90 day finding for a petition to list the

northern goshawk in Utah, Colorado, New Mexico,

and Arizona as endangered and to include critical

habitat (USDI Fish and Wildlife Service 1997). In

September 1991, a coalition of conservation organizations requested to amend the petition already under

consideration by the USDI Fish and Wildlife Service.

This revised petition requested expansion of the geographic region to include the contiguous United States

west of the 100th meridian and was accepted by the

USDI Fish and Wildlife Service (1997). Since this

petition’s acceptance, the USDI Fish and Wildlife

Service determined that listing as endangered was not

warranted. Through court action in 1992 and 1997,

the USDI Fish and Wildlife Service was ordered to

revisit their decision and emphasized the need to

address goshawk habitat in the Western United States.

The status of the goshawk and its population size

within Utah was unknown except for a few locations

on USDA Forest Service System administrated lands.

Intensive surveys in southern Utah on the Dixie National Forest and in northern Utah on the Ashley

National Forest identified nesting locations in a wide

range of forest cover types. However, information was

limited because survey efforts were targeted at proposed project areas.

In 1991, the goshawk was also designated as a

sensitive species in the USDA Forest Service, Intermountain Region. As a result of this designation,

special management was emphasized to ensure the

goshawk’s viability (USDA Forest Service 1988a). The

Utah Division of Wildlife Resources classified the

goshawk as a sensitive species in March 1997. The

purpose of this designation was to identify species in

the State that are most vulnerable to population

declines or habitat loss and to stimulate management

actions for the conservation of this species.

The Northern Goshawk in Utah: Habitat

Assessment and Management

Recommendations

Russell T. Graham

Ronald L. Rodriguez

Kathleen M. Paulin

Rodney L. Player

Arlene P. Heap

Richard Williams
2 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

To address the issue of declining goshawk habitat in

Utah, the technical team (appendix A) developed the

following questions:

1. Is there adequate nesting habitat available?

2. Is there adequate foraging habitat available?

3. Are northern goshawks able to move freely between habitat patches?

4. Is the population viable at the State level?

5. Where is the high value habitat?

6. How are current management policies affecting

goshawks?

7. What are the important habitat trends and their

implications for goshawks?

This assessment will attempt to address these

questions.

Background ____________________

General Taxonomy and Distribution

Distribution of the goshawk is Holarctic with three

recognized subspecies breeding in North America: the

northern goshawk (A.g. atricapillus), Queen Charlotte (A.g. laingi), and the Apache (A.g. apache) (USDI

Fish and Wildlife Service 1997). The northern goshawk is the most widespread of the three subspecies.

This subspecies nests from the boreal forests of north

central Alaska and northern Canada to western montane forests in the United States and Northern Mexico

(Brown and Amadon 1968). The Queen Charlotte

goshawk occurs along the coast and on islands of the

Pacific Northwest and on the Olympic Peninsula

(Brown and Amadon 1968). The Apache goshawk lives

in southern Arizona and Mexico (Brown and Amadon

1968). Goshawks are known to winter throughout

their breeding range and as far south as southern

California, northern Mexico, Texas, and the northern

portions of the Gulf states (Johnsgard 1990).

The goshawk is the largest of the three species of

Accipiter in North America. Members of the genus

inhabit coniferous, deciduous, and mixed forests. In

North America, goshawks vary from deep grey to slate

grey and deep neutral grey on their upper parts. The

top of the head is often slate black with the sides

heavily mottled with white. Adult goshawks have an

orange-red eye which becomes deeper red to mahogany in older birds. The female goshawk is larger

than the male weighing as much as 3.0 lb with a wing

span ranging from 41 to 45 inches. The male weighs up

to 2.4 lb with a wing span of 38 to 41 inches (Squires

and Reynolds 1997; Wheeler and Clark 1995). Both

sexes have short, rounded wings and a long square tail

making them well adapted for maneuvering in forested conditions (Reynolds and others 1992).

Historical Distribution in Utah

Little information exists on the historical distribution of goshawks in Utah. Early records indicate that

it was an uncommon permanent resident, primarily

found in montane conifer and quaking aspen (Populus

tremuloides) habitats throughout the State (Behle and

others 1985). But occasionally it nests in cottonwood

(Populus spp.) cover types in lower valleys (White

1965). Studies and surveys over the past 20 years

indicate that the goshawk occurs across the State in a

wide variety of forest types.

Characteristics of Occupied Habitats

in Utah

Nesting Habitat—The northern goshawk nests in

a wide range of forested habitats, from small clumps of

quaking aspen intermixed with sagebrush (Artemisia

spp.) in Nevada (Younk and Bechard 1994a) to ponderosa pine (Pinus ponderosa) and mixed conifer forests

in northern Arizona (Reynolds and Joy 1998), to temperate rain forests dominated by western hemlock

(Tsuga heterophylla) and spruce (Picea spp.) in southeastern Alaska (Iverson and others 1996).

In Utah, most of the 421 known nests located during

project level surveys occur in mid-elevation (6,000 ft)

to high-elevation (10,000 ft) sites which are currently

occupied by mature quaking aspen or coniferous forest. Few nests were found in high elevation Engelmann spruce (Picea Engelmannii) /subalpine fir (Abies

lasiocarpa) forests in northeastern Utah. The greatest

proportion of the known nests occurs in mixed lodgepole pine (Pinus contorta) and quaking aspen forests

(table 1). Engelmann spruce alone or mixed with

lodgepole pine is also frequently used for nesting.

Goshawk use these forest types even when there is

substantial insect-related mortality in the overstory.

On the Ashley National Forest in northeastern Utah,

many nests occur in lodgepole pine forests where up to

80 percent of the overstory trees are dead as a result of

a mountain pine beetle (Dendroctonus ponderosae)

outbreaks in the early 1980’s (Ashley National Forest

1998a; Dewey 1996; White 1992). The number of

young that fledged on these territories from 1989 to

1996 was comparable to the numbers fledged over the

same time period for many other populations in the

Western United States (Dewey 1996; Kennedy 1997).

Similarly, on the Dixie National Forest in southwestern Utah, nesting territories located on areas with

high mortality caused by spruce bark beetle

(Dendroctonus rufipennes) remained active (Dixie

National Forest 1997).

There are some regional differences in goshawk use

of certain forest cover types in Utah. In southern Utah,
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 3

Table 1—Proportion of nest stands by potential vegetation type

and cover type.

Proportion of nests by potential vegetation type

Potential vegetation typea Proportion of nests

Percent

White fir 9

Subalpine fir 38

Lodgepole pine 17

Engelmann spruce 2

Ponderosa pine 10

Quaking aspen 10

Douglas-fir 14

Pinyon pine/Utah juniper 0

Proportion of nests by cover type

Cover Typeb Proportion of nests

Percent

White fir 9

Subalpine fir 9

Lodgepole pine 8

Engelmann spruce 12

Ponderosa pine 12

Quaking aspen 10

Douglas-fir 7

Lodgepole pine/quaking aspen 20

Engelmann spruce/subalpine fir 1

Engelmann spruce/lodgepole pine 9

Douglas-fir/ponderosa pine/

quaking aspen/lodgepole pine 1

Douglas-fir/lodgepole pine 1

Quaking aspen/Engelmann spruce 1

a

Potential vegetation type: Defined as a classification system that

integrates a variety of physical and biological components including

climate, soil, geology and vegetation. These are identified by species

indicative of similar conditions (Hann and others 1997)

White fir (WF) = Abies concolor

Subalpine fir (SAF) = Abies Lasiocarpa

Lodgepole pine (LPP) = Pinus contorta

Engelmann spruce (ES) = Picea engelmannii

Ponderosa pine (PP) = Pinus ponderosa

Quaking aspen (QA) = Populus tremuloides

Douglas-fir (DF) = Pseudotsuga menziesii

Pinyon pine/Utah juniper (P/J) = Pinus edulis/Juniperus osteosperma b

Cover type: Defined as a plurality of one species or a mixture of two

or more species in a particular forest or stand.

Cottonwood = Populus spp.

Gambel oak (GO) = Quercus gambelii

Big tooth maple (M) = Acer grandidentatum

Engelmann spruce and subalpine fir cover types are

used frequently for nesting, while in northern Utah

these types are only rarely used, except where Engelmann spruce is mixed with lodgepole pine (table 1).

Squires and Ruggiero (1996) suggest that in southcentral Wyoming, lodgepole pine is preferred over

Engelmann spruce/subalpine fir cover types. Both

Douglas-fir (Pseudotsugamenziesii) and white fir (Abies

concolor) are only moderately used by nesting goshawks, compared to other cover types in the State.

Douglas-fir cover types are used somewhat more for

nesting in southern Utah compared to northern Utah.

Goshawks only moderately use ponderosa pine for

nesting in Utah (table 1), even though it is used extensively by goshawks in northern Arizona (Reynolds and

others 1994). Limited use of this type in Utah may be

due to the current forest conditions. Many ponderosa

pine forests in Utah were partially cut following mountain pine beetle outbreaks in the 1970’s. As a result,

many large trees were removed, which reduced nesting habitat for goshawks. In northeastern Utah, historical nests were observed in ponderosa pine forests

but no active nests have been located since the forests

were harvested in the 1980’s (Ashley National Forest

1998a). Southern Utah ponderosa pine forests were

also partially harvested in the 1980’s resulting in large

areas of low density, relatively small diameter forests

(Dixie National Forest 1997). In these forests there is

little evidence of goshawk nesting activity.

Cottonwood, pinyon/juniper (Pinus edulis/Juniperus

spp.), Gambel oak (Quercus gambelii) and maple (Acer

spp.) woodlands are not known to be used for nesting

in Utah. However, Bloom and others (1986) have

observed nests in Utah juniper (Juniperus osteosperma)

in northeastern California, but noted that ponderosa

pine was also present. Oak and oak/maple woodlands

in Utah are used by other accipiters, but seem to be

avoided by goshawks (Fischer and Murphy 1986;

Hennessy 1978). The few nests in cottonwood trees

were located in mixed deciduous/coniferous forests not

pure cottonwood groves. Although the woodland cover

types do not appear to be important for nesting, they

may be valuable to goshawks for foraging and roosting

during the nonbreeding season.

Nest Site Characteristics—Goshawks nest in sites

with similar structural characteristics within each

cover type. In general, goshawks nest in mature to old

forests with relatively large trees, high canopy closure

(relative to surrounding areas), sparse ground cover

and open understories. Nests are often located near the

bottom of moderately steep slopes, close to water, and

often adjacent to a canopy break (Squires and Reynolds

1997). Important internal components of forests in

Utah include snags, multiple canopies, and down woody

debris (Reynolds and others 1992). In Utah, these

components tend to vary across forest type (table 2). For
4 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Table 2—Characteristics of known nest sites in Utah by forest cover type (based on descriptiong provided by Natorthern Goshawk Interagency

Technical Team members and other listed technical contributors; appendix A).

Degree of

Forest Patch size/ Stand Landscape use for

Typesa heterogeneity structure features nesting

ES/SAF

ES/LLP

ES

ES/DF

SAF

Small (0.25 to 0.50 acre)

openings in large matrix of

predominantly mature to old

forest habitat; stand sizes

100s to 1000s of acres

Moderately dense to dense

stocking; trees with

interlocking crowns;

multistoried stands; large

trees; occasional patches

of Aspen; clumpy tree

distribution; sparse

understory vegetation;

abundant large woody

debris; large snags present.

Usually on benches

adjacent to drainages or

near other water sources.

Often near natural

openings such as wet

meadows.

High

LPP

LPP/QA

100s to 1000s of acres,

mostly homogeneous

Green stands have simple,

single-storied structures;

stocking varies from dense

to very dense ("doghair");

sparse understory

vegetation; little down

woody debris; closed

canopies; few snags.

Mature and old stands

often much different due to

insect activity; many snags,

abundant woody debris,

open canopies.

Limited to the Uinta

Mountains of

northeastern Utah.

Occupies benches,

plateaus, moderate

slopes along drainages at

mid-elevations. Seral

aspen often present,

especially on moister

sites. Most nests near

drainages or small

meadows.

High

QA 10s to 100s of acres, often as

forested islands mixed with

open habitats such as

sagebrush.

Moderately dense to dense

stands; interlocking crowns;

multistoried; large trees

present; stout forks form

nest platforms; diverse,

highly productive

understory; moderate

amounts of down woody

debris.

Mesic sites on flat to

moderate slopes, often

near natural openings.

Occupies elevational

zone between

sage/grasslands and

beginning of coniferous

forest.

Moderate to high

DF/QA

DF/SAF

DF

WF

Small (1/4 to 1/2 ac) openings

scattered throughout mature

forest. Stand size varies;

100s of acres in southern

Utah, 10s to 100s in north

and west.

Dense stands; complex,

multistoried structure; high

tree species diversity; large

trees present; interlocking

crowns; abundant down

woody debris

Limited to shady aspects,

high elevations in dry

habitats and to limestone

sites in Uintas.

Widespread in southern

Utah at appropriate

elevations.

Moderate to high where

patch size large; low

elsewhere

PP Small (1/4-1/2 acre) openings

mixed with patches of varying

sizes and ages of trees.

Stand size 100s of acres.

Two size classes, one with

large trees; sometimes

mixed with Q. aspen or D.

Fir; clumpy tree distribution;

more open stands than in

other types; large snags

present.

Found on benches,

foothills, plateaus; dry

sites but nests often near

drainages with perennial

water.

Moderate

Cottonwood

DF /PP/QA/LPP

Small patch size, high

variability in tree size and

density. Cottonwood often

present as small inclusions

along drainages in P/J cover

types.

Multistoried; high tree

species diversity; diverse

and productive understory;

mix of coniferous and

deciduous trees when

occuring in shady canyon

bottoms, dominated by

cottonwoods in broader,

lower elevation valleys.

Narrow, linear stands

along perennial streams

Moderate in canyon

bottoms, low for

exposed valley locations

(possible winter

habitat?)
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 5

example, spruce/fir forests have complex forest structures with multiple canopies and large amounts of

down woody debris. Lodgepole pine forests have simple

forest structures, single canopies and have small

amounts of down woody debris except in very old

forests.

Foraging Habitat—Goshawks prefer to forage in

closed canopy forests with moderate tree densities as

compared to young open forests (Fischer and Murphy

1986; Squires and Reynolds 1997). Goshawks take

prey from openings, although they usually hunt these

areas from perches near the edge (Younk and Bechard

1994b). Medium to large-sized birds (woodpeckers,

robins, grouse, or jays) and mammals (ground and tree

squirrels and hares) tend to dominate breeding season

diets (Squires and Reynolds 1997) (fig. 1). The particular species taken varies regionally, but the species

groups represented in goshawk diets are usually consistent throughout the Western United States. For

example, the red squirrel (Tamiasciurus hudsonicus)

and tassel-eared squirrel (Sciurus aberti) group are

important prey in the Southwestern United States

and a similar group consisting of the Douglas squirrel

(Sciurus douglasi) and northern flying squirrel

(Glaucomys sabrinus) are important in eastern Oregon and Washington (Reynolds and Meslow 1984;

Reynolds and others 1992; Watson and Hayes 1997).

Species listed as common prey, regardless of location,

include the American robin (Turdus migratorius),

Steller’s jay (Cyanocitta stellari), northern flicker

(Colaptes auratus), blue grouse (Dendragapus

obscurus), red squirrel, and golden-mantled ground

squirrel (Citellus lateralis) (Reynolds and Meslow 1984;

Reynolds and others 1992; Titus and others 1994;

Younk and Bechard 1994a). The important prey species identified in Utah from field observations made

during the breeding season are similar to those discussed above (table 3). However, due to the lack of data

based on direct observations, the variety of mammals

in goshawk diets in Utah may be underestimated

(Boal and Mannan 1994). However, this list includes

several mammals identified as “dominant prey” by

Squires and Reynolds (1997), and we feel it is a

reasonable representation of goshawk diets in Utah.

Reynolds and others (1992) defined desired conditions for foraging habitat on the basis of prey ecology.

Their “food web” approach to habitat management

received support from technical reviewers (Braun and

Table 2—Con.

Degree of

Forest Patch size/ Stand Landscape use for

Typesa heterogeneity structure features nesting

a

Refer to table 1 footnotes for cover type definitions.

Figure 1—Fledgling goshawks waiting to be fed.

P/J Large, homogeneous stands

(100s to 1000s of acres)

when on P/J sites. More

variable, often mixed with

small amounts of P. Pine, D.

Fir or Cottonwood when on

W. Fir or D. Fir sites.

Uniform tree distribution;

little decadence (snags or

down woody material)

except in very old stands

(200-400 yrs); untreated

stands have fairly dense

stocking levels and very

sparse understory

vegetation.

Hot, dry sites with poor

soils; often on south and

west facing slopes.

Low (possible winter

habitat?)

GO/M

GO/M

GO

Small patches in a highly

variable mix of open habitats,

aspen and conifer stands

depending on location

Dense stands; shrubby

growth form

Often on steep south or

west facing hillsides,

sometimes along stream

courses

Low
6 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

others 1996). We used this same approach to characterize foraging habitats in Utah, which is based on

prey species observed Statewide (table 4).

Nonbreeding Season Habitat—Braun and others (1996) noted that reproduction is less important

than other factors governing population dynamics.

Far more important are mortality and dispersal that

occur primarily outside of the breeding season. Unfortunately, little is known about goshawk habitat use in

the nonbreeding season. Reynolds and others (1994)

radio-tagged adult and juvenile goshawks in northern

Arizona and tracked them during fall and early winter. All but one of the adults stayed on their summer

ranges during this time. One adult female was relocated in pinyon/juniper woodlands approximately

10 miles from her nest. Most fledglings remained near

their natal sites. However, transmitters from two fledglings were recovered in pinyon/juniper woodlands,

apparently shed after dispersing from their natal site.

Squires and Ruggiero (1995) followed four adult goshawks from their breeding areas in south central

Wyoming to wintering areas up to 116 miles away in

northern and central Colorado. Habitats used by these

goshawks ranged from quaking aspen/mixed-conifer

forests to small cottonwood groves surrounded by

sagebrush.

The six of 10 female goshawks radio tracked in the

Uinta Mountains relocated to pinyon/juniper woodlands near patches of cottonwood during the winter

(Ashley National Forest 1998b). These woodlands were

located 60 miles from the nest area. However, one

female moved to pinyon/juniper woodlands near the

LaSal Mountains in southeastern Utah, approximately

190 miles from her nest area (Squires 1997). Four females remained in their nest areas, or in similar habitat

less than 10 miles away. Not all radio-tagged females

were located, so it is not known if these locations are

truely representative of winter habitat use for most

goshawks breeding in the Uinta Mountains (Ashley

National Forest 1998b; Squires and Ruggiero 1995).

Overwintering strategies for goshawks may be related to food availability. Doyle and Smith (1994)

observed goshawks on their Yukon study area yearround during periods of high snowshoe hare (Lepus

americanus) populations, but noted that goshawks

almost disappeared during winters when hare numbers were low. McGowan (1975) also speculated that

cyclic prey abundance accounted for observed fluctuations in goshawk numbers in interior Alaska, especially during the winter. However, this may be less

important in the Western United States where the

goshawk’s primary mammalian prey are less cyclic

(McGowan 1975). Populations of snowshoe hares appear to be considerably more stable in the Central

Rocky Mountains than in Canada (Dolbeer and Clark

1975). Because red squirrels are able to avoid starvation during food shortages by caching food, their populations also remain relatively stable (McGowan 1975).

The diversity of prey taken in the Western United

States may buffer goshawk populations against extreme fluctuations in individual prey species (Boal

and Mannan 1994).

Weather may also be a factor in determining when

and how far goshawks migrate to winter ranges.

Squires and Ruggiero (1995) noted that a long distance movement of goshawks coincided with a major

snowstorm. Severe weather conditions may increase

the importance of thermal cover for goshawks, and

deep snow cover may limit the kind and amount of prey

available. Either situation may cause goshawks to

seek out different habitats in the winter.

Table 3—Prey species used by nesting goshawks in Utah.

(based on descriptions provided by Northern

Goshawk Interagency Technical Team members

and others listed technical contributors; appendix A).

Species Northern Utah Southern Utah

Mammals

Snowshoe hare Observeda Observed

Cottontail rabbit Suspected Observed

Red squirrel Observed Observed

Uinta ground squirrel - Observed

Abert’s squirrel - Suspected

Flying squirrel - Suspected

Woodpeckers

Northern flicker Observed Observed

Three-toed woodpecker Observed Observed

Other woodpeckersb Observed Observed

Other birds

Gray jay Observed Suspected

Black-billed magpie Observed Suspected

American kestrel Observed -

Common raven Observed -

Clark’s nutcracker Observed Suspected

Steller’s jay Observed Observed

Grouse (ruffed and/or blue) Observed Observed

American robin Observed Observed

Townsend’s solitaire Observed -

Mourning dove - Observed

Mountain bluebird Observed Observed

Dark-eyed junco Observed -

Mallard Observed Suspected

Unidentified blackbird Observed -

a

Observed: biologists report identifying prey remains near an active

nest; suspected: present in habitats used by goshawks but no prey

remains identified to date. b

Includes downy and hairy woodpeckers, red-naped and Williamson’s

sapsuckers.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 7

Factors Influencing the Species

History of Goshawk Conservation Efforts—As

a result of studies conducted on nesting habitat in the

1970’s (Bartelt 1977, Hennessy 1978) several threats

facing the goshawk were recognized (Reynolds 1989).

In the 1980’s, the USDA Forest Service designated the

goshawk as a national indicator of mature and oldgrowth forests. Subsequently, at least 49 National

Forests selected the goshawk as a management indicator species used in Land Management Plans (Patla

1990; Sidle and Suring 1986).

This led to the development of management recommendations for western coniferous forests to protect

nest sites (Reynolds 1983). These recommendations

proposed that a 20 acre buffer of uncut habitat be left

in timber sale areas around two active and two replacement nest sites per nest area. In Arizona, an

evaluation of the 20 acre buffer indicated that these

small areas were not protecting nest areas adequately

when implemented (Crocker-Bedford 1990; CrockerBedford and Chaney 1988). In 1992, more comprehensive management recommendations for the goshawk

were developed for the USDA Forest Service, Southwestern Region (Reynolds and others 1992). This

effort recommended managing for 6,000 acre territories

to protect nests and provide adequate foraging habitat. During this same time period, Kennedy and

Stahlecker (1993) developed and tested a calling protocol for locating breeding goshawks.

Livestock Grazing—Domestic livestock have

grazed Southwestern ponderosa pine and mixed-species forests since the mid 1800’s (Cooper 1960;

Rasmussen 1941) and has affected both forest structure and composition. Within ponderosa pine forests,

dense grass cover can decrease seedling establishment and survival (Brawn and Balda 1988). However,

heavy livestock grazing reduced ground cover, which

encouraged the establishment of dense stands of saplings (Covington and Moore 1991; Reynolds and others

1992; Stein 1988). Fire suppression also allowed trees

to encroach into openings, subsequently reducing forage production. Grazing in high elevation meadows

and open parklands has changed plant community

composition and structure. These changes most likely

Table 4—Important habitat attributes for maintaining populations of selected goshawk prey in Utah (based on descriptions provided

by Northern Goshawk Interagency Technical Team members and others listed technical contributors; appendix A).a

Large down Mix of Most common

woody Large Understory structural Interlocking in these

Prey species debris Snags trees vegetation Openings stages tree crowns cover typesb

Mammals

Snowshoe hare Low None None High Low High None LPP, SAF, ES

Red squirrel High High High Med None Low High ES, LPP, DF

Woodpeckers

Northern flicker High High High Med Low High None PP, QA

Three-toed

Woodpecker Med High High None None Med None LPP, ES

Hairy Woodpeckers/

Williamson’s

sapsucker Med High High Med None Med None QA, LPP, ES,

DF, SAF

Downy

Woodpecker Med High High Med None Med None QA

Red-naped

sapsucker Med High High Med None Med None PP

Other Birds

Steller’s jay Low Low High Low None Low Low PP, P/J

Ruffed grouse High None Low High High High Low QA

Blue grouse Med None High High High High Low DF

American robin Low None Low High Med High Med PP, QA

Mountain bluebird Low High High High High High None QA, PP, P/J

a

After Reynolds and others 1992. Information on ruffed grouse and mountain bluebird from DeGraaf and others 1991, Ehrlich and others 1988.

Additional information on bird use of forest cover types from Forest Service breeding bird surveys (Ashley National Forest 1995). Information on

snowshoe hare from Dolbeer and Clark 1975; Koehler 1989; Koehler and Brittell 1990. Dominant tree species alone or in mixed stands. b

For full name description see table 1, footnotes.
8 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

have affected goshawks, but the extent of that effect is

poorly documented.

In Nevada, livestock grazing resulted in the deterioration and loss of some goshawk nesting habitat

(Herron and others 1985; Lucas and Oakleaf 1975).

Annual grazing by concentrated livestock removed

young stems and reduced quaking aspen’s ability to

regenerate (Mueggler 1989). Surveys in Nevada indicate that 85 percent of the known goshawk nests in the

Humboldt/Toiyabe National Forest were found in quaking aspen forests. In addition, 70 percent of all quaking

aspen in Nevada is located on USDA National Forest

System administered lands and the majority of these

forests have minimal regeneration (USDA Forest Service 1993). Grazing also alters both the structure and

species composition of the grass, forb and shrub

layers of quaking aspen forests which also modifies

goshawk foraging habitat (Reynolds and others 1992).

Riparian areas are the most productive and valuable

wildlife habitats wherever they occur. During the

past century, 70 percent of the wetland/riparian areas

have been negatively impacted throughout the West

(Lee and others 1989). Continued loss of forested

riparian wetlands in the Rocky Mountain States averages 1 percent per year or more (Lee and others 1989).

Because goshawks use riparian areas for both nesting

and foraging, reductions caused by livestock grazing

can negatively affect habitat for goshawk prey and

reduce or eliminate foraging habitat potential (Hargis

and others 1994; Patla 1994; Reynolds and others 1992).

Fire Suppression—Goshawk foraging and nesting habitat has also been impacted by fire suppression.

Throughout Western North America, prior to European settlement, ponderosa pine forests burned every

2 to 15 years. These fires were typically low-intensity,

lightning caused, noncatastrophic surface fires (Avery

and others 1976; Cooper 1960, 1961; Covington and

Moore 1991; Dieterich 1980a, 1983; Gruell and others

1982; McCune 1983; Reynolds and others 1992;

Swetnam 1988; White 1985 ). Both stand replacing

and surface fires occurred in mixed-conifer forests at

5 to 22 year intervals (Ahlstrand 1980, Weaver 1951,

Wright 1988). Effective wildfire suppression since the

1900’s has changed fire regimes, and in some areas,

entirely eliminated them (Dieterich 1980b, Keane and

others 1990, McCune 1983, Stein 1988, Weaver 1961).

Low intensity surface fires typically maintained

open conditions in dry forests by continually cleaning

the forest floor of small trees and lower vegetation,

allowing for easy hunting access. The lack of fire in

ponderosa pine forests has resulted in stands dominated by multiple canopies containing one or more

cohorts of Douglas-fir, white fir, or ponderosa pine.

Likewise, the lack of fire has resulted in the failure of

seral quaking aspen stands to regenerate; instead

they are being replaced by firs and spruce (Bradley

and others 1992). As stocking levels increase, “ladder”

fuels that carry fires from the surface into the crowns

develop (Madany and West 1980). This condition,

combined with a build-up of surface fuels, produces

severe and intense crown fires. Prior to European

settlement, large stand replacing events were thought

to be rare, especially in ponderosa pine forests and

possible other forest types (Brawn and Balda 1988;

Covington and Moore 1991).

Timber Harvest—Goshawks can breed successfully in forests where timber harvesting has occurred

(Reynolds and others 1994; Woodbridge and Detrich

1994) but they appear to prefer stands of mature and

over-mature trees for nesting and foraging (BrightSmith and Mannan 1994). Also, occupancy of the nest

stand has been positively associated with patch size

(Woodbridge and Detrich 1994). However, the effects

of reducing the number and size of mature trees on

existing goshawk densities or productivity is unknown.

Population models for species in fragmented forest

landscapes suggest that sharp declines in viability can

occur if habitat decreases over the long-term (Franklin

and Forman 1987; Lamberson and others 1992). The

removal of suitable nesting habitat through timber

harvesting or other management activities can be a

threat to the goshawk (McCarthy and others 1989;

Moore and Henny 1983; Reynolds 1989). Evidence

suggests that timber harvesting on the North Kaibab

Ranger District in Arizona caused goshawks to decline

from an estimated 260 nesting pairs to 60 nesting

pairs (Crocker-Bedford 1990). Due to commercial timber and fuel wood harvesting, snags and large trees

are less abundant in present-day forests.

Insect and Disease Outbreaks—The history of

Southwestern forests, particularly fire suppression

and timber harvesting, has altered the forest structure and composition in a manner that facilitates

insect and disease outbreaks (Parker 1991; Reynolds

and others 1992). Insects and diseases, along with fire,

are among the more important regulators of forest

density, composition, and structure. Observations on

the distribution and the severity of insects and disease

outbreaks prior to the past few decades are limited.

Evidence indicates that dwarf mistletoes

(Arceuthobium spp.) and root diseases (Armillaria

spp., Heterbasidianspp.) are increasing in Southwestern forests (Parker 1991) due to high stand densities

and species composition changes. As a result of these

changes, the potential for large scale epidemic outbreaks of bark beetles (Dendroctonus spp.) is present

in many ponderosa pine and mixed species forests

(Gardner and others 1997; Hedden and others 1981;

Rogers and Conklin 1991). Endemic levels of insects

and pathogens can play significant ecological roles by
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 9

causing tree mortality, defoliation, decay, or deformity, that are often important attributes for goshawk

nesting or foraging.

The composition and structural changes in the forests of Utah have increased epidemic frequencies of

insects. For example, the Engelmann spruce forests on

the Dixie and Manti-LaSal National Forests are currently experiencing spruce bark beetle epidemics. As

a result, trees 4 inches and larger are being killed in

5 to 10,000 acre patches. In northern Utah, similar

epidemics of mountain pine beetle occurred in 10,000

acre patches in lodgepole pine, affect about 100,000

acres total. Goshawk continue to nest successfully in

these beetle-killed forests (Ashley National Forest

1998b; Dewey 1996; Dixie National Forest 1997).

Competition, Predation, and Disease—Nesting

habitat structure with open conditions may allow for

the predation of goshawks, and especially their nestlings, by great horned owls (Bubo virginianus) (Boal

and Mannan 1994; Crocker-Bedford 1990; Moore and

Henny 1983; Woodbridge and Detrich 1994). Nestling

mortality may increase during periods of low food

availability (Crocker-Bedford 1990; Moore and Henny

1983; Rohner and Doyle 1992; Woodbridge and Detrich

1994; Zachel 1985). Moreover, the pine marten (Martes

americana) and fisher (Martes pennanti) can also be

predators (Patla 1990).

Open habitat may lead to the replacement of nesting

goshawks by red-tailed hawks (Buteo jamaicensis)

and great horned owls (Crocker-Bedford 1990; Moore

and Henny 1983). Great horned owls and the longeared owls (Asio otus) can use goshawk alternate nests

(Buchanan and Erwin 1997; Bull and others 1988;

Dewey 1996; Dixie National Forest 1997; Patla 1992;

Woodbridge and Detrich 1994). In northern California, goshawks moved after their nests were occupied

by spotted owls suggesting possible competition for

nest sites (Woodbridge and Detrich 1994).

Goshawks will attack red-tailed hawks, short-eared

owls (Asio flammeus), and great horned owls when

near nests (Cranell and Destefano 1992; Lindberg

1977). Raptors killed by goshawks include long-eared

owls, tawny owls (Strix aluco), nestling honey buzzards (Pernis apivorus), nestling and adult common

buzzards, nestling and adult sparrowhawks (Accipiter

nisus), other goshawks, and red-tailed hawks, American kestrel (Falco sparverius), Cooper’s hawk (Accipiter cooperii) and sharp-shinned hawk (Accipiter

striatus) (Kostrzewa 1991; Reynolds and others 1994;

White 1998). On the Dixie and Uinta National Forests,

goshawks have been observed defending nest territories against both red-tailed and Swainson’s hawks

(Buteo swainsoni) (Dixie National Forest 1997).

Goshawks have several diseases and body parasites

that may impact nesting and brooding success. Tuberculosis and fungal diseases are typically found in

goshawks (Squires and Reynolds 1997). Goshawks are

plagued by ectoparasites such as lice, and internal

blood parasites such as Leucocytozoon, Haemoproteus,

Trypanosoma, and microfilariae. Approximately 56

percent of North American goshawks suffer from such

internal parasites (Greiner and others 1975) but how

they impact goshawk populations is unknown.

Status and Distribution of Habitat

in Utah ________________________

Habitat Assessment

The goshawk has been located in a variety of forest

cover types throughout Utah. As interpreted from

Geospatial Analysis Processes (GAP, USGS 1995),

they range from the subalpine environments typified

by Engelmann spruce and subalpine fir to pinyon/

juniper woodlands bordering the grass and shrub

lands. In general, the elevations of these forests range

from 4,000 to 11,000 ft, with rugged and broken

topography. In addition to major mountain ranges,

such as the Uinta and Wasatch, Utah contains major

plateaus such as the Markagunt and Tavaputs. The

climate, and therefore the vegetation of Utah, is highly

influenced by elevation and latitude. In general, precipitation on forest lands ranges from 12 to 42 inches

annually. With this variation in topography, climate,

soils, and geology a wide range of forest compositions

and structures are typical.

The forests of Utah are and have been occupied by

humans for centuries. Native Americans used and

settled in many forests. European settlement of the

valleys started in earnest during the mid 1800’s. Along

with the disturbances caused by human presence

(harvesting, burning), natural disturbances from flood,

wind, fire, snow, and ice all shaped successional pathways and current vegetation. Since the early-to-mid

1900’s, effective fire exclusion has prevented fire from

playing its historical role of maintaining and regenerating many of these forests. Also, with European

settlement, forests in and along valley bottoms were

extensively harvested to supply materials for construction, mining, and the railroad industries. Timber

harvesting, mining, domestic livestock grazing, recreation, and fire exclusion continue to impact Utah

forests. The historic and current uses and diversity of

Utah forests, necessitated the development of a carefully structured assessment for goshawk habitat.

Effective assessments of natural resources require a

balance between data resolution and geographic extent. Both are referred to as scale often leading to

confusion. Resolution refers to the intensity or graininess of the data. Geographic extent refers to the area

(spatial scale) to be addressed (Graham and others

in press; Haynes and others 1996). Both must be
10 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Pinyon-juniper forest

FIRE

Skelton forest and bare soil

Annual stage

Years

Perennial grass/forb stage

Shrub stage

Shrub/open tree stage

Pinyon-juniper forest 300

100

25

4

2

0

appropriate to the questions being asked and the issue

being addressed. By definition, this assessment will

address goshawk habitat throughout Utah.

Another important component of assessments is to

conduct them across two or more spatial and temporal

scales (Graham and others in press). By conducting

assessments at multiple scales, the large geographic

extents can set context for the small. Similarly, the

long time frames provide context for the short. Conducting assessments at two scales assures processes

identifiable at one scale will not be overlooked if they

are not observable or easily addressed at the other. For

example, the migration or dispersal of the goshawk

could not easily be addressed by examining only nest

stands, and nest stand characteristics could not easily

be addressed using only landscape or subregional

assessments. Population trends also cannot be easily

addressed using nesting success for a single year, but

multiple year observations allow for meaningful descriptions of population trends.

Utah was the largest geographic area used for assessing goshawk habitat. It would have been useful to

look at a regional scale to set the Utah assessment in

context to explore how the habitat in Utah is related to

habitat in adjacent states. But, time, budget, and

personnel constraints, did not permit the wider analysis. Only recommendations and inferences on the

status of goshawk habitat within Utah were requested

by the involved and cooperating parties (appendix A).

This assessment is designed to provide general habitat trends for the next 25 years for Utah.

To fully understand influences of goshawk habitat

in Utah, and to disclose immediate threats and goshawk habitat risks to the State, a smaller geographic

area was required. Counties, watersheds, National

Forests, or other political or geographic delineations

could have been applied. An important component of

choice was using a geographic unit that would provide

interpretive power and be spatially explicit across the

forests and woodlands of the State, and be independent of ownership or administrative boundaries. The

most useful geographic unit was potential vegetation.

This classification system integrates a variety of physical and biological components including climate, soil,

geology and vegetation. Potential vegetation types are

identified by species indicative of similar conditions.

For example, pinyon/juniper indicates a warmer and

drier environment than ponderosa pine. Due to growth,

mortality, and disturbance, many other kinds of vegetation can occur on this type through time (fig. 2). In

some cases the indicator species may not be present,

due to disturbance. Pinyon/juniper is simply a vegetative indicator, and a name, for a physical and biological

environment stratification system useful for predicting response to disturbance (Hann and others 1997).

For this assessment of goshawk habitat, we defined

eight potential vegetation types. These potential vegetation types cover the most representative and important environments in Utah, from the warm and dry

pinyon/juniper type to moist and cool subalpine fir

type. We will use potential vegetation type to describe

components such as different seral stages, the range of

cover types, successional pathways, disease and insect

relations, and fire regimes on a given geographic unit.

Seral stages are different vegetative communities

that occur through time and in response to different

disturbances. These stages should not be confused

with vegetative structural stages (young, mid-aged,

mature, etc.) as defined by Reynolds and others (1992).

Potential Vegetation Type Descriptions

White Fir—Forest lands with white fir as the potential dominant vegetation species are probably too

dry and warm for subalpine fir (Abies lasiocarpa) or

Engelmann spruce (Picea engelmannii) to be dominant. This potential vegetation type occupies about

Figure 2—The successional pathway of pinyon/

juniper. Pinyon/juniper is the indicator of the

potential vegetation type, but depending on the

disturbance frequency, pinyon and juniper trees

may never occur on a given site.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 11

7 percent of the forested land in the State in montane

sites between 5,000 and 9,200 ft, depending on the

location within the State (table 5). This potential

vegetation type usually occurs on gravelly soils that

are well drained and derived from a variety of parent

materials. In the north, this type is often associated

with colluvium and in the south it is often associated

with limestone and sandstone. Including white fir, a

variety of other species can also occur in this type such

as juniper, pinyon pine (Pinus edulis), quaking aspen,

ponderosa pine, Douglas-fir, limber pine (Pinus flexilis),

bristle cone pine (Pinus longaeva), blue spruce (Picea

pungens), Engelmann spruce, subalpine fir, and

Gambel oak. Historically, fire intervals were indeterminate for the type (Bradley and others 1992), but

likely ranged between 8 and 18 years. In addition,

large volumes of ponderosa pine and Douglas-fir were

removed from this type in the early 1800’s. Root

diseases such as Fomes annosus and insects such as

spruce budworm (Choristoneura occidentalis) are only

two of the insects and pathogens common in this type,

especially in the tension zones.

Subalpine Fir—At the higher elevations throughout the State, the forest landscape is dominated by the

subalpine fir potential vegetation type. It covers approximately 17 percent of forest land in Utah and it

occurs between 6,000 and 11,000 ft, depending upon

the location (table 5). Pure stands of subalpine fir are

rarely found, but mixed conifer stands with Douglasfir and Engelmann spruce are much more common.

Quaking aspen, along with lodgepole pine, are common seral species with various amounts of ponderosa

pine, limber pine, blue spruce, and Gambel oak. Because this type can occur on all parent materials found

in the State, soils range from coarse to fine. The

climate can be characterized as cool, with frequent

summer frosts and deep snow packs (Lawton 1979).

Fire intervals have been estimated as low as 40 years

in some areas, to over 300 years in others (Bradley and

others 1992). In combination with harvesting, fire has

created many stands dominated by quaking aspen

(Mauk and Henderson 1984). Spruce beetle, Armilaria

root disease, and balsam bark beetle (Dendroctonus

confusus) are common disturbance agents as are

snow, ice and wind. All of these agents, singly and in

concert, can create a variety of different successional

pathways producing a variety of stand structures

and compositions.

Lodgepole Pine—This is the only potential vegetation type where lodgepole pine persists with no

evidence that another species is the potential climax

(Pfister and others 1977). This type occurs between

7,600 and 10,300 ft in the Uinta Mountains and

represents about 1 percent of the forest lands in the

State (table 5). Exposures are relatively warm and

usually quite arid with well drained soils (Mauk and

Henderson 1984). Soils are primarily derived from

quartzite with a wide range of depths. Lodgepole pine

in this type has both endemic and epidemic levels of

dwarf mistletoe, depending on the location. Also

Comandra blister rust (Cronartium commandrae),

and western gall rust (Endocronartium harknessii)

occasionally kill trees. Root and stem decays can kill

older trees and are often more damaging than rusts

(Krebill 1975). Within this type, there are small

amounts of quaking aspen, Engelmann spruce, subalpine fir, Douglas-fir, white fir, and common juniper.

For the most part, fires are either the smoldering type

where the surface fuels are slowly burned at 22 year

intervals (Arno 1976), or severe stand replacing events

occurring at intervals as great as 300 years (Romme

1982). Stand development is a combination of insect

and disease mortality, fuel accumulation, and fire

(Brown 1975). Dwarf mistletoe and bark beetles

(Dendroctonus ponderosae) can work singly or in concert to kill trees. Forests thinned by surface fires are

susceptible to mistletoe because well spaced trees

allowing easier dispersment of mistletoe seeds on

residual trees and new seedlings (Parmeter 1978).

Mountain pine beetles have caused extensive mortality in the type (Hutchinson and others 1965).

Engelmann Spruce—The Engelmann spruce potential vegetation type occurs at elevations from 9,000

to over 11,000 ft and occupies around 1 percent of the

forest and woodlands of Utah (table 5). In addition to

Engelmann spruce, which often lives 300 years, Douglas-fir, blue spruce, lodgepole pine and subalpine fir

are found in the type. At lower elevations, lodgepole

pine and quaking aspen are major seral species (Mauk

and Henderson 1984). Soils of this type are usually

gravelly and derived from quartzite in the northern

Utah, or weathered andesitic flows in the southern

Utah (Youngblood and Mauk 1985). Extensive winds

on these sites diminish the snow pack and tip over

trees. Fire is frequent at low elevations, but its effect

Table 5—Proportion of Utah forested land in each

potential vegetation type.

Potential vegetation typea Percent

White fir 7

Subalpine fir 17

Pinyon pine/Utah juniper 50

Lodgepole pine 1

Engelmann spruce 1

Ponderosa pine 5

Quaking aspen 10

Douglas-fir 9

a

Refer to footnotes in table1 for potential vegetation

type definition.
12 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

may be severe at higher elevations where infrequent

stand replacing events occur.

Ponderosa Pine—In northern Utah, the ponderosa pine potential vegetation type is mostly limited to

the eastern and southern Uinta Mountains, but it is

found throughout the southern part of the State. This

type occurs at elevations ranging from 6,800 to 9,000

ft. It represents about 5 percent of the forests and

woodlands of Utah (table 5). Important seral trees

include quaking aspen and Gambel oak. Other species

include pinyon pine, limber pine, Rocky Mountain

juniper (Juniperus scopulorum), or Utah juniper. Soils

in the north are usually well drained, gravelly and

shallow when over bedrock. In southern Utah, parent

materials can include basalt, andesetic flows, intrusive granitoids and others (Youngblood and Mauk

1985). In general, this type, especially in southern

Utah, receives considerable precipitation during the

summer with total amounts near 15.6 inches. Historically, fire was a frequent disturbance in the type, often

occurring every other year in some areas, but with 48

year intervals in others (Dieterich 1980a). Historically, throughout Utah the ponderosa pine potential

vegetation type burned at a frequency of less than 20

years (Bradley and others 1992). The intensities of

these fires were low, but they thinned and cleaned

stands of regeneration and surface fuels. Without fire,

this type is prone to both live and dead fuel accumulations, increasing the potential for stand replacing

fires. Historically, lightning, beetles and diseases constantly killed large trees which were burned, creating

a site well suited for regeneration. Domestic livestock

grazing, along with fire exclusion, has disrupted fire

cycles and created conditions that were rare or nonexistent in primeval forests (Bradley and others 1992).

Along with these structural changes, Armillaria, bark

beetles, dwarf mistletoe, and other pathogens and

insects attack, stress or kill trees.

Douglas-fir—The Douglas-fir potential vegetation

type covers a small portion of the south, while in the

north it is well represented. This type occurs from

5,000 to 8,800 ft in the north and up to 9,700 ft in the

south (Mauk and Henderson 1984, Youngblood and

Mauk 1985) and covers approximately 9 percent of the

forest and woodlands of Utah (table 5). This type

occurs on a variety of soils and parent materials but in

the Uintas it is restricted to calcareous substrates and

areas where the soils are at least weakly calcareous.

Soils are well drained and all textures are possible for

the surface, but most are loamy or finer. Forests on

this type range from scattered to dense depending on

exposure. Douglas-fir is the most common conifer but

ponderosa pine, quaking aspen, and lodgepole pine are

frequent seral species. Also, on the edges of the type,

white fir, juniper, limber pine and Engelmann spruce

occur occasionally. Root diseases, spruce budworm,

and Douglas-fir beetle are endemic in the type, with

occasional epidemic eruptions on local levels. Historically, in drier portions of the type, stands were open

allowing frequent (4 to 7 years) low intensity fires to

promote the establishment and dominance of seral

ponderosa pine. Higher severity and stand replacing

fires are possible when Douglas-fir ladder fuels allow

fires to reach the overstory crowns, especially at the

longer return intervals (50 years plus). In the moist

areas of the type, a more variable fire regime historically occurred, with both surface and stand-replacing

fires common. As a result, a mosaic of stand structures

and compositions existed. Fire return intervals were

probably in the range of 15 to 30 years (Bradley and

others 1992). This type was harvested heavily after

European settlement, with extensive removal of both

large Douglas-fir and ponderosa pine.

Quaking Aspen—Quaking aspen similar to lodgepole pine is a seral species growing on other potential

vegetation types. Only on the quaking aspen potential

vegetation type does this tree appear to be long persistent or climax. Quaking aspen vigorously regenerates

by root suckers following fire (Mueggler 1988) and it is

able to dominate a site rapidly after a disturbance. The

environmental conditions determining quaking aspen’s

role as a seral or climax species remain ill-defined

(Mueggler 1989). An occasional subalpine fir, Douglas-fir, lodgepole pine, or Engelmann spruce might

occur along with quaking aspen even when the latter

is persistant. Quaking aspen occurs at elevations

ranging from 5,500 to 10,500 ft on a variety of soils that

are derived from sandstone, limestone, quartzite and

granitics. It covers about 10 percent of the State (table

5). In southern Utah, it occurs primarily on volcanics.

Historically, livestock grazing and fire were the primary disturbances. Even-aged stands of quaking aspen usually originate from fire and may occur on other

potential vegetation types. In contrast, climax stands

of this tree tend to be uneven-aged where regeneration

is a gradual but continual process. Quaking aspen is

sensitive to fire because of its thin bark, and fire

scarred trees usually contain heart rot (Jones and

Debyle 1985). Fire appears to stimulate suckering by

killing most or all of the clonal stems (Brown and

Debyle 1987). Quaking aspen is the dominant tree

species in this type with most successional changes

occurring in the forb, shrub, and grass layers, as they

respond to different disturbances.

Pinyon/juniper—The pinyon/juniper potential vegetation type occupies approximately 50 percent of the

forest and woodlands in Utah (table 5). By far it is the

driest potential vegetation type growing at elevations

from 4,500 to 7,500 ft. It occurs on a variety of soils that

are derived from granites, limestones, volcanics, and
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 13

mixed alluvium (Evans 1988). Lower limit is set by

available water and upper limit by unfavorable temperatures. Douglas-fir and ponderosa pine potential

vegetation types border this type at high elevations

and grass/shrub dominated communities border it at

lower elevations. Pinyon pine usually dominate higher

elevations while juniper occupy lower elevations. Fires

open stands and create a mosaic of structures and

compositions (Bradley and others 1992). Fire return

intervals range from 8 and 50 years (Burkhardt and

Tisdale 1976; Moir 1982). Domestic livestock grazing

occurred on some sites in the Southwest for as long as

400 years (Tausch and others 1981). Succession after

fire begins with annuals and continues with mixes of

perennial grasses, forbs, and shrubs, culminating with

pinyon/juniper (Evans 1988) (fig. 1). In mature stands,

most trees are pinyon pine, and low-severity fires will

remove understory. Because of the scarcity of fuels to

carry a fire in closed stands, fires become rare (Bradley

and others 1992) but when fires invade from adjacent

types, especially if driven by wind, stand-replacing

fires can occur.

Delineation of Potential Vegetation Types

No map of potential vegetation types for Utah was

available. Using Geospatial Analysis Processes data

to identify patches of vegetation, 1,112 vegetative

polygons of forests and woodlands of Utah were identified (USGS 1995). To each of these polygons, a

potential vegetation type was assigned using inventory plot data points located near or in the polygon,

and by local knowledge supplied by resource managers familiar with the area. Inventory points were

random plots sampled by the Forest Inventory and

Analysis (FIA) group of the USDA Forest Service,

Rocky Mountain Research Station. In addition to the

potential vegetation type, data for each plot included

slope, aspect, elevation, current vegetation, and other

site-specific information. This auxiliary information

helped identify the potential vegetation type within

each polygon. Often, more than one point would be

located in a vegetation polygon, further strengthening

the potential vegetation type assignment. All polygons in Utah were assigned to one of eight potential

vegetation types (map 1).

Current Habitat

Current vegetation was determined using a combination of potential vegetation type, Geospatial Analysis Processes, and FIA data, along with expert knowledge of resource managers working in Utah. Current

forest cover type, structural stage (seedling, sapling,

young forest, middle-aged forest, mature forest or old

growth), stand size, and understory composition were

identified for each potential vegetation type polygon.

Coarse woody debris, snags, water, large trees, and

multiple canopies within in each polygon were also

determined. These variables described attributes believed to be important for one or more of the primary

prey species (table 4). When necessary to describe

current conditions accurately, some potential vegetation type polygons were divided into two or more

subpolygons.

Potential vegetation types in Utah currently support various forest cover types ranging from pure

ponderosa pine to complex mixtures of Douglas-fir,

ponderosa pine, quaking aspen, and lodgepole pine

(table 6). The pinyon/juniper cover type is most common, covering 51 percent of Utah’s forests and woodlands (table 7). Spruce and fir cover types are common

over the State’s forested lands. However the ponderosa pine cover type represents only 4 percent of the

forest and woodlands. The trend across the entire

State is for late seral species to be better represented

than early seral species (map 2).

Quaking aspen occupies 9 percent of Utah’s forests

and woodlands (table 7). It dominates 84 percent of the

quaking aspen potential vegetation type (table 8) but

is underrepresented in many potential vegetation

types where it is a major seral species. For example, in

the Douglas-fir, white fir and subalpine fir potential

vegetation types it represents less than 6 percent

(table 8). Most of these stands are located in central

and north-central Utah, and in the mountains of

southeastern Utah (map 2). Quaking aspen also occurs as a component of mixed species stands on 51

percent of the lodgepole potential vegetation type and

61 percent of the Douglas-fir potential vegetation type

(table 8). Goshawk nests are often associated with

mixed lodgepole pine and quaking aspen forests in

northeastern Utah (table 1). Mixtures of Douglas-fir

and quaking aspen are common in the Tavaputs Plateau of east-central Utah and in the Bear River Range

east of Logan, UT. Few goshawk nests have been

located in these forests and the importance as habitat

is unclear (map 2).

The cover types most often occupied by goshawks

(based on sightings and nest locations) are Engelmann

spruce, subalpine fir, lodgepole pine and quaking

aspen, either in single or mixed species forests (table 1).

Ponderosa pine can also be locally important, particularly in riparian areas where the species is mixed with

quaking aspen. Subalpine fir and Engelmann spruce

are late seral species dominating their respective

potential vegetation types. Lodgepole pine or a lodgepole pine mix occurs on over 75 percent of the lodgepole pine potential vegetation type but occupy less

than 20 percent of the subalpine fir and Engelmann

spruce potential vegetation types. Subalpine fir, Engelmann spruce, quaking aspen, and lodgepole pine
14 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Map 1—The distribution of potential vegetation types in Utah as derived from Geospatial Analysis Processes data, forest inventory

and analysis data, and local knowledge. WF = White fir, SAF = Subalpine fir, P/J = Pinyon juniper, LPP = Lodgepole pine, ES =

Engelmann spruce, PP = Ponderosa pine, QA = Quaking aspen, DF = Douglas-fir.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 15

(either alone or in mixed species stands) dominate the

tall forests in Utah and are all commonly used by

goshawks for nesting.

Other cover types used by goshawks include ponderosa pine, white fir and Douglas-fir. Ponderosa pine,

an important early seral species in many of the potential vegetation types, is currently under-represented

in the white fir and Douglas-fir potential vegetation

types (table 8). As a late seral species, it covers 84

percent of the ponderosa pine potential vegetation

type but is rarely found on any other. White fir dominates the white fir potential vegetation type, even

though ponderosa pine, quaking aspen, Douglas-fir,

and lodgepole pine are major seral species that can

exist on this potential vegetation type (Mauk and

Henderson 1984). In all potential vegetation types,

late seral species have greatest representation. With

the exception of lodgepole pine, ponderosa pine, and

quaking aspen potential vegetation types, these

conditions are unstable (Harvey and others in press)

(see section on “Trends and Risks to Habitat”).

Habitat Valuation Process

Forest cover type alone does not determine habitat

suitability for nesting goshawks or goshawk prey.

Stand structure, patch size, landscape features, woody

debris, snags, understory vegetation, openings, and

interlocking crowns are some of the habitat attributes

that are important for the goshawk and its prey (tables

1, 2, 4). Abundance of important prey species varies

with potential vegetation type (tables 3, 9). Each

vegetative polygon was evaluated by resource managers, as to its value for goshawk foraging and nesting

based on the presence or absence of these prey and

habitat characteristics. Each polygon was rated as

high, medium, or low quality in four categories: goshawk nesting habitat, small to medium-sized mammal habitat, woodpecker habitat, and other mediumsized bird habitat.

Nesting Habitat

Most high quality nesting habitat across all potential vegetation types occurs on the subalpine fir and

quaking aspen potential vegetation types (table 10;

fig. 3) . As would be expected, very little high quality

nesting habitat occurs on the pinyon/juniper potential

vegetation type. Within individual potential vegetation types, the subalpine fir, lodgepole pine, ponderosa

pine and quaking aspen are primarily composed of

Table 6—Possible forest cover types for each of the potential vegetation types.

Potential vegetation typesa

WF SAF P/J LPP ES PP QA DF

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Cover Typesb - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

PP QA P/J LPP ES PP QA DF

QA DF LPP/QA ES/LPP QA DF/QA

QA/M ES/LPP ES/SAF LPP LPP

DF ES QA PP

WF SAF SAF QO

LP LPP LPP/QA QA

LPP/QA LP

ES/SAF GO/QA

LP DF/PP/QA/LPP

CW

GO/M

a

Refer to footnotes in table 1 for potential vegetation type for definition.

b

Refer to footnotes in table 1 for cover type definition.

Table 7—The proportion of the current cover types found in

Utah forests and woodlands.

Current cover type Percent

White fir 6

Subalpine fir 8

Pinyon pine/Utah juniper 51

Lodgepole pine 2

Lodgepole pine/quaking aspen 2

Engelmann spruce 2

Engelmann spruce/subalpine fir 2

Engelmann spruce/lodgepole pine 4

Ponderosa pine 4

Cottonwood 1

Quaking aspen 9

Dougalas-fir 2

Douglas-fir/ponderosa pine/

Quaking aspen/lodgepole pine 0

Douglas-fir/quaking aspen 6

Gambel oak/big tooth maple 1

a

Refer to footnotes in table 1 for cover type definitions.
16 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Map 2—The distribution of current vegetation types in Utah as derived from Geospatial Analysis Processes data,

forest inventory and analysis data, and local knowledge. WF = White fir, SAF = Subalpine fir, P/J = Pinyon juniper,

LPP = Lodgepole pine, ES = Engelmann spruce, DF = Douglas-fir, CW = Cottonwood, GO = Gambel oak, MP = Maple,

PP = Ponderosa pine, LP = Limber pine, QA = Quaking aspen.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 17

Table 8—Proportion of each potential vegetation type currently in various forest cover types.

Current Potential vegetation typeb

Cover type WF SAF ES LPP PP DF QA P/J

- - - - - - - - - - - - - - - - - - - - - - - - Percent - - - - - - - - - - - - - - - - - - - - - - 

White fir 84 2 ------

Subalpine fir 1 45 - 2 6 - 3 2

Pinyon pine/Utah juniper - - - - - 99 - -

Lodgepole pine - - 14 2 - - - 16

Lodgepole pine/quaking aspen - 3 51 12 - - 2 -

Engelmann spruce - 12 1 18 ----

Engelmann spruce/subalpine fir - 8 - 49 ----

Engelmann spruce/lodgepole pine - 20 6 14 ----

Engelmann spruce/Douglas-fir - - - - - -2 -

Ponderosa pine 1 1 - 1 84 - 1 2

Cottonwood - - 2 - - 1 - -

Quaking aspen 2 4 11 2 9 - 84 -

Douglas-fir 3 3 2 - - - - 18

Douglas-fir/ponderosa pine/

quaking aspen/lodgepole pine 1 - 13 -----

Douglas-fir/subalpine fir - - - - - -1 -

Quaking aspen/subalpine fir - - - - - -1 -

Douglas-fir/quaking aspen - - - - - - - 61

Gambel oak - 1 - - - -42

Gambel oak/big tooth maple 10 -------

Gambel oak/quaking aspen - - - - - -3 -

a

Refer to footnotes in table 1 for potential vegetation type definition.

b

Refer to footnotes in table 1 for cover type definition.

Table 9—Occurrence of selected prey species in Utah potential vegetation types.a

Potential vegetation typeb

Prey species WF SAF ES LPP PP DF QA P/J

Mammals

Snowshoe hare - X X X - X X -

Red squirrel XXXXXX - -

Woodpeckers

Northern flicker XXXXXXXX

Three-toed woodpecker - X X X - X - -

Hairy woodpeckers and Williamson’s sapsuckers XXXXXXXX

Downy woodpecker - - - X X - X -

Red-naped - - - X - - X -

Other birds

Steller’s Jay XXXXXXXX

Ruffed grouse X - - XXXX -

Blue grouse XXXXXXX -

American robin XXXXXXXX

Mountain bluebird XXXXXXXX

a

Bird habitat information based on DeGraaf and others 1991; Red squirrel information based on Reynolds and others 1992; Snowshoe hare

information based on Dolbeer and Clark 1975, Koehler 1990, Koehler and Brittell 1989. b

Refer to footnotes in table 1 for potential vegetation type definitions.
18 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Table 10—Proportion of high, medium, or low nesting habitat

among the potential vegetation types.

Potential vegetation typea High Medium Low

- - - - - - Percent - - - - - - 

White fir 10 17 2

Subalpine fir 40 29 2

Pinyon pine/Utah juniper 0 0 91

Lodgepole pine 3 2 0

Engelmann spruce 1 2 1

Ponderosa pine 11 7 1

Quaking aspen 27 11 2

Douglas-fir 8 32 1

a

Refer to footnotes in table 1 for potential vegetation type definitions.

Figure 3—Quaking aspen is

one of the more important

forest types supporting goshawks in Utah both as a seral species and a long-term

persistent.

high value nesting habitat (table 11). Although nesting habitat is found in most potential vegetation types,

forests occurring on the subalpine fir and quaking

aspen potential vegetation types appear to be particularly suited for nesting. As would be expected, the

pinyon/juniper potential vegetation type was rated as

low value for nesting. No nests are known to occur in

pinyon/juniper habitats in Utah. The central mountains of the State have the greatest concentration of

high rated nesting habitat interspersed with medium

rated forest lands and bordered by the low rated

pinyon/juniper woodlands (map 3).

Foraging Habitat

Forests occurring on ponderosa pine, subalpine fir,

and quaking aspen potential vegetation types provide

Table 11—Proportion of each potential vegetation type in high,

medium, or low nesting habitat.

Potential vegetation typea High Medium Low

- - - - - - Percent - - - - - - 

White fir 31 52 17

Subalpine fir 55 39 6

Pinyon pine/Utah juniper 0 0 0

Lodgepole pine 58 34 8

Engelmann spruce 25 46 29

Ponderosa pine 54 32 13

Quaking aspen 64 25 11

Douglas fir 21 73 6

a

Refer to footnotes in table 1 for potential vegetation type definitions.

most of the high valued habitat for mammals (table

12). With the exception of the pinyon/juniper potential

vegetation type, most of the forests and woodlands of

Utah were rated high or medium for mammal habitat.

For both woodpeckers and other birds, the quaking

aspen potential vegetation type supports mostly high

rated habitat with only small amounts of low rated

habitat for any of the prey groups. The Engelmann

spruce potential vegetation type was rated medium

for woodpeckers and low for other birds. Fifty percent

of the forests on the ponderosa pine potential vegetation type were rated high for woodpeckers and 60

percent had a medium rating for other birds. Forests

growing on the white fir and Douglas-fir potential

vegetation types rated mostly medium as habitat for

each prey group.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 19

Map 3—Distribution of high, medium, or low value goshawk nesting habitat in Utah.
20 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

High value mammal habitat is well distributed

throughout the forests of the State especially through

the central mountains (map 4). This habitat quality is

likely related to the amount of cone producing trees

available and the amount of woody debris that occurs

in these forests. Forests and woodlands with a medium rating for mammal habitat are well distributed

across the State. Minor amounts of low value habitat

are located in east-central and southwestern Utah.

Similar to mammal habitat, high value woodpecker

habitat is also located in the central mountains (map 5).

Woodpecker habitat is usually good when snag densities are high, when both endemic and epidemic occurrences of insects and diseases are high. In contrast to

mammal habitat, there is much more low rated woodpecker habitat in pinyon/juniper woodlands. The largest concentration of medium valued woodpecker habitat was located in northeastern Utah. High value habitat

for medium-sized birds (other than woodpeckers) is

distributed north to south across the State (map 6).

High value habitat is interspersed with both low and

medium valued habitat throughout the State. A large

block of medium habitat for other birds is located in

east-central Utah. Forest grouse inhabit primarily

Douglas-fir and quaking aspen forests throughout the

State. Both quaking aspen and ponderosa pine forests

contain high numbers of songbirds. Engelmann spruce,

white fir, Douglas-fir, and lodgepole pine forests generally have lower numbers of songbirds except when

quaking aspen is present.

Combined Habitat Rankings

Nesting and foraging habitat ratings were used to

produce a combined goshawk rating for each of the

1,112 vegetative polygons in the State. Optimal habitat represents areas in the State in which mammal,

woodpecker, other bird, and nesting habitat were all

rated high. Optimal habitat would be expected to

consistently support breeding goshawks. If nests occurred in these areas, it is expected that they would

likely fledge young, even when annual fluctuations in

weather or prey reduce nest success in lower quality

habitats.

Goshawks are opportunists and able to adapt their

diet to take advantage of whatever prey species is

abundant in a given habitat and year (Squires and

Reynolds 1997). Therefore, to reflect this adaptability

we rated areas as “high value” if they were rated high

for nesting and also high for at least one prey group.

This combined habitat rating includes those areas

rated as “optimal” and areas where populations of one

or two of the prey groups are expected to be abundant.

While it seems intuitive that a variety of abundant

prey would be optimal, variety may be less important

than abundance. Therefore, habitats in which prey are

abundant but not necessarily diverse can still support

high densities of goshawks. Average nest productivity

may vary more from year to year in high value habitats

than in optimum habitats, since it includes some areas

where the prey base is limited to one species group.

However, long-term averages in goshawk densities

and nest success in optimum and high value habitats

may differ minimally.

Forty percent of the high value habitat and 25 percent

of the optimum habitat is located on the subalpine fir

potential vegetation type (table 13). The quaking aspen

potential vegetation type also contains high proportions of high value and optimum habitat. In contrast,

forests growing on the Engelmann spruce, white fir,

pinyon/juniper, and lodgepole pine potential vegetation types all had minimal amounts of high and optimum habitat. The majority of the high value habitat is

located in the central portion of the State (map 7).

Within the subalpine fir potential vegetation type,

54 percent is rated as high value habitat and 16 percent

rated optimum (table 14). Similarly, large proportions

of the quaking aspen and lodgepole potential vegetation

Table 12—The proportion of each prey habitat group rated high, medium, or low for each potential vegetation type.

Potential

vegetation Mammals Woodpeckers Other birds

typea High Medium Low High Medium Low High Medium Low

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Percent - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

White fir 44 53 2 58 27 15 9 71 19

Subalpine fir 79 18 2 57 36 6 22 41 37

Pinyon/Utah juniper 31 49 21 7 15 79 20 43 37

Lodgepole pine 57 42 1 50 48 2 62 25 12

Engelmann spruce 34 66 - 21 79 - 4 22 75

Ponderosa pine 76 24 0 50 27 23 21 60 19

Quaking Aspen 76 20 4 70 21 10 76 21 3

Douglas-fir 30 67 3 25 69 6 25 69 6

a

Refer to footnotes in table 1 for potential vegetation type definitions.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 21

Map 4—Distribution of high, medium, or low value small mammal habitat in Utah.
22 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Map 5—Distribution of high, medium, or low value woodpecker habitat in Utah.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 23

Map 6—Distribution of high, medium, or low value habitat for medium sized birds other than woodpeckers

in Utah.
24 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

types were rated as high or optimum habitat. The

majority of optimum habitat occurs in the center

portion of the State (map 8). These data show how

important the quaking aspen and subalpine fir potential vegetation types are in providing quality goshawk

habitat in Utah. Moreover, larger amounts of the

subalpine fir potential vegetation type could be growing quaking aspen.

Habitat Connectivity

Habitat is only connected and available to goshawks

if it is accessible from existing population centers.

That is, if the spatial distribution of habitat allows

each patch to be reached by individuals dispersing

from one or more adjacent patches. If every patch can

be reached and subsequently occupied, then all areas

would be considered connected. Connectivity has positive implications for population viability because it

allows juveniles to disperse from natal areas, and

allows individuals to emigrate to new areas when their

current habitat declines in value. Declines in habitat

value could be caused by stand-replacing fires, timber

harvesting, periodic lows in prey abundance, urban

encroachment, or other disturbances. Connected habitat ensures that individuals will be available to recolonize habitats or emigrate to new breeding territories throughout the State.

Distances involved in goshawk dispersal and habitat selection need to be determined prior to evaluating

connectivity (Keitt and others 1997). Perhaps the best

indication of connectivity is the distance goshawks

move from natal areas to adult breeding territories.

These distances can be determined by color-banding

nestlings or fledglings and then relocating them as

nesting adults. Several reports indicate that the dispersal distances of young goshawks range from 6 to 20

miles (Reynolds and Joy 1998; Woodbridge and Detrich

1994). Often, several years elapse between fledging

and relocation of adult birds, so the distances may be

the cumulative result of successive movements. In

addition, one banded female who fledged on the north

slope of the Uinta Mountains was found nesting 17

miles from her natal site (Ashley National Forest

1998b). Dispersal can also be estimated by observing

adults who breed on two or more spatially distinct

territories. Of the 19 reports of territory switching in

the contiguous Western United States, the distance

moved averaged less than 6 miles for both sexes

(Reynolds and Joy 1998; Woodbridge and Detrich 1994;

Younk and Bechard 1994b). In Alaska, female goshawks relocated to territories 27 miles apart (Iverson

and others 1996).

Winter movements of goshawks are considerably

longer. During the winter, female goshawks in the

Uinta Mountains usually move about 60 miles from

the last known nest site, but one female moved approximately 180 miles (Squires 1997). Adults in southern Wyoming were observed to winter in Colorado 116

miles from the nest sites (Squires and Ruggiero 1995).

In Alaska, after the breeding season, males have been

known to move 59 miles, females 34 miles, and juveniles up to 101 miles, with an average maximum

distance moved by juveniles of 39 miles (Iverson and

others 1996). These studies probably underestimate

winter movements because not all birds were relocated

and some may have traveled beyond the search radius.

Although goshawks are clearly capable of traveling

long distances to find suitable habitat, the previous

information indicates that 20 to 60 mile movements

are typical. Therefore, a maximum distance of 60

miles between patches of high value habitat would

represent a reasonable method of defining connectivity. We also restricted our definition to high value

habitat patches, even though goshawks may use

patches of low or medium quality as stepping stones

when dispersing from one high value patch to another.

This definition of habitat connectivity would conservatively ensure that goshawks will be able to disperse

freely throughout the State, always finding at least

high value habitat.

High value habitat in the State is well connected

except for two portions in the southwestern corner of

the State (map 9). Habitat in the LaSal and Abajo

Mountains were connected to each other. However,

they were separated by 66 miles from other high

valued habitat. Our analysis did not consider potential habitat in western Colorado, northern Arizona, or

northwestern New Mexico. It is likely these areas

could be well connected to these adjacent regions.

Table 13—Proportion of northern goshawk nesting habitat

rated as high and optimum in each potential

vegetation type.

Potential

vegetation

typea Highb Optimumc

- - - - - Percent - - - - - 

White fir 6 5

Subalpine fir 40 25

Pinyon/juniper 7 1

Lodgepole pine 3 5

Engelmann spruce 1 0

Ponderosa pine 10 7

Quaking aspen 26 44

Douglas-fir 8 13

a

Refer to footnotes in table 1 for potential vegetation type definitions.

b

High: Areas rated high as nesting habitat and high as habitat for one

or more prey groups (mammals, woodpeckers, and other birds). c

Optimum: Areas rated high as nesting habitat and high as habitat for

all three prey groups (mammals, woodpeckers, and other birds).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 25

Map 7—Distribution of high value goshawk habitat in Utah. Lands considered high value for nesting and high value

for at least one of the prey groups (mammals, woodpeckers, or other birds) were considered high value.
26 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Table 14—Proportion of the potential vegetation types with

high and optimum northern goshawk nesting habitat

ratings.

Potential

vegetation

typea Highb Optimumc

- - - - - Percent - - - - - 

White fir 19 7

Subalpine fir 54 16

Pinyon/juniper 3 0

Lodgepole pine 51 42

Engelmann spruce 22 2

Ponderosa pine 52 16

Quaking aspen 61 47

Douglas-fir 20 14

a

Refer to footnotes in table 1 for potential vegetation type definitions.

b

High: Areas rated high as nesting habitat and high as habitat for one

or more prey groups (mammals, woodpeckers, and other birds). c

Optimum: Areas rated high as nesting habitat and high as habitat for

all three prey groups (mammals, woodpeckers, and other birds).

of the soil is now close to the surface. In addition, the

crowns of late seral species are nutrient rich and

usually extend to the ground. Because of this, compression of the nutrients and microbiological attributes

accumulate near the soil surface where they are at

risk when these forests burn. In contrast, ponderosa

pine is deep rooted and has high crowns with relatively

lower nutrient content. So there is less risk to the

microbes and nutrients even if the forest is replaced.

Forests dominated by early seral species (especially

the pines) are, in general, more stable in both the

short- and long-term (Harvey and others in press).

In addition to forests in this potential vegetation

type being potentially unstable and at risk to fire, their

structural attributes make them undesirable for the

goshawk compared to more open ponderosa pine, Douglas-fir, or quaking aspen forests. As a result of currently dense stocking levels and multiple canopy layers, large trees for nesting would be limited. In addition,

dense, multistoried canopies would likely hinder foraging opportunities by obstructing flight and sight

lanes.

Subalpine Fir—The current vegetation of the subalpine fir potential vegetation type is dominated by

late seral species primarily subalpine fir and Engelmann spruce mixed with lodgepole pine (table 8).

These late seral species mixes are highly susceptible to

insect and disease epidemics, as exemplified by the

spruce beetle and balsam bark beetle mortality visible

in much of the potential vegetation type. Insect surveys conducted in 1996 indicate a large proportion of

the large trees in the potential vegetation type were

killed by beetles (Gardner and others 1997) (fig. 5).

This trend will likely continue, especially in areas with

a high dominance of Engelmann spruce. Without some

form of stand replacing disturbance, quaking aspen

and lodgepole pine, the two major early seral species of

the type, will continue to decline from their already

low representation. Quaking aspen occupies less than

4 percent of the potential vegetation type and lodgepole pine occurs on less than 1 percent of the area.

Quaking aspen is one of the most important cover

types supporting the goshawk in Utah. If quaking

aspen continues to decline in this potential vegetation

type, it will likely impact goshawks. Stand replacing

wildfires are an infrequent event in this potential

vegetation type but, with the large amount of dead and

down material found in this potential vegetation type,

intense and severe wildfires are an increasingly likely

possibility. Similar to the white fir potential vegetation type, wildfires in this type (because of the dominance of late seral species) would likely damage the

soil resource and might impair long-term productivity. In the absence of wildfire in this potential vegetation type late seral vegetation will likely increase beyond 45 percent of this area that it already occupies.

Trends and Risks to Habitat _______

Natural Threats

Forests are complex and dynamic. The potential

vegetation types of Utah range from subalpine fir to

pinyon/juniper. Each of these potential vegetation

types have a wide range of biophysical attributes that

result in a variety of stand structures and compositions influenced by a wide range of disturbance factors. These range from those induced by wind, snow,

ice, and fire to those that are human-caused. Landscapes of Utah are widely used by human habitation,

timber extraction, recreation, livestock grazing, and

are important sources of water. Because of these

current and potential disturbances, lands classified by

each of the potential vegetation types present their

own unique threats to the goshawk and to its habitat.

White Fir—The white fir potential vegetation type

is dominated by late seral species with over 80 percent

of the type occupied by white fir (table 8) (fig. 4). Even

though this type is capable of supporting ponderosa

pine and quaking aspen, only 3 percent of the potential

vegetation type was occupied by these early seral

species. Douglas-fir and ponderosa pine, also early

seral species, were highly prized lumber species and

many were removed in the late 1800’s and early

1900’s. Fires that historically burned in these forests

at intervals of 20 years or less now have potential to be

stand replacing. If the forests in this potential vegetation type were open and dominated by early seral species,

the fires would likely be of low intensity and severity.

Relatively shade tolerant late seral species tend to be

more shallow rooted than early seral species. Therefore, more of the nutrient and microbiological capital
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 27

Map 8—Distribution of optimum goshawk habitat in Utah. Lands that were considered high value for nesting

and high value for all of the prey groups (mammals, woodpeckers, or other birds) were considered optimum.
28 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Map 9—Connectivity of high value habitat patches (Lands considered high value for nesting and high value

for at least one of the prey groups (mammals, woodpeckers, or other birds) were considered high value)

showing connections. High value habitat was considered connected if an adjacent patch was within 60 miles.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 29

Figure 4—A dense forest of white fir and Douglas-fir growing on a white fir potential vegetation type.

These conditions are prone to stand replacing fires and epidemics of insects and diseases.

Figure 5—A typical stand of Engelmann spruce killed by spruce bark beetles. These conditions are of

low value for both goshawk nesting and foraging.
30 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

These subalpine fir dominated forests would provide

poor to marginal habitat as a result of cluttered

multistoried stands and lack of prey (except for the

snowshoe hare).

Lodgepole Pine—Lodgepole pine potential vegetation type covers only 1.3 percent of the State but it

is unusual in that, because lodgepole pine is normally

a seral species, there are only certain conditions that

allow it to persist over the long-term. There are few

other conifers that grow with lodgepole pine on this

potential vegetation type, making any threat to that

species a threat to forest cover. However quaking

aspen is a frequent seral species. Since the 1960’s bark

beetles have been very active in this potential vegetation type, killing large areas and opening many stands.

A large proportion of the potential vegetation type is

currently occupied by mid- to old-aged trees (table 15);

therefore the risk of additional insect related mortality is still high. In addition, some lodgepole pine stands

on this potential vegetation type are prone to develop

with high densities of slow growing trees. Historically,

lodgepole pine in this potential vegetation type was

affected by dwarf mistletoe and bark beetles, with fire

periodically regenerating the species. Much of this

potential vegetation type has been opened up by bark

beetles but it is regenerating to lodgepole pine under

the dead overstory. The present condition of the potential vegetation type appears to be part of normal cycle

and most stands will continue to develop naturally.

Surface fires that have frequented these forests could

once again thin the even-aged structure. In their

present form, most forests in this potential vegetation

type, with dead overstory trees and a dense young

understory, are good goshawk habitat. As the standing dead trees fall, they will decrease the habitat

value.

Engelmann Spruce—Engelmann spruce and subalpine fir mixed stands dominate this potential vegetation type. Similar to the white fir and subalpine fir

potential vegetation types, it is also dominated by late

seral species, subalpine fir and Engelmann spruce.

Also similar to other potential vegetation types where

quaking aspen is seral, only 2 percent of the type is

covered by quaking aspen but there is 12 percent of the

potential vegetation type covered by a mix of lodgepole

pine and quaking aspen. There is also a fair representation of lodgepole pine mixed with Engelmann spruce,

covering 14 percent of the potential vegetation type.

This potential vegetation type has a good mix of early

and late seral species. The current high proportion (79

percent ) of mid- and old-aged trees (table 15) make

these stands highly susceptible to infestations of spruce

bark beetles. Bark beetles tend to attack and kill large

trees within infested stands. As a result, nesting

habitat would likely be adversely affected. As the bark

beetle kills Engelmann spruce, however, there may be

enough of a seed source for the early seral species to

regenerate. It appears that, depending on the spatial

arrangement of the seral species in the long-term,

these forests will regenerate to a mixture of Engelmann spruce and early seral species. In the shortterm, forests growing on this potential vegetation type

will be susceptible to damaging wildfires but because

of their elevation, wildfires are likely to be infrequent.

Ponderosa Pine—Ponderosa pine dominates this

potential vegetation type even though Gambel oak, and

quaking aspen are important seral species (table 8).

Ponderosa pine is highly prized for its lumber; as a

result, the majority of the ponderosa pine potential

vegetation type has been partially cut, removing mature trees. Domestic livestock grazing, along with the

exclusion of fire, has disrupted native fire cycles and

probably contributed to the decrease of early seral

species. Ingrowth of small trees has created high,

large fuel loads in some areas, along with thick layers

of needles on the forest floor. However, this ingrowth

has not occurred to the same extent that it has occurred in other potential vegetation types. When fires

Table 15—Proportion of each potential vegetation type with various stand structures.

Current forest cover typea

Mid to old-agedc Interspersed oldd

Potential Vegetation Typeb ES LPP ES LPP

- - - - - - - - - - - - - Percent - - - - - - - - - - - - 

Subalpine fir 35 24 1 1

Lodgepole pine 7 79 5 7

Engelmann spruce 79 33 - -

Quaking aspen 2 2 - -

Douglas-fir - 16 - -

a

Refer to footnotes in table 1 for current cover type definitions.

b

Refer to footnotes in table 1 for potential vegetation type definitions.

c

Mid to old-aged forests with small patches.

d

Old-aged forest nterspersed with other structural stages.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 31

burn in these forests, trees can be killed and limited

soil damage is possible depending on the duration and

intensity of the fire. Stand-replacing fires are more

likely now, compared to the time prior to successful

fire exclusion. In some areas, root disease and bark

beetles are likely to stress and kill trees as a result of

the dense forest conditions. In the short-term, forests

growing on this potential vegetation type will probably continue to become more dense and more prone to

fire and disease, likely to adversely altering goshawk

foraging habitat. In addition, if large trees are not

produced, future nesting opportunities will be limited.

In the long-term, this type has the greatest potential

of all of the potential vegetation types in Utah for the

introduction of restorative mechanical and fire treatments. These treatments can clean stands, making

them more insect, fire, and disease resistant and

better goshawk habitat.

Quaking Aspen—The quaking aspen potential vegetation type covers 10 percent of Utah. Quaking aspen

stands dominate this potential vegetation type, occupying 84 percent of it. In addition, this potential

vegetation type and the quaking aspen it supports, are

some of the most valuable goshawk habitat in the

State. Many successional changes occur in the forb,

shrub, and grass layers as they respond to different

disturbances. But these changes are probably not a

great influence on habitat quality for goshawks. Since

quaking aspen is normally an early seral species, the

environmental conditions that make quaking aspen a

persistent species are unknown, but major disturbances might alter the environment, disrupting the

gradual and continuous regeneration. An important

characteristic of this potential vegetation type is that

the stands tend to be uneven-aged; quaking aspen

growing on other potential vegetation types tends to

be even-aged. The primary threats to quaking aspen

stands growing on this type are browsing by domestic

livestock and wild ungulates and stand-replacing fires

that are ignited from adjacent types. Without a major

disturbance or overgrazing, both in the short- and

long-term, these stands should remain relatively stable

and resilient.

Douglas-fir—Forests growing on the Douglas-fir

potential vegetation type are dominated by Douglas-fir

or Douglas-fir mixed with other species (79 percent)

(table 8). Less than 2 percent of the type is occupied by

ponderosa pine. The mixed species condition, as with

the other potential vegetation types, compresses nutrient and microbiological processes near the soil surface making them vulnerable to loss from wildfires

and some management activities. Because of multiple

canopies, live fuel loadings in many of these stands are

high and the structure facilitates the initiation and

spread of stand replacing wildfires. In addition to the

lack of ponderosa pine in this potential vegetation

type, there is an absence of quaking aspen, highly

important for goshawk habitat. Since European settlement, large ponderosa pine and Douglas-fir were frequently harvested in this type. Multiple canopies,

dominated by Douglas-fir, make the current conditions of this type very susceptible to root diseases and

insects. In the short-term, forests growing on this

potential vegetation type are relatively unstable and

prone to a wide range of stand replacing disturbances

including epidemics of insects and diseases. Similar to

stands growing on the ponderosa pine potential vegetation type, these too are good candidates for the

introduction of fire and restoration of seral species. In

the long-term, under active management to introduce

ponderosa pine and quaking aspen into the system,

these forests will become more stable and resilient. If

Douglas-fir continues to be the dominant species,

stands will continue to be unstable and decrease in

value for the goshawk.

Pinyon/Juniper—The pinyon/juniper potential

vegetation type covers approximately 50 percent of the

forests and woodlands of the State and is totally (100

percent) occupied by pinyon and juniper trees. No

recognizable amounts of early seral forbs, grasses, or

shrubs were evident from our assessment. No other

potential vegetation type is so dominated by the late

successional species. With this condition and the indeterminate successional pathways present in this type,

the short-term prognosis is a continued dominance of

pinyon and juniper. Throughout the State there have

been various attempts to transform many of these

woodlands to earlier successional stages with limited

success. Mechanical, chemical, and fire treatments

have been used to convert late seral pinyon/juniper to

grass, forb, and shrub communities (Everett 1987).

Post-treatment plant communities do not follow any

standard successional pathway and if a species is not

on the site at the time of disturbance, it will not be

there after the treatment (Everett 1987) (fig. 1). Moreover, these communities are susceptible to the introduction of exotics either intentionally or accidently.

The introduction of exotics also changes successional

pathways and makes future trends even more indeterminate. The introduction of cheatgrass (Bromus

tectorum) into this potential vegetation type has made

fires more intense, severe, and frequent. The resulting

fire cycle decreases the perennial shrubs, grasses, and

trees and increases the annuals that degrade the site

(West and Van Pelt 1987). Similar to the other potential vegetation types that are dominated by late seral

vegetation, the pinyon/juniper potential vegetation

type is unstable in the long-term, in this case because

of exotics and unknown successional pathways. In

Utah, there are no documented nests occurring in this

potential vegetation type but, because it occupies so

much of the State, it may be important to the goshawk,

especially as winter foraging habitat.
32 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Administrative Threats

Owners or administrators of the forests and woodlands of Utah include the USDI National Park Service,

USDI Bureau of Land Management, USDA Forest

Service, State of Utah, and private and Native Americans. Lands owned and managed by the different

entities are distributed throughout the State (map 10).

By far, the USDA Forest Service administers the

majority of the lands in these potential vegetation

types (table 16). Also, these lands contain the majority

of the high and medium valued nesting habitat

(table 17). The majority of the lands controlled by the

USDA Forest Service are important foraging habitat

for mammals and woodpeckers (table 18). The largest

proportion of high (60 percent) and optimum (56 percent ) value habitats are managed by the USDA Forest

Service with State, private, and Native American

entities managing smaller amounts (table 19). Lands

administered by the Federal agencies are managed by

laws, policies, and regulations that provide for the

protection and enhancement of wildlife habitat. Conversely, lands managed by State, private, and Tribal

entities are not controlled by such laws. Of the lands

administered by the State, 34 percent are rated as

high value habitat and 9 percent are rated as optimum

(table 20). On non-Federally administered lands there

is no assurance that they will be managed in a manner

which will be favorable to goshawks and their habitats. Activities on these lands that alter forest vegetation, such as timber harvest, fire, and livestock grazing, if not properly executed, could adversely affect

goshawk habitat at least for the short-term, and likely

for the long-term.

Threats From Management Activities

The subalpine-fir, white fir, lodgepole pine, ponderosa pine, and Engelmann spruce potential vegetation

types are primarily administered by the USDA Forest

Service (table 16). Private land owners control limited

amounts of the potential vegetation types, with the

exception of the white fir, quaking aspen, and Douglas-fir potential vegetation types where over 26 percent is controlled by private land owners. Because

there are minimal restrictions on the use of private

land, there are no assurances that goshawk habitat

will be sustained on these lands. Moreover, these

potential vegetation types are dominated by late seral

species prone to fire, insects, and disease. These are all

endemic processes that can have both positive and

negative effects to goshawk habitat. It is likely that

these lands will not be managed to reduce these

natural risks nor will they be managed to perpetuate

goshawk habitat.

The USDA Forest Service manages its forested lands

for a variety of objectives ranging from intensive forest

management to recreation (table 21). The largest

block of wilderness is in the Uinta Mountains in the

northeastern Utah (map 11). Range management is

emphasized (featured use or priority use) on 17 percent of the subalpine fir potential vegetation type and

4 percent of the white fir and Engelmann spruce

potential vegetation types. The majority of lands in

which range is emphasized are rated high or medium

for nesting (table 22). These lands are also good mammal habitat and rated medium for woodpeckers (table

23). In terms of overall habitat, 34 percent of lands

with a range emphasis (feature or priority use) were

rated as high value habitat and 17 percent were rated

as optimum (table 24). Of the high value habitat managed by the USDA Forest Service, 27 percent has a

range emphasis (table 25). This management direction potentially can decrease prey habitat by removing

cover and food for prey species. Indirectly it can interfere with fire regimes and native forest succession.

Depending on the intensity and duration, grazing

could be detrimental to goshawk habitat and in particular to aspen stands.

In general, timber management is emphasized on

25 percent or less of the subalpine fir, white fir, and

Engelmann spruce potential vegetation types (table 21).

Similar to where range is emphasized, the majority of

the lands where timber is emphasized is rated either

high or medium nesting habitat (table 22). These

lands are also excellent mammal habitat and moderately important for woodpeckers or other birds (table

23). Of the high valued habitat on USDA Forest

Service lands, timber is emphasized on only 20 percent

of the high value habitat and 18 percent of the optimum habitat (table 24).

Over 20 percent of subalpine fir and Engelmann

spruce potential vegetation types is in the mixed uses

management category. A variety of uses can occur on

these lands such as timber harvesting, livestock grazing and recreation. On these lands, the general standards and guides of the National Forest Plan applies,

and there is no single management emphasis. These

forests are managed within regulations and policies

that direct conservation and management of sensitive

species. Therefore, if proper management strategies

are implemented within these potential vegetation

types, forest management actions are not likely to

adversely affect goshawk habitat in the long-term.

The lodgepole pine, quaking aspen, and ponderosa

pine potential vegetation types are the only potential

vegetation types in Utah where the primary tree

species and the late successional species for the type

are the same. For the most part, lodgepole pine dominates the lodgepole pine potential vegetation type and
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 33

Map 10—Principle owners or administrators of the forest and woodlands of Utah. NRA = National Recreation

Area, NPS = National Park Service, Other = Other federal, PR = Private, NA = Native American, FS = Forest

Service, BLM = Bureau of Land Management, UT = State of Utah.
34 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Table 16—Proportion of each potential vegetation type managed by various administrative entities.

Potential vegetation typea

Entity WF SAF LPP ES P/J PP QA DF

- - - - - - - - - - - - - - - - - - - - - - - - - - - - Percent - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

Forest Service 55 61 77 60 10 54 48 28

Bureau of Land Management 8 10 2 - 60 21 4 19

State Of Utah 5 4 2 - 9 5 7 11

Native American 1 - 3 - 4 1 1 12

Private 26 15 4 - 12 8 38 28

National Park Service 2 - - - 3 5 - -

National Recreation Areas - - 1111 - -

a

Refer to footnotes in table 1 for potential vegetation type definitions.

Table 17—Proportion of land managed by various administrative entities

rated as high, medium, and low goshawk nesting habitat in Utah.

Entity High Medium Low

- - - - - - - - - percent - - - - - - - - - 

Forest Service 40 44 16

Bureau of Land Management 10 12 78

State 32 18 50

Native American 6 36 58

Private 26 30 44

National Park Service 9 7 83

Bankhead Jonesa 23 - 77

a

These lands were set aside to correct maladjustments in land use and thus

assist in control of erosion, reforestation, and protection of fish and wildlife by the

Bankhead-Jones Farm Tenet Act of 1937.

Table 18—The proportion of the high, medium, or low goshawk prey

habitat in for different owners or administrators.

Species High Medium Low

- - - - - - - - - percent - - - - - - - - - 

Mammals

Forest Service 58 37 5

Bureau of Land Management 35 46 19

State 31 59 10

Native American 10 80 11

Private 7 40 53

National Park Service 39 61 -

Bankhead Jones 64 36 -

Woodpeckers

Forest Service 47 40 14

Bureau of Land Management 72 20 9

State 18 34 47

Native American 5 53 42

Private 39 23 39

National Park Service 14 15 72

Bankhead Jones 23 5 72

Other birds

Forest Service 29 39 21

Bureau of Land Management 15 45 40

State 25 55 20

Native American 11 86 3

Private 40 43 17

National Park Service 45 25 30

Bankhead Jones 23 - 77
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 35

Table 20—Proportion of land managed by various administrative

entities rated as high value and optimum goshawk

habitat.

Entity Higha Optimumb

- - - - - percent - - - - - 

Forest Service 57 24

Bureau of Land Management 3 0

State 34 9

Native American 2 0

Private 7 5

National Park Service 4 4

Bankhead Jones 10 10

a

High: Areas rated high as nesting habitat and high as habitat for one

or more prey groups (mammals, woodpeckers, and other birds). b

Optimum: Areas rated high as nesting habitat and high as habitat for

all three prey groups (mammals, woodpeckers, and other birds).

Table 21—Proportion of potential vegetation type in various Forest Service management categories.

Management area Potential vegetation typea

categoryb PP QA WF SAF P/J ES LPP DF

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - percent - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

Non-forest 39 39 35 26 89 1 8 55

Wilderness 4 2 2 10 - 41 3 1

Administrative areas - - - 1 - 1 - -

Mixed use 16 18 18 23 4 30 16 9

Recreation emphasis 2 - - 1 - 1 2 -

Timber emphasis 13 11 25 18 - 22 58 11

Range emphasis 19 23 4 17 4 4 11 10

Private interface - 5 4 2 - - 2 13

Special use 1 1 - 1 ----

General direction (Dixie) 6 - 4 2 2 - - -

a

Refer to footnotes in table 1 for potential vegetation type definitions.

b

Explanation of management categories:

Wilderness—designated and proposed wilderness areas.

Administrative areas—variety of areas, from guard stations to municipal watersheds; usually in small parcels.

Mixed uses—currently achieving a variety of management goals, no change desired.

Recreation emphasis—concentrated recreation use and development.

Timber emphasis—provide opportunities for commodity production within ecological constraints.

Range emphasis—provide opportunities for livestock grazing within ecological constraints.

Private land interface—lands influenced by nearby private lands and managed cooperatively to meet resource objectives.

Special uses—activities conducted under special use permits, such as mining and summer homes.

General direction (Dixie)—management for a variety of resource conditions based on local objectives and priorities.

Table 19—Proportion of high and optimum value habitat

managed by various administrative entities.

Entity Higha Optimumb

- - - - - percent - - - - - 

Forest Service 60 56

Bureau of Land Management 12 5

State 6 7

Native American 1 0

Private 19 29

National Park Service 1 2

Bankhead Jonesc 0 0

a

High: Areas rated high as nesting habitat and high as habitat for one

or more prey groups (mammals, woodpeckers, and other birds). b

Optimum: Areas rated high as nesting habitat and high as habitat for

all three prey groups (mammals, woodpeckers, and other birds). c

See table 17 footnotes.
36 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Map 11—The major management categories for Forest Service administered lands in Utah.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 37

Table 23—Proportion of land in various Forest Service management catagories rated as high, medium, and low goshawk foraging

habitat.

Management area Mammals Woodpeckers Other birds

categorya High Med. Low High Med. Low High Med. Low

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - percent - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

Wilderness 54 44 2 38 50 12 28 32 40

Administrative areas 54 44 2 44 38 18 33 40 27

Mixed use 68 25 7 56 26 18 33 39 28

Recreation emphasis 32 68 0 26 26 48 74 24 22

Timber emphasis 75 22 3 55 42 3 34 46 20

Range emphasis 75 22 3 55 35 10 28 46 26

Private interface 54 41 5 60 22 18 68 30 2

Special use 86 13 1 80 13 7 65 22 13

General direction (Dixie) 38 25 37 34 15 51 39 51 10

a

See footnote, table 21, for management catagory definitions.

Table 22—Proportion of land in various management Forest Service

categories rated as high, medium, and low goshawk nesting

habitat.

Management

area categorya High Medium Low

- - - - - - - - - percent - - - - - - - - - 

Wilderness 33 50 16

Administrative areas 41 42 19

Mixed use 53 26 21

Recreation emphasis 66 7 27

Timber emphasis 47 49 5

Range emphasis 48 41 11

Private interface 50 32 18

Special use 75 17 7

General direction (Dixie) 24 24 52

a

See footnotes, table 21, for management category definitions.

quaking aspen dominates the quaking aspen potential vegetation type. These attributes make these

potential vegetation types unique. Similarly, quaking

aspen is the only early seral species on the ponderosa

pine type. The USDA Forest Service administers 77

percent of the lodgepole pine potential vegetation

type, over 45 percent of the quaking aspen and ponderosa pine potential vegetation types, and private owners control about 38 percent of the quaking aspen

potential vegetation type (table 16, Map 10). On the

proportion controlled by private owners there are

minimal restrictions on land uses so there are no

assurances that goshawk habitat will be sustained.

Over 75 percent of the lodgepole pine potential vegetation type is administered by the USDA Forest Service

with 58 percent managed with a timber emphasis. In

the quaking aspen and ponderosa pine potential vegetation types, less than 15 percent are managed with

a timber emphasis but over 15 percent of the types are

in the mixed use category. Of the lands managed for

a variety of uses, 53 percent are rated high for nesting

habitat and 68 percent high value for mammals

(tables 22, 23). Both mixed use and timber categories

are managed within the standards and guides of the

Forest Plans; if proper management strategies are

implemented, the impact on goshawks should be minimal. In the ponderosa pine and quaking aspen potential vegetation types, range use was emphasized in

over 15 percent of the area. Similar to the fir and

spruce potential vegetation types, livestock grazing

can change successional pathways and change fire

regimes. In particular, livestock and wild ungulate

grazing could retard and damage regeneration in the

quaking aspen potential vegetation type which depends on continual regeneration. This potential vegetation type is important because quaking aspen is the

only cover type and this tree species is widely used by

goshawks.
38 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Table 24—Proportion of land in various Forest Service

management categories rated as high and

optimum goshawk habitat.

Management area

categorya High Optimum

- - - - - percent - - - - 

Wilderness 23 8

Administrative areas 31 22

Mixed use 43 18

Recreation emphasis 10 4

Timber emphasis 39 18

Range emphasis 34 17

Private interface 41 39

Special use 67 54

General direction (Dixie) 20 0

a

See footnotes, table 21, for management catagory definitions.

Table 25—Proportion of high and optimum goshawk habitat

within Forest Service management categories.

Management area

categorya High Optimum

- - - - - percent - - - - - 

Wilderness 6 4

Administrative areas 0 1

Mixed use 35 30

Recreation emphasis 2 2

Timber emphasis 20 18

Range emphasis 27 28

Private interface 7 14

Special use 1 3

General direction (Dixie) 2 0

a

See footnotes, table 21, for management catagory definitions.

The majority (60 percent) of the pinyon/juniper potential vegetation type is administered by the Bureau

of Land Management with 15 percent or less privately

owned, administered by the State, or administered by

the USDA Forest Service. Because the successional

pathways are so indeterminate in this type, and the

majority of the type is occupied by late successional

species, management actions could easily cause declines in habitat quality. Exotic grasses have changed

the native successional pathways and disrupted the

native fire frequencies, severities, and intensities. All

these conditions indicate that the pinyon/juniper potential vegetation type will continue to experience

instability and invasion of exotics.

Recommendations ______________

In North America, goshawks nest in nearly every

forest type. Populations in Utah are similar in that

they nest in a broad range of vegetation types ranging

from subalpine fir to ponderosa pine. The forests and

woodlands of Utah that provide goshawk habitat are

diverse in species composition and structure. The

history of land-use is also highly variable with domestic livestock grazing occurring for 100 to 150 years and

timber harvest beginning in the late 1800’s. Tourism

and snow skiing have also become important land uses

along with timber and water production. With such

land uses came the desire to protect the forests and

woodlands from fire; effective fire exclusion began in

the mid-1900’s. As a result, the forests and woodlands

of Utah are now dominated by dense stands of late

seral species that are prone to epidemics of diseases

and insects. More important, many of the forests and

woodlands of Utah are prone to large-scale, standreplacing fire events. The condition of present day

forests is far different than those that occurred before

European settlement.

Conservation of the northern goshawk will require

the restoration and protection of degraded habitats

and protection of native processes. The following recommendations describe actions and long-term management strategies aimed at sustaining the habitat of

the goshawk and selected prey species for the forests

and woodlands of Utah. Synthesis of these attributes

can be used to define a desired habitat condition on a

particular site or landscape. The decision to apply

these recommendations is up to the specific private

land owner or administrator. Because these recommendations are directed at both habitat and native

processes, they will benefit a myriad of other plant and

animal species, not just goshawks. The recommendations are presented in two spatial scales. The first

spatial scale is the entire State of Utah and contains

general recommendations for achieving long-term goals

related to maintenance of goshawk habitat. The second spatial scale contains goals and recommendations

for specific potential vegetation types.

State of Utah Recommendations

The forests and woodlands of Utah are dominated by

unstable stands of late seral species. Early and midseral species should be increased using both mechanical means and fire.

Goshawk habitat throughout the State is well connected. These connections should be maintained and
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 39

strengthened. Activities near the edges of the high value

habitat should be designed to maintain or enhance

goshawk habitat values, irrespective of ownership.

Numbers and distribution of large trees in the landscape should be increased. Policies should be adopted

to manage for the production of large early seral

species through cleanings, thinnings, and weedings,

using mechanical means or fire. For a properly functioning system, approximately 40 percent of the landscape should be in large trees (relative to average for

the cover type and potential vegetation type) of a

variety of species (Quigley and others 1996; Reynolds

and others 1992; USDA Forest Service 1997).

It should be recognized that stands with a large

numbers of dead trees still have high habitat value for

goshawks in the short-term. Management activities

should be designed to maintain these structural attributes while facilitating the development of future

stands. Group selection or other similar treatments

might be preferred over clearcutting in order to maintain habitat values while decreasing the risk of loss

from windthrow or other similar disturbances.

Nest Sites—Both short- and long-term management activities should be planned to ensure that nest

sites contain large trees (relative to average for the

cover type and potential vegetation type) with open

understories and dense canopies (relative to average

for the cover type and potential vegetation type). Sites

near water are preferred and should be over 30 acres

(Reynolds and others 1992). Occupancy rate of nest

stands is positively correlated with stand size

(Woodbridge and Detrich 1994).

Foraging Areas and General Home Range—

Landscapes should include all of the attributes important for the goshawk and its prey such as: hunting

perches, large trees, grasses, forbs, shrubs, and interspersion of forest age/size classes (Reynolds and others 1992) in a variety of seral stages. A properly

functioning systems incorporates all these attributes

(USDA Forest Service 1997).

Potential Vegetation Type

Recommendations

In general, when the potential vegetation types of

Utah are in a proper functioning condition (USDA

Forest Service 1997) they will provide excellent habitat for the goshawk and its prey. The following recommendations highlight the necessity of managing forest

landscapes within their biophysical limits, and understanding how disturbances influence the resulting

stand compositions and structures.

Subalpine Fir—The subalpine fir potential vegetation type is capable of providing high quality goshawk and prey habitat. It is currently dominated by

late seral species throughout the State. Habitat should

be improved by promoting early seral species such as

quaking aspen, Douglas-fir, and lodgepole pine in a

forest mosaic with Engelmann spruce and subalpine

fir. These mixed forest cover types (especially mixes

with quaking aspen) would be highly used by the

goshawk and would have lower risk of epidemics of

insects and diseases, and stand-replacing fire. Fire or

mechanical treatments or both should be used to

create conditions favorable to lodgepole pine and quaking aspen. Treatments will be most effective if initiated where lodgepole pine and quaking aspen are still

present. Patch size can be variable in this type, tending to be large (10 to 100 acres) at lower elevations but

small (tree length in diameter) at the upper elevations.

Lodgepole Pine—Although the lodgepole potential vegetation type has a limited distribution in the

State, it is of high value to the goshawk (fig. 6). The

persistent lodgepole cover on this type is probably an

interaction of insects, diseases, and fire. Fires historically occurred at low frequencies, but over large areas

(hundreds to thousands of acres) (Bradley and others

1992). Treatments should be planned to ensure that a

lodgepole seed source is present to ensure rapid regeneration. Most likely, no other tree species with the

Figure 6—An active goshawk nest located in a

lodgepole pine stand experiencing high mortality.
40 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

exception of quaking aspen will be available to regenerate the sites. Where quaking aspen is a seral species,

it should be maintained. Openings can be large (up to

hundreds of acres) where serotinous cones are present,

but need to be small (25 acres) when nonserotinous

cones are present.

Engelmann Spruce—The Engelmann spruce potential vegetation type is similar to the subalpine fir

potential vegetation type, and mixed stands of early

and mid-seral species are excellent habitat. At the

higher elevations, openings for regeneration should be

small (tree length in opening diameter) being cognizant of the potential for wind damage. At the lower

elevations, patch size should be appropriate for effective regeneration of quaking aspen and lodgepole pine,

given site conditions and the availability of seed source

or clone.

Ponderosa Pine—Stands of ponderosa pine located on the ponderosa pine potential vegetation type

are often overly dense, containing numerous small

trees. Treatments should be planned to convert these

stands, occupied by small crowded stems, into open

stands dominated by large fire resistant trees (fig. 7).

Cleanings, weedings, and thinnings through mechanical means or fire could be used to create these conditions (fig. 8). Nonuniform, irregular tree spacing

should be encouraged. Quaking aspen regeneration

should be encouraged in this potential vegetation type

to add diversity and promote stability. The goshawk

recommendations developed for ponderosa pine by

Reynolds and others (1992) are applicable to this

potential vegetation type.

Quaking Aspen—Quaking aspen is the only cover

type that occurs on this potential vegetation type.

Unlike seral quaking aspen on other potential vegetation types, long persistent versions of this tree can

successfully regenerate under an existing canopy of

mature trees; therefore it often occurs in uneven-aged

stands. Treatments designed to stimulate quaking

aspen regrowth should take this into account, perhaps

by creating successive small openings rather than

large-scale overstory removals through fire or mechanical means. However, if stands are basically

healthy, there should be no need to treat quaking

aspen stands on this potential vegetation type.

Douglas-fir—The Douglas-fir potential vegetation

type supports a variety of forest cover types, including

lodgepole pine, quaking aspen, and ponderosa pine.

All are important to goshawks and they should be

regenerated in this type. Both fire and mechanical

means are appropriate for managing the array of early

and mid-seral species that are possible. This potential

vegetation type is currently dominated by dense,

multistoried stands of Douglas-fir that are unstable or

prone to epidemics of insects and diseases, and prone

to stand replacing fires. Treatments need to be planned

to rejuvenate stands without destroying the forest

structure important to the goshawk. For example,

group selection, group shelterwoods and variable

spaced shelterwoods along with stand maintaining

fires are all feasible options.

White Fir—The white fir potential vegetation type

is capable of supporting a wide variety of tree species,

including many that are important to goshawks (for

example, quaking aspen, ponderosa pine, Douglasfir). It has high potential as goshawk habitat. However, most of the type is presently occupied by multistoried stands dominated by white fir. These stands,

cluttered with many small limbs, reduce flight lanes

without providing perches or nest platforms for the

goshawk. Fire and mechanical means are also appropriate in this type for managing the array of early and

mid-seral species that are possible. Similar to the

Douglas-fir type, treatments should be planned to

introduce and maintain the seral species, yet not

eliminate the mature forest structure important to the

goshawk.

Figure 7—A stand containing large ponderosa pine

well suited for both goshawk nesting and foraging.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 41

Figure 8—Cleaning a ponderosa pine using prescribed fire.

Pinyon/Juniper—Although no nests have been

located in Utah, this potential vegetation type may be

important as winter foraging habitat. Currently, the

pinyon/juniper potential vegetation type is predominantly covered by late seral pinyon pine and juniper

trees. This potential vegetation type is prone to standreplacing fires and the introduction of exotic species.

The successional pathways of this potential vegetation type are indeterminate, and usually conditions

after disturbance are less stable than the current late

seral condition. It is believed to be useful for prey to

increase the other seral stages (for example, the open

shrubby stage). Early and mid-seral stages are productive and support many of the birds taken by goshawks, along with black-tailed jackrabbits (Lepus

californicus) and ground squirrels.

Assessment Questions __________

This assessment has attempted throughout these

pages to answer the questions initially posed in the

“Introduction” section. These questions are repeated

below with brief answers that synthesize the substantial, comprehensive information contained herein.

1. Is there adequate nesting habitat available?

Presently there appears to be adequate nesting

habitat in the State to maintain a breeding population

of goshawks. Based on the presence of habitat features

and cover types that are important to goshawks,

nearly all the montane forests of Utah are of either

high or medium value for nesting (map 3). The only

areas consistently rated as low value for nesting were

pinyon/juniper woodlands.

2. Is there adequate foraging habitat available?

Based on habitat features important to selected prey

used by goshawks, it appears that foraging habitat is

presently available throughout the State. Nearly all

the forested lands in the State contained mediumrated or better habitat for two or more prey groups.

Even much of the pinyon/juniper woodland type has

good prey habitat.

3. Are northern goshawks able to move freely

among all available habitat patches?

Goshawks appear to be able to move freely among

habitat patches throughout Utah. Using a conservative estimate of 20 to 60 miles as the distances over

which goshawks explore habitats annually, all patches

of high value habitat are likely to be detected from one

or more adjacent high value patches (map 9). In most

cases, the patches are contiguous or separated by

distances of less than 20 miles. The longest distance

between patches occurs in southeastern Utah, where

high value habitat in the La Sal and Abajo Mountains

is more than 60 miles from the nearest high value
42 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

habitat elsewhere in Utah. These areas are likely

connected to habitat in Colorado.

4. Is the population viable at the State level?

This assessment cannot answer the question of

population viability directly because there are inadequate demographic data available. Most of the currently forested lands were rated as medium or high

value for both nesting and foraging habitat. Where

surveys have been conducted, goshawks are present

and are nesting successfully. Furthermore, all available habitat patches are connected, and no known

population is isolated. In general, existing habitat

appears to be capable of supporting a viable population of goshawks at the State spatial scale. However,

even though high quality habitat does not appear to be

lacking at the State spatial scale, on the local landscape, habitat deficiencies may be present.

5. Where is the high value habitat?

High value habitat is distributed throughout the

State, with 60 percent controlled by the USDA Forest

Service (map 7, table 19).

6. How are current management policies affecting northern goshawks?

Current management policies are affecting northern goshawks in a variety of ways. On National Forest

Service administered lands, 20 percent of the high

value habitat is being managed with a timber emphasis, 35 percent with mixed uses, and 27 percent with a

range emphasis. Each of these management categories allows for activities that either can degrade or

improve goshawk habitat. The information in this

assessment does not reveal any substantial deficiencies in habitat quality in any management category

(tables 22, 23, 24, 25). There are two possible explanations for these results: (1) management activities

are having no negative effect on goshawk habitat;

(2) management activities are having some negative

effects on goshawk habitat, but the effects are not

detectable at either scale used in this assessment. No

data are available to determine which is the true

explanation. Current management policies have the

potential to degrade habitat if any one activity is overapplied or misapplied. For example, timber harvesting can convert mature stands to younger structures,

which can negatively impact goshawks. Range management can affect goshawks when it removes cover

and food for prey and when it interferes with the regeneration of quaking aspen stands. Both wild ungulates

and domestic livestock can browse suckers, and if

repeated frequently, quaking aspen clones can be replaced by other vegetation. In contrast, current management policies provide latitude for improving goshawk habitat if applied within reasonable ecological

constraints. For example, partial cutting systems

used to maintain or improve stand characteristics for

goshawks and their prey would have an overall positive effect on goshawk habitat. In addition, timber

harvesting has the potential to convert cover types to

earlier seral vegetative communities, which is generally good for goshawks. Thus current management

policies provide for a wide range of implementation

options, with a correspondingly wide range of possible

effects on goshawk habitat. The critical decisions are

those being made on individual project level analyses,

because this is where managers can use the best available information to ensure that projects are providing

for goshawk habitat needs.

7. What are the important habitat trends and

their implications for goshawks?

The most obvious trend in Utah forests and woodlands is the lack of early and mid-seral species in all of

the potential vegetation types. Existing stands on the

Douglas-fir and white fir potential vegetation types

are highly unstable and stands on the ponderosa pine

potential vegetation type are at high risk to standreplacing fire events. If forest management stresses

properly functioning condition, importance of large

trees, maintaining native processes, using adaptive

management, and recognizing the role of fires, the

habitat outlook could be favorable for the goshawk and

its prey. Development of procedures and techniques to

protect large trees during restoration treatments, and

to grow them at accelerated rates, will also help

improve the outlook for structural aspects of goshawk

habitat, especially in the ponderosa pine potential

vegetation type.

Urbanization and more intensive uses of the forests

by humans could degrade goshawk habitat, especially

on private lands. Private lands in Utah will continue

to be developed, making the lands administered by

Federal entities increasingly important for goshawks.

This trend could also affect the connectivity of the

habitat across the State.

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Watson, J. W.; Hays J. 1997. Prey remains from northern goshawk

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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999 47

Appendix A ____________________

Northern Goshawk Interagency Technical

Team

Russ Graham

Research Forester

Rocky Mountain Research Station, Moscow

Forestry Sciences Laboratory

1221 South Main

Moscow, ID 83843

Frank Howe

Non-game Avian Program Coordinator

Utah Division of Wildlife Resources

1594 W. North Temple

Salt Lake City, UT 84114-6301

Kathy Paulin

Wildlife Biologist

Ashley National Forest

355 North Vernal Ave.

Vernal, UT 84078

Rod Player

Wildlife Biologist

Manti-LaSal National Forest

599 West Price River Drive

Price, UT 84501

Ron Rodriguez

Wildlife and Rare Plant Program Leader

Dixie and Fishlake National Forests

82 North 100 East

Cedar City, UT 84720

Terrie Jain

Forester

Rocky Mountain Research Station, Moscow

Forestry Sciences Laboratory

1221 South Main

Moscow, ID 83843

Arlene Heap

GIS Specialist

Dixie National Forest

82 North 100 East

Cedar City, UT 84720

Jerry Sentz

Wildlife Biologist

Bureau of Land Management State Office

324 South State Street

Salt Lake City, UT 84111

Richard Williams

Wildlife Ecologist

Wasatch-Cache National Forest

8236 Federal Building

125 S. State Street

Salt Lake City, UT 84138

Marilet Zablan

Wildlife Biologist

U.S. Fish and Wildlife Service

Lincoln Plaza

145 East 1300 South, Suite 404

Salt Lake City, UT 84115

Northern Goshawk Technical Contributors

Tracy Abelson

Wildlife Biologist

Evanston Ranger District

1565 HWY 150 South Suite A

P.O. Box 1880

Evanston, WY 82931-1880

Mike Britten

National Park Service, Denver

12795 W. Alameda Parkway

Denver, CO 80228

Dan Arling

Wildlife Biologist

Ogden Ranger District

507 25th Street, Suite 103

Ogden, UT 84401

Stephen Blatt

Wildlife Biologist

Flaming Gorge National Recreation Area

P.O. Box 279

Manila, UT 84046

Lisa Church

Zone Wildlife Biologist

Fillmore Ranger District

390 S. Main

Fillmore, UT 84631

Sarah Dewey

Biological Technician

Ashley National Forest

355 North Vernal Avenue

Vernal, Utah 84078

Mark Madsen

Biological Technician

Dixie National Forest

82 North 100 East

Cedar City, UT 84720

Heather J. Musclow

Wildlife Biologist

Moab Ranger District

2290 S. West Resource Blvd.

P.O. Box 386

Moab, UT 84532

Jose Noriega

Wildlife Biologist

Powell Ranger District

P.O. Box 80

225 E. Center

Panguitch, UT 84759

Carol Nunn-Hatfield

Wildlife Biologist

Spanish Fork Ranger District

44 West 400 North

Spanish Fork, UT 84660

Kreig Rasmussen

Zone Wildlife Biologist

Fishlake National Forest

115 E. 900 N.

Richfield, UT 84701
48 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-22. 1999

Steve Romero

Wildlife Biologist

Price Ranger District

599 West Price River Dr.

Price, UT 84501

JoAnne Stenten

Wildlife Biologist

Teasdale Ranger District

P.O. Box 99

138 E. Main

Teasdale, UT 84773

Dave Stricklan

Wildlife Biologist

Pleasant Grove Ranger District

390 North 100 East

Pleasant Grove, UT 84602

Priscilla Summers

West Zone Wildlife Biologist

Dixie National Forest

82 North 100 East

Cedar City, UT 84720

Leslie Welch

Wildlife Biologist

Roosevelt and Duchesne Ranger Districts

Ashley National Forest

Roosevelt, Utah 84066

Matt Obradobich

Wildlife Biologist

Bureau of Land Management

Henry Mountain Field Office

Hanksville, UT

Ron Bolander

Threatened and Endangered Species Coordinator

Bureau of Land Management

Utah State Office

Salt Lake City, UT 84111

List of Reviewers

Dr. Pat Kennedy

Dept. Of Fishery and Wildlife Biology

Colorado State University

Fort Collins, CO

Dr. Clayton White

Department of Zoology

Brigham Young University

Provo, UT

Dr. Alan Harvey

Rocky Mountain Research Station

Moscow, ID

Dr. Wayne Shepperd

Rocky Mountain Research Station

Fort Collins, CO

Dr. Dennis Ferguson

Rocky Mountain Research Station

Moscow, ID

Ronald Balander

Bureau of Land Management

State Office

Salt Lake, UT

Steve Hedges,

Bureau of Land Management

Beaver River Resource Area

Cedar City, UT

Rebecca Bonebrake

Bureau of Land Management

Beaver River Resource Area

Cedar City, UT

Robert Cambell

Fishlake National Forest

Richfield, UT

Daniel Deiss

Dixie National Forest

Cedar City, UT

JoAnn Stenten

Dixie National Forest

Teasdale, UT

Jose Noriga

Dixie National Forest

Panguitch, UT

Priscilla Summers

Dixie National Forest

Cedar City, UT

Donald Fullmer

Manti LaSal National Forest

Price, UT

Randy Hickenbottom

USDA Forest Service

Intermountain Region

Ogden, UT

Steve Anderson

Humbolt-Toiyabe National Forest

Ely, NV

Sherel Goodrich

Ashley National Forest

Vernal, UT

Larry Johnson

Wasatch-Cache National Forest

Evanston, WY

Chuck Frank

Wasatch-Cache National Forest

Evanston, WY

Stephen Blatt

Ashley National Forest

Manila, UT

Doug Page

Unita National Forest

Heber City, UT

Dan Arling

Wasatch-Cache National Forest

Ogden, UT

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Telephone (435) 865-3700

FAX (435) 865-3791

Mailing Address Dixie National Forest

USDA Forest Service

85 North 100 East

Cedar City, UT 84720-2686
The United States Department of Agriculture (USDA) prohibits discrimination in

its programs on the basis of race, color, national origin, sex, religion, age, disability,

political beliefs, and marital or familial status. (Not all prohibited bases apply to all

programs.) Persons with disabilities who require alternative means for communication of program information (braille, large print, audiotape, etc.) should contact

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(TDD). USDA is an equal employment opportunity employer.

The Rocky Mountain Research Station develops scientific information and technology to improve management, protection, and use of

the forests and rangelands. Research is designed to meet the needs

of National Forest managers, Federal and State agencies, public and

private organizations, academic institutions, industry, and individuals.

Studies accelerate solutions to problems involving ecosystems,

range, forests, water, recreation, fire, resource inventory, land reclamation, community sustainability, forest engineering technology,

multiple use economics, wildlife and fish habitat, and forest insects

and diseases. Studies are conducted cooperatively, and applications

may be found worldwide.

Research Locations

Flagstaff, Arizona Reno, Nevada

Fort Collins, Colorado* Albuquerque, New Mexico

Boise, Idaho Rapid City, South Dakota

Moscow, Idaho Logan, Utah

Bozeman, Montana Ogden, Utah

Missoula, Montana Provo, Utah

Lincoln, Nebraska Laramie, Wyoming

*Station Headquarters, 240 West Prospect Road, Fort Collins, CO 80526