Northern Goshawk and Its 

Prey in the Black Hills: Habitat 

Assessment

Russell T. Graham

Shelley Bayard de Volo

Richard T. Reynolds

United States Department of Agriculture

Forest Rocky Mountain General Technical

Service Research Station Report RMRS-GTR-339 August 2015
Graham, Russell T.; Bayard de Volo, Shelley; Reynolds, Richard T. 2015. Northern 

goshawk and its prey in the Black Hills: Habitat assessment. Gen. Tech. Rep. 

RMRS-GTR-339. Fort Collins, CO: U.S, Department of Agriculture, Forest Service, Rocky 

Mountain Research Station. 177 p.

Abstract

The northern goshawk is classified as a Sensitive Species in all USDA Forest Service 

regions, including on the Black Hills National Forest in western South Dakota and northeastern Wyoming. An assessment was conducted of the quality of northern goshawk 

nesting and foraging habitat, along with the habitat quality of 22 of the goshawk’s prey 

species. A Delphi (expert panel) evaluation of goshawk and prey habitat in 3,414 watersheds averaging 449 acres (182 ha) in size was completed by wildlife biologists from the 

Black Hills National Forest. The quality of goshawk nesting and foraging habitat and of 

prey group habitats was reported individually, then combined for each watershed. The optimum goshawk and prey habitat, totaling 67 watersheds or 34,427 acres (13,932 ha), was 

distributed throughout the nearly 1.5 million-acre (about 607,000-ha) Black Hills National 

Forest. Panel members found that the Bear Lodge Mountains, located in northeastern 

Wyoming, proportionally had the most optimum, high-, and medium-rated habitat. Wildfire, 

bark beetles, urban encroachment, and timber harvest can negatively affect northern goshawks and their prey’s habitat. However, increasing the amount and presence of quaking 

aspen forests within the Black Hills will most likely improve the habitat of the goshawk by 

improving the habitat for many of its prey. Using previously articulated conditions as a template in the Forest Vegetation Simulator, we designed an example 100-year silvicultural 

system to create and maintain forest conditions for the northern goshawk and its prey on 

the Black Hills Experimental Forest.

Keywords: northern goshawk, Accipiter gentilis atricapillus, silviculture, forest structure, 

bark beetles, ponderosa pine, forest management.

Authors 

Russell T. Graham is a research forester (silviculturist) with the U.S. Department of 

Agriculture, Forest Service, Rocky Mountain Research Station, in Moscow, Idaho. His 

research activities include the role that coarse woody debris plays in forests, large-scale 

ecosystem assessment and planning, describing northern goshawk habitat, and developing forest management strategies (silvicultural systems) for a wide array of management 

objectives.

Shelley Bayard de Volo is an environmental coordination specialist for the Larimer 

County Engineering Department in Fort Collins, Colorado. She studied wildlife for several 

decades in California, Arizona, Colorado, and South Dakota. During her 15-year tenure 

with the Rocky Mountain Research Station in Fort Collins, Colorado, she assisted in studying demographic and habitat relationships for northern goshawks on the Kaibab Plateau, 

Arizona. She also determined genetic diversity for Kaibab goshawks and investigated 

genetic relationships for goshawk populations across North America. 

Richard T. Reynolds is a research wildlife biologist with the Rocky Mountain Research 

Station in Fort Collins, Colorado. He has investigated the relationship between the composition and structure of habitats as well as the demographic performance of apex avian 

predators in forested ecosystems for more than 40 years. His recent research focuses on 

relationships between individual and population demographics of northern goshawks and 

the structure and composition of their habitats in ponderosa pine and dry mixed-conifer 

forests on the Kaibab Plateau, Arizona.
Contents

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

Goshawks .............................................................................................. 9

Goshawk Habitats............................................................................ 10

Goshawks in the Black Hills............................................................. 17

Characteristics of Occupied Habitats in the Black Hills ................... 18

Assessment Methods ........................................................................... 23

Expert Panels .................................................................................. 23

Analysis ........................................................................................... 27

Results: Goshawk Habitat .................................................................... 28

Foraging Habitat .............................................................................. 31

Results: Prey Habitat ........................................................................... 31

Forest Generalists ........................................................................... 34

Hares and Rabbits ........................................................................... 38

Tree Squirrels ................................................................................. 40

Ground Squirrels ............................................................................. 41

Woodpeckers .................................................................................. 44

Woodrats ........................................................................................ 45

Combined Prey Habitat ................................................................... 45

Results: Goshawk and Prey Habitat ..................................................... 48

Goshawks and Their Prey in the Black Hills ........................................ 50

Factors Affecting Black Hills Goshawks .............................................. 53

Bark Beetles ................................................................................... 59

Wildfire Hazard ............................................................................... 64

Predation, Competition, and Disease .............................................. 66

Silvicultural System Simulation for Creating and 

 Maintaining Goshawk Habitat in the Black Hills ........................... 72

Discussion ........................................................................................... 80

Acknowledgments ................................................................................ 84

Literature Cited ..................................................................................... 85

Appendix: Natural History and Habitat for Selected Northern 

 Goshawk Prey Species ............................................................... 122

American Robin ............................................................................. 122

American Three-Toed Woodpecker ............................................... 124

Black-backed Woodpecker ........................................................... 128

Black-Headed Grosbeak................................................................ 131

i
ii

Bushy-Tailed Woodrat (Pack Rat) .................................................. 133

Cottontails ...................................................................................... 134

Gray Jay ........................................................................................ 138

Hairy Woodpecker ......................................................................... 140

Least Chipmunk ............................................................................. 144

Lewis’s Woodpecker ...................................................................... 146

Mourning Dove .............................................................................. 149

Northern Flying Squirrel ................................................................. 154

Red-headed Woodpecker .............................................................. 158

Red-naped Sapsucker ................................................................... 160

Red Squirrel ................................................................................... 163

Ruffed Grouse ............................................................................... 165

Thirteen-Lined Ground Squirrel .................................................... 169

Western Tanager ........................................................................... 170

White-Tailed Jackrabbit.................................................................. 172

Merriam’s Wild Turkey ................................................................... 173
USDA Forest Service RMRS-GTR-339. 2015. 1

Introduction

The years following World War II saw a dramatic increase in the need for 

lumber, and timber production became the dominant use on many national forest 

lands. In response to concerns of unequal emphasis on timber production, Congress 

passed the Multiple-Use Sustained-Yield Act of 1960 (MUSYA; P.L. 86-517), which 

authorized and directed that national forests be managed under principles of multiple 

use and to produce a sustained yield of products and services. However, commercial 

timber harvest continued to dominate Forest Service management; and in the Pacific 

Northwest, clearcutting was the harvest method of choice, often in old-growth forests, 

to the dismay of many environmental organizations (Wellock 2010). Additionally, 

the National Environmental Policy Act of 1969 required interdisciplinary teams to 

develop environmental impact statements (EISs) for federal forest planning, and the 

Endangered Species Act of 1973 (ESA; P.L. 91-135, 83 Stat. 275) brought the U.S. 

Fish and Wildlife Service (USFWS, a regulatory agency) into the discussion on how 

to manage public lands to conserve habitat for rare species and ecological diversity 

(Peck 2000). Nevertheless, not until passage of the National Forest Management Act 

(NFMA; P.L. 94-588) of 1976 was wildlife to be integrated into the management of 

national forest lands. Prior to the Act, big game, such as deer and elk (Cervidae spp.), 

and game birds, such as grouse and turkeys (Galliformes spp.) were often the only 

wildlife species considered in forest management, and good timber management was 

thought to represent good wildlife management (Wellock 2010). 

The northern spotted owl (Strix occidentalis caurina) was listed as threatened 

by the USFWS in 1990, and the loss of old-growth habitat was given as the primary 

reason. An Interagency Scientific Committee was formed to address the conservation 

of the owl and presented its recommendations in 1990 (Thomas and others 1990). The 

committee recommended that large tracts of old-growth forest be set aside for the owl 

in the Pacific Northwest. When implemented, the recommendations severely reduced 

the amount of timber being harvested and set a standard, if not a process, that could 

be used to address similar wildlife issues on National Forest System lands. In northern 

Arizona, Crocker-Bedford (1990) suggested that timber harvesting (cutting large trees) 

was causing declines in northern goshawk (Accipiter gentilis atricapillus; hereafter 

referred to as goshawk) populations similar to the effect timber harvesting was having on the northern spotted owl in the Northwest (fig. 1). Using this information, 

Figure 1—The secretive northern goshawk lives in 

northern-latitude forests around the world.
2 USDA Forest Service RMRS-GTR-339. 2015.

environmental organizations sought more extensive protection of goshawk habitat in 

Arizona and New Mexico, as the viability of the species could be threatened, which 

would violate NFMA (Kennedy 2003). 

In response to this perceived violation, the regional forester of the Forest Service 

Southwestern Region (Region 3, primarily Arizona and New Mexico) was asked in 

February 1990 to suspend all timber harvesting in goshawk territories until long-term 

survival of the species was assured (Peck 2000). That summer, the regional forester 

organized a scientific committee, similar to the one formed in the Northwest for the 

northern spotted owl, to review goshawk management needs in Region 3. In fact, 

at the first meeting with the regional forester, a copy of the northern spotted owl 

conservation strategy was offered to the committee as a model and potential process 

(Graham, personal communication). In 1992, Reynolds and others published their 

management recommendations for the goshawk in the Southwest, which did not 

include forest reserves (unlike the spotted owl strategy), and which suggested that 

goshawks are forest generalists whose populations are regulated by prey availability. 

Environmental groups and opposing state agencies continued to affirm that the species 

was an old-growth obligate that deserved protection under ESA. A 1991 petition to the 

USFWS to list goshawks as threatened or endangered within the western United States 

was denied on taxonomic grounds (Peck 2000). Since then, there has been periodic 

court litigation associated with goshawk listing or forest management actions that may 

affect the species. However, no changes in listing status for goshawks have resulted 

from subsequent petitions or the numerous court actions (Kennedy 2003). 

The U.S. Forest Service (USFS), in cooperation with each state as directed by 

NFMA, identifies sensitive species that may be significantly affected by national forest land and resource management. The purpose of classifying a species as “sensitive” 

is to provide special management attention and emphasis to help ensure the species’ 

viability on national forests and grasslands, as well as to preclude contributing to 

trends toward endangerment and, ultimately, the need for listing under the ESA. The 

goshawk is also regarded as a sensitive species in all Forest Service regions and a 

species of concern in all USFWS regions in the United States (Kennedy 2003). States 

also use such a designation, and both South Dakota and Wyoming list the goshawk as 

sensitive based on Natural Heritage Program rankings. This program indicated that 

breeding populations were rare in South Dakota, although abundant in some local 

locations. A non-breeding population was also defined as rare throughout its South 

Dakota range, meaning the goshawk was vulnerable to extinction (Kennedy 2003). 

As a result of these concerns and the concern that goshawk populations or habitat 

abundance could be decreasing within the Forest Service Rocky Mountain Region 

(Wyoming, South Dakota, Nebraska, Kansas, and Colorado), the goshawk was added 

to the region’s Sensitive Species list (Kennedy 2003). Management of forests containing listed species adds oversight by the USFWS involving biological assessments, 

consultation, and biological opinions (Goblea and others 1999). 

Straddling the Wyoming and South Dakota border in the USFS Rocky Mountain 

Region (Region 2) are the ponderosa pine (Pinus ponderosa)-dominated Black Hills 

(fig. 2), formed by a regional uplift of the Earth’s surface millions of years ago. About 

two-thirds of this elliptically shaped domal structure lies in South Dakota and the 

other third, the Bear Lodge Mountains, is located in northeastern Wyoming (fig. 3). 
USDA Forest Service RMRS-GTR-339. 2015. 3

Figure 2—Ponderosa pine forests dominate the Black Hills of western South Dakota 

and northeastern Wyoming.

Figure 3—Although most of the Black Hills National Forest occurs in the Black 

Hills of South Dakota, a portion also occurs in the Bear Lodge Mountains of 

Wyoming.
4 USDA Forest Service RMRS-GTR-339. 2015.

The Black Hills have a total land base of about 6,000 mi2 (15,540 km2)—125 mi from 

north to south and about 60 mi from east to west (200 by 96 km)—and goshawks 

have been known to occur throughout the area. White spruce (Picea glauca), quaking 

aspen (Populus tremuloides), and even limber pine (Pinus flexilis) and lodgepole pine 

(Pinus contorta) occur in the Black Hills. Nevertheless, nearly 1.5 million acres (about 

607,000 ha) of ponderosa pine dominate the forests of the Black Hills (Boldt and Van 

Deusen 1974; Shepperd and Battaglia 2002) (fig. 4). 

This amount of forest is remarkable in that the Black Hills have experienced 

more than a century of consumptive use (Boldt and Van Deusen 1974). During this 

period, virtually all of the area’s unreserved and operable forest acres have been cut 

over at least once, and many acres have received multiple partial cuts (fig. 5). Large 

tracts that were logged free of regulatory restraints prior to establishment of the Forest 

Figure 4—Ponderosa pine forests dominate the Black Hills vegetation, with a considerable 

amount of white spruce occurring in the north-central Black Hills and a variety of other conifers, hardwoods, meadows, and prairies comprising the remainder.
USDA Forest Service RMRS-GTR-339. 2015. 5

Reserve in 1897 were commercially clearcut and practically stripped of all trees large 

enough to yield a mine timber or a railroad tie. Persistent harvesting, coupled with the 

destructive impacts of wildfire, insects, diseases, and wind, have nearly eliminated the 

original old-growth stands on most of the commercial forest acres in the Black Hills 

and left only a few scattered old-growth remnants on the remaining acreage (Boldt and 

Van Deusen 1974; Walters and others 2013).

The unregulated harvest was controlled by the early 1900s, and for 50 years 

or so, a range of partial cutting systems was used to manage the forests, resulting in 

highly heterogeneous forests containing a wide variety of tree sizes arranged in a wide 

variety of mosaics (Harmon 1955) (fig. 6). However, wildfires burned and bark beetles 

and diseases killed trees during this period, adding complexity to the forests. In the 

1960s, forest management changed to more intensive practices that tended to develop 

two and three age classes or canopies in many forests (Boldt and Van Deusen 1974) 

(fig. 7). 

Figure 5—Timber harvesting commenced in the Black Hills in 1898 with Case 

One, the first commercial timber sale on federal property in the United States. 

The top photo shows Case 78 cutting in 1910, and the bottom photo shows tractor yarding near Moskee, Wyoming, in 1938. 
6 USDA Forest Service RMRS-GTR-339. 2015.

Figure 6—A variety of forest structures remained after the 

Boodleman area was harvested in 1911.

Figure 7—By the mid- to late 1960s, most harvesting in the Black Hills was done 

using two-step shelterwoods.
USDA Forest Service RMRS-GTR-339. 2015. 7

Despite these massive changes over the last 100 years, most of the area is forested and, in many areas, densely covered with trees, which can lead to large wildfires. 

The last few years have also seen an epidemic (wide spread) of bark beetles that are 

killing large expanses of the ponderosa pine forests (fig. 8). A key feature of these forests is the intermediate shade tolerance of ponderosa pine, which allows regeneration 

under partial shade as well as full sunlight. Ponderosa pine seed is produced almost 

every year, with abundant crops every 2 to 5 years (Boldt and Van Deusen 1974). 

Frequent rain showers throughout the growing season, which lasts from early March to 

August, is the major climatic factor contributing to the prolific growth and establishment of ponderosa pine (fig. 9). In response to the natural disturbances and because of 

the ease of regeneration and prolific growth that occurs in the Black Hills since Case 

One in 1898, the area has had one of the most consistent commercial timber harvest 

programs in the United States (Clow 1998; Freeman 2015). 

Figure 8—Since 

2010, mountain 

pine beetles have 

been killing large 

expanses of 

ponderosa pine, 

especially in the 

central Black Hills.

Figure 9—Because 

of the spring and 

summer rains in 

the Black Hills and 

abundant seed 

crops, ponderosa 

pine readily regenerates and carpets 

the forest floor in 

most locales.
8 USDA Forest Service RMRS-GTR-339. 2015.

Figure 10—Locations of goshawk nests discovered between about 1980 and 2010 in the Black 

Hills.

Regardless of the forest’s condition, interest in goshawk occupancy in the area 

has increased and concerns that timber management activities might disturb nesting 

and cause nest abandonment have grown (Kennedy 2003). However, goshawks have 

continued to nest, reproduce, and forage in these forests. More than 200 nests were 

discovered over the last 20 years that are in territories distributed somewhat uniformly 

throughout the Black Hills (fig. 10). However, as a sensitive species and given the 

years of disturbance and harvesting occurring in the Black Hills, some uncertainty 

remains as to the status of the goshawk and its prey’s habitat in the area (Klaver and 
USDA Forest Service RMRS-GTR-339. 2015. 9

others 2012). Although precise information on the goshawk and its prey is difficult to 

obtain owing to the species’ elusiveness and the expense of conducting nest searches, 

the habitats of the goshawk and its prey in the Black Hills can be assessed using expert 

knowledge via a Delphi process. Such processes are not as rigorous as scientifically 

sampling goshawks, their prey, and the habitats they each use but can be informative 

and provide relevant information for managers to make informed decisions regarding 

a sensitive species. Examples of major resource assessments using such panels include 

Quigley and others (1996), Graham and others (1999, 2000), and Shaw (1999). As 

such, there is a considerable legacy and background on conducting such assessments 

that provide a template for assessing the habitat of the goshawk and its prey in the 

Black Hills. 

Goshawks 

General Taxonomy and Distribution

The goshawk is a wide-ranging species that occupies most northern latitude 

forests circling the globe. This Holarctic distribution includes most boreal and temperate forests of Eurasia and North America (Squires and Reynolds 1997). The Eurasian 

goshawk (A. g. gentilis) consists of up to six subspecies while three subspecies have 

been variously accepted within the North American group (A. g. atricapillus). The 

northern goshawk (continental type, A. g. atricapillus) is the most widespread of the 

three North American subspecies, breeding from north-central Alaska to Nova Scotia, 

Canada, and south into eastern mixed deciduous and western montane forests of the 

United States and northern Mexico (Brown and Amadon 1968; Squires and Reynolds 

1997). Although it was previously described (Tavener 1940), the USFWS only recently recognized the Queen Charlotte goshawk (A .g. laingi) which occupies the coastal 

regions of southeast Alaska and British Columbia, Canada (American Ornithologists’ 

Union 1983; USFWS 2007, 2009). Goshawks inhabiting the Sky Islands (i.e., isolated 

forested plateau landforms surrounded by deserts) of southeast Arizona and northern 

Mexico were described as a third subspecies named Apache goshawk (A. g. apache) 

(DeBano and others 1995; Friedmann 1950; van Rossem 1930). Although the Apache 

goshawk is not formally recognized by the American Ornithologist’s Union or the 

USFWS, others consider them well differentiated and worthy of recognition (Snyder 

and Snyder 1991; Whaley and White 1994). 

Goshawks winter locally throughout their breeding range and as far south as 

southern California, northern Mexico, Texas, and the northern portions of the Gulf 

States and Florida (Johnsgard 1990). They typically winter close to their breeding 

territories in order to continue defending them. At times, however, they make shortdistance movements to lower elevations in the winter to hunt rabbits, hares (both are 

lagomorphs), ground squirrels (Spermophilius), and birds. Goshawks inhabiting the 

northern latitudes make southward irruptions (movements) on 10-year cycles when 

prey (specifically, grouse and snowshoe hare [Lepus americanus]) populations crash. 
10 USDA Forest Service RMRS-GTR-339. 2015.

Goshawk Habitats

Across their range, goshawks use a wide variety of forested habitats, including 

mixed hardwood and eastern hemlock (Tsuga canadensis) forests in the eastern United 

States, ponderosa and lodgepole pine-dominated and mixed-conifer forests of the 

Rocky Mountains and Pacific Northwest, ponderosa pine forests in the southwestern 

United States and Black Hills of northeastern Wyoming and western South Dakota, 

and fragmented stands of quaking aspen within open sagebrush (Artemisia spp.) 

steppe habitats of the Great Basin (Bartelt 1977; Bechard and others 2006; DeStefano 

and others 2006; Erickson 1987; Graham and others 1999; Hayward and Escano 1989; 

Patla 1997; Reynolds and others 1992; Speiser and Bosakowski 1987; Younk and 

Bechard 1994). As a forest-dwelling predator of small mammals and birds, goshawks 

build nests in well-defined forest structures that are surrounded by forests, providing 

protection and foraging opportunities for young goshawks (post-fledging family areas) 

(Reynolds and others 1982, 1984). Home range and foraging areas are located in a 

forest setting that will provide sufficient prey to support the typical goshawk family of 

one to four nestlings during the spring and summer months (Kennedy 2003; Reynolds 

and others 1992).

Nest areas

Nest areas include the nest tree and its immediate surroundings. They are often 

used for more than 1 year, and many nest areas are used intermittently for decades 

(Crocker-Bedford 1990; Reynolds 1983; Steenhof 1987). Nest areas are occupied by 

breeding goshawks from early March until late September and are the focus of all 

movements and activities associated with nesting (Reynolds 1983). Nest areas can 

include one or more forest stands and several alternative nest structures and can occur 

over a wide range of landforms (Palmer 1988; Reynolds and others 1992). Most nest 

areas are either on slopes with northerly exposures (northwest to northeast) or in drainages or canyon bottoms protected by such slopes. Goshawks nest in both deciduous 

and coniferous trees, including in Fremont cottonwood (Populus fremontii), quaking 

aspen, ponderosa pine, lodgepole pine, white spruce, Douglas-fir (Pseudotsuga menziesii), and subalpine fir (Abies lasiocarpa). Goshawks are thought to favor nest sites 

closely associated with forest openings such as meadows, forest clearings, logging 

trails, and dirt roads, but this is not always the case (Erickson 1987; Gromme 1935; 

Hall 1984; Hayward and Escano 1989; Reynolds and others 1982). Similarly, water 

proximity is a feature associated with many goshawk nests—nests in Colorado quaking aspen were often near running water and many South Dakota nests were within 

0.5 mi (0.8 km) of water. Like openings, however, nearby water is not always necessary (Bartelt 1977; Bond 1942; Hargis and others 1994; Reynolds and others 1982; 

Squires and Reynolds 1997).

Nest areas ranging in size from 20 to 25 acres (8 to 10 ha) vary in shape and are 

determined by nesting goshawk behavior. Nest areas usually contain relatively high 

tree canopy cover and a high density of large trees (Bartelt 1977; Crocker-Bedford and 

Chaney 1988; Daw and others 1998; Hall 1984; Hayward and Escano 1989; Kennedy 

1988, 2003; McGowan 1975; Moore and Henny 1983; Reynolds 1982; Reynolds and 

others 1982; Saunders 1982; Speiser and Bosakowski 1987). Although goshawks are 

considered habitat generalists at large spatial scales and use a wide variety of forest 
USDA Forest Service RMRS-GTR-339. 2015. 11

types, they tend to nest in a relatively narrow range of forest structural conditions 

(Erickson 1987; Hargis and others 1994; Palmer 1988; Reynolds and others 1982; 

Saunders 1982; Squires and Reynolds 1997; Squires and Ruggiero 1996). Goshawks 

appear to choose nest trees based on size and structure rather than species. In 

Wyoming and California, goshawks chose the larger trees in a forest to nest, however, 

in some eastern forests, nests were not always built in the largest tree occurring in the 

nest area (Saunders 1982; Speiser and Bosakowski 1989; Squires and Ruggiero 1996).

Although nest area canopy closure is often cited as an important habitat feature, 

the nest tree itself may be dead and offer little canopy cover (Dick and Plumpton 

1998; Squires and Reynolds 1997). Goshawks have been known to nest in dead eastern white pines (Pinus strobus), quaking aspens, and lodgepole pines (Kennedy 2003; 

Martell and Dick 1996; Porter and Wilcox 1941). Nesting in dead trees may often 

reflect the hawk’s fidelity to a nest that persists after the tree dies. The dense vegetation and sheltered slopes provide relatively mild and stable microenvironments, as 

well as protection from goshawk predators such as other goshawks, great-horned owls 

(Bubo virginianus), red-tailed hawks (Buteo jamaicensis), coyotes (Canis latrans), 

bobcats (Lynx rufus), raccoons (Procyon lotor), and humans (Moore and Henny 1983; 

Reynolds and others 1982). 

Goshawks typically construct their nests in the lower one-third of the crown 

within the nest tree (fig. 11). Nest height is a reflection of tree height but nests are 

typically located 30 to 40 ft (9 to 12 m) above ground level. Goshawks build nests 

on one or two branches near the tree bole (occasionally on a limb 3.2 to 6.6 ft [1 to 

2 m] from the bole) or in forks of the main stem (Bull and Hohmann 1994; Moore 

Figure 11—Goshawk nests are bulky structures of branches, lined with leaves, and placed in the 

lower portion of the tree canopy.
12 USDA Forest Service RMRS-GTR-339. 2015.

and Henny 1983; Reynolds and others 1982; Speiser and Bosakowski 1987). They are 

normally bulky structures of twigs and branches reaching up to 3 ft (90 cm) in height 

with outside diameters ranging from 1.5 to 4.0 ft (45 to 122 cm) and inside diameters 

of 0.75 to 1.75 ft (23 to 53 cm). Goshawk nests often contain shallow cups (e.g., 

≤ 9 inches [23 cm] deep) and are usually lined with such items as fresh tree boughs, 

dry or fresh leaves, grasses, mosses, feathers, clay, and bark chips (Allen 1978; Bull 

and Hohmann 1994; McGowan 1975; Peck and James 1983).

Goshawk breeding territories typically include one or more alternate nests, any 

one of which may be used over several years. Nests are usually located within 0.25 

miles (0.4 km) of each other; however they can be as close as 150 ft (46 m) or distributed over larger areas (Reynolds and Joy 1998; Reynolds and others 1994, 2005; 

Reynolds and Wight 1978; Speiser and Bosakowski 1987; Woodbridge and Detrich 

1994). As a group, alternate nests in a territory are thought to be surrounded by a 

post-fledgling family area, an area preferentially used by the adult female for foraging 

during the late nesting period and by fledged young during the 1 to 2 months they are 

dependent on the adults for food (Reynolds and others 1992; Wiens and others 2006). 

Post-fledging family area 

In radiotelemetry studies of the post-fledging behavior of goshawks, Kennedy 

(1989) and Kennedy and others (1994) described an area used by the adult female and 

young from the time the young leave the nest until they no longer depend on the adults 

for food. All the activities of young fledglings occurred in this area, centered near the 

nests, as the fledglings were dependent on the adults. However, as their flight skills 

improved, the fledglings moved over ever-larger distances from the nest (Kennedy and 

others 1994; Kennedy and Ward 2003). Reynolds and others (1992) defined this as the 

post-fledgling family area (PFA) and suggested that, for conserving this important part 

of a breeding home range through management, the desired forest structure is intermediate between the higher tree density of the nest area and the more open structure of 

prey habitats in foraging areas (Daw and DeStefano 2001; Reynolds and others 1992, 

2006). PFAs vary in size from 200 to 600 acres (81 to 243 ha) and may correspond 

to the territory (a defended area) of a pair of goshawks. Similar to the other spatial 

components of a goshawk breeding territory, the size and shape of PFAs often depend 

on local conditions. PFAs provide the young goshawks with protection from predators 

and sufficient prey for the adult female and for the fledglings to develop their hunting 

skills in the weeks before they disperse (Finn and others 2002; Kennedy 1989, 2003; 

Reynolds and others 1992). 

Reynolds and others (1992), following Kennedy (1989), developed the PFA 

concept, and several other researchers provided further evidence of an area around 

goshawk nests that reflects PFA conditions: McGrath and others (2003) in eastern 

Oregon and Washington; Johansson and others (1994) in Utah; Daw and DeStefano 

(2001) in Oregon; Penteriani and others (2001) in France; and Kennedy and others (1994) in New Mexico. (Note: some authors describe forest conditions in the 

“post-fledgling family area” while others describe conditions in a much smaller “postfledgling area” that is used by the fledglings alone.) The size of PFAs likely varied 

depending on local environments, availability of prey, predation risk and whether the 

adult female’s core area was included (Kennedy 2003).
USDA Forest Service RMRS-GTR-339. 2015. 13

Foraging area

Adult male goshawks consume about 3.7 ounces (103.5 g) of birds or 4.3 ounces 

(121.1 g) of mammals each day (Fischer and Murphy 1986). Using these estimates, 

a family of two adults and two fledglings would likely consume between 125 and 

150 pounds (57 to 68 kg) of birds and mammals during a typical 6-month breeding 

season. As with most raptors, males provide most of the food while females stay close 

to the nests—first to incubate eggs, then to brood and protect the young, and lastly to 

help provide her young with food (fig. 12). Therefore, home range size and habitat 

used by foraging goshawks is largely determined by the movements and activities 

of hunting males as they capture most of the required amount of prey to support the 

family. Goshawks hunt a wide variety of prey species, mostly medium- to large-sized 

birds (e.g., woodpeckers [Picidae spp.], grouse, jays [Corvidae spp.]) and mammals 

(e.g., squirrels, rabbits) or the larger prey available to forest-dwelling hawks (Kennedy 

2003; Reynolds and Meslow 1984; Reynolds and others 1992; Storer 1966) (fig. 13). 

Although the particular species represented in goshawk diets vary regionally, when 

prey are grouped into guilds (groups of animals with similar habitats, foods, and foraging behavior) there is surprisingly little variation across the North American goshawk 

range. For example, Steller’s jay (Cyanocitta stellari), blue grouse (Dendragapus 

obscurus), and golden-mantled ground squirrel (Citellus lateralis) are common in the 

diets of Rocky Mountain and southwestern U.S. goshawks, but in the eastern United 

States, these species are replaced by the blue jay (Cyanocitta cristata), ruffed grouse 

(Bonasa umbellus), and eastern gray squirrel (Sciurus carolinensis). In northern latitudes, goshawks eat snowshoe hares, which are replaced in more southern latitudes by 

black-tailed jackrabbits (Lepus californicus) and cottontail rabbits (Sylvilagus spp.). 

Figure 12—Nestling goshawks are protected by the female, while the male does most of the hunting, unless prey populations are low, requiring both parents to hunt.
14 USDA Forest Service RMRS-GTR-339. 2015.

Figure 13—Goshawks prey on a variety of small mammals (e.g., (A) red squirrels; (B) ground 

squirrels; (C) chipmunks; and birds such as (D) woodpeckers, and (E) young turkeys.

The size of nesting goshawk home ranges has been estimated by several 

techniques, including plotting the foraging radius as the distances between goshawk 

nests in which grouse leg bands were found and the locations where the grouse were 

originally banded; plotting distances from nests based on sight records; and plotting 

with radiotelemetry (Austin 1993; Bright-Smith and Mannan 1994; Craighead and 

Craighead 1969; Eng and Gullion 1962; Hargis and others 1994; Iverson and others 

1997; Reynolds 1983). Large prey such as rabbits and hares tend to have less dense 

(A) (B)

(C)

(E)

(D)
USDA Forest Service RMRS-GTR-339. 2015. 15

populations than smaller species, requiring goshawks to hunt over large areas in 

order to secure enough food for their family (Schoener 1983). Depending on habitat 

and estimation method, goshawk nesting home ranges in North America range 

from approximately 1,200 to 10,000 acres (approximately 500 to 4000 ha) (Austin 

1993; Hargis and others 1994; Iverson and others 1996; Kennedy and others 1994). 

However, 5,000- to 7,000-acre (about 2000 to 2800-ha) home ranges are typical for 

most western forests (Eng and Gullion 1962; Kennedy and others 1994; Reynolds 

1983; Reynolds and others 1992). This body size/home range size relationship is also 

noted with the sharp-shinned hawk (Accipiter striatus) as it feeds on small birds and 

has nesting home ranges of about 1,200 acres (485 ha), and with the Cooper’s hawk 

(Accipiter cooperii), which feeds on birds and mammals of intermediate size and has 

home ranges of about 4,000 acres (1620 ha) (Craighead and Craighead 1969; Meyer 

1987; Platt 1973; Reynolds 1983).

Telemetry studies attempt to determine what habitats goshawks use for foraging, 

but the species’ elusive behavior and rapid movements through its large home ranges 

makes it difficult to identify actual habitat use (if they are really hunting) (Reynolds 

and others 2006a). Goshawks hunt in forest types containing a broad range of forest 

structures (Austin 1993; Beier and Drennan 1997; Bright-Smith and Mannan 1994; 

Hargis and others 1994; Kenward 1982; Widén 1989). Their hunting success depends 

not only on prey density but also on habitat features that allow them to hunt (Widén 

1997). Goshawks are short-perch-short-flight predators (Widén 1997). That is, they 

search the immediate surroundings for prey in the lower vegetation column from tree 

perches (Reynolds and others 1984, 1992) for short periods (seconds) and then make 

short flights to new perches (Kenward 1982; Widén 1985). These foraging tactics may 

be a major factor influencing their preference for hunting in mature forests that contain 

mature-to-old large trees, high canopy base heights, and relatively open understories. 

These conditions provide abundant prey and perches, yet they are open enough to 

allow the goshawk to detect their prey, and to maneuver during attacks (Widén 1997). 

Most studies suggest that goshawks primarily hunt in mature and old forests, but they 

also use a variety of other forest age classes, structures, and compositions (Reynolds 

and others 2006a). Goshawks have been known to hunt in forest openings, along forest 

edges, and as they cross openings between woodlands (Kenward 1982). For example, 

the edge of quaking aspen groves intermingled with sagebrush is a condition favored 

by hunting goshawks in Nevada (Younk and Bechard 1994). It is also important to 

note that while some habitats may be avoided by foraging goshawks, those habitats 

may be important for prey reproduction (Boal and others 2003; Reynolds and others 

1991, 2006). 

Non-breeding season habitat 

Goshawk winter habitat use is not as well documented as breeding habitat but 

is likely to vary depending on prey availability. Prey availability is likely a key factor 

influencing whether goshawks overwinter within their nesting ranges or elsewhere 

(Squires and Reynolds 1997). For example, goshawk populations in Canadian boreal 

forests, where the primary prey is snowshoe hare and ruffed grouse, fluctuate as 

the populations of these prey vary on an approximately 10-year cycle (Doyal and 

Smith 1997; Mueller and others 1977). Following spring declines in hare and grouse 
16 USDA Forest Service RMRS-GTR-339. 2015.

populations, fall and winter goshawk populations also decrease. As these boreal forest 

goshawk populations decrease, goshawk numbers increase in southern Canada and 

the northern United States, suggesting that goshawks leave their northern territories 

to find better winter foraging to the south where hare and grouse populations do not 

cycle as strongly (Keith and Rusch 1988). During years when boreal grouse and hare 

numbers are high, fall-winter goshawk populations remain similar to summer populations, indicating goshawks winter within their breeding range.

Within the western United States, most radiotelemetry studies show that 

goshawks venture from their breeding ranges, but the regularity of such movements 

is unknown. In Wyoming, winter movements of four adult goshawks (two female 

and two male) were monitored with radiotelemetry. In all four cases, the goshawks 

moved south from their breeding territories 40 to 87 mi (65 to 140 km), and two were 

confirmed to spend their winters in southern locations and return to their breeding territories the following spring. One of the goshawks was confirmed killed, and another 

was not detected again until it returned to its breeding territory the following spring. 

Because these birds were followed for only 1 year, it is unknown as to whether their 

fall-winter movements south were normal migratory behavior or just seasonal wandering. As well, prey populations were not sampled, so causal effects are unknown. 

Fifteen goshawks (5 males, 10 females) from the Uinta Mountains in Utah 

were radio-tracked during the winters of 1998-1999 and 1999-2000, but only three 

goshawks were followed both years. Two males and nine females moved from their 

nesting area an average of 34 mi (55 km) during the winter and the three goshawks 

monitored for two winters traveled an average of 35 mi (57 km) from their nesting 

ranges during the winter (Stephens 2001). In two other Utah studies, goshawks were 

tracked with satellite telemetry (Sonsthagen and others 2006a; Underwood and others 

2006). Distance moved differed among individuals—where some remained resident 

on their breeding territories, some were semi-migratory (within 60 mi [100 km] 

from breeding site), and some were migratory (>60 mi [100 km] from breeding site). 

Goshawks that moved to lower elevation pinyon-juniper (Pinus edulis-Juniperus spp.) 

forests increased their home range size, presumably because prey abundance and 

availability was lower in these habitats (Sonsthagen and others 2006b). Pinyon-juniper 

habitat used by these hawks had high herbaceous cover and moderate shrub cover 

often intermixed with sagebrush- (Artemisia spp.) dominated openings. In addition, 

steep, forested ravines were frequently used by wintering goshawks in otherwise 

nonforested areas (Underwood and others 2006). In another study, 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. However, one adult female was relocated in pinyon-juniper woodlands approximately 10 mi (16 km) from her nest. Most fledglings remained near their nest 

sites. Transmitters from two fledglings were recovered in pinyon-juniper woodlands, 

apparently shed after dispersing. 

These studies showed that some goshawks move long distances to winter in 

areas away from their breeding sites, while most wintering goshawks apparently 

remain within or very close to their breeding territories. Why some goshawks depart 

their breeding ranges and others do not may have to do with territoriality combined 
USDA Forest Service RMRS-GTR-339. 2015. 17

with prey availability. Goshawks that remain resident may aggressively push intruding 

goshawks out of their territory, especially when prey becomes limited. As winter prey 

availability declines below some threshold, one strategy would be to move to everlower elevations in search of food. Another theory suggests that goshawks that depart 

their breeding ranges are exhibiting winter site fidelity, returning to areas where they 

survived their first winter (Harmata and Stahlecker 1993). 

Goshawks in the Black Hills

No mention of goshawks was made in George Bird Grinnell’s report to William 

Ludlow in the “Reconnaissance of the Black Hills of Dakota, 1874” (Grinnell 1875).

Their absence from the report, however, is not surprising considering that goshawks 

are an elusive species that are difficult to observe in their forested habitats. Over 

and Thomas (1921) noted the “goshawk was probably only a winter visitor in 

South Dakota,” but also noted that “it probably nests sometimes in our state.” On 

4 August 1939, a fledgling female goshawk was collected in Wind Cave National 

Park (Pettingill and Whitney 1965). ORNIS (http://www.ornisnet.org) and an online 

database of bird specimens in museum collections showed an adult female collected in 

November 1906 by H. Behrens near Hermosa, South Dakota. Pettingill and Whitney 

(1965) also collected goshawks in the Black Hills during fall and winter, furthering 

evidence that goshawks winter in the Black Hills. Because recently observed (since 

1973) wintering goshawks in the Black Hills were seen near known goshawk nest 

sites, it is possible that some of the historical wintering birds also nested in the area 

(Bakker 2005). (Note: We discovered an apparent error in Pettingill and Whitney 

[1965] as they reported a female collected on 27 November 1895 southeast of Hill 

City, South Dakota (Female No. 8840, University of Minnesota), whereas photos 

provided by the University of Minnesota’s Bell Museum of two collection tags on 

this goshawk indicated the bird was collected on either 27 November or 27 February 

1945.) 

More recently, Wild (1973) reported that members of the Wilson Society found a 

nesting pair of goshawks in June 1965 near Sylvan Lake in the central Hills. In 1972, 

Wild (1973) observed three nesting pairs of goshawks in the central hills (Lawrence 

County), and during 1973 and 1974, USFS personnel reported several additional nests 

(Bartelt 1977). During 1975 and 1976, Bartelt (1977) visited some of these same nests 

and discovered an additional seven nests, and he described the habitat conditions at 

these nest sites. During 1980 and 1981, Erickson (1987) studied the habitat at some 

of the same nests as Bartelt (1977) as well as at new nests. Combined, these reports 

totaled 45 known nests in the Black Hills. Bartelt (1977) noted in his summary that 

“goshawk nests had become unusually abundant in the forest since 1972.” Whether 

this “abundance” was observed because of recent goshawk population increases or 

because increased human activity (birding/timber sales/active nest searches, road access) facilitated increased detection is unknown. During a seven-year period (2003 to 

2009), the South Dakota Game, Fish, and Parks commissioned a systematic survey for 

breeding goshawks, which resulted in the monitoring of 53 nests, of which 35, or 66 

percent, fledged young (Knowles and Knowles 2009).
18 USDA Forest Service RMRS-GTR-339. 2015.

Characteristics of Occupied Habitats in the Black Hills

Goshawk nesting 

Surveys conducted by the Black Hills National Forest show that goshawk nests 

occur at all elevations but are most common between 4,000 and 6,000 ft (1200 to 

1800 m) (Burns, personal communication). Similarly, Erickson (1987) visited 45 nest 

sites that ranged in elevations between 5,085 and 6,299 ft (1550 to 1920 m). Both 

Erikson (1987) and surveys by the Black Hills National Forest show that nests were 

typically situated on gentle terrain, and Erikson (1987) measured slope angles ranging 

from 2.5 to 58.0 percent and averaging 12.6 percent (fig. 14). Similarly, Bartelt (1977) 

reported slope angles at nests ranging from flat to 10 percent. Nests are frequently on 

benches or bowl-shaped landforms in the upper one-third of mountain valleys. Nests 

occur on all slope aspects but are most common on northeastern and eastern facing 

slopes. Of the nests Erikson (1987) visited, 43 percent were on north- to northwestfacing slopes, 36 percent were on west-facing slopes, and 21 percent were on south-to 

southwest-facing slopes. Likewise, all of the nests Bartelt (1977) visited were on 

north-facing slopes and located near the top of a ridge. Such sites offer protection from 

winds and solar insolation, which appear to be an important factor in nest site selection 

(Reynolds and others 1982). Surveys by the Black Hills National Forest and Erikson 

Figure 14—In the Black Hills, goshawk nests are frequently located on 

gentle slopes, as pictured.
USDA Forest Service RMRS-GTR-339. 2015. 19

(1987) indicated that goshawk nests in the Black Hills were often associated with a 

forest opening. Bartelt (1977) described such openings as being 0.12 to 0.50 acres 

(0.05 to 0.20 ha) in size and were within 30 to 50 ft (10 to 15 m) of a nest. Erikson 

(1987) reported that 21 percent of the nests he visited to be near meadows and 79 

percent to be within 240 ft (73 m) of old logging roads. Of the 21 nests Bartelt (1977) 

studied, half were in the northern Black Hills where ponderosa pine is intermingled 

with quaking aspen and white spruce. 

Goshawk nests in the Black Hills were most often in ponderosa pine trees. 

Knowles and Knowles (2009) located 21 nest trees, all but one was ponderosa pine 

and one was a white spruce with a broken top. One nest was discovered in a quaking 

aspen tree that was interspersed with ponderosa pine trees. Of the approximately 

240 nests discovered on the Forest, nearly all occur in areas with trees exceeding 

9.0 inches (22.8 cm) in diameter at breast height (DBH) and many were built in trees 

larger than 16.0 inches (40.6 cm) DBH (Bartelt 1977; Burns, personal communication; 

Knowles and Knowles 2009). Bartelt (1977) noted that most nests were placed in the 

lower portion of the tree canopy or in the bottom one-third of the canopy, with nest 

heights averaging 45 ft (13.8 m) above ground level. 

Tree densities around nests ranged from 120 to 480 trees/acre (297 to 

1186 trees/ha), and basal area often exceeded 125 ft2/acre (28.7 m2/ha). These tree 

densities result in canopy cover that is rarely less than 50 percent and usually greater 

than 60 percent (Bartelt 1977; Burns, personal communication; Knowles and Knowles 

2009) (fig. 15). Not only does this canopy architecture occur around nests, but it 

Figure 15—Canopy cover around goshawk nests in the Black Hills is 

rarely less than 50 percent.
20 USDA Forest Service RMRS-GTR-339. 2015.

typically extends upslope from the nest toward the ridge top (if a slope exists). Nest 

areas can have fairly open to moderately dense understories and often have small 

groups of young trees or saplings less than 9 inches (23 cm) DBH in close proximity. Bartelt (1977) described the densities in these small groups to be less than 400 

trees/acre (162 trees/ha) of 40 ft (12 m) or shorter trees. Moreover, Erikson (1987) 

described nest sites as having uneven–aged, multilayered canopies with modest foliar 

height diversity. Snags, downed wood, and old stumps are key components of Black 

Hills nest areas (Bartelt 1977). For example, Knowles and Knowles (2009) found an 

average of 24 dead trees/acre (9.7 trees/ha) within 60 ft (18 m) of the 21 nest trees 

they visited. Erickson (1987) did not quantify the amount of decadence near the nests 

but said nest areas were characterized by abundant standing dead vegetation and much 

dead and down woody material. The effects of snags, logs, and woody debris on the 

“quality” of nest areas has not been reported but may simply reflect the decadence of 

the older forest sites preferred by goshawks for nesting. 

Year-round habitat is of great importance. In winter, goshawks may remain within 

their breeding season home ranges, expand their home ranges to include additional habitats 

during the winter, or move to established, separate winter ranges. Whether goshawks in 

the Black Hills remain in or depart from their breeding territories is unknown, but they 

have been reported in winter months at lower elevations in the Black Hills. It is unknown 

whether these observations were of local goshawks or immigrants. 

Goshawk prey

The species composition of prey in goshawk diets depends on the composition of the local bird and mammal populations and their relative abundances and 

availabilities to hunting goshawks (Reynolds and others 2006a). The mix of bird 

and mammal prey in the Black Hills is somewhat unique in that both eastern and 

western U.S. birds and mammals are represented (fig. 16). For example, Steller’s jays 

(Cyanocitta stelleri), golden-mantled ground squirrels (Callospermophilus laterali), 

and Williamson’s sapsuckers (Sphyrapicus thyroideus) are typical western U.S. prey 

items but are absent in the Black Hills fauna and absent in Black Hills goshawk diets. 

Instead, blue jays (Cyanocitta cristata) and red-headed woodpeckers (Melanerpes 

erythrocephalus), members of the local fauna, are common prey species in the Black 

Hills as well as elsewhere in the east where these species occur. Some prey species 

restricted to the western or eastern United States, but co-occur in the Black Hills, are 

the mountain cottontail (Sylvilagus nuttallii), eastern cottontail (Sylvilagus floridanus), 

Lewis’s woodpecker (Melanerpes lewis), and red-headed woodpecker (Melanerpes 

erythrocephalus). Prey occurring in both eastern and western U.S. forests and in the 

Black Hills includes the red squirrel (Tamiasciurus hudsonicus), ruffed grouse, northern flying squirrel (Glaucomys sabrinus), northern flicker (Colaptes auratus), hairy 

woodpecker (Picoides villosus), and American robin (Turdus migratorius). Black Hills 

goshawks prey on at least 33 different species of birds and mammals with 22 of those 

species considered potentially important. However, red squirrels, northern flickers 

(Colaptes auratus), ruffed grouse, gray jays (Periosoreus canadensis), young turkeys 
USDA Forest Service RMRS-GTR-339. 2015. 21

Figure 16—Prey species from both the eastern United States, including (A) eastern cottontail, and 

(B) blue jay, and the western United States, including (C) mountain cottontail, occur in the Black 

Hills.

(Meleagris gallopavo), and cottontail rabbits make up a substantial portion of the diets 

(table 1 and appendix). 

In the four studies that documented prey remains found at Black Hills nest sites, 

only the red squirrel was observed at all four. Of other mammals, least chipmunks 

were observed in three studies; thirteen-lined ground-squirrels, mountain cottontails, 

and white-tailed jackrabbits were observed in two; and flying squirrels were observed 

in one. For birds, ruffed grouse, wild turkeys, and American robins were observed in 

two studies; and northern flickers, black-backed woodpeckers (Picoides arcticus), and 

three-toed woodpeckers (Picoides dorsalis) were observed in one (table 1). Although 

these studies have small sample sizes, they demonstrate the range of prey species 

captured by goshawks in the Black Hills and, by extension, the variety of habitats 

the prey occupy and the variety of habitats where goshawks hunt. Nine years of line 

transect surveys of bird faunas include goshawk detections in a variety of habitats, 

including non-forested, burned, riparian, shrubland, grassland, and meadow habitats 

as well as quaking aspen, white spruce, old ponderosa pine, mesic ponderosa pine, and 

dry ponderosa pine forests (Giroir and others 2007; Hutton and others 2006; Panjabi 

2001; White and others 2010). The short-perch-short-flight hunting tactic utilized by 

goshawks is uniquely suited for hunting over large areas, which typically include a 

wide variety of habitats and is reflected in the diversity of prey species taken. 

(A) (B)

(C)
22 USDA Forest Service RMRS-GTR-339. 2015.

Table 1—Selected prey species for the Black Hills. Prey was grouped according to the 

habitats in which they occur, and a weight (1-3) was assigned to the group that was used to 

assess the value of the group in sustaining goshawks in the Black Hills. The habitats of high 

and medium important prey in a group are described in the Appendix.

 Species (Importance) Group Source1 Comments

(2) Heavy-bodied ground-feeding birds (Galliformes)

ruffed grouse High W, B Young and adults

wild turkey High W, B Young

sharp-tailed grouse Low WB Associated with meadows

domestic chicken Low WB Forest/urban interface

(2) Forest generalists

mourning dove Medium WB Forest/urban interface

rock dove Low K 

American robin Medium B, E, 

western tanager Medium WB 

black-headed grosbeak Medium WB 

Townsend’s solitaire Low E 

junco Low B, E 

gray jay Medium B 

(2) Hares and rabbits (Lagomorphs)

eastern cottontail Medium W 

mountain cottontail High B, K 

white-tailed jackrabbit High B, E 

(3) Tree squirrels

eastern fox squirrel Low W, B, E, K Associated with bur oak 

(Bear Lodge)

red squirrel High B 

northern flying squirrel Medium W, B

(2) Ground squirrels

least chipmunk Medium W, B, E, K High elevations, burned 

areas

thirteen-lined ground squirrel High B, E Soils suitable for burrowing

(2) Woodpeckers

American three-toed woodpecker Medium E 

Lewis’s woodpecker Medium WB 

northern flicker High E 

red-naped sapsucker Medium WB 

hairy woodpecker Medium WB 

red-headed woodpecker Medium WB 

black-backed woodpecker Medium E 

(1) Woodrat and other mammals

bushy-tailed woodrat Medium B Buildings, mining areas

black-tailed prairie dog Low WB 

masked shrew Low B 

voles Low B, K 

western harvest mouse Low B 

northern pocket gopher Low B 

1 W = Wild (1973), B = Bartelt (1977), E = Erickson (1987), K = Knowles and Knowles (2009), and WB = wildlife 

biologists. The checklist of birds and mammals for the Black Hills and the expert knowledge of the wildlife biologists 

on the Black Hills National Forest were used in conjunction with the authors’ knowledge to determine the presence 

and importance of the prey in the diets of Black Hills goshawks. 
USDA Forest Service RMRS-GTR-339. 2015. 23

Assessment Methods

Prey Identification

To assess goshawk prey habitats in the Black Hills, we first identified a suite 

of potentially important prey species (table 1). A checklist of birds and mammals for 

the Black Hills combined with the expert knowledge of the wildlife biologists on the 

Black Hills National Forests and the authors’ knowledge of goshawk diets and foraging ecology was used to estimate the potential occurrence and relative importance of 

the prey in Black Hills goshawk diets. We reviewed the relative importance of different bird and mammal prey species in goshawk diets throughout the Rocky Mountains 

and elsewhere, and compared and contrasted these diets with published Black Hills 

diets and Black Hills faunal lists. We reviewed literature on the likely relative abundances and availability of these species in the Black Hills and compared these to their 

occurrence in the diets of Black Hills goshawks (Bartelt 1977; Erickson 1987; Hansen 

and others 2011; Knowles and Knowles 2009; Mills and others 1995; Panjabi 2005; 

Pettingill and Whitney 1965; Rumble and others 1999; Turner 1974; White and others 2010; Wild 1973). To aid the assessment of current Black Hills prey habitats, we 

describe the distribution, habitat, diet, home range, and populations of prey species in 

the appendix. 

Expert Panels

A Delphi process for rating the quality of goshawk habitat in the Black Hills was 

a compromise of data resolution, expert availability, and time required to complete 

the assessment. We evaluated various spatial entities and scales that we thought would 

be appropriate. The Black Hills National Forest keeps extensive vegetative data that 

could be assembled in various sizes and units of different vegetative configurations, 

which we thought would be ideal. However, upon examining the map of such information, we found that the sizes, shapes, and descriptions of the data were highly variable, 

making it difficult to assess key habitat features for goshawks and their prey. From this 

evaluation, we tried different-sized watersheds as a sampling unit. The units (or polygons) needed to be small enough to provide sufficient resolution to distinguish tree 

species, tree sizes, aspect, slope, canopy cover, vegetation arrangements, openings, 

and juxtaposition of these elements but also be large enough to produce a number of 

sample units that could be evaluated in a reasonable timeframe. We settled on using a 

9th code watershed. Following is an example of this hierarchal watershed classification 

(USGS 2014): 

 1. Region—Missouri, 

 2. Subregion—Cheyenne, 

 3. Basin—Belle Fouche, 

 4. Subbasin—Redwater, 

 5. Watershed—Sand Creek, 

 6., 7. Subwatersheds—Cold Springs Creek and Idol Gulch, and 

 8., 9. Unnamed watersheds located along the Wyoming/South Dakota border south 

of Beulah, Wyoming, and east of Spearfish, South Dakota (fig. 17). 
24 USDA Forest Service RMRS-GTR-339. 2015.

Figure 17—Example of the hierarchal watershed classification used to identify watersheds in the United States. For 

example, level 1: Missouri, 2: Cheyenne, 3: Belle Fouche, 4: Red Water, 5: Sand, 6: Cold Spring, 7: Idol Gulch, and 

two smaller level 8 and 9 watersheds not shown on the map. As a result, the hierarchy can define any watershed. 

For this assessment, the 9th level or 9th code watershed was chosen.
USDA Forest Service RMRS-GTR-339. 2015. 25

The 9th code watersheds we used in our assessment ranged in size from 53 to 

1,270 acres (21 to 514 ha) and averaged 449 acres (182 ha). There is considerable 

variation in tree size, distribution, and associated vegetation from the southern to 

northern Black Hills. Therefore, we divided our assessment into four geographic areas 

that generally followed the boundaries of the four ranger districts located on the Black 

Hills National Forest: Bear Lodge Mountains (in Wyoming), Northern Hills, Mystic 

(central Black Hills), and Hell Canyon (southern Black Hills). This division resulted 

in 324 watersheds in the Bear Lodge Mountains area averaging 387 acres (157 ha) 

in size, 762 watersheds in the Northern Hills area averaging 487 acres (197 ha), 985 

watersheds in the Mystic area averaging 488 acres (195 ha), and 1,342 watersheds in 

the Hell Canyon area averaging 432 acres (175 ha) (fig. 18).

Figure 18—Distribution of the 3,414 9th code watersheds used in the assessment.
26 USDA Forest Service RMRS-GTR-339. 2015.

For the expert panel process, we arranged 10 days of workshops: two days 

for each of the four areas, one day of training, and one extra day. Eight Black Hills 

National Forest wildlife biologists familiar with goshawks and their prey were recruited to rate the physical and vegetative condition of each watershed relating to the 

goshawks and their prey individually and by prey group (guild) (fig. 19). The experts 

rated each watershed as high, medium, or low value for goshawk nesting habitat and 

foraging habitat and for providing high-, medium-, or low-rated habitat for seven prey 

groups: turkeys and grouse, forest generalists, hares and rabbits, tree squirrels, ground 

squirrels, woodpeckers, and woodrats (Neotoma spp.) (table 1). Workshops were held 

at central locations in each of the assessment areas to ensure we had local knowledge 

as well as wildlife biologists from throughout the Black Hills to do the rating. For each 

watershed, we provided a true-color aerial photo delineating watersheds and showing 

the current vegetation and detailed vegetative structure and composition, as well as 

the juxtaposition of roads, buildings, power lines, openings, and other germane habitat 

features. In addition to the photos, panelists (working in pairs) were provided with 

quantitative vegetative descriptions (e.g., tree size, trees/acre, basal area/acre, canopy 

cover, and tree species), slope angles, slope aspects, and elevations to help them judge 

the quality of the watershed related to goshawks and their prey. 

Figure 19—During the workshop, experts considered detailed data from each watershed in order 

to rate the quality of both goshawk and its prey habitats (Delphi process).
USDA Forest Service RMRS-GTR-339. 2015. 27

Analysis

Using the categories high, medium, and low to rate the habitat elements eliminated the possibility of the experts subdividing their ratings into proportions (e.g., 1.2 

or 2.5). After the ratings were completed, we translated the three categories into numbers in order to compute our composite ratings: high = 3, medium = 2, and low = 1. 

Based on the relative importance (considering each species’ frequency in diets and 

their average biomass) of a prey species in Black Hills goshawk diets, we considered 

the woodrat to have the lowest value, tree squirrels to be three times more important 

than a woodrat, and the other species to be two times more important than a woodrat. 

Using these values, we weighted the scores the wildlife biologists provided for each 

prey group in the watershed and summed the weighted values to give an overall value 

of each watershed’s biophysical characteristics related to providing prey habitat. 

Although prey habitat is important, we considered both goshawk nesting and foraging 

habitat to be more important and used the values of these two entities provided by the 

wildlife biologists as multipliers of the prey habitat in our final ratings. As a result, the 

overall goodness of a watershed for providing habitat for the goshawk and its prey was 

computed:

 PH = (TS × 3) + (RH × 2) + (TG × 2) + (WP × 2) [eq. 1]

+ (FG × 2) + (GS × 2) + (WR × 1)

Final score = (PH × GN) + (PH × GF) [eq. 2]

where:

PH = weighted prey habitat

TS = wildlife biologist watershed rating for tree squirrels

RH = wildlife biologist watershed rating for rabbits and hares

TG = wildlife biologist watershed rating for turkeys and grouse

WP = wildlife biologist watershed rating for woodpeckers

FG = wildlife biologist watershed rating for forest generalist

GS = wildlife biologist watershed rating for ground squirrels

WR = wildlife biologist watershed rating for wood rats

GN = wildlife biologist watershed rating for goshawk nesting

GF = wildlife biologist watershed rating for goshawk foraging

For example, watershed 596 located in the southwest section of the Hell Canyon 

area was rated by the wildlife biologists as having high tree squirrel habitat (3), medium rabbit and hare habitat (2), high turkey and grouse habitat (3), high woodpecker 

habitat (3), high forest generalist habitat (3), high ground squirrel habitat (3), and 

medium woodrat habitat (2). Goshawk nesting and foraging habitat were rated as high 

(3, respectively), therefore:

 PH = TS × 3 + RH × 2 + TG × 2 + WP × 2 + FG × 2 + GS × 2 + WR × 1 [eq. 1]

 39 = (3 × 3) + (2 × 2) + (3 × 2) + (3 × 2) + (3 × 2) + (3 * 2) + (2 × 1)

 Final score = PH × GN + PH × GF 234 = (39 × 3) + (39 × 3) [eq. 2]
28 USDA Forest Service RMRS-GTR-339. 2015.

This calculation was completed for all 3,414 9th code watersheds in the Black 

Hills. Final scores ranged from 28 (where the entire prey and goshawk habitat 

characteristics were rated as low) in many watersheds to 234 (watershed 596; equations 1 and 2). We arrayed the watersheds from the one with the highest score to those 

with the lowest and then computed the percentile distribution. From that, we defined 

both optimum goshawk and optimum prey habitat as watersheds with percentiles 

≥98 percent, high-rated as watersheds with percentiles ≥95 percent and <98 percent, 

medium-rated as watersheds with percentiles ≥50 percent and <95 percent, and lowrated as watersheds with percentiles <50 percent. 

Results: Goshawk Habitat

Nest Areas

Goshawk nest areas have a relatively high tree canopy cover and a relatively 

high density of large trees (Bartelt 1974; Crocker-Bedford and Chaney 1988; Hall 

1984; Hayward and Escano 1989; Kennedy 1988; McGowan 1975; Moore and Henny 

1983; Reynolds and others 1982; Saunders 1982; Speiser and Bosakowski 1987). 

Most nest areas are either on slopes with northerly exposures (northwest to northeast) 

or in drainages or canyon bottoms protected by such slopes. Studies suggest that the 

relatively dense vegetation in nest areas provides goshawks a relatively mild and 

stable microenvironment, as well as protection from predators (e.g., other goshawks, 

great-horned owls, red-tailed hawks, coyotes, bobcats, raccoons, and humans) (Moore 

and Henny 1983; Reynolds and others 1982). Nest areas are relatively small compared 

to the sizes of watersheds defined in this assessment. Therefore, a particular watershed’s medium or low rating for nest area habitat does not necessarily mean that it 

does not contain one or more 20 to 30-ac (8 to 12-ha) patches of high quality nest area 

habitat. Whether goshawks will nest in a particular watershed depends to a great extent 

on (1) the availability of a suitable nest area, (2) the location of its suitable nest area 

relative to the location of nests of neighboring goshawk pairs, and (3) the quality of 

surrounding goshawk foraging vegetation structures and prey habitats. 

A small amount of area within the Black Hills was rated as high-quality nest 

area habitat for the goshawk (fig. 20). The northeastern edge of the northern Hills 

stands out for its concentration of the limited high-rated nest area habitat as does the 

Bear Lodge Mountains area for its proportionally large amount of high-rated nest 

area habitat. Also, the Bear Lodge Mountains area has a good amount of contiguous 

medium-rated nest area habitat (fig. 21). The Jasper Fire area in the south-central 

Black Hills and the southern prairie areas also stand out for their extensive amount of 

low-rated nest area habitat (figs. 20 and 22).
USDA Forest Service RMRS-GTR-339. 2015. 29

Figure 20—The northeastern perimeter of the Black Hills has a concentration of high rated (shown in red) goshawk nesting habitat.
30 USDA Forest Service RMRS-GTR-339. 2015.

Figure 21—The Bear Lodge Mountains contained a large portion of the habitat rated as moderate and high for 

nesting, as typified by large and closely spaced trees.

Figure 22—The area burned by the Jasper Fire in 2000 resulted in low-rated goshawk habitat but transitory 

woodpecker habitat. 
USDA Forest Service RMRS-GTR-339. 2015. 31

Foraging Habitat

Limited radiotelemetry evidence suggests that goshawks prefer mature forests 

for foraging. For example, Fischer (1986) found that a radio-tagged male in Utah preferentially foraged in “mature” Douglas-fir/white fir (Abies concolor) stands. Widén 

(1989), studying radio-marked goshawks in winter in intensively managed conifer 

forests in Sweden, found that both sexes of goshawks preferentially foraged in forests 

greater than 60 years of age. However, age is not always a good indicator of forest 

structure or tree size (Reynolds and others 1992). Habitats used for foraging by goshawks in North America have been documented in a small number of telemetry studies 

(Austin 1993; Beier and Drennan 1997; Boal and others 2002; Bright-Smith and 

Mannan 1994; Hargis and others 1994). These studies suggest goshawks select foraging areas with specific structural attributes, including old or mature forest stands with 

open understories, relatively high densities of large trees, and relatively high canopy 

cover. It is possible, however, that actual foraging habitat selection occurs at spatial 

and temporal scales difficult to investigate using radiotelemetry (USFWS 1998). Small 

openings, tree fall gaps, edges, riparian zones, and rock outcrops are examples of 

small-scale landscape elements that may be important to foraging goshawks (Squires 

and Reynolds 1997). A measure of foraging habitat quality is the co-location of vegetation structural attributes that compliment goshawk hunting behavior with abundant 

prey. Prey abundance may be higher in areas with a diversity of habitats supporting a 

diversity of prey species. 

Proportionally, the Bear Lodge Mountains have more high- and medium-rated 

goshawk vegetation structural attributes suitable for foraging than any other place in 

the Black Hills (fig. 23). Similarly, the area near Mount Rushmore is high-rated for 

foraging, and the majority of the northern Hills have a medium rating for foraging 

(figs. 23 and 24). The Jasper Fire area is an area of low-rated structural attributes for 

foraging. The southern Hills contains a small amount of high-rated foraging structures 

and a modest amount of medium-rated foraging structures, very likely because of 

islands of forest intermixed with the prairie (fig. 23).

Results: Prey Habitat 

Grouse and Turkey

Turkeys and grouse (Galliformes) are an important food source for goshawks in 

the Black Hills. These ground-dwelling birds are in the larger size class of goshawk 

prey and return a lot of biomass for the energy the goshawks expend in capturing 

them (fig. 25). Given the opportunity, goshawks will prey on young wild turkeys. 

However, adult turkey hens can be an effective deterrent against predation through 

grouping of their young and aggressive behavior toward hunting goshawks (Lehman 

2003; Reynolds, personal observation). Nevertheless, Rumble, who studied Merriam’s 

turkeys (Meleagris gallopavo Merriami) in the Black Hills, witnessed a goshawk 

preying on young turkeys (4 weeks old) as they flew from their roost. He noted that 

the goshawk failed in its first attempt to catch a turkey but was successful with its 

second attempt and flew off, with extreme difficulty, downhill with the young turkey 

in its talons (Rumble, personal communication).
32 USDA Forest Service RMRS-GTR-339. 2015.

Figure 23—The Bear Lodge, northwestern Black Hills, and the area on the eastern edge of the central Black Hills contained the 

majority of the high-rated goshawk foraging habitat. The Northern Hills and Bear Lodge Mountains areas were also dominated by 

medium-rated foraging habitat.
USDA Forest Service RMRS-GTR-339. 2015. 33

Figure 24—The area around Mount Rushmore and especially to the west was high-rated for goshawk foraging habitat.

Figure 25—Young turkeys (A) and ruffed grouse (B) are some of the larger prey that goshawks kill in the Black 

Hills. 

In the Black Hills, Rumble and Anderson (1993) studied radio-tagged turkeys 

over a 3-year period (1986 to 1989) and described their habitat. They found that 

ponderosa pine forests with moderate (41 to 70 percent) and high (71 to 100 percent) 

canopy cover were used year-round. During spring and summer, turkeys’ use of 

moderate canopied pine habitats increased, after which they switched to more closed 

canopy habitats during fall and winter. Overall, use of ponderosa pine habitats with 

low (0 to 40 percent) canopy cover was minimal but increased in the summer when 

turkeys foraged on grass seeds, which were abundant in open habitats. 

(A) (B)
34 USDA Forest Service RMRS-GTR-339. 2015.

Across most of their range, ruffed grouse are strongly associated with quaking aspen forests and woodlands (Rusch and Keith 1971a; Rusch and others 2000; 

Wiggins 2006). Forests containing mosaics of openings and young (especially quaking 

aspen) to old forest structures provide both cover and foraging opportunities for ruffed 

grouse, especially if those areas are contiguous across the landscapes rather than 

isolated fragments (Bump and others 1947; Rusch and others 2000). Small openings 

(<1.0 acre [0.4 ha]) containing herbs, forbs, and fruit-bearing shrubs provide important 

brood foraging habitat, and patches of mature forest provide thermal cover during 

winter (Sharp 1963). Within the Black Hills, ruffed grouse are more prevalent in the 

Bear Lodge Mountains and northern Hills. These areas often have ponderosa pine 

forests interspersed with small groves of quaking aspen and bur oak (Quercus macrocarpa), valleys with mixtures of paper birch (Betula papyrifera) and hazelnut (Corylus

cornuta), and riparian corridors (White and others 2010). Turkey and grouse habitat in 

ponderosa pine forests may be optimal for goshawk hunting where trees occur in small 

groups or patches with closed canopies (interlocking tree crowns) that are separated by 

small grass-forb-shrub openings (Reynolds and others 1992, 2006). 

The very northern portion of the Black Hills offers the largest amount of habitat 

for these heavy-bodied, ground-feeding birds as it is typified by open prairie meadows 

intermixed with ponderosa pine. Also, the Bear Lodge Mountains proportionally 

have some of the larger amounts of turkey and grouse habitat in the Black Hills. This 

is likely related to the high amount of bur oak, which supplies the favored food of 

acorns, as well as a mixture of meadows and even grain fields present on the ridge 

tops. As a result, nearly all of the Bear Lodge Mountains are medium- and high-rated 

for grouse and turkey habitat. However, young turkeys are the most likely prey resource and would only be available during the nesting season, while grouse would be 

available year-round (fig. 26). 

Forest Generalists

Forest generalists include American robins (Turdus migratorius), mourning 

doves (Zenaida macroura), and other small birds. In general, such species are of 

medium importance in goshawk diets. The wide-ranging American robins inhabit 

woodlands, hardwood and coniferous forests, riparian areas, shelterbelts, wooded suburban areas, gardens, agricultural lands, and parks and lawns interspersed with shrubs. 

In the Black Hills, robins are typically found wherever there are trees. Robins use 

ponderosa pine, white spruce, quaking aspen, and bur oak forests in various combinations and amounts (Franzreb and Ohmart 1978; Panjabi 2001; Pettingill and Whitney 

1965; Sallabanks and James 1999; Savard and Falls 1981; Siegel 1989; Stauffer and 

Best 1980; Yahner 1983) (fig. 27). 
USDA Forest Service RMRS-GTR-339. 2015. 35

Figure 26—The Bear Lodge, northwestern Black Hills, and southern Black Hills stand out as areas having high-rated turkey and 

grouse (Galliformes) habitat.
36 USDA Forest Service RMRS-GTR-339. 2015.

Western tanagers (Piranga ludoviciana) occur throughout the Black Hills, 

particularly at the lower elevations. They are most abundant in the southwestern 

Black Hills and are less common in the north, especially in the Bear Lodge Mountains 

(Panjabi 2001). Most often, they are found in ponderosa pine forests and riparian 

woodlands, but recent surveys found them in quaking aspen, white spruce, shrubland, 

and burned habitats (Panjabi 2001; Pettingill and Whitney 1965; South Dakota 

Ornithologists’ Union 1991; White and others 2010). Mourning doves are usually 

found near forest edges in openings, along stream borders, or where two forest types 

meet. Gray jays (Perisoreus canadensis) are coniferous and mixed-coniferous forest 

dwellers whose habitat usually contains white spruce trees (Strickland and Ouellet 

2011).

The habitat for these forest generalists is medium rated throughout most of 

the Black Hills. The Bear Lodge Mountains provide abundant high-rated habitat for 

this group of birds, most likely associated with the presence of bur oak that is often 

mixed with meadows and fields. Another two centers of high-rated habitat occur along 

the Wyoming border southwest of Spearfish and another occurs just west of Mount 

Rushmore. These areas again have an intermixture of forest and meadow habitats and 

urban settings that are frequently associated with this group of prey species (fig. 28). 

Figure 27—Forest generalists are song and other small birds that inhabit a variety 

of habitats. Examples are (A) American robin, (B) mourning dove, and (C) grey jay 

(C)

(A) (B)
USDA Forest Service RMRS-GTR-339. 2015. 37

Figure 28—The Bear Lodge Mountains area and the area west of Mount Rushmore contain a large amount of high-rated forest 

generalist habitat. 
38 USDA Forest Service RMRS-GTR-339. 2015.

Hares and Rabbits

Jackrabbits and cottontail rabbits (lagomorphs) are some of the larger prey that 

goshawks feed on in the Black Hills, making them high value (fig. 29). In the Black 

Hills, eastern (Sylvilagus floridanus similis) and mountain cottontails (Sylvilagus nuttalli grangeri) occupy brushy ravines, streamside thickets, and the forested edges of 

valley streams. Mountain cottontails inhabit pine-clad uplands and white spruce-filled 

canyons, usually near an abundance of rocks, fallen logs, shrubbery, or old buildings, 

all of which are usually in close proximity to small, open, grassy areas. Desert cottontails (Sylvilagus audubonii) occupy grasslands along the entire interface of the Black 

Hills and surrounding prairies, up to 5,000 ft (1524 m) in elevation. They are common 

in the upland prairie of Wind Cave National Park located in the southern Black Hills 

(Turner 1974). 

White-tailed jackrabbits (Lepus townsendii) use many habitats, but appear to 

prefer grasslands and grassy forest openings (Higgins and others 2002) (fig. 30). They 

also use pastures, fields, and sagebrush habitats. In the Black Hills, white-tailed jackrabbits are not abundant and are probably more numerous on the prairies and plains 

surrounding the region; in the southern Black Hills, they occur with black-tailed jackrabbits (Lepus californicus) (Bailey 1926). White-tailed jackrabbits inhabit woodlands 

up to 6,000 ft (1829 m), using isolated grassy areas such as Reynolds Prairie (Deer 

Field Lake/Rochford area), Gillette Prairie (Hill City area), and the Bald Hills (Pactola 

Reservoir area). At the upper elevations, they frequent open woodlands of quaking 

aspen, ponderosa pine, and white spruce that border meadows and pastures. Whitetailed jackrabbits are more abundant, however, on the surrounding flats where they 

inhabit the open prairie and upland grasslands of places such as Wind Cave National 

Park (Turner 1974). Like turkey and grouse, hare and rabbit habitats in ponderosa pine 

forests may be optimal where trees occur in small groups or patches with closed canopies (interlocking tree crowns) that are separated by small grass-forb-shrub openings 

(Reynolds and others 1992, 2006).

Figure 29—Jackrabbits 

and cottontails are some 

of the larger mammals 

that goshawks hunt in 

the Black Hills. Pictured 

here are (A) black-tailed 

jackrabbit, (B) eastern 

cottontail, and (C) mountain cottontail.

(B)

(C)

(A)
USDA Forest Service RMRS-GTR-339. 2015. 39

Figure 30—The Jasper Fire area and vicinity have a large area of medium-rated jack and cottontail rabbit habitat. Much of the 

southern Black Hills mixed prairie and forests are high-rated rabbit (lagomorphs) habitat.
40 USDA Forest Service RMRS-GTR-339. 2015.

Much like with the ground squirrels and turkeys, the greatest occurrence of 

high-rated habitat for the jackrabbits and cottontails occurs in the far southern Hills 

(fig. 30). Extensive amounts of meadows and the prairie habitats bordering islands 

of ponderosa pine typify these locations (fig. 31). However, medium-rated jackrabbit 

and cottontail habitat occurs throughout the Black Hills, most likely associated with 

the abundance of meadows intermixed with forest. The area west of Mount Rushmore 

stands out as an important prey location for hares and rabbits. The area burned by the 

Jasper Fire also contains significant amounts of medium-rated hare and rabbit habitat. 

In contrast to other prey, little high-rated and a modest amount of medium-rated rabbit 

and hare habitat occurs in the Bear Lodge Mountains (fig. 30).

Tree Squirrels 

In the Black Hills, red squirrels (Tamiasciurus hudsinicus dakotensis) are most 

common above 5,200 ft (1585 m) but can be found throughout the Black Hills above 

3,800 ft (1158 m) (fig. 32). Black Hills red squirrels prefer mature coniferous forests 

Figure 31—The southern Black Hills contain a mix of prairie and forests that offer good cottontail 

and jackrabbit habitat as well as limited goshawk habitat.

Figure 32—Red squirrels and less abundant flying squirrels are the most important goshawk prey 

in the Black Hills.
USDA Forest Service RMRS-GTR-339. 2015. 41

and can be twice as abundant in white spruce forests as in ponderosa pine forests 

(Turner 1974; White and others 2010). However, they also live in pure mature stands 

of quaking aspen and in those mixed with ponderosa pine and bur oak (Higgins and 

others 2002; Turner 1974). A common characteristic of these forests is they usually 

have groups of trees with interlocking crowns. In addition, red squirrel inhabited forests usually contain trees of different ages and sizes along with cone-producing trees 

and large trees that can be used for nesting (Vahle and Patton 1983; Patton and Vahle 

1986). 

Across their range, northern flying squirrels (Glaucomys sabrinus) are associated with mature forests containing large diameter trees, large snags, downed logs, 

coarse woody debris, understory cover, and truffle abundance (Carey 1995; Carey 

and others 1999; Holloway and Malcolm 2007; Meyer and others 2005; Pyare and 

Longland 2002; Smith 2007; Smith and others 2004; Weigl 2007). Northern flying 

squirrels use den sites in natural and woodpecker-excavated cavities in trees, and stick 

nests built by birds and other squirrels (Hough and Dieter 2009c; Wells-Gosling and 

Heaney 1984) (fig. 32). 

Tree squirrels are the most important prey item in the diets of Black Hills goshawks, and were therefore considered three times more valuable than a woodrat to the 

goshawk diet. A key feature used by the wildlife biologists for rating the quality of the 

habitat for the tree squirrels was the presence of large trees with interlocking crowns. 

With this feature, the area around Mount Rushmore and the Norbeck Wildlife Preserve 

and Black Elk Wilderness supplied a concentration of high-rated tree squirrel habitat, 

as did a portion of the Bear Lodge Mountains area (fig. 33). The area burned by the 

Jasper Fire and the prairie area in the far southern Black Hills had plentiful low-rated 

habitat for tree squirrels. Most of the northern Hills were rated as having medium 

habitat for tree squirrels. 

Ground Squirrels 

Chipmunks and thirteen-lined ground squirrels (Spermophilus tridecemlineatus), are important prey in the diets of Black Hills goshawks (Bartelt 1977; Erickson 

1987; Promessi and others 2004; Rogers and others 2006; Squires 2000; Squires and 

Reynolds 1997; Turner 1974) (fig. 34). In the Black Hills, these squirrels occupy areas 

of short grass, including moderately grazed pastures, mowed borders of roadways, 

campgrounds, and upland meadows occurring up to 6,500 ft (1981 m) in elevation 

(Higgins and others 2002; Streubel and Fitzgerald 1978; Turner 1974). 

The Bear Lodge Mountains with meadows, grassy fields, and farm fields 

have a large amount of high-rated ground squirrel habitat, and the remainder of the 

Black Hills is mostly rated as medium quality for ground squirrels (fig. 35). With the 

thirteen-lined squirrel favoring mowed grassy areas and even campgrounds, the area 

around Mount Rushmore and extending to the west also contained high-rated ground 

squirrel habitat. Similarly, the prairie edge in the southern Black Hills was also highrated for ground squirrels. 
42 USDA Forest Service RMRS-GTR-339. 2015.

Figure 33—The Bear Lodge and the area around Mount Rushmore stand out as locations of high-rated 

tree squirrel habitat.

Figure 34—Thirteenlined ground squirrels 

(A) and chipmunks 

(B) are the main 

ground squirrel prey of 

Black Hill’s goshawks.

(A) (B)
USDA Forest Service RMRS-GTR-339. 2015. 43

Figure 35—High-rated chipmunk and thirteen-lined ground squirrel habitat is prominent west of Mount Rushmore, in the Bear Lodge 

Mountains area, and in the southern Black Hills. 
44 USDA Forest Service RMRS-GTR-339. 2015.

Woodpeckers 

We identified seven species in the woodpecker prey group as being important 

to goshawks in the Black Hills (table 1 and fig. 36). The northern flicker (Colaptes 

auratus) was identified as a highly important prey item and the three-toed (Picoides 

dorsalis), Lewis’s (Melanerpes lewis), hairy (Picoides villosus), red-headed 

(Melanerpes erythrocephalus), and black-backed (Picoides arctictus) woodpeckers 

and the red-naped sapsucker (Sphyrapicus nuchalis) were identified as moderately 

important prey items. The northern flicker’s body size, conspicuous markings, and 

behavioral displays make it common prey of the goshawk. Northern flickers use open 

woodlands, fields, and meadows (Scott and others 1977). They are cavity nesters, as 

are the rest of the species in the woodpecker group. For example, hairy woodpeckers 

have a greater preference for habitats with abundant snags and available cavities over 

other vegetative conditions (Cary 1901; Rumble and others 1999). Similarly, Lewis’s 

woodpeckers have been noted using the McVay burn area north of Hill City, South 

Dakota, where there was an abundance of snags (Pettingill and Whitney 1965). Most 

woodpeckers prefer grouped snags to single snags. Uniquely, red-naped sapsuckers 

like cavities that have been softened by wood rots (fungi) that can occur in trees with 

broken tops or other physical damage (Crockett and Hadow 1975).

As a group, the woodpeckers use a variety of forest conditions that includes 

coniferous and deciduous habitats, open pine forests, and landscapes that have 

experienced wildfires or beetle epidemics (Jackson and others 2002). For example, 

black-backed woodpeckers are strongly associated with recently burned and/or 

beetle-infested conifer forests, and in the southwestern part of the Black Hills, Lewis’s 

woodpeckers have been seen using burnt timber on the sides of canyons (Cary 1901; 

Rumble and others 1999). Forest edges often are preferred by woodpeckers, as demonstrated by Lewis’s woodpeckers (Pettingill and Whitney 1965). Similarly, three-toed 

woodpeckers are often observed using patchy environments and often seen foraging 

Figure 36—Woodpeckers are important prey species for Black Hills goshawks. Pictured are 

(A) the northern flicker, (B) Lewis’s woodpecker, and (C) hairy woodpecker.

(A) (B) (C)
USDA Forest Service RMRS-GTR-339. 2015. 45

near the edge of ponderosa pine and white spruce stands (Mohren 2002). Woodland 

and riparian habitats are also well used by woodpeckers in the Black Hills, as demonstrated by Lewis’s woodpeckers frequently using riparian woodlands dominated by 

cottonwoods (Populus spp.) or open areas with oaks (Quercus spp.) (South Dakota 

Ornithologists’ Union 1991). In addition to these riparian habitats, Lewis’s woodpeckers also use habitats with extensive shrub layers (Giroir and others 2007; Hutton and 

others 2006; Panjabi 2001, 2003; White and others 2010). 

High-rated woodpecker habitat was dispersed mostly throughout the central and 

northern Black Hills with a few high-rated woodpecker habitats in the Bear Lodge 

Mountains (fig. 37). The area near Mount Rushmore once again provided some of the 

largest amount of high-rated prey habitat, this time for woodpeckers. Probably the 

main characteristic of woodpecker habitat was the presence of snags as in the Jasper 

Fire area. Prairie habitats in the southern Black Hills contained large, contiguous 

amounts of low-rated woodpecker habitat, while the majority of the remaining Black 

Hills was rated medium. 

Woodrats 

Bushy-tailed woodrats (packrats) use of forested habitats makes them potential 

prey for goshawks (fig. 38). The presence of rocky shelters such as those found in 

caves, crevices of cliffs, mineshafts, and piles of large boulders are indicative of 

woodrat habitat (Finley 1958; Smith 1997; Turner 1974). They also use abandoned 

buildings and wood piles (Grayson 2000). Shrub cover is an important habitat component, as it provides valuable cover while foraging. Den and foraging sites are therefore 

often in edge habitats and openings in the forest where shrub cover is present, especially where it is located near islands of rocky outcrops (Finley 1958).

The majority of the Black Hills is rated as low-quality woodrat habitat, with the 

exception of the area west of Mount Rushmore that has abundant rock cliffs often associated with buildings and some grassy meadows that received a high rating, as well 

as an area on the northeastern edge of the Black Hills that contains high-rated woodrat 

habitat (fig. 39).

Combined Prey Habitat 

As previously mentioned, we considered woodrats to be the least important of 

the prey occurring in the diets of Black Hills goshawks, tree squirrels to be three times 

as important as woodrats, and the other species two times as important as woodrats. 

These were the weights we gave to the rankings the wildlife biologists assigned to 

each group of prey for each 9th code watershed. We summed these values to arrive at 

a composite rating for all the entire suite of prey groups for each watershed. For example, watershed 1095 in the Hell Canyon area had high-rated (3) habitat for all seven 

prey groups, and, using the appropriate weight for each prey group, the watershed had 

a composite prey score of 42 (fig. 18). 
46 USDA Forest Service RMRS-GTR-339. 2015.

Figure 37—High- and medium-rated woodpecker habitat is distributed throughout the central Black Hills, Northern 

Hills, and Bear Lodge Mountain areas. The area near Mount Rushmore also contains a good quantity of highrated woodpecker habitat. 

Figure 38—The bushytailed woodrat (pack rat) 

is the lowest valued prey 

species found in the diets of 

Black Hills goshawks.
USDA Forest Service RMRS-GTR-339. 2015. 47

Figure 39—Very little high-rated woodrat habitat was found in the Black Hills. The exception is the area near Mount Rushmore 

that contains many rocky outcrops and buildings that provide habitat.
48 USDA Forest Service RMRS-GTR-339. 2015.

Prey Habitat = Tree Squirrel × 3 + Rabbits Hares × 2 + Turkeys Grouse × 2

+ Woodpeckers × 2 + Forest Generalists × 2 + Ground Squirrels × 2 +

Woodrats × 1 [eq. 1]

42 = 3 × 3 + 3 × 2 + 3 × 2 + 3 × 2 + 3 × 2 + 3 × 2 + 3 × 1

This was the only watershed to receive this combined prey score, but several 

watersheds had a score of 14, indicating that the habitat in the watershed was rated 

low (1) for all of the prey groups. We arrayed the watersheds using the final scores and 

then computed the percentile distribution (see “Methods”). Using this distribution, we 

defined optimum, high, medium, and low prey habitats.

The Bear Lodge Mountains stand out as having a considerable amount of 

optimum and high-rated prey habitat, and nearly all of the remainder of the area had 

a medium rating for prey habitat (fig. 40). Similarly, the very southern part of the 

Black Hills where the prairie and the forest intermix also had a considerable amount of 

moderately rated habitat and a small amount of optimum and high-rated prey habitat. 

The area around Mount Rushmore and particularly to the west also is a conspicuous 

location of optimum, high-, and medium-rated habitat for goshawk prey. The Jasper 

Fire area and the area around Lead and Deadwood associated with fire and urban 

development had a large expanse of low-rated prey habitat. 

Results: Goshawk and Prey Habitat

Composite scores of goshawk and prey habitat were computed by multiplying 

the goshawk nesting ratings by the combined and weighted prey habitat and then 

adding that value to the quantity of goshawk foraging multiplied by the combined 

and weighted prey habitat (equations 1, 2). Watershed 596, located in the southwest 

section of the Hell Canyon area, received the highest composite score of 234. Many 

watersheds received the lowest composite score of 28. 

Prey Habitat = TS × 3 + RH × 2 + TG × 2 + WP × 2 + FG × 2 

+ GS × 2 + WR × 1 [eq. 1]

 Highest: 39 = 3 × 3 + 2 × 2 + 3 × 2 + 3 × 2 + 3 × 2 + 3 × 2 + 2 × 1

 Lowest: 14 = 1 × 3 + 1 × 2 + 1 × 2 + 1 × 2 + 1 × 2 + 1 × 2 + 1 × 1

 Final score = Prey Habitat × Goshawk Nesting 

 + Prey Habitat × Goshawk Foraging [eq. 2]

Highest: 234 = 39 × 3 + 39 × 3

Lowest: 28 = 1 × 14 + 1 × 14 

We arrayed the watersheds using the final scores and then computed the percentile distribution (see “Methods”). Using this distribution, we defined optimum, high, 

medium, and low rated goshawk and prey habitats.
USDA Forest Service RMRS-GTR-339. 2015. 49

Figure 40—Tree squirrels were considered to be three times more important and the other prey were considered to be two 

times more important than woodrats in the diets of Black Hills goshawks. The Bear Lodge Mountains stand out as proportionally containing the most medium- and high-rated prey habitat in the Black Hills. Also, the prairie intermixed with the forests 

located in the southern Black Hills has abundant medium-rated prey habitat and some high-rated habitat. 
50 USDA Forest Service RMRS-GTR-339. 2015.

Optimum and high-rated goshawk habitats are not plentiful in the Black Hills 

but are distributed over the extent of the Black Hills. Proportionally, the Bear Lodge 

Mountains have more optimum, high-, and medium-rated habitat than anywhere in 

the Black Hills (figs. 41 and 42). A very small amount of the Bear Lodge Mountains 

was rated low for goshawk and prey habitat combined. The northwestern corner of the 

northern Hills along the Wyoming border also contained a concentration of optimum 

and high-rated habitat intermixed with medium-rated habitat. Although the area near 

Mount Rushmore provided abundant prey habitat, its overall rating for goshawks was 

predominantly medium, exemplifying the importance we placed on nesting and foraging habitat in determining the goodness of a watershed related to the goshawk. Again, 

the Jasper Fire area contains much contiguous low-rated goshawk habitat. The forest 

intermixed with the prairie habitats in the southern Black Hills supplied a small and 

isolated amount of optimum habitat. The Jasper Fire and adjacent areas are the most 

conspicuous areas without high-rated or optimum habitat. Perhaps the most unique 

area of high and optimum habitat is the small patch located northwest of Rapid City 

and southeast of Nemo on the Black Hills National Forest boundary (fig. 42). 

Goshawks and Their Prey in the Black Hills 

More than 1.5 million acres (607,000 ha) of goshawk habitat in the Black 

Hills were assessed by the expert panels (table 2). The Black Hills were divided up 

into 3,414 watersheds that were distributed among four areas. The smallest was the 

Bear Lodge Mountains located in Wyoming that contained 325 watersheds covering 

110,159 acres (44,580 ha) (figs. 3 and 18). Proportionally, the Bear Lodge Mountains 

has the largest amount of high-rated and optimum goshawk habitat (17 percent). Sixtytwo percent of the Bear Lodge Mountains were rated as medium goshawk habitat and 

21 percent was rated as low. Conversely, 63 percent or 360,320 acres (145,816 ha) of 

the southern Black Hills contained low-rated goshawk habitat (fig. 41). The Jasper 

Fire, which burned more than 83,000 acres (33,589 ha) in 2000, significantly diminished goshawk habitat in this area. In addition, the mountain pine beetle epidemic that 

is underway in the Black Hills is also converting many thousands of acres to low-rated 

habitat with abundant trees of all sizes being killed. However, there are 15,948 acres 

(6,454 ha) of optimum and highly rated habitat distributed throughout the area that 

could be added to the epidemic in the coming years (table 2).

Of the 3,414 watersheds in this assessment, 67 were rated optimum for goshawk 

habitat, 99 were rated high, 1,535 were rated medium, and 1,713 were rated low 

(table 2). The vast majority of the Black Hills is rated low (46 percent) and medium 

(48 percent) for providing goshawk habitat, with only 2 percent rated optimum and 

4 percent rated high. The biggest factor in these proportions is the lack of big trees 

that goshawks prefer for nesting and hunting and the absence of quaking aspen that 

provide habitat for some important prey species (table 2). 
USDA Forest Service RMRS-GTR-339. 2015. 51

Figure 41—The area burned by the Jasper Fire located in the south-central Black Hills contained the largest area of low-rated 

goshawk and prey habitat combined. Proportionally, the Bear Lodge Mountains area contained the largest amount of high-rated 

and optimum goshawk habitat in the Black Hills. A large portion of the Northern Hills area was medium-rated for both goshawks 

and their prey.
52 USDA Forest Service RMRS-GTR-339. 2015.

Figure 42—Except for the Jasper Fire burn area in the south-central Black Hills, optimum and high-rated combined goshawk 

and prey habitat are distributed throughout the Black Hills. Proportionally, the Bear Lodge Mountains contain the largest 

amount of optimum and high-rated habitat.
USDA Forest Service RMRS-GTR-339. 2015. 53

Factors Affecting Black Hills Goshawks 

Forest Management 

No other national forest in the United States has had so long a history of active 

vegetative management as the Black Hills National Forest. Beginning with Case One 

in 1899 when the Homestake Mining Company purchased 15 million board feet of 

lumber and 5,100 cords of wood near Nemo, nearly all of the Black Hills National 

Forest has had some form of harvest activity (Boldt and Van Deusen 1974; Clow 

1998) (fig. 43). In addition, millions of tourists come to the Black Hills each year to 

Table 2—The number of watersheds and number of acres of optimum, high-, medium-, and 

low-rated goshawk habitat occurring in the Black Hills National Forest that occurred in 

the different areas used in the assessment.

Area Optimum High Medium Low

Number Acres Number Acres Number Acres Number Acres

Bear Lodge 14 7293 23 11,738 170 67,787 118 23,341

Northern Hills 15 9202 31 18,020 400 198,714 316 145,246

Mystic 20 9235 30 16,146 546 275,882 389 179,227

Hell Canyon 18 8697 15 7251 419 196,606 890 360,320

 Total 67 34,427 99 53,155 1535 738,989 1713 708,134

Figure 43—The top photo, 

taken in 1938, shows a 

1905 harvest. The bottom 

photo, taken in the early 

1940s, shows a 1911 harvest with the subsequent 

regeneration thinned. Both 

photos show the wide 

variety of forest structure 

created by these early 

treatments.
54 USDA Forest Service RMRS-GTR-339. 2015.

visit destinations such as Mount Rushmore, Custer State Park, Deadwood, the Sturgis 

Motorcycle Rally, and Devils Tower, and to hunt and fish (Pretes 2003) (fig. 44). To 

provide for many of these values the Black Hills National Forest has more than 20 

management areas designated for resource production, big game and resource production, with forest products, recreation, and big game production being emphasized over 

the largest area (fig. 45). Resource production emphasis dominates the management 

direction in the central and northern Black Hills with a large amount of the Bear Lodge 

dedicated to this activity. Depending on how and when the vegetation is manipulated 

(e.g., harvested, thinned, wild and prescribed fire), management may have a positive 

or negative impact on the habitat of the goshawk and its prey (Bull and Wales 2001; 

Reynolds and others 1992). 

Figure 44—Millions of people come to the Black Hills each year to see Mount Rushmore, 

Devils Tower, and other sites, as well as to attend one of the largest motorcycle rallies in the 

United States.
USDA Forest Service RMRS-GTR-339. 2015. 55

Figure 45—Map of the emphasis areas on the Black Hills National Forest. All of these management priorities potentially affect 

(directly or indirectly) the habitat of goshawks and their prey.
56 USDA Forest Service RMRS-GTR-339. 2015.

In general, the Black Hills has had a robust commercial timber harvest program 

for nearly a century, but as Baker (1934) stated in his silviculture text, there is an 

infinite number of ways in which a forest can be cut. Therefore, how these activities 

influenced the goshawk and its prey is uncertain, as around 200 known goshawk 

nests are distributed across the Black Hills. (Note: the extent to which these nests 

indicate numbers of breeding territories is unknown as some are clearly alternates 

within territories; see fig. 10). Before Case One, timber cutting practices in the black 

Hills entailed removing practically all trees that could produce a mine timber or a 

railroad tie. In response to this cutting, in 1913 Assistant Chief Forester W.B. Greeley 

and Assistant District (Regional) Forester C.W. Granger directed the Black Hills and 

Harney National Forests to adapt a conservative cutting policy using selection silvicultural systems (Newport 1954). However, such practices were not used in earnest 

until the early 1920s and then generally prevailed until the mid- to late-1960s (Boldt 

and Van Deusen 1974; Harmon 1955; Westveld 1935). These selection systems and 

high-risk marking were used to cover as much of the forest as possible to reduce risk 

and anticipated bark beetle mortality, and tended to leave a variety of forest structures 

(Alexander 1987; Harmon 1955; Keen and Salman 1942; Miller and Keen 1960) 

(fig. 46). After the 1960s a two-cut shelterwood became the standard harvesting practice that tended to homogenize stand structure, especially if associated with uniform 

thinnings (Alexander 1987) (fig. 47). 

Figure 46—A variety of the shelterwood and selection cuttings that were used in 1911 created 

heterogeneous forest structures, as illustrated by these 1951 photographs. 
USDA Forest Service RMRS-GTR-339. 2015. 57

Timber management activities, especially those that cause forest fragmentation, 

create uniform and monotypic forests, increase the extent of young forests, and reduce 

tree species diversity have been considered threats to goshawk habitat (Kennedy 2003; 

USFWS 1998). Forest conditions favored by goshawks, especially nest area characteristics, have been frequently described, but little information is available on how timber 

management directly impacts goshawk populations (Kennedy 2003; Reynolds and 

others 1992; Squires and Reynolds 1997). One of the limitations of studies investigating the effects of timber harvest on goshawk breeding habitat is that few studies have 

investigated goshawk habitat in forests not managed for timber harvest. However, 

some magnitude of forest change may cause goshawks to abandon nests, leave a 

Figure 47—A shelterwood located in the Bear Lodge Mountains (A) photographed in 1975 and 

one on the Mystic Ranger District (B) photographed in 2006; both show uniform tree spacing. 

(B)

(A)
58 USDA Forest Service RMRS-GTR-339. 2015.

territory, fail to lay eggs, or fail to return to a territory (Reynolds and others 1992). By 

far, the best documented impact of tree harvests on goshawk breeding comes from the 

removal of nest trees, snags, downed wood, forest canopy, and entire nest areas (Beier 

and Drennan 1997; Bright-Smith and Mannan 1994; Crocker-Bedford 1990; Reynolds 

1989; USFWS 1998; Woodbridge and Detrich 1994). However, Penteriani and Faivre 

(2001) found no difference in productivity of goshawk pairs reproducing in unlogged 

versus logged nesting stands during a long-term study (1984 to 1995 in Italy and 1993 

to 1999 in France). When considering the same nest stand before and after timber 

harvest, the authors noted no short-term differences in productivity. Nonetheless, it 

was observed that 87.5 percent of goshawk pairs nesting in logged stands moved away 

only when the original stand canopy cover was altered by >30 percent. Even then, they 

moved only to the nearest neighboring mature stand suggesting goshawks will tolerate 

some levels of timber harvesting within the nest stand and may move to alternate nests 

areas if available. 

Studies of goshawk habitat relations conducted on timberland may reflect the 

history of timber harvest in those areas. Finn and others (2002) using lands within 

Olympic National Park (Washington) as well as adjacent managed forest lands 

documented that loss of mature forest was detrimental to goshawk site occupancy and 

productivity in this area. Widén (1997) suggested that changes from selective cutting 

to clearcutting, replanting, and thinning in Finland and Scandinavia (Fennoscandia) 

from the 1950s to the 1980s are a result of changes in forest management practices 

that have altered goshawk foraging areas in this region. As a result of this intensive 

management, the boreal forest landscape of Fennoscandia is a highly fragmented 

patchwork of clearcuts and forest stands in different successional stages, and the proportion of old-growth forest has declined dramatically (<5 percent of Swedish forests 

are old-growth). Widén developed a cogent argument that suggests this landscape 

change has caused goshawk declines by reducing the availability of foraging habitat 

not nesting habitat. Goshawks can successfully nest in small patches of mature or 

old-growth forest (as small as 1 acre [0.4 ha]), but their foraging ranges cover 5,000 

to 15,000 acres (about 2000 to 6000 ha), and in boreal forest in Europe they prefer 

large patches of mature forest for hunting. Widén suggested that changes in the boreal 

landscape have resulted in a deterioration of goshawk hunting ranges, making it more 

difficult for them to secure adequate food for breeding. This factor is probably more 

important than a shortage of nest sites. He also noted that declining prey densities 

(e.g., forest grouse and medium-sized mammals) may be associated with timber 

management, which would negatively affect goshawk numbers. As such, we know 

goshawk reproduction is influenced by prey availability (Byholm and others 2002; 

Lindén and Wikman 1980; Ranta and others 2003; Salafsky and others 2005, 2006; 

Tornberg 2001); the degree to which forest management in North America positively 

or negatively influences prey abundance and availability is not well documented. 

Another factor in forest management is the potential for human activity to 

adversely impact goshawk nesting success (Squires and Reynolds 1997). Given the 

attraction to the Black Hills beauty and recreational opportunities, many people wish 

to live permanently or have seasonal residences in the area (fig. 48). As such, the 

majority of the South Dakota portion of the Black Hills is considered to be within the 
USDA Forest Service RMRS-GTR-339. 2015. 59

Wildland-Urban Interface (WUI) (fig. 49).The exception to the concentration of WUI 

lands in South Dakota is the Bear Lodge Mountains in Wyoming, which have few 

WUI lands. 

Bark Beetles 

Mountain pine beetles (Dendroctonus ponderosae) are capable of severely affecting the forests of the Black Hills (fig. 50). The beetle has been an endemic (local, 

small-scale) disturbance in the area as long as records have been kept; between 1895 

and 1910 beetle epidemics (large scale) killed between one and two billion board feet 

of timber (Boldt and Van Deusen 1974; Newport 1954). In the 1930s and 1940s, bark 

beetle epidemics occurred in various locales throughout the Black Hills, and in the 

1960s and 1970s, the northern Hills experienced a severe outbreak (McMillin and 

Allen 1999). Beginning in earnest in 2000, the central Black Hills has been experiencing a major epidemic of mountain pine beetles with major levels of tree mortality 

occurring from the vicinity of Mount Rushmore north nearly to Lead and Deadwood 

(fig. 51). Several areas rated as high or optimum goshawk habitat have been considerably impacted by beetle mortality (figs. 52 and 53). However, optimum and high-rated 

habitat in the Bear Lodge Mountains, northwestern, and southern Black Hills areas 

have not yet affected by beetles. 

Stands with greater than 110 ft2/acre (25.3 m2/ha) of basal area and containing 

trees between 8 and 12 inches (20 and 30 cm) DBH, which typify many of those set 

aside for goshawk nesting, appear to be highly susceptible to bark beetles. This is 

especially true when beetle populations are at epidemic levels, as they were in 2013 in 

many places in the Black Hills. Also during high beetle populations, trees of all sizes 

become susceptible to beetle attack (Negrón and others 2008; Schmid and Mata 1992). 

Figure 48—Both summer and permanent homes are distributed throughout the Black Hills.
60 USDA Forest Service RMRS-GTR-339. 2015.

Figure 49—The eastern half of the Black Hills contains a number of homes, towns, camps, and tourist attractions, exemplifying 

the large amount of wildland-urban interface (WUI) lands that occur in the Black Hills. Within Wyoming, they were defined as being within 300 feet of a dwelling; and in South Dakota, the distances defining WUI were 3 miles (yellow), 1.5 miles (aqua), and

0.5 miles (red).
USDA Forest Service RMRS-GTR-339. 2015. 61

Figure 50—Mountain pine beetles have been an endemic (low level) and epidemic (wide spread) disturbance in the Black 

Hills since the reserve was first surveyed by Graves in 1898.
62 USDA Forest Service RMRS-GTR-339. 2015.

Figure 51—Existing mountain pine beetle mortality (1996–2011) is shown in black, surrounded by a grey 300-m buffer that is at high 

risk for infestation. The central Black Hills is at particularly high risk for mountain pine beetle activity.
USDA Forest Service RMRS-GTR-339. 2015. 63

Figure 52—Several watersheds that were rated as optimum and high for goshawk habitat are either at risk or have been lost to 

mountain pine beetles.
64 USDA Forest Service RMRS-GTR-339. 2015.

As stated previously, a variety of partial cutting strategies used for several decades 

throughout the Black Hills tended to leave heterogeneous forest structures, especially 

with trees larger than 10 inches (25.4 cm) DBH. But the homogenization of Black 

Hills forests in the last 50 years may have contributed to the aggressive nature of the 

2000–2015 beetle epidemic (Bentz and others 2009; Shepperd and Battaglia 2002). 

For example, even stands that have some uneven-aged qualities still have small ranges 

in diameters (as reported by Negrón and others [2008]) where the mean diameter was 

8.3 inches (21.1 cm) DBH with a standard error of 0.28 inches (0.7 cm). 

Wildfire Hazard 

A large portion of the Black Hills is considered very high risk for uncharacteristically severe wildfire (fig. 54). The two notable exceptions are where the Jasper Fire 

burned and the mixture of forest and prairie on the southern edge of the national forest. 

The very high hazard areas are intermixed with high and moderately high fire hazard 

areas. One could infer that a wildfire would tend to be mixed in its severity, but the 

Jasper Fire provides evidence that under high and extreme burning conditions, most of 

the Black Hills would be prone to severe crown fires (fig. 55). This, combined with the 

bark beetle and WUI threats to the forests, means there is considerable potential for 

loss of goshawk habitat in most of the Black Hills. 

Figure 53—Many goshawk nest areas, including the nest and surrounding trees, are being severely 

damaged by bark beetles in the Black Hills.
USDA Forest Service RMRS-GTR-339. 2015. 65

Figure 54—With the exception of the far southern Hills and the area where the Jasper Fire burned most of the Black Hills is at 

high risk for stand replacing wildfires (high shown in red).
66 USDA Forest Service RMRS-GTR-339. 2015.

Predation, Competition, and Disease

Predation

Although goshawks are top level predators, they become prey for other predators. Typical bird predators include great horned owls (Bubo virginianus), red-tailed 

hawks (Buteo jamaicensis), golden eagles (Aquila chrysaetos), and bald eagles 

(Haliaeetus leucocephalus). Tree climbing mammals such as pine martens (Martes 

americana) and bobcats (Lynx rufus) can prey on goshawks in the nest, and coyotes 

(Canis latrans) and red foxes (Vulpes vulpes) can prey on fledglings when they are on 

the ground (Patla 1990). 

Figure 55—Wildfires present a risk to the goshawk and its prey, as exhibited by the Red Point of 

2003 (A) and Jasper Fire of 2000 (B).

(B)

(A)
USDA Forest Service RMRS-GTR-339. 2015. 67

Great-horned owls are probably the most important bird predator that goshawks 

encounter because of their killing capacity and abundance (Craighead and Craighead 

1969; Reynolds and others 2006b) (fig. 56). Not only do they kill and consume 

nestlings and fledglings, but they also prey on adults (Boal and Mannan 1994; 

Crocker-Bedford 1990; Moore and Henny 1983; Rohner and Doyle 1992; Woodbridge 

and Detrich 1994). Territories of goshawks often overlap with those of great-horned 

owls, and because great-horned owls fledge their young while goshawks are still 

incubating, goshawks become particularly vulnerable to predation by the owls. Greathorned owls have also been known to prey on adult goshawks during the winter (Boal 

and others 2005). Similarly, a bald eagle in Wyoming killed a male goshawk as it was 

foraging in cottonwood trees along a river (Squires and Ruggiero 1995).

Goshawks in the Black Hills undoubtedly encounter great-horned owls, but the 

extent of the impact on goshawk populations there is unknown. During 7 years of goshawk surveys in the Black Hills, 22 percent (4 of 18) of nest failures were attributed 

to predation by great-horned owls or red-tailed hawks (Knowles and Knowles 2009). 

A similar loss of goshawks (18 percent) was attributed to bird predators in Minnesota 

(Boal and others 2005). Goshawk predation by great-horned owls in the Black Hills 

likely depends on owl abundance. A 2009 survey, designed to detect great-horned owls 

in the Black Hills, found that 47 percent of the routes surveyed contained owls, indicating they were widespread but less abundant than expected (Drilling 2010). 

The number of goshawks taken by predators during the nesting seasons may 

be related to prey abundance (Crocker-Bedford 1990; Moore and Henny 1983; 

Rohner and Doyle 1992; Woodbridge and Detrich 1994; Zachel 1985). When prey 

abundance is low, females spend more time away from the nest hunting, thereby leaving the fledglings unprotected. When prey is abundant, as in supplemental feeding 

experiments, females tend to have higher nest attendance compared to unfed females 

(Rohner and Doyle 1992; Ward and Kennedy 1994; Zachel 1985). 

Figure 56—Great horned owls are perhaps the most abundant predator that goshawks encounter. The two species also compete for nest habitat and prey.
68 USDA Forest Service RMRS-GTR-339. 2015.

Pine marten were reintroduced to the Black Hills (1980s) and are potential 

predators of nesting and wintering goshawks (Paragi and Wholecheese 1994). 

However, their potential impact on goshawks is low as there are few individuals 

and their distribution is limited to mature white spruce forests and riparian habitats 

in the northern Hills (Fecske and others 2002). There is evidence that under certain 

conditions, goshawk populations can be impacted by predation to an extent sufficient 

to limit populations. For example, during the early 1970s, goshawk populations in 

Wisconsin were increasing, but by the 1980s, nest failures from fisher (Martes pennanti) predation were affecting the population (Erdman and others 1998). If predation 

is limiting goshawk population abundance, it is likely to be site- and predator-specific 

and temporally and spatially variable. 

Competition 

Goshawks compete with other goshawks (intraspecific competition) for nesting 

and foraging habitat. Goshawks are very territorial, meaning they will defend a territory from use by other goshawks (Newton 1979; Reynolds and others 1992, 2006). As 

such, territoriality places a limit on the number of goshawks breeding within an area, 

which can affect populations (Reynolds and others 2006b). Defensive behavior allows 

an individual or nesting pair to secure the necessary prey, nest area, roost sites, and 

water for survival. However, to exploit good foraging opportunities, goshawks may 

use areas outside their defended territory and may even share these areas with other 

goshawks (Hargis and others 1994). In addition, territoriality can be a major determinant of nest locations, although the distribution of good and poor habitat, based on 

forest structure, usually determines nest locations within a territory (Reich and others 

2004). When landscapes are saturated with breeding goshawks, competition for nest 

sites may result in a surplus of non-breeding “floater” hawks. These individuals are 

forced into non-breeding status and must wait for a territory vacancy resulting from a 

goshawk death or an individual leaving the area. Thus, non-territorial individuals act 

to stabilize local and regional populations through local recruitment and immigration 

from more distant populations.

Male goshawks are smaller than females and are the primary hunters during 

most of the breeding season (fig. 57). This reverse size dimorphism may have evolved 

to increase foraging efficiency of males and nest protection abilities of females, but 

also serves to reduce competition for prey between males and females (Reynolds 

1972; Newton 1979). It is theorized that this trait allows the smaller males to capture 

the smaller prey that are more abundant, especially during the spring and summer. 

Larger females are better able to defend nests, produce large eggs, incubate a brood, 

and take larger prey during the non-breeding season. Therefore, by exploiting different 

prey resources the competition between pairs of goshawks is reduced. 

Goshawks compete with other owls and hawks for nest sites. This interspecific 

competition frequently occurs with red-tailed, Cooper’s, and sharp-shinned hawks 

along with great-horned owls (figs. 56 and 58). These other raptors often use nests that 

were built by goshawks, forcing the goshawks to switch to, or build, an alternate nest 

within their territory. These other raptors also exhibit territorial behavior that could limit 

the use of an alternate goshawk nest by one of their own species. Different nesting 

preferences by the competitors also reduce the frequency of goshawk nests being usurped. 
USDA Forest Service RMRS-GTR-339. 2015. 69

Figure 57—Male goshawks 

are smaller than females 

(reverse dimorphism) that 

favor the female staying and 

protecting the nest while the 

smaller male, using minimal 

energy, can feed the family. 

Figure 58—Cooper’s hawk, 

a close relative of the goshawk, can use goshawk 

nests and compete for the 

same prey.
70 USDA Forest Service RMRS-GTR-339. 2015.

For example, goshawks typically nest in relatively dense habitats on slopes or in drainage bottoms while red-tailed hawks prefer to nest in open habitats or on ridge tops (La 

Sorte and others 2004; Reynolds and others 1982). Additionally, great-horned owls are 

habitat generalists that typically nest in fragmented landscapes, but are often relatively 

common in more open ponderosa pine forests (Houston and others 1998).

 Interspecific competition for prey occurs particularly with great-horned owls, 

other hawks, and small carnivores such as the weasel, pine martin, bobcat, coyote, 

and red fox (fig. 59). Red-tailed hawks prey on rabbits, squirrels, woodpeckers, and 

grouse and are the most abundant raptor in the Black Hills making them one, if not the 

greatest, competitor of the goshawk for prey (Panjabi 2003; White and others 2010). 

However, the wide diet niche of goshawks (Reynolds and Meslow 1984) affords 

them some buffer against competition. Where prey is limited to a few species (e.g., 

snowshoe hare and grouse), wintering goshawks may respond to prey reductions and 

presumed increased competition by moving to areas where prey are more diverse and 

perhaps more abundant. This interspecific competition can affect the survival of individuals or goshawk reproduction and can limit goshawk population sizes (Birch 1957). 

Figure 59—Red-tailed hawks and coyotes are two of 

the many predators that hunt much of the same prey as 

goshawks.
USDA Forest Service RMRS-GTR-339. 2015. 71

Bacterial and Parasitic Diseases

Like all birds, goshawks are susceptible to disease caused by bacteria, fungi, 

viruses, and parasites. The distribution and abundance of disease agents vary by season, habitat, and region. In many cases, infections in individual raptors, or their local 

population, depend on the distribution and abundance of disease and how they are 

transmitted (e.g., mosquitos, flies, and infected prey). 

Bacterial infections are probably the most important disease affecting raptors. 

Wild hawks acquire most bacterial infections through direct transmission from infected prey, which include gregarious wild birds (e.g., pigeons, doves, starlings, sparrows, 

and water birds), scavengers (crows), and domestic poultry. Bacterial infections can 

be transmitted between adult and nestling goshawks, and, in some cases, by insects. 

Infectious bacterial diseases found in raptors include avian cholera (Pasteurella 

multocida), erysipelas (Erysipelothrix rhusiopathiae), chlamysiosis, mycoplasmosis (Mycoplasma spp.), botulism, and avian tuberculosis (Mycobacterium avium). 

Contaminated bird feeders are important sources of Salmonella and mycoplasmosis 

infection from forest generalists, jays, and woodpeckers. Waterfowl can become sickened with avian cholera when lake water is contaminated. Most bacterial diseases are 

transmitted through direct contact with infected individuals, objects, dirt, or water. 

Disease-causing fungal agents are normally present in a goshawk’s environment, 

and disease usually results when a goshawk becomes immunosuppressed or otherwise stressed (Friend and Franson 1999). Aspergillosis (Asperigillus spp.), a fungal 

infection affecting the respiratory tract, was more common (53 percent) in migrating 

goshawks during an invasion year compared to a non-invasion year (7 percent), suggesting that stress increases a goshawk’s susceptibility to infection (Redig and others 

1980; Squires and Reynolds 1997). Inhalation is the primary route for Asperigillus 

infection.

As with bacterial diseases, viruses are transmitted to raptors when they feed on 

infected prey, through insect vectors, or through contact with contaminated surfaces. 

Viral diseases include avian leukosis sarcoma, Newcastle disease, West Nile virus, 

bronchitis, laryngotracheitis, avian pox, and herpesvirus. In Minnesota, West Nile 

virus caused death in wild and captive goshawks, but the threat to wild goshawk 

populations in the western United States may be lower because of the low abundance 

of mosquitos at elevations over 5,700 ft (1737 m) (Eisen and others 2008; Hull and 

others 2010; Wünschmann and others 2005). Raptors can, however, become infected 

with West Nile virus from eating infected prey making fledgling and adult goshawks 

that move to lower elevation habitats in late summer more susceptible to infection 

(Komar and others 2003).

Parasites are probably more common in goshawks than the aforementioned 

pathogens, and the physical costs associated with their infection can range from negligible to fatal (Newton 1998). For instance, a goshawk infested with parasitic worms 

may not feel the effects as long as prey is not limited. When prey becomes limited, 

goshawks with significant parasite loads will be more susceptible to starvation than 

those with milder infections. Intestinal parasites influence physical condition, affecting 

molt and overall energy levels. Goshawks become infected with intestinal roundworms 

(Ascarida galli, Capillaria spp., and Serratospiculun spp.), flat worms (Tremetodes), 
72 USDA Forest Service RMRS-GTR-339. 2015.

and tape worms, all of which they get from prey. They can also be infected by blood 

parasites, including malaria (Plasmodium spp.), coccidia, leucocytozoon, haemoproteus, tripanosoma, microfilariae, and Trichomonas gallinae. Free ranging and falconry 

goshawks in Germany apparently act as final hosts for several Sarcocystis spp., which 

infect wild and domestic pigeons (Olias and others 2011). Heavy infestations of ectoparasites (e.g., fly larvae, myiasis, and mallophaga lice) usually occur in individuals 

already weakened by other factors (Reynolds and others 2006b; Squires and Reynolds 

1997). 

The importance of disease as a limiting factor to goshawk populations is unknown because diseases often predispose individuals to other mortality agents, making 

the determination of the ultimate cause of death equivocal (Esch 1975). However, in 

comparison to starvation and trauma, disease was not a significant cause of death in 

other raptor species (Keymer and others 1981; Redrobe 1997). Goshawks found dead 

in Europe indicated that starvation was the most important mortality factor followed 

by trauma and then combinations of starvation and disease (Kenward and others 1991; 

Tornberg and others 2006). The lack of strong evidence that disease limits North 

American and European goshawk populations combined with data from other birds, 

suggests that the effects of disease on goshawks are likely to be small or non-existent 

(Newton 1989; Reynolds and others 2006a; Rutz and others 2006). Nonetheless, 

disease may have its greatest impact on goshawk populations during periods of 

stress related to food shortages and weather when disease-weakened individuals are 

predisposed to a variety of mortality factors. Managing forests with considerations for 

intermixing habitats of both goshawks and their important prey species is a sensible 

plan for sustaining predator and prey populations and minimizing the frequency and 

degree of food shortages (Reynolds and others 1992, 2006a). 

Silvicultural System Simulation for Creating and 

Maintaining Goshawk Habitat in the Black Hills 

A silvicultural system is a planned series of treatments through the life of a forest directed at meeting forest management objectives (Baker 1934). A very important 

concept presented by Reynolds and others (1992; 2006a) was to create heterogeneous 

forests composed of up to six structural stages ranging from openings and seedlings 

to old vegetative complexes at both fine and landscape scales (Long and Smith 2000). 

Also, Reynolds and others (1992) recognized that high forest canopy cover was an essential component of goshawk habitat, especially in the older structures. As such, their 

canopy cover recommendations only applied to older vegetative structures, which, at 

a fine scale, could be less than 0.25 acres (0.1 ha) in size. This is an important concept 

when designing ponderosa pine forest conditions that are resilient to mountain pine 

beetle activity and yet capable of supporting goshawks and their prey. Depending on 

forest conditions—as previously stated, the majority of the Black Hills have been 

harvested and homogenized—it may take decades or even a century or more to create 

the desired conditions. Using Reynolds and others (1992) as a template, the following 

silvicultural system was designed to create and maintain forest conditions for the goshawk and its prey on the Black Hills Experimental Forest informed by those described 

by Harmon (1955) and Miller and Keen (1960). However, as Baker (1934) stated, 
USDA Forest Service RMRS-GTR-339. 2015. 73

there is an infinite number of ways a forest can be treated, and this is only one of many 

that could be developed to produce goshawk habitat. The stand we selected for this 

example is located on the Black Hills Experimental Forest, which is about 2 mi (about 

3 km) west of Highway 385 on the Rochford Road-616 and about 8 mi (about 13 km) 

east of Rochford, in the heart of the Black Hills (fig. 60).

Figure 60—The stand selected to simulate a silvicultural system aimed at producing and maintaining goshawk habitat was located in the northeastern portion of the Black Hills Experimental Forest.
74 USDA Forest Service RMRS-GTR-339. 2015.

For the most part, the Black Hills Experimental Forest received a major timber 

harvest in the 1980s that emulated the two-step shelterwood system that was used 

extensively throughout the Black Hills. In doing so, the majority of the stands have 

a few residual large trees overtopping an abundant amount of seedlings and saplings (fig. 61). Using actual tree data, from a harvested stand, the Forest Vegetation 

Simulator (FVS) projected the prescription and the Stand Visualization System (SVS) 

was used to display the results of the simulation (Dixon 2002) (figs. 61, 62, and 63). 

The “paint gun” tool available in SVS was used to identify individual trees for removal chosen by location and tree size (fig. 64). An individual irregular selection system 

was simulated using FVS and displayed using SVS for 100 years aimed at producing 

and maintaining goshawk habitat (table 3) (Graham and Jain 2005; Graham and others 

2007; Reynolds and others 1992).

Figure 61—The stand used in the simulation was typical for the Black Hills (located on 

the Black Hills Experimental Forest) as it was harvested in the 1980s and contains abundant natural regeneration. Marked trees are to be left after a harvest.
USDA Forest Service RMRS-GTR-339. 2015. 75

2 4 6 8 10 12 14 16 18 20

0

20

40

60

80

100

120

Trees/acre

Diameter (inches)

Figure 62—The diameter distribution of the stand used in the simulation located on the Black Hills 

Experimental Forest after the first entry (harvesting and masticating unwanted tree regeneration) of an irregular selection system aimed at creating and maintaining goshawk habitat.
76 USDA Forest Service RMRS-GTR-339. 2015.

Figure 63—Actual ponderosa 

pine stand located on the Black 

Hills Experimental Forest with 

each tree positioned after the 

initial harvest (2013) using irregular selection to create and 

maintain northern goshawk 

habitat displayed using the 

stand visualization system 

(SVS). 

Figure 64—The Forest Vegetation Simulator (FVS) and the Stand Visualization System (SVS) 

were used to simulate forest treatments for 100 years to create and maintain goshawk habitat. 

The paint gun in SVS was used to locate actual trees (mapped in the field) to leave or remove in 

the simulation. As the paint gun points to a tree, its characteristics are displayed (see Figure 61).
USDA Forest Service RMRS-GTR-339. 2015. 77 Table 3—Stand characteristics of a 100-year simulation using the Forest Vegetation Simulator (FVS) for producing and maintaining goshawk habitat on the Black Hills Experimental Forest. Before treatment Removals After treatment Year Trees BA SDI Height DBH Total Merchantable Trees Total Merchantable BA SDI Height DBH Per acre ft2/acre Feet Inches ft3/ac ft3/acre BF/acre Per acre ft3/acre ft3/acre BF/acre ft2/ac Feet Inches 2013 170 74 142 64 8.9 1987 1755 9300 17 153 117 600 66 127 64 8.9 2023 150 71 134 65 9.3 1991 1759 9366 28 0 0 0 71 128 65 10.3 2033 120 75 134 65 10.7 2133 1890 10282 6 196 175 929 68 122 62 10.4 2043 112 72 128 63 10.9 2060 1819 10019 36 7 0 0 71 117 63 13.1 2053 74 75 121 63 13.6 2166 1909 10676 0 0 0 0 75 121 63 13.6 2063 73 78 125 64 14.0 2275 2006 11343 2 166 153 856 73 117 62 13.8 2073 69 76 121 63 14.2 2216 1971 11194 3 332 309 1849 66 108 58 13.6 2083 84 70 118 59 12.4 1992 1760 9960 8 11 0 0 69 114 59 12.9 2093 75 72 118 60 13.3 2081 1840 10470 7 186 164 951 66 108 58 13.3 2103 67 69 111 59 13.7 1990 1760 10067 0 0 0 0 69 111 59 13.7 2113 66 72 115 60 14.2 2084 1825 10515 0 0 0 0 72 115 60 14.2 BA = Basal area. SDI = Stand density index. DBH = Diameter breast height (4.5 ft). BF = Board foot.
78 USDA Forest Service RMRS-GTR-339. 2015.

Following is an outline of the 100-year simulation by decade, beginning in 2013:

•  2013:

•  Through mastication, all but 100 trees/acre (247/ha) of the regeneration were 

removed.

•  Seventeen saplings and pole-sized trees per acre (42/ha) were removed. These 

trees were removed from below larger trees to reduce ladder fuels that would 

minimize the chance of a surface fire burning the crowns of larger trees. These 

trees were selected on an SVS view using the paint gun to select the tree for 

removal (figs. 62 through 64).

•  2023:

•  Twenty-eight saplings per acre (69/ha) were removed leaving as irregular spacing as possible to create diverse structure as the forest develops. 

•  Prescribed fire was used to control the abundant regeneration. 

•  2033:

•  Six trees per acre (15/ha) were removed near or on the edge of tree groups. Trees 

were selected using the paint gun. Even though the basal area was 75 ft2/acre (17 

m2/ha), there is evidence that groups of trees can be attacked by mountain pine 

beetles. However, at this density the overall stand hazard to bark beetle attack is 

low.

•  Prescribed fire was used to control the abundant regeneration. 

•  2043:

•  Thirty-six non-merchantable trees per acre (89/ha) were removed, once again 

picking ladder fuel trees and those that might contribute to increasing density of 

tree groups. 

•  Prescribed fire was used to control the abundant regeneration. 

•  2053:

•  Prescribed fire was used to control the abundant regeneration.

•  2063: 

•  Two trees per acre (5/ha) in and near groups of trees were removed to reduce 

the risk of a group being attacked by mountain pine beetles even though stand 

density is 78 ft2/acre (18 m2/ha). 

•  Prescribed fire was used to control the abundant regeneration.

•  2073: 

•  Three trees per acre (7/ha) in and near groups of trees were removed to reduce 

the risk of a group being attacked by mountain pine beetles even though stand 

basal area is 76 ft2/acre (17 m2/ha).

•  Through a combination of mechanical and prescribed fire treatments, 100 

seedlings per acre (247/ha) were nurtured and arranged in an irregular pattern 

avoiding creating ladder fuels that would risk the loss of large trees in advent of 

a wildfire.
USDA Forest Service RMRS-GTR-339. 2015. 79

•  2083:

•  Eight small trees per acre (20/ha) were removed, producing 11 ft3/acre (0.8 m3/

ha). They were chosen using the paint gun to protect tree groups from wildfire 

and potential mountain pine beetle impact. 

•  Where needed, seedlings were thinned to create heterogeneous structures involving all tree cohorts. These structures by now contain trees ranging from 2 to 

more than 24 inches (5 to 61 cm) DBH. 

•  2093:

•  Seven trees per acre (17/ha) in and near tree groups were removed to reduce the 

risk of a group being attacked by mountain pine beetles even though stand basal 

area density is 72 ft2/acre (16m2/ha). This treatment would produce 951 board 

feet/acre. 

•  Prescribed fire was used to control the abundant regeneration.

•  2103:

•  Prescribed fire was used to control the abundant regeneration.

•  2113:

•  Prescribed fire was used to control the abundant regeneration.

After 100 years, as displayed by SVS, the stand on the Black Hills Experimental 

Forest would have 66 trees/acre (163/ha), 72 ft2 of basal area/acre (17 m2/ha), and 

10,515 board ft/acre (table 3). Trees would average 60.0 ft (18.3 m) in height and 

14.2 inches (36.1 cm) DBH. Most importantly, they would be arranged in clumps and 

groups with minimal ladder fuels present and high canopy cover within the larger tree 

clumps or groups offering tree squirrel habitat while minimizing the risk of bark beetle 

attack (fig. 65). Note that this prescription describes a series of treatments that can be 

modified as the forest develops over decades of using robust adaptive management 

principles (fig. 66). 

There are an infinite number of ways a forest can be treated to create desired 

conditions, and there are an infinite number of forest conditions growing on an infinite 

number of biophysical settings, which often have many competing values that need to 

be considered if not sustained. The importance of the silvicultural system in this application is that all treatments proposed are designed to create and maintain desirable 

conditions for the goshawk and its prey. This vision was a direct result of the conditions articulated by Reynolds and others (1992). We recognize that these conditions 

have not been tested scientifically but they do reflect historical conditions as described 

by Pearson (1950) in the southwestern United States and as viewed by George Custer 

when he came through the Black Hills in 1874 (Brown and Cook 2006; Grafe and 

Horstead 2002) (fig. 67). 
80 USDA Forest Service RMRS-GTR-339. 2015.

Figure 65—The resulting forest structure after a 100-year simulation of a stand located on the Black Hills Experimental 

aimed at creating and maintaining goshawk habitat. Note the tree diameters ranged from 2 to 26 inches and the trees, 

snags, and down logs are irregularly distributed. Trees/acre

0

5

10

15

20

Alive Dead Down

2 468 10 12 14 16 18 20

Diameter (inches)

22 24 26

Discussion 

The habitats of goshawks and their prey in the Black Hills are highly diverse and 

at risk to change. Unfortunately, for the most part, both have been assessed as being 

low to medium quality for sustaining goshawks and their prey. With this challenge 

comes the opportunity to use the findings of this assessment in planning and management at multiple levels. No matter the question at hand, forest management requires 

some level of information such as this assessment for making informed decisions 

(Graham and others 2000; Kaufman and others 1994). 
USDA Forest Service RMRS-GTR-339. 2015. 81

Figure 66—Overhead views for each year of the simulation after a treatment (e.g., precommercial thinning and 

commercial harvest). 
82 USDA Forest Service RMRS-GTR-339. 2015.

Broad-scale assessments can provide context for actions and information applicable at lower or finer scales (Haynes and others 1996). For example, finding that 

a small quantity of optimum and high-rated goshawk and prey habitats are distributed 

somewhat evenly across the Black Hills and Bear Lodge Mountains provides context 

for management activities that may occur within one of these areas. Field evaluations 

can determine the particular state of the high-rated or optimum habitat and can inform 

actions that may enhance or protect the area. Also, broad-scale findings can be used to 

set priorities, especially when combined with other information such as the watershed 

assessment or bark beetle strategy. 

The Bear Lodge Mountains stand out as proportionally having the largest 

amount of medium-rated to optimum goshawk habitat of any place in the Black Hills. 

In addition, the area is not currently at high risk to bark beetle attack and has minimal 

WUI lands. However, most of that area is at high risk to loss from wildfire. Therefore, 

the Bear Lodge Mountains offer the most opportunities for designing and implementing forest treatments that will enhance or maintain key goshawk habitat features yet 

reduce the risk of high severity wildfire and bark beetle attack. 

The presence and abundance of quaking aspen is a key habitat feature for most 

birds that goshawks prey on in the Black Hills (see appendix). For example, 11 of 

the 13 birds reviewed used quaking aspen frequently and red-naped sapsuckers are 

considered a quaking aspen obligate. Quaking aspen is very important for maintaining black-headed grosbeak populations and ruffed grouse depend heavily on quaking 

aspen for foraging, nesting, and cover (Hansen and others 2011). Ruffed grouse were 

abundant residents in the Black Hills when Custer came to the Hills in 1874 and into 

the beginning of the 20th century suggesting that a considerable amount of quaking 

Figure 67—In 1874 when General Custer visited the Black Hills, many 

areas contained abundant snags, down logs, clumped trees, and stands 

with rather open understories, as shown here both in the foreground and 

background.
USDA Forest Service RMRS-GTR-339. 2015. 83

aspen occurred in the Hills (Grinnell 1875; Knight 1902; Over and Thomas 1921). 

However, recent accounts indicate that ruffed grouse are rare in the Hills and only 

small populations live in the northern portion (Pettingill and Whitney 1965; South 

Dakota Ornithologists’ Union 1991; White and others 2010). These ruffed grouse 

population trends are most likely related to the reduced amount (7 percent) of the 

current forest types of the Black Hills (all owners) that are considered quaking aspen 

(Hansen and others 2011; Walters and others 2013). As such, increasing the amount of 

quaking aspen in the Black Hills through harvesting, tending, prescribed fire, or other 

means will have a positive impact on populations of several prey species (e.g., birds) 

as well as goshawk populations as they are food limited (Reynolds and others 1992; 

Reynolds and others 2006a, b; Salafsky and others 2005).

Mountain pine beetles have been observed in the Black Hills since the forest 

reserve was described by Graves in 1899 (Graves 1899). In 1901, Hopkins completed 

a detailed survey of Black Hills bark beetles and was the first to provide recommendations to stave off beetle attack (Hopkins 1902, 1905). Tree density, tree size, tree vigor, 

tree juxtaposition, site productivity, weather, bark beetle populations, and several other 

known and unknown factors all interact to determine bark beetle dynamics (Fettig and 

others 2007; Larsson and others 1983; Olsen and others 1996; Schmid and Mata 2005; 

Stevens and others 1980). Nevertheless, a common thread in bark beetle conditions in 

the Black Hills is the presence of dense, uniform stands of trees in excess of 5 inches 

(12.7 cm) DBH and having densities in excess of 100 to 120 square ft of basal area 

per acre (27.5 m2/ha) making them at considerable risk to bark beetle attack (Schmid 

and others 1994). In addition, the biological principal that environmental complexity 

leads to stability (versus uniformity leads to instability), applies to Black Hills forests 

as their diversification will likely make them more resilient to the episodic bark beetle 

population outbreaks (Graham 1959). Similarly, Bentz and others (2009) attributed the 

homogenization of forests as a major contributor to insect epidemics, as did Sartwell 

and Stevens (1975) and Fettig and others (2007). 

Wildfire, bark beetles, and lack of quaking aspen are impediments to producing and maintaining goshawk habitat. Conscious planning and management of Black 

Hills forests with considerations of the habitat structures used by goshawks and each 

of their prey species as described in this assessment have the capacity to produce and 

sustain the desired habitats and, ideally, support viable populations of goshawks. The 

forest structures suggested by Reynolds and others (1992) for sustaining goshawks and 

their prey in the Southwest have been challenged (Beir and Ingraldi 2012; Beir and 

others 2008; Reynolds and others 2012), but this model still appears to be appropriate 

for creating heterogeneous forests dominated by large trees, open understories, small 

openings, numerous snags, downed logs, and relatively high canopy-base heights 

(Kennedy 2003; Reynolds and others 2013). The 100-year silvicultural system simulated on the Black Hills Experimental Forest is an example of how a stand could be 

treated to produce the desired habitat conditions (fig. 66 and table 3). This model is 

only one of many ways in which a forest can be treated, but the desired conditions 

closely resemble historic ponderosa pine forests as described by Pearson (1950) in the 

Southwest, Miller and Keen (1960) in the Northwest, and viewed by Custer when he 

came through the Hills in 1874 (Grafe and Horstead 2002) (figs. 67 and 68).
84 USDA Forest Service RMRS-GTR-339. 2015.

Acknowledgments

We thank Craig Bobzien, forest supervisor, who provided encouragement and 

freed many staff members of the Black Hills National Forest to help complete the 

assessment. Blaine Cook and Kerry Burns deserve special thanks for coordinating the 

staff support, providing data, and time for the assessment. The GIS work and maps 

would not have been possible without the excellent help of Todd Mills. The wildlife 

biologists of the Black Hills National Forest: Matt Stefanich, Valerie Carlson, Jeff 

Goldberg, Shirlene Haas, Patti Lynch, Lou Conroy, Brad Phillips, Jamie Wheeler, Rob 

Nagel, and Terra Houska, along with Chad Lehman from Custer State Park and Shelly 

Deisch from the South Dakota Game and Fish, helped us with the assessment and 

many served as experts rating the quality of goshawk and prey habitats and they all 

deserve a very special thanks.

Figure 68—Occasionally in the Black 

Hills, there are areas that contain large 

trees, down logs, open understories, and 

generally irregular in spacing. However, 

these areas are prone to rapid colonization by small trees that can compromise 

their fire and bark beetle resilience.
USDA Forest Service RMRS-GTR-339. 2015. 85

Jonathan Sandquist of the Rocky Mountain Research Station, Moscow, Idaho, 

deserves special thanks for his help in preparing and displaying the silvicultural system used to simulate the creation of goshawk habitat in the Black Hills.

Lane Eskew, former RMRS Publishing Services group leader, and his staff— 

Suzy Stephens, Nancy Chadwick, and Loa Collins—as well as Julie Chase deserve 

special thanks for producing the publication. Melinda Larson did an excellent job of 

editing the manuscript and added greatly to its content. Kathy Graham also supplied 

editing help that is greatly appreciated.

We also are grateful for the effort our reviewers put into reading and improving 

this assessment: Blaine Cook, Kerry Burns, Kurt Allen, Douglas “Sandy” Boyce, 

Mark Rumble, Mike Battaglia, Peter McDonald, Jeff Underhill, Scott Baggett, and Jim 

Youtz. All deserve special thanks as they did an outstanding job. 

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Appendix: Natural History and Habitat for Selected 

Northern Goshawk Prey Species

We reviewed the life histories, ecologies, habitats, and distribution (i.e., northern 

Black Hills versus southern Hills) and abundance of goshawk prey species information 

in the Black Hills—information that was used in this assessment to rate the quality of 

existing habitat for goshawks and their prey across the Black Hills. We first identified 

prey species for this assessment from three goshawk diet studies in the Black Hills 

(Bartelt 1974; Erickson 1979, Knowles and Knowles 2009). Given these limited diet 

data, we reviewed bird and mammal (faunal) lists from the Black Hills for prey species that occurred in goshawk diets elsewhere in the western United States, firstly in 

ponderosa pine forests and secondarily in other forest types, which were potentially 

missed in the two Black Hills diet studies. Here, we report on those literature reviews 

of the natural history, ecology, habitat requirements, and population trends of 21 species. The structure of reviews for each species begins with general information that, 

more often than not, comes from studies conducted in geographic areas other than the 

Black Hills and ends with specific information from reports and publications based on 

studies conducted in the Black Hills.

American Robin

The American robin (Turdus migratorius) is a moderate-sized passerine 

(e.g., small perching bird) about 10 inches (25.4 cm) in length and weighing about 

3.2 ounces (90.7 g) (Kilgore 1971; Ramsden and others 1979). Robins comprised 

6.6 percent of the diet of northern goshawks in eastern Oregon and 5.6 percent of 

36 prey deliveries to 7 goshawk nests in north-central New Mexico (Kennedy 1991; 

Reynolds and Meslow 1984). In the Oregon Coast Range 13 percent of the goshawk’s 

diet was robins and 3.2 percent in southeast Alaska (Lewis and others 2006; Thrailkill 

and others 2000). Of 400 pellets collected at 40 nests in south-central Wyoming, 234 

(30 percent) included robin remains (Squires 2000). Robins made up 3.6 percent of 

goshawk diets in ponderosa pine forests of northeastern California and 4.7 percent 

in Idaho (Patla 1997; Promessi and others 2004). Erickson (1987) and Bartelt (1977) 

found robin remains at 4 of 5 nests they visited in the Black Hills.

Distribution 

The American robin is a common and widespread songbird throughout the 

United States (including Alaska), most of Canada, and Mexico. Most robins migrate 

south during winter however, many individuals winter as far north as southeast Alaska, 

southern Newfoundland, and South Dakota (Sallabanks and James 1999). In the Black 

Hills, robins are common summer residents at all elevations, transients during spring 

and fall, and rare winter visitors (Pettingill and Whitney 1965). 

Habitat

Robins inhabit woodlands, hardwood and coniferous forests, riparian areas, 

shelterbelts, wooded suburban areas, gardens, agricultural lands, parks, and lawns 

(Franzreb and Ohmart 1978; Sallabanks and James 1999; Savard and Falls 1981; 

Siegel 1989; Stauffer and Best 1980; Yahner 1983). In the western United States, 
USDA Forest Service RMRS-GTR-339. 2015. 123

robins are found throughout the ponderosa pine, mixed-conifer, and quaking aspen 

forests (Franzreb and Ohmart 1978; Siegel 1989; Winternitz 1976). Robins were not 

detected above 9,000 ft (2743 m) in the San Francisco Mountains of north-central 

Arizona (Coons 1984). In the Black Hills, robins are commonly found wherever there 

are trees. They inhabit ponderosa pine, white spruce, quaking aspen, and bur oak forests in all possible combinations. They are common in riparian areas and orchards, as 

well as in burns, meadows, and residential areas (Panjabi 2001; Pettingill and Whitney 

1965).

American Robins show a preference for nesting in coniferous trees early in the 

breeding season (April through June) and then nest more often in deciduous trees later 

in the summer (June through July) (Savard and Falls 1981; Yahner 1983). Thirty-six 

percent of the nests discovered by Winternitz (1976) were in pure ponderosa pine 

forests and 27 percent in quaking aspen/willow (Salix spp.) stands. In non-urban areas, 

mean heights of American robin nests ranged from 2.3 to 4.7 ft (0.7 to 1.4 m) above 

ground level (Howell 1942; Preston 1946; Preston and Norris 1947; Savard and Falls 

1981; Stauffer and Best 1980; Young 1955). In riparian habitats in Iowa, the mean 

height of nests was 32.2 ft (9.8 m) (Stauffer and Best 1986). Dellinger and others 

(2007) found a positive relationship between nest survival and decreasing nest height 

and reported more nests near forest edges such as roads and trails. Similarly, Davidson 

and Knight (2001) found that daily nest survival increased with proximity to forest 

edge and decreased with proximity to forest interiors. Savard and Falls (1981) noted 

that vertical distribution of foliage was more important in determining nest height than 

was foliage volume. More nests were located in the foliage layer just below the layer 

with the greatest volume regardless of tree type (conifer or deciduous). Howell (1942) 

noted 50 percent foliage cover around nests in the Pacific Northwest. In the Black 

Hills, American robins were most abundant in sapling to pole-sized quaking aspen and 

paper birch trees with greater than 70 percent canopy cover (Mills and others 2000). 

The time robins spent foraging on the ground decreased steadily as the distance from 

cover increased (Oyugi and Brown 2003).

Diet

Across their range, robins eat insects and worms primarily during the spring, 

while fruits dominate their diets in the fall and winter (Martin and others 1951; Russell 

and others 2009; Wheelwright 1986; Witmer 1996). In mixed-species and ponderosa 

pine forests in California, beetles (coleopterans) were the most common robin food 

(Otvos and Stark 1985). Similarly, Wheelwright (1986) found beetles comprised 40 

percent of the robin’s invertebrate diet while caterpillars, earthworms, flies, sowbugs, 

snails, spiders, termites, millipedes, and centipedes were also consumed (Martin and 

others 1951). Sugary, lipid-rich fruits, though low in protein, are also consumed by 

robins and in the eastern United States cherries (e.g., Prunus sp.) made up 23 percent 

of their diet (Witmer 1996). 

Home range

Robin territories ranged in size from 0.3 to 2 acres (0.1 to 0.8 ha) and varied 

inversely with population density in New York, Wisconsin, and Tennessee (Sallabanks 
124 USDA Forest Service RMRS-GTR-339. 2015.

and James 1999). Knupp and others (1977) reported robins defending immediate nest 

areas while still foraging in undefended areas up to 985 ft (300 m) away.

Populations

In an old ponderosa pine forest in northern Arizona robin nesting densities 

ranged from 2.3 to 20.0 breeding birds/100 acres (5.7 to 49.4/100 ha), in harvested 

forests densities ranged from 0.5 to 9.4 breeding birds/100 acres (1.2 to 23.3/100 ha), 

and in a harvested forest that retained over 90 ft2/acre (20.7 m2/ha) of trees greater 

than 20 inches (51 cm) DBH, robin densities averaged 3.3 breeding birds/100 acres 

(8.1/100 ha) (Haldeman 1968; Siegel 1989). In Arizona, robin breeding densities 

ranged from 2.0 to 7.5 birds/100 acres (4.9 to 18.5/100 ha) in undisturbed old ponderosa pine forests and in partially harvested mixed conifer forests, breeding densities 

ranged from 2.0 to 12.8 robins/100 acres (4.9 to 31.6/100 ha) (Franzreb 1977). 

Clearcut mixed conifer forests had robin breeding densities of 0.5 birds/100 acres 

(1.2/100 ha) (Haldeman 1968; Szaro and Balda 1979).

In the Black Hills from 2001 through 2009, average densities of American robins in white spruce forests were 150 birds/mile2 (58 birds/km2) and the density in the 

southern Hills was 41 birds/mile2 (16 birds/km2). Robin abundance averaged 49 birds/

mile2 (19 birds/km2) in burned ponderosa pine, 65 birds/mile2 (24 birds/km2) in old 

ponderosa pine, and 93 birds/mile2 (36 birds/km2) in the northern Black Hills (White 

and others 2010). Breeding density in the northern part of Rapid City, South Dakota, 

was 10 pairs/100 acres (24.7/100 ha) (Pettingill and Whitney 1965). 

Shirley (2005) noted that robin abundance was negatively correlated with 

conifer density in British Columbia. Drolet and others (1999) found abundant robins 

living within poorly stocked boreal forests in Quebec. American robin densities were 

also found to be positively correlated with the proportion of quaking aspen occurring 

in the overstory. Stands with quaking aspen density expressed as basal area greater 

than 64 percent of the total basal area, contained high bird densities (Scott and Crouch 

1988). 

In the western United States American robins were associated with ponderosa 

pine forests (Saab and Powell 2005). Robin populations can significantly increase 

when ponderosa pine forests are severely burned, however spring fires can negatively 

affect robin populations (Kotliar and others 2007; Snyder 1992). Robins often respond 

positively to low and moderately severe prescribed fires in ponderosa pine forests that 

increase food availability (Dickson and others 2009; George and Zack 2008; Russell 

and others 2009; Smucker and others 2005). In beetle-killed lodgepole (Pinus contorta) and ponderosa pine forests that were harvested but retained structural complexity 

had high nest survival rates (Kroll and others 2010). 

American Three-toed Woodpecker

The American three-toed woodpecker (Picoides dorsalis, formally P. tridactylus) is a medium-sized black and white woodpecker measuring 8 inches (20 cm) 

long and weighing 1.6 to 2.3 ounces (46 to 66 g) (Banks and others 2003; Leonard 

2001). Although they are not abundant, their close association with spruce (Picea spp.) 

forests makes it an available prey species for goshawks where they co-occur (Squires 

and Reynolds 1997). In general, woodpeckers (including the hairy and black-backed 
USDA Forest Service RMRS-GTR-339. 2015. 125

woodpeckers) regularly occur in goshawk diets (Lewis and others 2006; Promessi and 

others 2004; Rogers and others 2006; Smithers and others 2005; Squires 2000; Watson 

and others 1998). The three-toed woodpecker was found in goshawk prey remains in 

south-central Wyoming and in the Black Hills (Erickson 1987; Squires 2000).

Distribution

American three-toed woodpeckers occur throughout boreal and montane forests 

in North America, ranging from Alaska and Canada through northern, central, and 

southern Rocky Mountains in Idaho, Montana, Utah, Wyoming, Colorado, New 

Mexico, the Colorado Plateau in Utah, Arizona, New Mexico, the Cascade Mountains 

in Oregon and Washington, and in the northeastern United States. Three-toed woodpeckers are absent from Sierra Nevada mountains of California and Nevada. They live 

in the Black Hills where their distribution strongly coincides with white spruce forests 

(Leonard 2001; Steffen 1981; White and others 2010). 

Habitat

American three-toed woodpeckers use mature and old coniferous forests with 

abundant insect-infested snags, dying trees, and woody debris (Goggans and others 1989; Koplin 1969; Leonard 2001). Some studies indicate they prefer moist to 

swampy areas and select nest sites relatively close to water (Hoffman 1997; Short 

1974). Three-toed woodpeckers are strongly associated with burned and insect infested coniferous forests (Bull and others 1986; Hoffman 1997; Hoyt and Hannon 2002; 

Koplin 1969; McCambridge and Knight 1972; Murphy and Lehnhausen 1998). 

In the western United States, three-toed woodpeckers use lodgepole pine, 

ponderosa pine, quaking aspen, and mixed-conifer forests (Goggans and others 1989; 

Mohren 2002). In the Black Hills, they use mixtures of ponderosa pine, white spruce, 

and quaking aspen despite the fact that white spruce and quaking aspen-dominated 

forests make up less than 6 percent of the Hill’s forests (Mohren 2002). These woodpeckers use forests with minimal understory vegetation and those with high densities 

of small diameter and short snags. Three-toed woodpeckers are often found in forests 

disturbed by fire, flood, and wind or in old and decadent forests (Wiggins 2004). In 

beetle-infested forests of Oregon, 16 pairs of three-toed woodpeckers selected unharvested, pure lodgepole pine or mixed-conifer dominated by lodgepole pine forests for 

nesting (Goggans and others 1989). Likewise, in Oregon, Bull (1986) found three-toed 

woodpecker nests in pure lodgepole pine stands. In Idaho and Montana, 84 percent of 

the nests discovered were located in unharvested forests and in northwestern Montana, 

three-toed woodpeckers nested in only partially cut and burned forests, as opposed to 

those that were clearcut (Caton 1996; Hutto and Gallo 2006; Leonard 2001). Since 

three-toed woodpeckers have only been detected in mature white spruce, quaking 

aspen, and ponderosa pine forests in the Hills, it is likely they use these same areas for 

nesting. 

Three-toed woodpeckers use live and dead trees for nesting, depending on how 

much decay a potential nest tree has. This woodpecker used more live (65 percent) 

than dead (35 percent) trees in Oregon and all had intact tops (Goggans and others 

1989). In Montana, 97 percent of nest trees were dead and only 3 percent were alive, 

of which 80 percent had intact tops (Caton 1996). In Idaho and Montana, 59 of 61 
126 USDA Forest Service RMRS-GTR-339. 2015.

nests were in snags (Leonard 2001). In British Columbia, nearly half of 23 nest trees 

were located in Douglas-fir (Pseudotsuga menziesii) and ponderosa pine snags with 

broken tops (Steeger and Dulisse 2002). 

Three-toed woodpeckers excavate cavities in dead and live trees with decay, as 

the soft wood is easy to excavate. Both sexes build cavities which can take days to 

complete (Leonard 2001). In British Columbia, 5 of 13 nests were in lodgepole pine 

trees and the remaining 8 were in five other tree species (Steeger and Dulisse 1997). 

In Idaho and Montana, 31 percent of the nests were in Douglas-fir trees, 29 percent in 

lodgepole pine, 19 percent in ponderosa pine, and 14 percent in subalpine fir (Abies 

lasiocarpa) trees (Leonard 2001). In another Montana study, nests were located in quaking aspen (44 percent), western larch (Larix occidentalis) (30 percent), Engelmann 

spruce (Picea engelmannii) (18 percent), subalpine fir (4 percent), black cottonwood 

(Populus trichocarpa) (2 percent), and lodgepole pine (2 percent) trees (Caton 1996). 

Nests in Colorado were in Engelmann spruce (81 percent), lodgepole pine (12 percent), and subalpine fir (7 percent) trees (Koplin 1969). Bailey and Niedrach (1965) 

reported Colorado nests in quaking aspen and Engelmann spruce trees. In British 

Columbia, lodgepole pine (43 percent) and western larch (30 percent) trees were used 

most often, followed by quaking aspen (9 percent), Douglas-fir (9 percent), ponderosa 

pine (4 percent), and western red cedar (Thuja plicata) (4 percent) trees (Steeger and 

Dulisse 2002). Not much has been documented on three-toed woodpeckers’ nests in 

the Black Hills, but Pettingill and Whitney (1965) reported a nest in the dead portion 

of a live white spruce.

Like black-backed woodpeckers, three-toed woodpeckers tend to use relatively 

small trees for nesting. In bark beetle-infested forests of Oregon, three-toed woodpeckers nest trees averaged 11 inches (28 cm) DBH (Goggans and others 1989). In 

Montana, nest cavities were found in quaking aspen, Engelmann spruce, and western 

larch trees having a mean DBH of 12 inches (31 cm) and mean height of 76 ft (23 m) 

(Caton1966). Also in Montana, the mean DBH of nest trees was 9.8 inches (25 cm) 

(McClelland and others 1979). Nest trees in British Columbia averaged 10 inches 

(26 cm) DBH with a mean height of 69 ft (21 m) (Steeger and Dulisse 1997).

Foraging habitat consists of dying or recently killed trees that are beetleinfested. In Canada, three-toed woodpeckers used trees with 3 to 6 inch (8 to 15 cm) 

DBHs while black-backed woodpeckers used trees with 7.5 to 9.8 inch (19 to 25 cm) 

DBHs (Villard 1994). In Oregon, 3 three-toed woodpeckers foraged in mixed-conifer, 

lodgepole pine-dominated mixed-conifer, and lodgepole pine forests (Goggans and 

others 1989). They rarely foraged in seedling, sapling, multi-storied, or cut-over 

forests. In northeastern Colorado, three-toed woodpeckers foraged primarily on the 

trunks of burned Engelmann spruce trees but also used lodgepole pine and subalpine 

fir trees (Koplin 1969). Likewise, Bull and others (1986) found three-toed woodpeckers in Oregon used far more dead (78 percent) than live trees for foraging. Three-toed 

woodpeckers in Manitoba, Canada, foraged 95 percent the time on dead trees (Villard 

1994). In the Black Hills, Mohren (2002) found that three-toed woodpeckers predominantly foraged on 9 inch (23 cm) DBH snags with broken tops. In Oregon, foraging 

trees averaged 9.5 inches (24 cm) DBH and 62 ft (19 m) tall (Bull and others 1986).

Three-toed woodpeckers prefer to forage on gently sloping to flat terrain (Bull 

and others 1986; Goggans and others 1989; Hoffman 1997; Short 1974). In the Black 
USDA Forest Service RMRS-GTR-339. 2015. 127

Hills, three-toed woodpeckers foraged in patchy forests where they used the borders of 

ponderosa pine and white spruce stands (Mohren 2002). However, three-toed woodpeckers avoid foraging in areas with abrupt forest edges such as those on clearcuts 

(Gagne and others 2007).

Diet

Three-toed woodpeckers predominantly consume bark beetles of the family 

Scolytidae as well as other insects, arthropods, vegetable matter, and sap (Koplin 

1969; Massey and Wygant 1954; Villard 1994). They forage by scaling, pecking, or 

flaking tree bark to expose the beetles and larvae that lie just below the surface (Bull 

and others 1986; Murphy and Lehnhausen 1998; Short 1974; Villard 1994). This is 

in contrast to the excavating that black-backed woodpeckers do to reach wood boring beetles (Cerambycidae). Three-toed and black-backed woodpeckers do not have 

similar foraging habits where three-toed woodpeckers tend to forage higher on tree 

boles and on smaller trees than black-backed woodpeckers (Short 1974; Villard 1994). 

Three-toed woodpeckers rarely forage on the ground or on downed logs (Villard 

1994). 

Home range

Home range sizes of three-toed woodpeckers are highly variable depending on 

time of year and available nest trees and food. Male home range sizes in Oregon, for 

example, varied in size from 131 to 751 acres (53 to 303 ha) (Goggans and others 

1989). 

Populations

Densities of three-toed woodpeckers tend to be lower in undisturbed forests than 

in burned and beetle-infested forests. In Colorado, Koplin (1969) found 0.10 three-toed 

woodpeckers/acre (0.25/ha) in an unburned Engelmann spruce-fir-lodgepole pine forest 

and 5.05 woodpeckers/acre (12.5/ha) in the same forest two years after it burned, 

about a 50-fold increase. In Grand Teton National Park, Wyoming, densities in unburned 

Engelmann spruce-fir forest were estimated at 0.04/100 acres (0.1/100 ha), and in 

14 recently burned forests in Montana, the densities were 1.3 woodpeckers/100 acres 

(3.2/100 ha) (Hutto 1995; Taylor and Barmore 1980). 

From 2001 to 2009 in the Black Hills, densities of three-toed woodpeckers in 

white spruce forests averaged 0.01/acre (0.02/ha) (White and others 2010).While observed in other forests, they were always associated with small stands of white spruce 

(Panjabi 2001, 2003). Interestingly, over a 9-year period, three-toed woodpeckers 

were never detected within major burns in the Black Hills (Giroir and others 2007). 

Likewise, in a survey in the Black Hills, Mohren (2002) only found this species in low 

densities within primarily white spruce and quaking aspen forests. He also detected 

them in other forests but, again, always associated with white spruce. Mohren (2002) 

did not find them in the large burns of the southwestern Hills. In unburned forests, 

Mohren (2002) estimated densities of 0.04/100 acres (0.09/ha) and population abundance of 320 individuals in 2001 and 440 in 2002. 

Little is known of reproductive success for three-toed woodpeckers or factors 

that influence it. Tree harvesting likely has a negative influence on fledging success 
128 USDA Forest Service RMRS-GTR-339. 2015.

and predators are also responsible for nest failures. In Oregon, Goggans and others 

(1988) found a few nests in harvested areas but 2 of 3 failed, whereas 5 out of 12 in 

unharvested stands failed. Within beetle-infested forests of British Columbia, where 40 

percent of the lodgepole pine volume had been removed, hatching success for 8 nests 

was 100 percent but only 3 nests fledged young (Steeger and Dulisse 1997). 

Black-Backed Woodpecker 

The black-backed woodpecker (Picoides arctictus) is medium-sized, measuring 

9 inches (23 cm) in length and weighing 2.2 to 3.1 ounces (61 to 88 g). Although they 

are not particularly abundant, their close association with conifer forests makes them 

potential prey for goshawks (Squires and Reynolds 1997). Several woodpeckers in the 

genus Picoides are eaten by goshawks, but the only known black-backed woodpecker 

killed by goshawks was in the Black Hills (Erickson 1987; Lewis and others 2006; 

Promessi and others 2004; Rogers and others 2006; Smithers and others 2005; Squires 

2000; Watson and others 1998).

Distribution

Black-backed woodpeckers occur throughout the boreal and montane forests of 

Canada and Alaska, montane forests of the western United States, including the Sierra 

Nevada Mountains of California, Cascade Mountains of Oregon and Washington, 

and Rocky Mountains of Idaho and northwestern Wyoming. They are absent from the 

southern Rocky Mountains (e.g., Arizona, Colorado, and New Mexico) but occur in 

the Black Hills (Dixon and Saab 2000; Steffen 1981; White and others 2010).

Habitat

Black-backed woodpeckers are strongly associated with recently burned and/

or beetle-infested conifer forests and they use a variety of conifer species throughout 

their range. In Alberta, Canada, they were often found in burned conifer forests (minor 

deciduous component) containing light to moderately burned, small diameter trees 

(Hoyt and Hannon 2002). In Alaska, moderate to heavily burned spruce trees were 

used most often as they contained abundant beetles (Murphy and Lehnhausen 1998). 

Within Oregon, black-backed woodpeckers used beetle infested ponderosa and lodgepole pine forests (Bull and others 1986). Likewise, in the Black Hills, they selected 

beetle infested ponderosa pine for foraging rather than for nesting (Bonnot and others 

2008, 2009).

Black-backed woodpeckers also use unburned forests, but this use is poorly 

understood. In Alberta, Canada, black-backed woodpeckers used old (>110 years) and 

unburned black (Picea mariana) and white spruce stands located 47 to 93 mi (75 to 

150 km) from recently (2 years) burned forests. However, no woodpeckers were 

observed in unburned forests within 31 miles (50 km) of the 2-year-old burn (Hoyt 

and Hannon (2002). Also Hoyt and Hannon (2002) suggested woodpeckers occupying unburned forests foraged in burned areas on the abundant insect populations. In 

unburned areas of the Black Hills, black-backed woodpeckers selected mature forests 

with high canopy cover (>70 percent), high tree and snag density, trees and snags 

with small diameters and short heights, and little or no ground cover (Mohren 2002). 

The author also suggested that forests with high canopy cover and high stem densities 
USDA Forest Service RMRS-GTR-339. 2015. 129

might reduce black-backed woodpecker’s vulnerability to goshawks. Such forests 

would also tend to have large amounts of dead and decaying trees and high insect 

populations (Hoyt and Hannon 2002; Mohren 2002).

In the Black Hills, abundance and availability of wood boring insects typically 

associated with high snag densities were the most important factors influencing blackbacked woodpeckers’ choice of nest sites (Bonnot and others 2008). For example, 

nest sites contained 108 snags/acre (267/ha) with DBHs exceeding 6 inches (15 cm) 

(Bonnot and others 2009). Likewise, in Idaho, nest density was higher in unharvested 

stands as opposed to harvested stands in which 50 percent of the snags had been 

removed. In the unharvested stands there were 33 trees/acre (81/ha) with an average 

DBH of 9 to 21 inches (23 to 53 cm). Also, in the unharvested areas, most of the trees 

were snags and of those 6.9 trees/acre (17/ha) had DBHs greater than 21 inches (53 

cm) (Saab and Dudley 1998).

Black-backed woodpeckers frequently select nest sites well within a burn’s 

interior. In the Black Hills, they selected nest sites located farther from an unburned 

forest edge than random sites. Vierling and others (2008) suggested that predators such 

as tree squirrels, chipmunks, and raccoons (Procyonlotor sp.) that typically occupy the 

forest interior and edge likely influence the woodpecker’s nest site selection. Blackbacked woodpeckers also select quaking aspen and old pine snags for nest sites some 

distance from beetle-infested tree patches where they feed (Bonnot and others 2009).

Black-backed woodpeckers excavate cavities in both live and dead deciduous 

trees such as quaking aspen, maple (Acer spp.), and birch, but they also nest in many 

dead and live conifers. Typically, both sexes participate in excavating a new cavity 

each year (Dixon and Saab 2000). While some black-backed woodpeckers in the Black 

Hills nest in live ponderosa pine and quaking aspen trees, the majority of nest cavities 

were excavated in snags (Bonnot and others 2009; Mohren 2002). Snags were large 

and often had broken tops and abundant decay making them easy to excavate (Bonnot 

and others 2009; Mohren 2002). Average cavity heights ranged from 16 ft (5 m) in 

Oregon to 36 ft (11 m) in Montana (Bull and others 1986; Caton 1996). In the Black 

Hills, cavity heights ranged from 2 ft (0.6 m) to 35 ft (10.5 m), and successful nests 

tended to be higher (Bonnot 2006) Average nest tree heights ranged from 62 ft (19 m) 

in Oregon to 105 ft (32 m) in Wyoming (Bull and others 1986; Hoffman 1997). 

In Idaho, nests in ponderosa pine and Douglas-fir trees averaged 15.5 inches 

(39 cm) DBH, and in Oregon, ponderosa pine nest trees averaged 12.2 inches (31 cm) 

DBH (Bull and others 1986; Dixon and Saab 2000). In the Black Hills, the probability 

of a black-backed woodpecker selecting a nest tree was negatively associated with 

increasing tree diameter (Bonnot and others 2009). Black-backed woodpeckers may 

select small trees for nesting due to the greater proportions of sapwood to heartwood. 

These woodpeckers can readily excavate nests in sapwood as it usually contains more 

decay than heartwood. This strategy reduces the competition for nest cavities with 

larger woodpeckers that cannot expand the cavity for their own use (Bull and others 

1986).

Post-burn harvesting can reduce the amount and quality of black-backed 

woodpecker habitat. In Idaho, nesting densities were more than double in unlogged 

post-burn forests compared to harvested areas in the same burn (Saab and Dudley 

1998). This result was true when all or half of the merchantable trees were removed 
130 USDA Forest Service RMRS-GTR-339. 2015.

post-fire. Despite differences in the number of nests among post-burn conditions, 

there was no difference in nesting success among the post-fire conditions created 

by no harvesting, removing all merchantable trees, and removing 50 percent of the 

merchantable trees. After wildfires in Montana, black-backed woodpeckers nested in 

unharvested areas, occurred sporadically in partially harvested areas, and were absent 

from areas that were clearcut (Caton 1996). 

Diet

Black-backed woodpeckers consume wood-boring beetle larvae (e.g., longhorn), 

wood-boring jewel beetles, metallic wood-boring beetles (both Buprestidae), and bark 

beetles (Bent 1939; Dixon and Saab 2000). They also feed on ants, spiders, fruits, 

acorns, and tree cambium tissue (Beal 1911). As excavators, black-backed woodpeckers are well suited for extracting insect larvae from trees and down logs (Murphy and 

Lehnhausen 1998). For example, in boreal forests of Manitoba, Canada, this species 

foraged on fallen trees 41 percent of the time. Likewise, in spruce-larch (Larix spp.) 

bogs in New York, they were often seen foraging at the base of trees and on downed 

logs. Where they co-exist with three-toed woodpeckers, black-backed woodpeckers 

forage lower on tree trunks and on larger trees than do three-toed woodpeckers (Short 

1974; Villard 1994). 

Home range

The home range size of black-backed woodpeckers is likely to vary with time 

since bark beetle infestation occurred. In bark beetle infested lodgepole pine forests 

in Oregon, the home range of three black-backed woodpeckers ranged from 178 to 

810 acres (72 to 328 ha) during the post-fledgling period (Goggans and others 1989). 

In southwestern Idaho, post-fledging home range sizes of four adults in post-burn 

ponderosa pine and Douglas-fir forests ranged from 284 to 1893 acres (115 to 766 

ha) and increased with time since fire (Dudley and Saab 2007). A single black-backed 

woodpecker living in southwestern Idaho had a breeding season home range of 178 

acres (72 ha) and another used 151 acres (61 ha) in Vermont (Dixon and Saab 2000).

Populations

Populations of black-backed woodpeckers substantially increase following 

wildfires due to the abundant food supply. As the sapwood deteriorates after a fire, 

wood-boring beetle populations decrease and black-backed woodpeckers typically 

disperse and may abandon nests (Murphy and Lehnhausen 1998; Nappi and Drapeau 

2009). Densities can be 6 to 20 times higher in burned compared to unburned forests, 

an observation that suggests burned forests are essential for maintaining black-backed 

woodpecker populations ((Mohren 2002; White and others 2010 Hutto 1995). In 

2000, woodpecker densities in unburned Black Hills forests were 0.11 bird/100 acres 

(0.28/100 ha), and in 2001, they were 0.10 birds/100 acres. These densities were similar to those found in other unburned forests (Apfelbaum and Haney 1981; Bock and 

Lynch 1970; Mohren 2002; Murphy and Lehnhausen 1998). 

Reproductive success of black-backed woodpeckers in burned forests decreases 

with time since the fire and predation was usually the cause of nest failure (Bonnot 

and others 2008; Nappi and Drapeau 2009; Vierling and others 2008). It is thought that 
USDA Forest Service RMRS-GTR-339. 2015. 131

as a forest regenerates after fire, the newly established vegetation provides cover for 

mammals that can prey on the fledglings. Nesting success in Black Hills beetle-killed 

forests was 78 percent in 2004 and 44 percent in 2005 (Bonnot and others 2008). 

Similarly, from 2002 through 2004 in the Black Hills, nesting success was 60 percent 

in low severity burns, 50 percent in medium severity burns, and 80 percent in high severity burns (Vierling and others 2008). These rates were similar to those of 87 percent 

in burned forests in Idaho, 100 percent in burned forests of Wyoming, and 69 percent 

in beetle infested forests in Oregon (Dixon and Saab 2000; Goggans and others 1988). 

The effect of fire severity on nest success was likely related to the amount of cover left 

after a fire. As such, predators are likely to have a greater impact on nesting success in 

areas with the large amounts of cover after a burn or in areas where nests are located 

near unburned forests (Saab and Vierling 2001). Burned mature forests with high canopy cover also tend to have more nests and better nesting success than burned young 

forests with low canopy cover (Nappi and Drapeau 2009; Vierling and others 2008).

Black-Headed Grosbeak

The black-headed grosbeak (Pheucticus melanocephalus) is a medium-sized 

songbird measuring 7 to 7.5 inches (18 to 19 cm) in length and weighing 1.4 to 

1.8 ounces (40 to 50 g) (Ortega and Hill 2010). Although rare, black-headed grosbeaks 

were found in goshawk prey remains in eastern Oregon, California, and Wyoming 

but have not been found in prey remains of the Black Hills (Bloom and others 1986; 

Reynolds and Meslow 1984; Squires 2000). 

Distribution 

Black-headed grosbeaks occur across western North America, from southwestern Canada (southern British Columbia and Alberta and southwestern Saskatchewan) 

south to Mexico (Baja California and central Mexico) and east to southwestern Texas 

and western North Dakota (Ortega and Hill 2010). Black-headed grosbeaks are summer residents in the lower elevations along the edges of the Black Hills as typified 

by populations found near Rapid City, Wind Cave National Park, and Hot Springs 

(Over and Thomas 1921; Panjabi 2003; Pettingill and Whitney 1965; South Dakota 

Ornithologists’ Union 1991). Grosbeaks are migratory, breeding in North America and 

wintering in Mexico and Central America. 

Habitat 

Black-headed grosbeaks use large shade trees with well-developed shrub understories that include abundant vegetative edges and structural diversity (Dykstra and 

others 1999). They live in riparian and flood plains, openings in pine forests, quaking 

aspen groves, pinyon/juniper (Pinus edulis/Juniperus spp.) woodlands, oak (Quercus

spp.) forests, savanna, orchards, deserts/dry grasslands, and urban yards (Ortega and 

Hill 2010; South Dakota Ornithologists’ Union 1991). In the Black Hills, black-headed 

grosbeaks are frequently found in foothill and mountain riparian habitats containing cottonwood (Populus spp.), willow, box elder (Acer negundo), and chokeberry 

(Prunus virginiana) (Panjabi 2001, 2003). Quaking aspen is an important component 

of their habitat, and bur oak is frequently used in the Bear Lodge Mountains (Pettingill 

and Whitney 1965). 
132 USDA Forest Service RMRS-GTR-339. 2015.

Black-headed grosbeaks nest in small deciduous trees and shrubs usually near 

streams. Nests are loosely built cups, without cementing materials, made of twigs, 

pine needles, rootlets, plant stems, and other green material. Plant species used for 

nesting include: willow, oak, alder, maple, blackberry (Rubus spp.), cottonwood, 

elderberry (Sambucus spp.), juniper, and pinyon pine (Ortega and Hill 2010; Ortega 

and Ortega 2003; Weston 1947). In the Black Hills, grosbeaks nest in low deciduous 

shrubs in riparian areas. Near Rapid City, nests were located 8 to 12 ft (2.4 to 3.7 m) 

off of the ground in willows (Salix spp.). In Spearfish Canyon, nests were located in 

chokecherry, and box elder 5 to 6 ft (1.5 to 1.8 m) off of the ground (Pettingill and 

Whitney 1965).

Diet

Black-headed grosbeaks consume grains, fruits, seeds, beetles, leaf buds, flowers, flower buds, moths, butterflies, and other insects (Ortega and Hill 2010; Weston 

1947). This species switches among food items as they become available throughout 

the breeding season. 

Home range

Little is known about the home ranges of black-headed grosbeaks. Both males 

and females aggressively defend their territories, which are established by singing 

males. One study found home ranges of 6.7 acres (2.7 ha) in Utah and 2 acres (0.8 ha) 

in New Mexico (Hill 1988b; Ritchison 1983). 

Populations 

Black-headed grosbeak abundance varies across its range with the highest 

densities reported in California and southwestern Oregon and the lowest in grassland 

and desert habitats (Ortega and Hill 2010). In 2002, grosbeak densities in the Black 

Hills were 10.3/100 acres (25.4/100 ha) in foothill riparian habitats, 5.2/100 acres 

(12.8/100 ha) in mountain riparian habitats, 2.6/100 acres (6.32/100 ha) in quaking aspen forests, and 0.7/100 acres (1.65/100 ha) in ponderosa pine forests of the northern 

Hills (Panjabi 2003). Similarly, White and others (2010) estimated densities of grosbeaks to be 1.1/100 acres (2.63/100 ha) in ponderosa pine forests of the northern Hills. 

Adult grosbeaks are preyed upon by goshawks, Cooper’s hawks, sharp-shinned 

hawks, and domestic and feral cats. In the Sandia Mountains of New Mexico, Hill 

(1988) found males having good nest success defending territories that were structurally heterogeneous. In contrast, homogenous, densely vegetated habitats tended to 

contain Steller’s jays and other nest predators, making the male grosbeaks less effective at protecting their nests. In the Black Hills, blue jays are probably nest predators 

as they co-occur with black-headed grosbeaks in riparian habitats (Panjabi 2003). 

Because gray jays live at higher elevations, they are probably an infrequent nest predator of grosbeaks. Insecticides may reduce food supply, which can contribute to adult 

mortality, as can intense animal grazing that reduces shrub cover, thereby exposing 

grosbeaks to predators. As migrants, this species likely faces other threats during migration and where they overwinter (Gardali and Nur 2006; Ortega and Hill 2010).

Egg laying by other birds in grosbeak nests (nest parasitism) can be problematic, 

especially in intensely grazed habitats. The brown-headed cowbird (Molothrus ater), 
USDA Forest Service RMRS-GTR-339. 2015. 133

though a rare summer resident in the Black Hills, has the potential to use grosbeak 

nests. There is evidence throughout the Black Hills that other birds were using grosbeak nests to some degree. It has been observed that the densities of the brown-headed 

cowbird were high in the same riparian habitats used by black-headed grosbeaks 

(Panjabi 2001, 2003; Pettingill and Whitney 1965). 

Bushy-Tailed Woodrat (Pack Rat)

Bushy-tailed woodrats (Neotoma cinerea) are moderate-sized rodents. Males 

weigh around 13 ounces (337 g) and average 15 inches (379 mm) in total length and 

females weigh around 10 ounces (275 g) and average 14 inches (356 mm) in length. 

Body size also varies geographically with bushy-tailed woodrats living in colder 

climates (e.g., higher latitudes and elevations) being larger than those living in warmer 

climates. In the Black Hills, average length of 8 males was 14 inches (359 mm) and 

their average weight was 9.6 ounces (273 g) (Grayson 2000; Turner 1974). Their use 

of forests makes bushy-tailed woodrats potential goshawk prey (Promessi and others 

2004; Reynolds and Meslow 1984; Watson and others 1998). Although their nighttime 

foraging behavior probably limits their availability, they can sometimes be active in 

the late afternoon. Bartelt (1977), for example, found woodrat remains at 3 of the 

5 nests he visited in the Black Hills.

Distribution

Bushy-tailed woodrats occur in Canada from the Yukon and Northwest 

Territories, through British Columbia and western Alberta, south to northern 

California, northern Arizona, and New Mexico, and as far east as South and North 

Dakota. In the Black Hills, bushy-tailed woodrats live at the higher elevations and 

down to about 4,000 ft (1219 m) (Smith 1997). 

Habitat

Bushy-tailed woodrats are often associated with Douglas-fir, spruce, quaking 

aspen, and ponderosa pine forests. Rocky shelters such as caves, crevices, cliffs, and 

piles of large boulders are key habitat features (Finley 1958; Smith 1997). They also 

use abandoned buildings, mine tunnels, and wood piles (Grayson 2000).They build 

dens (middens) within or near these structures, which can be associated with cavities 

in both live and dead trees and downed logs (Carey 1991; Finley 1958; Grayson 2000; 

Smith 1997; Ulev 2007). Dens are constructed from sticks, bones, conifer cones, 

feathers, owl pellets, bits of rope, leather, and paper that are stuffed into crevices or 

cavities (Higgins and others 2002; Turner 1974). Within dens, cup-shaped nests are 

constructed from shredded plant material such as leaves, bark, or dry grass (Smith 

1997). One to four nests may occur in a single den, but a den is usually occupied by 

one woodrat at a time. Ten by ten foot (3 by 3 m) dens are normal for woodrats and 

a single den has been known to be occupied by woodrats for more than 40,000 years 

(Bentancourt and others 1990). 

Shrub cover along forest edges provides excellent woodrat foraging, especially 

if it is located near rock outcrops where they prefer to den (Finley 1958). Riparian 

areas not only provide cover but also supply stream noise, which further protects the 

woodrats from predators. Such habitats in the Black Hills were occupied by woodrats 
134 USDA Forest Service RMRS-GTR-339. 2015.

in the steep canyons of Beaver Creek, Ditch Creek, and Big and Little Spearfish 

Canyons (Turner 1974). Heavy grazing can degrade riparian habitats, interrupt woodrat dispersal, and isolate family groups (Carey 1991).

Diet

Bushy-tailed woodrats feed mostly on shrub and tree leaves, but they also consume seeds, bark, and fruits (Smith 1997). In Colorado, 89 different plant species were 

consumed by woodrats, with tree needles being the most common along with leaves 

from cherry (Prunus spp.), current (Ribes spp.), rose (Rosa spp.), and aster (Aster

spp.) shrubs (Finley 1958). Woodrats begin in late summer collecting and storing food 

they will consume during the winter. This year-round activity potentially makes them 

important prey for wintering goshawks. 

Home range

Bushy-tailed woodrats are territorial and strongly defend their food stores and 

dens against non-family members (Carey 1991). They have large home ranges with 

some in Canada being 20 times larger than those of other woodrats. Male home ranges 

averaged 15.1 acres (6.12 ha), and female home ranges averaged 8.8 acres (3.56 ha) 

(Topping and Millar 1996). In Oregon, home range for a single family group might be 

2 to 5 acres (0.8 to 2 ha), but individuals typically venture up to 450 ft (137 m) from 

their den to forage, suggesting that home ranges can be as large as 15 acres (6 ha). 

Woodrat movements up to 1,250 ft (381 m) have been recorded (Carey 1991).

Populations

Because the rocky habitats used for dens vary spatially, bushy-tailed woodrat 

populations vary seasonally and annually (Smith 1997). In addition, such shelters 

provide stable living conditions all year, especially where snow depths are great 

and winters are cold. Therefore, these habitats may be the most important factor for 

determining bushy-tailed woodrat populations (Carey 1991). Areas with high populations may attract predators, which can exert significant pressure (e.g., predation and 

emigration) on a family group even resulting in local extinction. Facilitated by riparian corridors, dispersal of offspring is important for colonization of vacated habitats 

(Carey 1991). In Canada, one family group occupying 2 to 5 acres (0.8 to 2 ha) was 

typical and 5 woodrats/100 acres (12.4/100 ha) was an average population density 

(Banfield 1974). In Douglas-fir forests of Oregon, the density of bushy-tailed woodrats in closed-canopy areas along streams was 44/100 acres (108/100 ha), in rocky 

sites it was 20/100 acres (50/100 ha), and in mixed-conifer forests woodrat density 

was 8/100 acres (20/100 ha) (Carey and others 1992).

Cottontails

The eastern cottontail (Sylvilagus floridanus similis), mountain (or Nuttall’s) 

cottontail (S. nuttalli grangeri), and desert (or Audubon’s) cottontail (S. audubonii 

baileyi) are medium-sized rabbits (lagomorphs) with males averaging 13.8 inches 

(35.2 cm) long and their weight averages 25.3 ounces (719 g). Females average 14.5 inches (37.2 cm) in length and weigh an average of 27.9 ounces (790 g) 

(Chapman 1975; Orr 1940). Their widespread distribution, occurrence in numerous 

habitats and relatively large body size make them a common and important goshawk 
USDA Forest Service RMRS-GTR-339. 2015. 135

prey throughout North America (Reynolds and Meslow 1984; Reynolds and others 2006). Of 670 prey deliveries in Arizona, 89 eastern cottontails (13.3 percent) 

represented 42.3 percent of the total biomass consumed (Rogers and others 2005). In 

Minnesota, eastern cottontails comprised 1.1 percent of goshawk diets and accounted 

for 4.8 percent of total biomass consumed (Smithers and others 2005). In Idaho, cottontails comprised 2 percent of the goshawk’s diet, in New Mexico 29 percent of the 

prey taken by goshawks were cottontails, and 13 percent in Arizona (Kennedy 1991; 

Mannan and Boal 1993; Patla 1997; Salafsky and others 2005). In the Black Hills, 

cottontail remains were found beneath 3 of 5 nests Bartelt (1977) visited and cottontail 

remains were found below several nests visited by Knowles and Knowles (2009). 

Distribution

Eastern cottontails have a wide distribution, occurring from extreme southern 

Canada south into South America and from the eastern United States across the 

Central Plains to the foothills of the Rockies (Chapman and others 1980). Eastern cottontails are uncommon in the Black Hills but do occur below 4,200 ft (1280 m) in the 

eastern portion of the Hills where desert cottontails also live (Turner 1974). Mountain 

cottontails range across the Intermountain West from just north of the Canadian 

border south to the American Southwest, and from the eastern slope of the Rockies 

to the eastern slope of the Cascade-Sierra Nevada range (Chapman 1975). Being the 

most abundant rabbit in the Black Hills, mountain cottontails occupy the central and 

western portions of the Black Hills, living in both ponderosa pine and white spruce 

forests, down to about 4,500 ft (1372 m) (Higgins and others 2002; Turner 1974). At 

lower elevations in the western Black Hills, mountain cottontails use forest edges and 

brushy draws where they may occur with desert cottontails. However, in the eastern 

Black Hills the two species are usually separated (Turner 1974). Desert cottontails 

range across the arid regions of the western United States and Mexico from near the 

Canadian border in Montana south to central Mexico and west to the Pacific coast 

(Chapman and Willner 1978). In the Black Hills, they are common in the upland 

prairie of Wind Cave National Park. The desert cottontail occupies lower elevation 

habitats around the entire Black Hills and surrounding prairies, up to 5,000 ft (1524 m) 

(Turner 1974). 

Habitat

Cottontails are well adapted to a variety of vegetative types and therefore thrive 

in patchy landscapes such as desert scrub, grassland, woodland, and montane coniferous forest (Frey and Malaney 2006; Mankin and Warner 1999). Dense vegetation near 

the ground is a key determinant of habitat suitability (Althoff and others 1997). In the 

Black Hills, eastern and mountain cottontails occupy brushy ravines, streamside thickets, and forested edges of valley streams (Turner 1974). Mountain cottontails inhabit 

ponderosa pine uplands and white spruce filled canyons that often have an abundance 

of rocks, fallen logs, and shrubs (Turner 1974). Desert cottontails use open grasslands 

and pastures of lower elevations in the Hills. In the south-central Black Hills, Stebler 

(1939) found mountain cottontails in mountain prairies dominated by short grasses and 

sagebrush (Artemisia) but they were not found in ponderosa pine and bur oak forests 

or in riparian areas of the Hills.
136 USDA Forest Service RMRS-GTR-339. 2015.

Cottontails prefer areas with well-developed shrub and herbaceous understories 

for food and escape cover (Allen and others 1982; Althoff and others 1997; Bond and 

others 2001; Boyd and Henry 1991; Cayot 1978; Pils and others 1981). Farmsteads 

that contain buildings, trees, and shrubs are also frequently used by cottontails 

(Mankin and Warner 1999). In subalpine forests in New Mexico, mountain cottontails 

commonly used forest edges containing bristlecone pine (Pinus aristata), quaking 

aspen, and abundant ground cover (Malaney and Frey 2006).

In New Mexico, eastern and mountain cottontails chiefly inhabit ponderosa 

pine, mixed-species, and spruce-fir forests (Findley 1987). Frey and Malaney (2006) 

found that mountain cottontails occupied a wide range of elevations and vegetative 

zones where they preferred warm, open habitats or burned areas. In Arizona, eastern 

cottontails are generally restricted to oak woodlands associated with riparian habitats (Cockrum 1982). In Colorado, mountain cottontails decreased in abundance as 

elevation increased from 6,800 to 8,900 ft (2072 to 2713 m) (Cayot 1978). At higher 

elevations, mountain cottontail abundance tended to be greater on southeastern aspects 

where ponderosa pine was more common and bitterbrush (Purshia tridentata) ground 

cover increased to 50 percent. Prevalence of bare ground, common juniper, and 

downed timber were negatively associated with mountain cottontail abundance (Cayot 

1978). In southern British Columbia, mountain cottontails used ponderosa pine forests, 

sagebrush dominated prairies, riparian areas, open Douglas-fir forests, and lodgepole 

pine forests (Sullivan and others 1989). 

Most eastern cottontail nests are located in grass, dense shrubs, or among 

downed logs (Allen and others 1982; Althoff and others 1997). Althoff and others 

(1997) noted increased use of burrows when above ground temperatures dropped below freezing. Bond and others (2002a) speculated where winters are long and severe, 

shrub dominated habitats become important as they tend to moderate air temperatures.

Diet

Diets vary greatly among species and geographic region, but a wide variety of 

vegetation is acceptable provided that the cottontail’s basic nutritional requirements 

are met (Chapman and others 1982). In a given geographic area, cottontails may eat 

more than 100 plant species but preferences vary locally (DeCalesta 1971). Bond and 

others (2002b) reported that eastern cottontails were food generalists at the microhabitat scale but showed a preference for certain land cover types. Herbaceous vegetation 

is the primary food during the growing season, while bark, buds, and twigs are consumed during the remainder of the year (Althoff and others 1997; Chapman and others 

1982). Feeding on woody vegetation during the fall and winter is assumed to relate 

to reduced availability of herbaceous vegetation rather than a preference (Chapman 

and others 1982). In southern portions of the southwestern United States where winter 

climates are mild, herbaceous vegetation may provide an adequate year-round food 

source (Allen 1984). Eastern cottontails may eat snails, moth pupa, or cottontail carcasses when other foods are unavailable (Higgins and others 2002).

Mountain cottontail and most likely eastern cottontail nests are cup-like cavities scraped in the ground and lined with fur, grass, and small sticks (Chapman 1975; 

Higgins and others 2002). Chapman (1975) reported that mountain cottontails living 

in dense sagebrush or riparian vegetation probably spend most of their time above 
USDA Forest Service RMRS-GTR-339. 2015. 137

ground, but in areas with sparse vegetation, they take protection in burrows or rock 

crevices. They preferred crevices in outcrops as daytime retreats in a sagebrush/juniper 

habitat in Oregon. Also, the abundance of such daytime retreats was related to population numbers (McKay and Verts 1978). Conversely, in Colorado, Cayot (1978) found 

no relationship between the presence of rocks and mountain cottontail populations. 

This disparity might be a result of variability in vegetative cover quantity and quality.

Home range 

Home ranges of 25 radio-tagged eastern cottontails in a 14 acre (5.7 ha) woodlot 

in southwestern Wisconsin varied by individual, sex, and season (Trent and Rongstad 

1974). Adult male home ranges increased from an average of 6.8 acres (2.8 ha) in the 

spring to an average of 9.9 acres (4 ha) in early summer and decreased to an average 

of 3.8 acres (1.5 ha) by late summer. Adult female home ranges in the spring averaged 

4.3 acres (1.7 ha) and in the summer, fall, and mid-winter they averaged 2.1 acres 

(1.5 ha). Fall home range sizes of juveniles did not differ and there were no gender 

differences (Trent and Rongstad 1974). In Wisconsin, Mississippi, and Illinois, male 

home ranges were larger during the breeding than the non-breeding season and were 

larger than female home ranges during any season (Bond and others 2001; Mankin and 

Warner 1999). On agricultural land in Mississippi, breeding season home ranges for 

males averaged 14.8 acres (6.0 ha) and female’s averaged 7.5 acres (3.0 ha). Smaller 

home ranges for females were attributed to their parental care and their “central place” 

foraging behavior close to their nest (Bond and others 2001). In summary, eastern 

cottontail home range size ranged from 0.20 to 20 acres (0.08 to 8.1 ha), with most 

studies reporting home ranges smaller than 9.9 acres (4 ha) (Mankin and Warner 

1999). 

Populations 

Cottontail populations are characterized by substantial seasonal and annual fluctuations. Scribner and Warren (1990) estimated winter densities of eastern cottontails 

in Texas to range from 3.2 to 4.9 individuals/acre (1.3 to 2.0/ha). After reproduction 

and juvenile dispersal, the densities in these areas peaked at 10.9 to 11.3 individuals/

acre (4.4 to 4.6/ha). Fall density of eastern cottontails in southwestern Wisconsin 

woodlots was estimated to be 3.6/acre (1.5/ha) (Trent and Rongstad 1974). In this 

population, the annual survival rate was estimated to range between 0.15 and 0.2 

depending on the estimation method. Fall and winter eastern cottontail densities over 

a 5-year period in southern Wisconsin ranged from 7.4 to 23.7 individuals/acre (3.0 to 

9.6/ha). On an experimentally managed 50-acre (20.2-ha) woodlot in Wisconsin 

cottontail densities ranged from 3.7 to 12.9 individuals/acre (1.5 to 5.2 ha) (Pils and 

others 1981). In Illinois, habitats predominantly soybean and corn row crops supported 

0.08 to 4.00 eastern cottontails/100 acres (2 to 10/100 ha) (Mankin and Warner 1999). 

Food availability and quality were considered the primary factors regulating rabbit 

populations (Lochmiller and others 1995). Population densities of mountain cottontails 

in ponderosa pine forests in southern British Columbia varied annually from 0.09 to 

0.17 individuals/acre (0.04 to 0.07/ha). McKay and Verts (1978) found that mountain 

cottontail population densities varied annually from 0.03 to 1.03 individuals/acre (0.1 

to 0.42/ha) in shrub-juniper woodlands in central Oregon. 
138 USDA Forest Service RMRS-GTR-339. 2015.

Plant species richness and cover likely increases forage efficiency and reduces 

predation risks to cottontails by reducing their exposure (Bond and others 2001). 

Malaney and Frey (2006) found early successional vegetative stages located adjacent 

to dense canopied sites were preferred by cottontails. Although prescribed fires may 

create short-term negative consequences for cottontails, fire improves forage quality 

for at least two seasons after burning, especially when arranged with patchy mosaics 

of food and cover (Bond and others 2002a). All cottontails make extensive use of 

trails, paths, and roads (Higgins and others 2002). Malaney and Frey (2006) hypothesized that mountain cottontails used high elevation spruce-fir forests in New Mexico 

because logging, fire, and roads created fine-scale openings and early successional 

vegetation, which they preferred.

Gray Jay

The gray jay (Periosoreus canadensis) is a small corvid (i.e., related to crows 

and ravens) typically weighing 2.2 to 2.9 ounces (62 to 82 g) and measuring 10.6 to 

12.2 inches (27 to 31 cm) tall (Strickland and Ouellet 2011). Although not abundant, 

they occupy forests year-round so are an important winter prey for goshawks. In the 

Black Hills, Bartelt (1977) found the remains of a gray jay at one of the nests he visited (Bloom and others 1986; Cleghorn 1913; Patla 1997; Promessi and others 2004; 

Reynolds and Meslow 1984; Smithers and others 2005; Squires 2000; Watson and 

others 1998). 

Distribution

The gray jay is widespread in boreal forests of Canada, northern New England 

(Vermont, New York, and New Hampshire), the Great Lakes states (Wisconsin and 

Michigan), and western mountain states (Washington, Oregon, California Idaho, Utah, 

Colorado, New Mexico, Arizona, and South Dakota) (Strickland and Ouellet 2011). In 

the Black Hills, gray jays are common permanent residents in forests above 4,000 ft 

(1219 m), but are found less frequently in the Bear Lodge Mountains of Wyoming and 

the extreme easterly and southern portions of the Black Hills (Pettingill and Whitney 

1965; Panjabi 2003). 

Habitat

Gray jays are strongly associated with pure spruce forests across their range 

but also use mixed spruce and other conifer forests (Strickland and Ouellet 2011). In 

Ontario, Canada, jays were most abundant in lowland black spruce (Picea mariana) 

bogs and less abundant in areas of mixed quaking aspen, white birch, (Betula pendula) balsam fir, (Abies balsamea), and white spruce. Gray jays are most common in 

lodgepole pine forests in the Yukon and in pure jack pine (Pinus banksiana) forests 

in Saskatchewan (Kirk and Hobson 2001; Sinclair and others 2011). In New Mexico, 

they used forests dominated by Engelmann spruce and subalpine fir (Bailey and others 

1928). And in Colorado, they were found mainly in Engelmann spruce, subalpine fir, 

lodgepole pine, quaking aspen, and willow forests (Bailey and Niedrach 1965). Gray 

jays tend to use forest edges as they provide many insects and nesting songbirds both 

of which are consumed by the gray jay (Ibarzabal and Desrochers 2004). For example, 
USDA Forest Service RMRS-GTR-339. 2015. 139

in managed forests of Quebec, gray jays were frequently found within 100 ft (about 

30 m) of forest edges. 

In the Black Hills, gray jays use dense ponderosa pine and white spruce forests 

and, on occasion, mixed species forests (Pettingill and Whitney 1965). Recent monitoring indicated that gray jays used white spruce dominated forests more than other 

types, but they were also found in burned areas and ponderosa pine dominated habitats 

(Panjabi 2001, 2003; White and others 2010). Although found in forests of all ages, 

they appear to prefer mature coniferous forests (Rutter 1969; Strickland and Ouellet 

2011; Theberge 1976). Black Hills’ gray jays were most abundant in mature ponderosa 

pine forests when canopy cover exceeded 40 percent compared to sapling and polesized ponderosa pine stands (Mills and others 2000; Rumble and others 1999). Use 

also varied seasonally with mature and old ponderosa pine forests preferred in the 

summer, while sapling and pole-sized stands were used in the winter. 

Nest sites are chosen by the male who also initiates nest construction. Nests are 

cup-shaped and situated at low to moderate heights, mostly in spruce, but hemlock 

(Tsuga spp.), fir (Abies spp.), pine (Pinus spp.), tamaracks (Larix spp.), and willows 

are sometimes used (Strickland and Ouellet 2011). Nests are constructed of twigs, 

bark, lichens, and cocoon material from tent caterpillars. Nest trees located adjacent 

to a forest opening, which provides a southwestern exposure, allows the nest to be 

warmed by the sun (Strickland and Ouellet 2011). Nests are often placed near the tree 

trunk or on a horizontal branch.

Diet

Gray jays have a broad diet and they are “scatter hoarders” based on their wellknown habit of caching food for winter consumption. Food items are first coated with 

sticky saliva, then worked into tree bark, pine needle bunches, tree-forks, and under 

lichen (Strickland and Ouellet 2011). Cached food is important for winter consumption and likely contributes to their propensity for late winter (February through March) 

nesting. Gray jays consume conifer seeds but do not extract seeds from cones. They 

eat mushrooms including the Amanita (which is known for its toxicity and hallucinogenic properties), slime molds, and engorged winter ticks removed from ungulates 

(Addison and others 1989; Strickland and Ouellet 2011). Gray jays are predatory, 

consuming eggs, nestlings, along with juvenile and adult birds (Barnard 1996; Boulet 

and others 2003; Darveau and others 1997; Pike 1978; Tozer and Allen 2004). They 

also eat small mammals (e.g., mice) and amphibians (Gill 1974; Tordoff 1980). Dead 

birds and mammals of all sizes are an important winter food. As demonstration of their 

broad diet, gray jays often find food in picnic areas and camp grounds (Strickland and 

Ouellet 2011). 

Home range

Mated pairs occupy territories during the breeding season, but an additional 

1 to 2 non-breeding individuals may also occupy a territory during the non-breeding 

season. These may include a juvenile born on the territory or one from another territory. Territory size in Ontario, Canada, was 319 acres (129 ha) but only 67 to 171 acres 

(27 to 69 ha) on Queen Charlotte Island, British Columbia (Strickland and Ouellet 

2011). In Manitoba, Canada, home range size was approximately 161 acres (65 ha) 
140 USDA Forest Service RMRS-GTR-339. 2015.

and in the Yukon Territory, home ranges were 57 acres (23 ha) for non-food supplemented gray jays and 37 acres (15 ha) for food supplemented individuals (Walley 

1987). 

Populations

While much of the gray jays’ range in Canada and Alaska has not been covered 

by Breeding Bird surveys, the data collected so far indicate no significant continental 

trends in populations. Climate warming may be contributing to range reduction in the 

southern part of the species’ range. Long-term research on a population in Ontario 

revealed a trend toward earlier breeding, declining reproductive success, and increasing rates of vacancies on territories. It appears that prolonged warmer autumns result 

in the decomposition of stored foods, which negatively impacts reproductive success 

the following breeding season. This declining population trend is likely related to the 

high number of young breeders that are less experienced and unable to compensate for 

the reduced food supply. In these conditions, young breeders tend to desert their nests, 

further impacting population numbers (Waite and Strickland 2006). 

When habitats are saturated, territorial behavior limits gray jay populations 

which in turn ensures sufficient year-round food and cache sites for population 

stability. Density at habitat saturation in various locations in Canada was estimated 

at: 1.5 individuals/100 acres (3.7/100 ha) on Anticosti Island, Quebec, 0.6/100 acres 

(1.4/100 ha) in la Vérendrye, Quebec, 0.3/100 acres (0.7/ha) in Algonquin Provincial 

Park, Ontario, 0.6/100 acres (1.5/100 ha) in Manitoba, and 1.0/100 acres (2.4/100 ha) 

in the Yukon. Autumn densities of gray jays increased to 4.2/100 acres (10.3/100 ha) 

for Anticosti Island, 1.4/100 acres (3.5/100 ha) for la Vérendrye, and 0.7/100 acres 

(1.7/100 ha) in Algonquin Provincial Park. In Algonquin Provincial Park, the 

authors noted that much of the area they studied was never occupied by gray jays 

(Strickland and Ouellet 2011). Densities in the Black Hills from 2001 to 2009 were 

7.9 jays/100 acres (19.4/100 ha) in white spruce forests, 7.7/100 acres (19.1/100 ha) in 

ponderosa pine forests, 1.7/100 acres (4.2/100 ha) in old ponderosa pine forests, and 

1.2/100 acres (3/100 ha) in burned forests (White and others 2010). 

Although gray jay mortality rates can be high, the bird can be long-lived. 

Nicholls (2009) reported that two gray jays living in Colorado were at least 17 years 

old and in Algonquin Provincial Park, Canada, one female and one male were both 

at least 16 years old (Strickland and Ouellet 2011). Mortality of young jays can be 

rather high. Strickland (1991) reported that 52 percent of the fledglings that stayed on 

their natal territories in Ontario and Quebec died by mid-October while 85 percent of 

those dispersing died. Of those surviving at the beginning of winter, 50 percent died 

by spring. Adult mortality was higher in the summer compared to winter, but annual 

mortality averaged about 20 percent (Strickland and Ouellet 2011). 

Hairy Woodpecker

Hairy woodpeckers (Picoides villous) are medium-sized birds that vary in size 

depending on the latitude where they live. Males weigh more than females and the average weights of male hairy woodpeckers were: 1.5 ounces (43 g) in Chiapas, Mexico, 

2.6 ounces (75 g) in South Dakota, and 3.4 ounces (95 g) in Alaska. The average 
USDA Forest Service RMRS-GTR-339. 2015. 141

weight of females living in South Dakota was 2.3 ounces (65 g) (Jackson and others 

2002). 

Hairy woodpeckers are a common prey of goshawks (Lewis and others 2006; 

Mannan and Boal 1993; Reynolds and Meslow 1984; Rogers and others 2006; 

Smithers and others 2005). In south-central Wyoming, 0.5 percent of regurgitated 

pellets found at 40 nests contained hairy woodpecker remains (Squires 2000). Over 

10 years, hairy woodpeckers comprised 1.3 percent of prey remains collected at 82 

nest sites in Washington (Watson and others 1998). 

Distribution 

Hairy woodpeckers are widely distributed and abundant throughout North 

America, having the widest distribution of all the Picoides woodpeckers. They range 

year-round from Central America north into Mexico, the United States, and most of 

Canada and Alaska (Jackson and others 2002). In the Black Hills, hairy woodpeckers 

are permanent residents at all elevations and are the most abundant cavity-nesting species found in the Hills during winter (Pettingill and Whitney 1965; Rumble and others 

1999).

Habitat 

This common woodpecker occupies coniferous and deciduous forests, burned 

forests, and beetle-infested forests. Hairy woodpeckers show a preference for open 

ponderosa pine and quaking aspen forests and tend to be more abundant when canopy 

cover is less than 70 percent (Jackson and others 2002; Mills and others 2000). In 

west-central Colorado when quaking aspen amounts exceeded 1 percent of the basal 

area in mixed species stands the density of woodpeckers was 3 to 5 birds/100 acres 

(7.4 to 12.3/100 ha) and in stands with less than 1 percent quaking aspen woodpecker 

density was 10 birds/100 acres (24.7/100 ha) (Scott and Crouch 1988). In the Black 

Hills, ponderosa pine harvesting that reduced stand density by 53 percent (expressed 

by basal area) and canopy cover by 58 percent had no significant effect on hairy 

woodpecker populations (Anderson and Crompton 2002). However, increasing canopy 

cover in the Black Hills positively influenced their abundance in mixed quaking aspen 

and paper birch forests (Mills and others 2000; Rumble and others 1999). 

Hairy woodpeckers prefer to nest in live trees located in open woodlands with a 

deciduous understory. In hidden locations, such as on the underside of a tree limb, they 

excavate nest entrances ranging in diameter from 1.6 to 1.8 inches (4 to 4.6 cm) that 

are often used for several years. Because other cavity nesters such as starlings (Sturnus 

vulgaris) can use nest openings of this size, competition for nest sites may occur 

(Scott and others 1977). The heights of hairy woodpecker nests varied from 15 to 45 ft 

(4.6 to 13.7 m) but were typically located 35 ft (10.7 m) above the forest floor (Scott 

and others 1977). Scott and others (1980) located 2 hairy woodpecker nests in quaking 

aspen snags and 6 in live quaking aspen trees. Nest heights averaged 33 ft (10.1 m), 

tree heights averaged 59 ft (18 m), and tree DBH averaged 15 inches (38 cm). In 

Arizona, hairy woodpeckers showed a preference for nesting in ponderosa pine snags 

with DBHs exceeding 20 inches (51 cm) (Horton and Mannan 1988). Nest densities 

in a burned ponderosa pine forest in Idaho were 0.98 nests/100 acres (2.4/100 ha) and 

in a burned and harvested site where 40 percent of snags greater than 9 inches (23 cm) 
142 USDA Forest Service RMRS-GTR-339. 2015.

DBH were removed, there were 0.39 nests/100 acres (0.96/100 ha) (Saab and others 

2007, 2009).Winter roost trees in a burned ponderosa pine forest in Arizona had an 

average DBH of 22 inches (56 cm), which was 2.5 times larger than the average DBH 

of trees in the surrounding forest (Covert-Bratland and others 2007). 

The forests hairy woodpeckers used during the summer and winter in the central 

Black Hills were similar. The size and number of snags and number of suitable and 

available cavities are better habitat descriptors than vegetative structure (Rumble and 

others 1999). Also in the Black Hills, timber harvesting that reduced snag density 

but maintained similar tree sizes to non-harvested areas did not impact woodpecker 

abundance (Dykstra and others 1997). As such, it appears that hairy woodpeckers do 

not prefer forests with large live trees or snags in the Black Hills, nor was their occurrence related to snag condition or density (Dykstra and others 1999; Mills and others 

2000). Similar findings occurred in a burned ponderosa pine forest in Oregon where 

hairy woodpecker abundance decreased in response to post wildfire tree harvesting 

but populations did not differ between two harvest intensities. In the same study, no 

differences in woodpecker populations were detected between areas with 12 snags/

acre (30/ha) and areas with 2 snags/acre (5/ha) (Cahall and Hayes 2009). The mere 

presence of snags may be as important as their numbers or densities, as noted in east 

Texas where hairy woodpeckers were found in clearcut forests containing 0.8 hardwood 

snags/100 acres (2/100 ha) but were absent from forests with no snags (Dickson and 

others 2009). Winter and breeding densities of hairy woodpeckers were 3.6 to 7.6 birds/100 

acres (8.8 to 18.7/100 ha) in harvested hardwood forests in Kentucky that contained 6 to 

13.3 snags/acre (14.8 to 32.9/ha) and 1.6 to 6 birds/100 acres (4.0 to 14.8/100 ha) were 

found in unharvested forests that contained 7.3 snags/acre (18/ha) (McPeek and others 1987). However, there is concern in some areas that timber harvest, fuel wood 

removal, or intense surface fires that decrease snag numbers may adversely affect 

hairy woodpecker populations (Balda 1975; Thomas and others 1979).

Diet

Hairy woodpeckers prefer to feed on insects living on dead or diseased trees, 

with approximately 80 percent of their diet being larval and adult beetles, ants, and 

caterpillars. Males tend to forage farther from the nest and consume larger insects 

(e.g., wood borers) than females who forage close to the nest on the surface of trees, 

shrubs, or on the ground for small insects and plant material (Morrison and With 1987; 

Scott and others 1977). Beetles, primarily wood boring and bark beetles, comprised 

64 percent of the diets of hairy woodpeckers in California followed by carpenter ants 

(Scott and others 1977). In Arizona, ponderosa pine trees in both unburned and burned 

forests infested by bark beetles were 9 to 12 times more frequently foraged on by 

hairy woodpeckers than uninfested trees (Pope and others 2009). In the Black Hills, 

the abundance of mountain pine beetles makes them an ample food source (Anderson 

2003). This insectivorous diet is often supplemented with fruit, grains, nuts, and ponderosa pine seeds (Otvos and Stark 1985).

With the presence of insects, hairy woodpeckers appear to be opportunists when 

it comes to choosing trees for foraging. Throughout the year in the Sierra Nevada, 

they frequently used both white fir (Abies concolor) and ponderosa pine for feeding 

(Morrison and others 1987; Morrison and With 1987). They foraged on live trees and 
USDA Forest Service RMRS-GTR-339. 2015. 143

snags with similar frequency, but about 70 percent of their foraging time was spent on 

dead portions (e.g., bole and limbs) of live trees averaging 17.4 inches (44 cm) DBH. 

No difference in tree size preference for feeding was exhibited by either males or 

females, nor did feeding tree size differ between winter and breeding season (Morrison 

and With 1987). In the western Sierra Nevada during the breeding season, both sexes 

preferred foraging on tree trunks at heights from 33 to 39 ft (10 to 12 m), but these 

heights increased in the winter (Morrison and others 1987; Morrison and With 1987). 

In mixed-conifer forests of the Sierra Nevada, hairy woodpeckers foraged throughout 

tree canopies as well as on trees 4 to 12 inches (10 to 30 cm) DBH (Morrison and 

others 1986). However, in many areas, hairy woodpeckers frequently forage on large 

trees and snags (Covert-Bratland and others 2006; Pope and others 2009; Spiering 

and Knight 2005). In an unburned ponderosa pine forest in northern Arizona, hairy 

woodpeckers preferred to forage on 12 to 17 inch (30 to 42 cm) DBH trees located in 

patches 1.4 times less dense than surroundings areas but with a higher density of large 

trees (Covert-Bratland and others 2006). 

Home range 

Food abundance and presence most likely determine home range sizes for hairy 

woodpeckers. In a 1-year-old burned ponderosa pine forest, a winter home range size 

was estimated at 3.6 acres (1.46 ha), but 5 years later it was 19.0 acres (7.85 ha). This 

increase was most likely related to the decrease in both insect populations and standing snags since the fire (Covert-Bratland and others 2006). In Arizona’s ponderosa 

pine forests, two-thirds of hairy woodpecker roost trees were located outside or on the 

edge of the home range. Eight of nine woodpeckers traveled more than 0.62 mi (1 km) 

from the roost to the farthest point in their home range (Covert-Bratland and others 

2007).

Populations

In sapling, pole-sized, and mature ponderosa pine forests in the Black Hills, 

hairy woodpeckers were evenly distributed throughout the landscape at 3.2 birds/100 

acres (8 birds/100 ha) regardless of snag densities and tree diameters (Spiering and 

Knight 2005). Sampling across multiple habitats from 2001 through 2009 indicated 

that hairy woodpecker densities in all unburned ponderosa pine and mixed ponderosa 

pine/white spruce forests in both the northern and southern Black Hills ranged from 

1.6 to 2.4 birds/100 acres (4 to 6 birds/100 ha). However, in a burned forest 4.9 

birds/100 acres (12 birds/100 ha) were found (White and others 2010). 

 Hairy woodpecker populations tend to increase after low, medium, and high 

severity wildfires and prescribed fires in ponderosa pine forests, though their densities decreased with time since fire (Covert-Bratland and others 2006; Dickson and 

others 2009; Pope and others 2009). In Arizona, Pope and others (2009) found winter 

hairy woodpecker densities to be 4.4 birds/100 acres (10.8/100 ha) or 5 times greater 

than densities found in unburned forests. Covert-Bratland and others (2006), also in 

Arizona, reported greater abundance of hairy woodpeckers in burned forests during 

the winter for 2 years, but abundances in burned and unburned forests were similar 

7 years after the burn. Hairy woodpecker abundance also increased in response to a 
144 USDA Forest Service RMRS-GTR-339. 2015.

severe mountain pine beetle outbreak in British Colombia though reproduction did not 

(Edworthy and others 2011).

Szaro and Balda (1982) studied the effects of timber harvest on breeding birds 

in ponderosa pine forests of Arizona. During all study years, with the exception of 

clearcuts, hairy woodpeckers were found in all types of harvested stands, including 

uncut areas where trees had not been removed for 60 years, light harvests in which 

large trees and dense thickets were selectively harvested, unharvested areas, and in 

areas that were thinned. Hairy woodpecker densities averaged about 3 pairs/100 acres 

(7.4/100 ha) across all forest conditions (Szaro and Balda 1982, 1986).

Least Chipmunk

Least chipmunks (Tamias minimus) weigh from 1.5 to 1.9 ounces (42 to 53 g) 

and range in length from 7.3 to 8.7 inches (18.5 to 22.2 cm), with male chipmunks in 

the Black Hills weighing 1.6 ounces (46 g) and measuring 7.7 inches (19.5 cm) long 

(Schlimme 2000; Turner 1974). Ten percent of the regurgitated pellets collected at 

40 goshawk nests in south-central Wyoming contained the remains of least and Uinta 

chipmunks (Neotamias umbrinus) (Squires 2000). In 23 nest sites located in mixed 

ponderosa pine and spruce forests in northeastern California, 7.2 percent of the prey 

was chipmunks and 6.1 percent of prey consumed at 82 goshawk nests in Washington 

was chipmunks (Promessi and others 2004; Watson and others 1998). In the Black 

Hills, least chipmunk remains were found at all 5 nests studied by Bartelt (1977) and 

Erickson (1987). 

Distribution

Least chipmunks are the smallest and most widely distributed of the North 

American chipmunks making them important goshawk prey. However, it is difficult 

to determine the chipmunk species at nest sites. They range as far north as the central 

Yukon in Canada, east to the northern Great Lakes states, and south to parts of Arizona 

and New Mexico, and in the Rocky Mountains they have been observed at elevations 

exceeding 11,483 ft (3500 m). However, on the Colorado Front Range, fewer least 

chipmunks were observed at higher elevations compared to lower elevations. At higher 

elevations, populations can suffer serious declines and possible local extinction as a 

result of harsh and prolonged winters with deep snow (Bergstrom and Hoffmann 1991; 

Hadley and Wilson 2004a).The western third of South Dakota, including the arid 

badlands, contains least chipmunks and it is the only chipmunk that lives in the Black 

Hills (Higgins and others 2002; Turner 1974; Verts and Carraway 2001). 

Habitat

Least chipmunks use a wide variety of habitats occurring at many elevations, 

including greasewood flats, sagebrush deserts, pinyon-juniper woodlands, oak 

woodlands, deciduous and coniferous forests, and alpine tundra (Higgins and others 

2002). Least chipmunks are typically associated with forest openings and areas close 

to escape cover, which also influences their foraging behavior (Root and others 2001; 

Smith 1995; Verts and Carraway 2001). As such, forest management activities and 

disturbances that create forest openings, such as thinning or wildfires, can favor chipmunk occupancy. In New Mexico and Arizona, thinning and wildfires that resulted 
USDA Forest Service RMRS-GTR-339. 2015. 145

in more snags, stumps, and even slash piles left after thinning were beneficial to least 

chipmunk populations (Converse and others 2006). Similarly, forest diversity created 

by ski runs in spruce-fir forests in Colorado with and without scattered trees in them 

provided habitat favored by these chipmunks (Hadley and Wilson 2004b). 

In Arizona and New Mexico, least chipmunks frequently use spruce-fir forests 

containing rocky or mesic habitats (Hoffmeister 1986). These chipmunks are generally 

absent from homogenous conifer forests but were found in ponderosa pine, Douglasfir, and mixed subalpine fir and spruce forests along the Colorado Front Range 

(Hadley and Wilson 2004a). However, they were not found in closed lodgepole pine 

forests in the same area (Bergstrom and Hoffmann 1991). In Montana lodgepole pine 

forests, least chipmunks were only found in areas disturbed by harvesting (Martinsen 

1968). They were also found in prey remains at goshawk nests in Wyoming but the 

forest conditions are unknown (Squires 2000). Also in Colorado, least chipmunks were 

found in meadows above tree line, shrubby habitats, and woodlands containing dense 

ground-level vegetation (Bergstrom and Hoffmann 1991; Hadley and Wilson 2004b; 

Vaughan 1974). Least chipmunks also often climb or perch in shrubs and trees to feed 

and nest (Verts and Carraway 2001). In all forests, these chipmunks use logs, stumps, 

and rocks as observation points and burrow locations (Higgins and others 2002; 

Vaughan 1974; Winterrowd and Devenport 2004). 

Least chipmunks dig burrows beneath rocks, logs, or tree roots. In the subalpine 

forests of Colorado, they showed a preference for locating burrows under large rocks 

and, on occasion, used woodpecker cavities for nests (Verts and Carraway 2001). 

Burrows provide protection from predators, protection from heat and cold, sites for 

bearing and raising young, and locations for food caches (Bihr and Smith 1998; Heller 

and Poulson 1972; Higgins and others 2002). Burrows are small and grass-lined chambers located about 1 foot (30 cm) below the soil surface. They are reached by one or 

two tunnels with 1.5 inch (3.7 cm) diameter entrances, usually 2 to 3 ft (61 to 91 cm) 

long (Bihr and Smith 1998; Higgins and others 2002).

Diet

Least chipmunks consume both plant and animal material, and their diet varies 

depending on local food availability (Devenport and others 1998; Verts and Carraway 

2001). Diets vary across regions and elevations but typically include a variety of 

nuts, grains, conifer seeds, fruits, flowers, leaves, mushrooms, and insects, with 

seeds usually making up of more than 50 percent of a chipmunk’s diet (Higgins and 

others 2002; Vaughan 1974). They forage during the day when temperatures are usually moderate and return to a den at night (Vaughan 1974). In subalpine meadows in 

Colorado, least chipmunks ate flowers and forbs in the early summer and occasionally 

raided “sap wells” established by red-breasted sapsuckers. By mid-summer, insects 

and larvae made up most of their diet and seeds and berries were consumed in autumn 

(Devenport and others 1998; Vaughan 1974). In autumn, they cache seeds, nuts, and 

grains beneath stumps or logs and in small pits (i.e., scatter hoarding) and later move 

this cached food to their burrows. Least chipmunks will consume this stored food between bouts of torpor (i.e., semi hibernation state lasting hours to weeks). When torpor 

begins and ends depends on the latitude and amount of snow cover. Least chipmunks 
146 USDA Forest Service RMRS-GTR-339. 2015.

generally emerge from their burrows in March and April and are active above ground 

through October or November (Verts and Carraway 2001). 

Home range

Least chipmunks are not sociable and do not tolerate least chipmunks within the 

immediate area of their burrows or in vegetation patches where they forage. However, 

home ranges generally overlap and individuals occasionally forage next to one another (Higgins and others 2002; Winterrowd and Devenport 2004). Home range size 

depends on habitat quality and can vary from less than 1 acre (0.4 ha) up to several 

acres (Higgins and others 2002). In a harvested lodgepole pine forest in Montana, 

least chipmunk home ranges changed between seasons and years in response to food 

availability (Martinsen 1968). The average male home range size over 2 years was 

3.2 acres (1.29 ha), and the average female home range size was 2.4 acres (0.97 ha). 

Male home ranges in Alberta, Canada, averaged 3 acres (1.22 ha) in size and female 

home ranges averaged 1.6 acres (0.66 ha) in size (Sheppard 1972). In ponderosa pine 

forests of Colorado, male home ranges varied from 3.9 to 13.4 acres (1.6 to 5.4 ha) in 

size and a single female’s home range covered 3.4 acres (1.4 ha) (Bergstrom 1988).

Populations 

In a burned ponderosa pine forest in New Mexico, least chipmunk densities 

ranged from 0 to 0.8 chipmunks/acre (0 to 1.9/ha) (Converse and others 2006). In 

subalpine meadows of Colorado, mean chipmunk density over three summers ranged 

from 4.6 to 9.0 chipmunks/acre (11.4 to 22.2/ha) (Vaughan 1974). Also in Colorado, 

least chipmunk densities on open ski runs and along ski run edges averaged 1.1/acre 

(2.6/ha), whereas no chipmunks were trapped or observed in adjacent spruce-fir forests (Hadley and Wilson 2004a).

Lewis’s Woodpecker

The Lewis’s woodpecker (Melanerpes lewis) is a medium to large woodpecker 

measuring 10.0 to 10.5 inches (25.4 to 26.7 cm) long and weighing 3 to 4 ounces 

(85 to 113 g) (Abele and others 2004). Woodpeckers, in general, are a favored prey of 

goshawks, but the Lewis’s woodpecker has only been reported in the diets of Oregon 

goshawks (Lewis and others 2006; Promessi and others 2004; Reynolds and Meslow 

1984; Rogers and others 2006; Smithers and others 2005; Squires 2000; Watson and 

others 1998). Although they are rare in the Black Hills, Lewis’s woodpeckers have a 

close association with open ponderosa pine forests, which dominate the Black Hills, 

making them potential goshawk prey (South Dakota Ornithologists’ Union 1991; 

Squires and Reynolds 1997). 

Distribution

Lewis’s woodpeckers occur from southwestern British Columbia south into 

the Cascade Mountains (Washington and Oregon), Sierra Nevada (California and 

Nevada), Colorado Plateau (eastern Utah and northern Arizona), and Rocky Mountains 

(New Mexico, Colorado, Idaho, Montana, Wyoming, and South Dakota). In the 

Black Hills, Lewis’s woodpeckers are uncommon summer residents and rare winter 

residents and have been reported to leave higher elevation habitats (e.g., McVey burn) 
USDA Forest Service RMRS-GTR-339. 2015. 147

for lower ones in August and September (Pettingill and Whitney 1965; South Dakota 

Ornithologists’ Union 1991). 

Habitat

Breeding habitats for Lewis’s woodpeckers include open ponderosa pine forest, open riparian woodland dominated by cottonwoods, quaking aspen stands, oak 

woodlands, and burned or harvested pine forests and they avoid dense forests (Bock 

1970; Tobalske 1997; Vande Voort 2011; Vierling 1997). Lewis’s woodpeckers frequently use open and burned forests as they usually have an abundance of snags, a 

shrub dominated forest floor, and abundant insect populations. Open tree canopies also 

provide space for these woodpeckers to fly-catch and avoid being captured by hawks 

(Saab and Vierling 2001). 

In the Black Hills, Lewis’s woodpeckers used riparian woodlands dominated 

by cottonwoods or open areas with oaks (South Dakota Ornithologists’ Union 1991). 

In the southwestern Hills, they were seen using burned forests along canyons (Cary 

1901). Also in the Hills, they use vegetative edges in ponderosa pine forests and 

burned areas with an abundance of snags (Pettingill and Whitney 1965). From 2001 to 

2009, although rarely detected, Lewis’s woodpeckers were observed in burned areas of 

the southwestern Black Hills, ponderosa pine forests in the southern Black Hills, montane riparian areas, and within shrublands (Giroir and others 2007; Hutton and others 

2006; Panjabi 2001, 2003; White and others 2010). 

Forests with large diameter trees, open tree canopies, and a shrub-dominated 

forest floor are preferred by Lewis’s woodpeckers for nesting (Bock and Lynch 1970). 

In Wyoming, they nested in burned areas with an open canopy and nest trees were 

typically dead, burned, or decaying (Linder 1994; Tobalske 1997). Common nest trees 

include large conifers and deciduous trees such as cottonwood, willow, and paper 

birch. Nest trees tend to be tall and of large diameter. For example, in riparian areas 

on the plains of Colorado, all nest trees were in decaying or dead cottonwoods that 

averaged 67 ft (20.4 m) tall and 3.7 ft (113 cm) DBH compared to random trees that 

averaged 41 ft (12.5 m) tall and had an average DBH of 25.1 inches (64 cm) (Vierling 

1997). In Wyoming, 35 nest trees averaged 34.7 ft (10.59 m) tall and 19.2 inches 

(49 cm) DBH (Linder 1994). In Idaho, average DBH for 354 nest trees (snags) in a 

burned and mostly harvested forest was 18 inches (46 cm). In a Black Hills burned 

forest, Lewis’s woodpeckers nested in highly decayed snags that averaged 15.1 inches 

(38 cm) DBH (Gentry and Vierling 2008).

Lewis’s woodpeckers are weak excavators and tend to use cavities excavated 

by other Lewis’s woodpeckers, northern flickers, and hairy woodpeckers (Tobalske 

1997). When they do excavate their own nests, they do so in highly decayed and/or 

soft-wooded trees and snags. In the Black Hills, 40 of 55 nests were in old cavities and 

15 were in old cavities modified by Lewis’s woodpeckers (Gentry and Vierling 2007). 

Mean cavity height in the Black Hills was 27.9 ft (8.5 m) and the ratio of cavity height 

to snag height was 0.85, indicating that Lewis’s woodpeckers tended to nest near the 

top of snags (Gentry and Vierling 2007).

Nest sites appear to be an important factor influencing reproductive success. 

Populations in burned forests have higher reproductive success compared to those 

living in hardwood riparian areas. For example, in Idaho, nest success in burned 
148 USDA Forest Service RMRS-GTR-339. 2015.

ponderosa pine stands was 78 percent compared to 46 percent in Colorado riparian 

areas (Saab and Vierling 2001). In burned forests of Wyoming, nest success was 

85 percent, 56 percent in Colorado plains riparian areas, and 25 percent in Colorado 

cottonwood dominated woodlands (Linder 1994; Tashiro-Vierling 1994). Higher nest 

success in burned ponderosa pine forests suggests they contain source populations

of Lewis’s woodpeckers. Saab and Vierling (2001) found that fecundity (number of 

young produced by reproductive females) was 0.69 in ponderosa pine forests compared to 0.38 in riparian areas.

In the Black Hills, nest survival was 90 percent for 55 nests from 2002 through 

2005. The nests occurred in burned ponderosa pine forests with only four failures: two 

predations, one nest snag falling, and one adult abandonment (Gentry and Vierling 

2007). Fortunately for Lewis’s woodpeckers in the Black Hills, typical nest predators 

such as the black bear, (Ursus americanus), grizzly bear (Ursus arctos horribilis), and 

Stellar’s jay do not co-occur with them, and the pine marten (Martes americana) is restricted to white spruce forests. Similar to other populations of Lewis’s woodpeckers, 

burned forests in the Hills are source habitats, as adult females were replaced at a rate 

of 1.54 young female per adult female from 2001 to 2005 (Gentry and Vierling 2007). 

Diet

The Lewis’s woodpecker forages on non-wood boring insects, including ants, 

bees, wasps, beetles, and grasshoppers. They also consume acorns, nuts, grains, and 

fruit and store these items in bark crevices in the fall and winter (Tobalske 1997). 

Lewis’s woodpeckers forage by fly-catching from perches and gleaning insects 

from the trunks and limbs of trees and shrubs but do not dig in the soil (Bock 1970; 

Tobalske 1997). They forage on large snags, telephone poles, fence posts, and any 

location with an open view. In cottonwood trees on the plains in Colorado, foraging during October through April consisted of gleaning (30 percent), storing acorns 

(26 percent), fly-catching (24 percent), and working acorn stores (20 percent) (Hadow 

1973).

Lewis’s woodpecker’s migratory patterns are highly variable both within 

and among years. In general, individuals in Washington, Idaho, and Montana are 

non-resident while those in the central portions of the range are partially resident 

(Tobalske 1997). For example, during the winter of 1969 through 1970, some Lewis’s 

woodpeckers on the Colorado plains wintered on their breeding grounds while others 

moved to winter along the foothills west of Pueblo, Colorado (Hadow 1973). In the 

two subsequent years, no Lewis’s woodpeckers were observed in the same foothills 

during the winter. In the Black Hills, during the winter Lewis’s woodpeckers moved 

to cottonwood dominated riparian areas located at lower elevations and it was uncertain whether some individuals used these areas year-round (Pettingill and Whitney 

1965; South Dakota Ornithologists’ Union 1991). During winter migration, Lewis’s 

woodpeckers form loose flocks of adults and fledglings (Tobalske 1997). Once at 

their winter sites, they become territorial and mated pairs sometimes share stored food 

(Bock 1970; Vierling 1997). 

Winter habitat includes oak woodlands, commercial orchards, corn fields, and 

cottonwood dominated riparian areas. Important winter habitat features include large 

trees, snags, and utility poles that have cracks that can be used for storing acorns and 
USDA Forest Service RMRS-GTR-339. 2015. 149

grains. For example, on the Colorado plains wintering Lewis’s woodpeckers used dead 

and decaying cottonwoods that averaged 57.4 ft (17.5 m) tall with an average DBH of 

41.3 inches (104.8 cm) (Tobalske 1997). 

Home range

Home range characteristics of Lewis’s woodpeckers are not well known but 

are expected to vary with food availability and distribution. During the breeding 

season, Lewis’s woodpeckers defend their nest snags but several pairs may nest in 

very close proximity or even in the same snag (Bock 1970; Currier 1928; Hadow 

1973; Tashiro-Vierling 1994). 

Populations 

Determining population trends for Lewis’s woodpecker has been difficult because populations fluctuate as their habitat changes. In addition they have a sporadic 

distribution and most often their presence is uncommon or rare (Tobalske 1997). 

Between 1960 and 1991, Breeding Bird Survey (BBS) and Christmas Bird Counts 

(CBC) data indicate that populations may have declined by as much as 60 percent 

(Tobalske 1997). This trend estimate, however, was based on a small number (20) of 

CBC routes and unspecified sizes of BBS samples (Tashiro-Vierling 1994; Tobalske 

1997). From 1966 through 1994, 61 BBS census routes indicated relative abundance 

of Lewis’s woodpeckers to be 0.18 birds/25 miles (1.2/50 km). The Black Hills is the 

most northeasterly part of the Lewis’s woodpecker range, and, although Cary (1901) 

noted they were common there, others noted their rarity in the region (Grinnell 1875; 

Pettingill and Whitney 1965). In 9 years of monitoring in the Black Hills, fewer than 

10 individuals were seen per year, except in the last year when 34 individuals were 

detected in burned habitats (White and others 2010).

Mourning Dove

The mourning dove (Zenaida macroura) is a moderately sized bird averaging 

12 inches (30.5 cm) in length and averaging 8 ounces (227 g) in weight. In Oregon, 

Reynolds and Meslow (1984) found mourning doves the ninth most common prey 

item and they made up 3 percent of the goshawk’s diet. Despite its common occurrence in goshawk diets elsewhere, the mourning dove was absent from the prey 

captured by goshawks in the Black Hills. 

Distribution

The mourning dove is the most abundant and widely distributed dove in North 

America, ranging from southern Canada throughout the contiguous United States, 

Mexico, and into Central America and they may also breed in southeastern Alaska 

(American Ornithologists’ Union 1983; Martin and others 1951; Otis and others 2008). 

Mourning doves are a locally abundant summer resident in the Black Hills but migrate 

out of the area for the winter (Pettingill and Whitney 1965). While they occur across 

the Black Hills, they are most abundant in the southwestern portions (Panjabi 2001). 

Habitat

The mourning dove inhabits farmlands, ranchlands, deserts, grasslands, woodlands, and forests (Soutiere and Bolen 1972). In the Southwest, mourning doves 
150 USDA Forest Service RMRS-GTR-339. 2015.

frequent grasslands, pinyon-juniper woodlands, oak woodlands, and ponderosa pine 

forests. They do occur in mixed species forests above 7,000 ft (2134 m), although 

their densities are lower than in other habitats (Davis and Sintz 1973; Franzreb 1977; 

Sedgwick 1987). At elevations below 7,000 ft (2134 m), also in the Southwest, mourning doves prefer pinyon-juniper woodlands and riparian areas for nesting. In the Black 

Hills, mourning doves occupy ponderosa pine forests, burned forests, deciduous 

forests, riparian areas, agricultural lands, and residential areas (Pettingill and Whitney 

1965; Panjabi 2001, 2003). Within forests, mourning doves prefer vegetative edges. In 

contiguous forests, stream borders or the junctions between forest types are preferred. 

Broad or abrupt borders between fields and forest are not as favorable as narrow, 

finger-like or peninsular-shaped forest edges (Hopkins and Odum 1953). In forest and 

woodland habitats, mourning doves often nest near 1- to 5-acre (0.4- to 2.0-ha) vegetative openings.

In New Mexico of the 40 nests Davis and Sintz (1973) visited, 78 percent were 

located where tree cover was patchy to moderately dense and 22 percent were found 

in dense or open forests. Mourning doves typically select large trees for building their 

nests. For example, in southwestern New Mexico, the average DBH of 40 nest trees 

was 18.6 inches (47.2 cm), while the average DBH of all woody plants in the area 

was 13.8 inches (35.1) (Davis and Sintz 1973). In Arizona Haldeman (1968) observed 

mourning doves nesting in large yellow-barked ponderosa pines and other large 

conifers. In Iowa, Jumber and others (1956) reported nest trees averaged 17.4 inches 

(44.2 cm) DBH and McClure (1946) reported 20.3 inch (51.6 cm) DBH nest trees. 

The DBH of mourning dove nest trees in California averaged 13.0 inches (33.0), in 

Nebraska they averaged 10.2 inches (25.9 cm), and in pinyon-juniper woodlands of 

northwestern Colorado they ranged from 33 to 40 inches (83.8 to 101.6 cm) DBH 

(McClure 1946; Sedgwick 1987). 

In New Mexico mourning dove nest trees averaged 26 ft (7.9 m) tall with most 

nests placed 8 to 12 ft (2.4 to 3.7 m) above the forest floor (Davis and Sintz 1973). 

Soutiere and Bolen (1972) found doves living within the rolling plains of Texas 

preferred to nest in mesquite (Hilaria spp.) trees with large branches. Such trees 

with sturdy horizontal limbs allow nests to be built away from tree trunks to provide 

unobstructed flight paths (Harris and others 1963; Knight and others 1984; Putera and 

others 1985; Yahner 1983). Also securely constructed nests, influenced by their placement, determined the probability of nest success (Coon and others 1981).

For up to 30 days after hatching mourning dove fledglings use reference areas 

(RAs) for resting and feeding interactions primarily with the male parent. Located 

under dense canopies interspersed with openings, an average of three 3.3 ft2 (0.31 m2) 

RAs were used by mourning dove fledglings. The RAs were usually located on the 

forest floor or on a tree limb within 150 ft (45.7 m) of the nest tree (Hitchcock and 

Mirarchi 1986). Fledglings more than 13 days old used non-vegetated, forest floor 

RAs, more frequently (59 percent) than those located on tree limbs. The length of RA 

tree crowns averaged 26.3 ft (8.0 m) and their crown ratios averaged 76 percent. Such 

trees were used for both RAs and roosting with RA trees averaging 13.3 inches (33.8 

cm) DBH and roost trees averaged 13.7 inches (34.8 cm) DBH (Grand and Mirarchi 

1988). 
USDA Forest Service RMRS-GTR-339. 2015. 151

Diet

Mourning doves are versatile and opportunistic feeders. Feeding on the ground, 

they consume seeds, grains, small amounts of other vegetative material, and traces of 

insect and animal parts (Best and Smartt 1986; Griffing and Davis 1974; Martin and 

others 1951; Tyler and Jenkins 1979). 

Home Range

In Missouri, adult mourning doves moved up to 4.8 miles (7.7 km) from nest 

sites to feeding areas (Sayre and others 1980). In an Idaho desert, Howe and Flake 

(1988) reported maximum daily movements of 5 adult doves to be 0.7 to 2.4 miles/

day (1.1 to 3.9 km). The average distance traveled from a nest to a feeding area was 

2.3 miles (37 km) and the average distance traveled to water was 1.1 miles (1.8 km). 

Populations

Mourning dove nesting densities in Illinois apple orchards ranged from 0.6 to 

12.9 nests/acre (1.53 to 31.75 nests/ha) (Putera and others 1985). In a wooded floodplain in New Mexico, nest densities were 3.3 nests/acre (8.1 nests/ha) and 18.2 nests/

acre (45.0 nests/ha) in a small, isolated shelterbelt in North Dakota (Davis and Sintz 

1973; Randall 1955). In Washington fruit orchards, Knight and others (1984) reported 

that the number of mourning doves nests ranged from 0 to 6.6/100. The average density of breeding mourning doves in a dense ponderosa pine forest was 1.2/100 acres 

(3.0/100 ha), in an old ponderosa pine forest their average density was 1.1 breeding 

pairs/100 acres (2.7/100 ha), and in an open old ponderosa pine forest their average 

density was 1.4 breeding pairs/100 acres (3.5/100 ha) (Siegel 1989). An old ponderosa 

pine forest near Flagstaff, Arizona contained 7 pairs/100 acres (17.2/100 ha) and a 

mixed-species forest on the San Francisco Mountains, also near Flagstaff contained 

3 pairs/100 acres (7.4/100 ha) (Haldeman 1968). In old mixed-species forests of 

Oregon, no breeding mourning doves were detected in the first 2 years of monitoring, 

but 0.1 birds/100 acres (0.2/100 ha) were detected during the third year. In thinned 

mixed-species forests in Oregon, densities averaged 0.5 breeding birds/100 acres 

(1.2/100 ha) (Mannan and Meslow 1984). Although some birds were noted, no breeding birds were counted in mixed-species stands in Arizona (Franzreb 1977).

Northern Flicker

The northern flicker (Colaptes auratus) is a relatively large woodpecker whose 

size varies geographically and with subspecies. In general, males are larger than 

females and flickers in northern latitudes are larger than those living farther south 

(Wiebe and Moore 2008). Typical length is 11.8 to 13.8 inches (30 to 35 cm) (Wiebe 

and Moore 2008). The weight of males in Colorado averaged 5.5 ounces (156 g) and 

the weight of females averaged 4.9 ounces (139 g) (Short 1965).

Because the northern flicker is distributed throughout the United States and 

with its conspicuous markings it is a common goshawk prey. In Oregon, 6 percent 

of 228 prey remains found at 59 goshawk nests were flickers and in New Mexico, 

14.3 percent of 106 prey remains found at goshawk nests were flickers (Kennedy 

1991; Reynolds and Meslow 1984). On the Kaibab Plateau in Arizona, Mannan and 

Boal (1993) found flickers in 5.2percent of 289 prey remains discovered at 22 nests 
152 USDA Forest Service RMRS-GTR-339. 2015.

and Reynolds and others (1994) found flickers in 24 percent of prey collected at 37 

nests. In the Warner Mountains of California, flickers comprised 6.8 percent of 221 

prey remains found at 23 nests (Promessi and others 2004). In Wyoming, 270 of 793 

regurgitated pellets (34 percent) found at 40 nests contained flicker remains (Squires 

2000). In Idaho, northern flickers comprised 9.4 percent of the goshawk’s diet (Patla 

1997). Flickers were also present in goshawk diets in the Black Hills National Forest 

(Erickson 1987).

Distribution

The northern flicker is a common resident in many forests of the United 

States. Two subspecies are the yellow-shafted flicker (C. a. auratus), which occurs 

in the eastern United States and across most of Canada, and the red-shafted flicker 

(C. a. cafer) which ranges across the western United States and Mexico. They readily 

hybridize across the Great Plains and through southwestern Canada. The Black Hills 

lie in the center of this zone where most flickers are thought to be hybrids (Pettingill 

and Whitney 1965; Short 1965). However, Short (1965) also referred to the Black 

Hills flickers as an “outlying cafer (red-shafted) population.” Flickers are year-round 

residents at all elevations in the Black Hills (Pettingill and Whitney 1965; Wiebe and 

Moore 2008). 

Habitat

Northern flickers nest in open woodlands, fields, and meadows. Scott and others 

(1977) reported flickers usually place nests along vegetative edges and in continuous forests only in and around openings (Scott and others 1977). For example in the 

quaking aspen forests of Utah nests were most often associated with meadow edges 

(Lawler and Edwards 2002). In mixed quaking aspen forests with a 98 percent quaking 

aspen component, northern flicker density averaged 7 birds/100 acres (17.2/100 ha) 

and in areas with less quaking aspen the flicker density was 1 to 4 birds/100 acres 

(2.5 to 9.9/100 ha) (Scott and Crouch 1988). Dobkin and others (1995) reported a 

70 percent average canopy cover above flicker nests in quaking aspen forests of the 

Black Hills. Also in the Hills, northern flickers were most abundant in mixed ponderosa pine, quaking aspen, and paper birch forests with more than 70 percent canopy 

cover (Mills and others 2000). 

Flickers excavate 2.75-inch (6.99-cm) diameter nest entrances in dead limbs of 

cottonwood, pine, oak, and juniper trees up to 100 ft (30.5 m) but typically they are 

 located between 10 and 30 ft (3 and 9 m) above the forest floor (Fisher and Wiebe 

2006; Martin and others 2004; Scott and others 1977). Fisher and Wiebe (2006) reported that nests located higher in trees compared to those at lower locations suffered 

less predation from squirrels and their nests were less frequently taken by European 

starlings.

In Arizona, northern flicker nests were frequently found in unharvested areas 

with ponderosa pine snags greater than 20 inches (50.8 cm) DBH (Horton and Mannan 

1988). Flickers also preferred ponderosa pine trees for nesting in New Mexico 

(Arsenault 2004). In burned ponderosa pine forests in the Black Hills, nest tree DBHs 

averaged 11.6 inches (29.4 cm) and nest density was associated with high pre-fire 

canopy cover (Vierling and others 2008). Scott and others (1980) characterized 
USDA Forest Service RMRS-GTR-339. 2015. 153

29 nests located in ponderosa pine, subalpine fir-spruce, and quaking aspen forests. 

Eight were in ponderosa pine snags, 6 were in quaking aspen snags, 14 were in 

live quaking aspen trees, and one was in an unidentified conifer snag. Nest heights 

averaged 36 ft (11 m), nest tree heights averaged 64 ft (20 m), and nest tree DBHs 

averaged 16 inches (41 cm). Average DBH for quaking aspen nest trees in Oregon was 

11.5 inches (29.1 cm) and 13.7 inches (34.7 cm) in British Colombia (Dobkin and others 1995; Martin and others 2004). In a mixed-species forest in Arizona, 36 nests were 

located and 21 were in quaking aspen snags, 5 in dead portions of live quaking aspen 

trees, and 10 in live quaking aspen trees. Average nest height was 53.5 ft (16.3 m), 

and average nest tree DBH was 17.7 inches (45 cm). Areas around nests contained an 

average of 18 aspen snags per acre (44/ha) and 9 conifer snags per acre (22/ha) (Li and 

Martin 1991). 

Flickers in British Colombia foraged primarily in areas with short grass and 

abundant bare ground that also contained a high density of small anthills. The proximity of these foraging areas to vegetative edges determined the distances flickers 

traveled to find forage which often exceeded 0.9 miles (1.5 km) (Elchuk 2002; Elchuk 

and Wiebe 2003b).

Diet

In most habitats animal matter comprises the majority (60 percent) of the northern flicker’s diet and 75 percent of that was ants and the remainder included beetles, 

wasps, caterpillars, crickets, and larval forms of many species (Scott and others 1977). 

Plant material commonly found in flicker diets includes seeds, cultivated grains, and 

fruits (Scott and others 1977). In a California ponderosa pine forest, 87 percent of 

the total food volume consumed by northern flickers was sawflies, wasps, bees, ants, 

and an additional 9 percent were aphids, leaf hoppers, and other Homoptera (i.e., 

largest insect order) species (Otvos and Stark 1985; Scott and others 1977). In British 

Columbia, flickers avoided large anthills of aggressive wood ants (Formica spp.) 

(although they would eat stray individuals), preferring to feed on smaller ants (e.g., 

Lasius spp. Tapinoma sessile) (Elchuk and Wiebe 2002). During inclement weather 

when ants stay mostly beneath ground, flickers pried open pieces of cow dung to 

obtain other insects for food (Elchuk and Wiebe 2002).

Home range 

In British Columbia, northern flicker home ranges consisted of grasslands interspersed with patches of quaking aspen, Douglas-fir, and lodgepole pine and their size 

averaged 61.8 acres (25 ha) and ranged from 12 to 269 acres (5 to 109 ha). Individual 

birds used multiple core areas averaging 17.3 acres (7 ha) in size which were located 

near nest trees and foraging areas. Home range size averaged 44.5 acres (18 ha) for renesting birds while those in a first laying attempt used smaller areas. Home range size 

increased with increasing distance to the nearest neighbor (Elchuk and Wiebe 2003b). 

Flickers fiercely defend nest areas with agonistic (e.g., related to fighting or threatening) calls and displays, but do not defend feeding areas (Elchuk and Wiebe 2003a). 

Elchuk and Wiebe (2003a) observed up to 21 breeding pairs/mile2 (8/km2) and noted 

50 percent home range overlap. 
154 USDA Forest Service RMRS-GTR-339. 2015.

Populations

Northern flicker populations exhibited little change in response to a variety of 

conditions in mixed-species and ponderosa pine forests in the western United States. 

Only in areas that were clearcut did the flicker show a population decline (Franzreb 

and Ohmart 1978; Kilgore 1971; Mannan and Meslow 1984; Medin 1985; Szaro and 

Balda 1979). On the Kaibab Plateau in northern Arizona, flicker breeding densities 

in dense old forests was 6.7 pairs/acre (16.6/ha), 6.4 pairs/acre (15.8/ha) in light 

harvested old forests, and 3.4 pairs/acre (8.4/ha) in open old ponderosa pine forests 

(Siegel 1989).

In the Black Hills, northern flicker density was 41.2 birds/mile2 (15.9 /km2) in 

burned forests, 6.5 birds/mile2, (2.5 /km2) in ponderosa pine forests, 8.8 birds/mile2

(3.4 /km2) in old ponderosa pine forests, and 9.8 birds/mile2, (3.8/km2) in white spruce 

forests (White and others 2010). Flicker densities in burned areas increased steadily 

with time since fire, rising from 4.1 birds/mile2 (1.6 /km2) in 2001 to 41.2 birds/mile2

(15.9 /km2) in 2009. A similar trend was observed by Saab and others (2007) over 

10 years in a burned ponderosa pine forest in Idaho. Edworthy and others (2011) found 

that abundance of individuals and nests increased following a mountain pine beetle 

outbreak in British Columbia’s Douglas-fir zone.

In Arizona Szaro and Balda (1982) found that with the exception of clearcuts, 

northern flickers were located in all types of tree harvesting including areas where 

trees had not been cut for 60 years. They found birds in light harvests where large trees 

and dense thickets were selectively removed, in strips of moderate tree harvests, unharvested areas, and in areas intensely harvested. Northern flicker densities averaged 

about 3 pairs/100 acres (7.4/100 ha) and did not differ among harvest areas (Szaro and 

Balda 1982, 1986). In Idaho, flickers used large patches of severely burned ponderosa 

pine that had high canopy cover before burning and contained both large snags and 

high snag densities (Russell and others 2007; Saab and others 2009). Flicker nest 

densities were higher in unharvested burned areas compared to harvested burned areas 

(Saab and others 2007). Management activities that emulate mixed severity fire effects 

and retain high numbers of large snags in clumps are likely to benefit flicker populations (Saab and others 2009; Vierling and others 2008). 

Northern Flying Squirrel

The northern flying squirrel (Glaucomys sabrinus) is a medium-sized gliding 

squirrel ranging from 10.8 to 13.5 inches (27.4 to 34.2 cm) in length and weighing 

about 2.6 to 4.9 ounces (75 to 140 g) (Malamuth and Mulheisen 1999). The length 

of flying squirrels in the Black Hills averaged 11.8 inches (30 cm) compared to the 

13.0 inch (32.9 cm) average length of those living in western Wyoming (Turner 1974).

In California, 6 percent of 234 prey items were flying squirrels and in Idaho, 

they comprised 1 percent of goshawks’ diet (Bloom and others 1986; Patla 1997). In 

mixed-conifer forests in Oregon, flying squirrels made up 7 percent of goshawk diets 

and in Washington, 4.2 percent of prey items at 82 nests over a 10-year period were 

flying squirrels (Reynolds and Meslow 1984; Watson and others 1998). Goshawks 

also consumed flying squirrels in temperate rainforests of southeast Alaska and ponderosa pine forests of northeastern California (Lewis and others 2006; Promessi and 
USDA Forest Service RMRS-GTR-339. 2015. 155

others 2004). Although found in the Black Hills, flying squirrel remains were found at 

only one of the five goshawk nests visited by Bartelt (1977).

Distribution

Northern flying squirrels live in forests throughout northern North America, 

from southeastern Alaska across the southern tier of Canadian provinces and south 

into the Great Lakes states, New England, and the Appalachians. In the western United 

States, the species’ range extends south into California and into Idaho, Montana, 

Utah, northern Wyoming, and western South Dakota. In California, they inhabit the 

Coast, Klamath, Southern Cascade, Sierra Nevada, and Transverse mountain ranges 

(Williams and others 1992). The distribution of northern flying squirrels in South 

Dakota is limited primarily to the isolated population in the Black Hills in white 

spruce forests located above 4,500 ft (1372 m) elevation. This population is located 

approximately 245 mi (394 km) east of its nearest neighboring population in Park 

County, Wyoming (Turner 1974; Wells-Gosling and Heaney 1984). 

Habitat

Flying squirrels are forest dwelling and are found only in areas with trees of 

sufficient size and density that provide for denning and gliding (Jameson and Peeters 

1988). Northern flying squirrels inhabit a variety of coniferous forests in California, 

including mixed-conifer, Douglas-fir, red fir (Abies magnifica), white fir, ponderosa 

pine, lodgepole pine, and oak woodlands from sea level up to 7,500 ft (2286 m) 

elevations (Ingles 1965; McKeever 1961; Williams and others 1992). In general, they 

tend to nest in mesic ponderosa pine, quaking aspen, spruce, and paper birch forests 

(Hough and Dieter 2009a; Kruger 2004; Turner 1974). 

Northern flying squirrels typically live in dense and mature forests however they 

are opportunist and capable of adjusting to a wide range of forest conditions (Carey 

and others 1992; Cotton and Parker 2000; Hough and Dieter 2009b; Lehmkuhl and 

others 2006; Smith and others 2005; Thomas and others 1990; Waters and Zabel 1995; 

Weigl 2007). Raphael and others (1986) and Rosenberg and Anthony (1992) found 

similar squirrel abundance in both mid-aged and old forests. Mid-aged forests may 

appear to support healthy squirrel densities but, in reality, they are population drops 

from neighboring old forests and usually do not maintain viable populations (Fisher 

and Wilkinson 2005; Smith and Person 2007). Cotton and Parker (2000) noted that 

flying squirrels in mid-aged spruce-fir forests selected the larger, taller, and older trees 

for nesting. Not surprisingly, flying squirrels were not found within clearcuts less than 

20 years old and forest openings (Gashwiler 1970; Williams and others 1992). Also 

snags, downed logs, coarse woody debris, thick litter layer, and understory cover are 

important for habitation (Carey 1995; Carey and others 1999; Holloway and Malcolm 

2007; Meyer and others 2005, 2007; Pyare and Longland 2002; Smith 2007; Smith 

and others 2004; Weigl 2007). 

Flying squirrels glide from tree to tree relying on elevated launch and landing 

sites. Large openings or wide tree spacing probably limits their movement and increases their vulnerability to predation (Wells-Gosling and Heaney 1984; Williams and 

others 1992). In Douglas-fir forests of northern California, Rosenberg and Raphael 

(1986) found squirrels in 60 to 80 percent of stands larger than 50 acres (20.2 ha) 
156 USDA Forest Service RMRS-GTR-339. 2015.

compared with 15 percent occupancy of stands of 25 to 50 acres (10.1 to 20.2 ha) and 

less than 10 percent occupancy of stands less than 15 acres (6.1 ha) in size. Lehmkuhl 

and Ruggiero (1991) suggested northern flying squirrels could be at risk of local extinction because of mature forest fragmentation. 

Northern flying squirrels den in natural and woodpecker-excavated cavities in 

trees, drey nests comprised of sticks, dry leaves, and grass built by birds and squirrels, and tree branches deformed by dwarf mistletoe (Arceuthobium spp.) (Hough and 

Dieter 2009c; Wells-Gosling and Heaney 1984). One female may use up to seven 

dens in both hardwoods and conifers for nesting, daytime resting, and protection from 

weather (Carey 1991; Carey and others 1997). Flying squirrels tend to select nest trees 

that are older, taller, and larger than random trees (Bakker and Hastings 2002; Carey 

and others 1997; Cotton and Parker 2000; Meyer and others 2005). In the Black Hills, 

cavity nests were located in dead and live quaking aspen, paper birch, and ponderosa 

pine trees. However, drey squirrel nests were only found in live ponderosa pine and 

white spruce trees (Hough 2008). Snags were used almost five times more often than 

expected based on their availability, and DBH of all nest trees was larger than available snags, averaging 11.4 inches (29 cm) DBH (Hough and Dieter 2009c). Carey 

(1991) found nest cavities in live conifers averaging 49 inches (124 cm) DBH and in 

snags averaging 35 inches (89 cm) DBH.

Diet 

Although they are tree dwelling, flying squirrels often forage on the ground 

for seeds and mushrooms. In the Sierra Nevada Mountains tree lichens, an important 

flying squirrel food, were more abundant in old red and white fir forests than in young 

forests (Waters and Zabel 1995). Mushrooms are strongly associated with deep soil 

surface organic layers, decayed logs, and high canopy cover, which are typically found 

in mature and old forests located on cool and moist aspects (Gabel and others 2010; 

Lehmkuhl and others 2004; Luoma and others 1991; Maser and others 1978, 1985; 

McKeever 1960; Tevis 1956; Williams and others 1992). In Oregon, over 80 percent 

of the summer diet consisted of mushrooms and 71 percent of these mushrooms were 

gilled (Basidiomycetes) and 26 percent was case (Ascomycetes). Also in Oregon, 

50 percent of the year-round flying squirrel diet was lichens (Maser and others 1978; 

Maser and others 1985). In the Sierra Nevada, Hall (1991) reported that mushrooms 

and lichens were the primary year-round food for flying squirrels and they likely 

cached mushrooms to eat during the winter. In the northern Black Hills, over 90 percent of flying squirrel feces collected contained fungal spores, predominantly from 

genus Rhizopogon (e.g., fungi growing on tree roots) (Gabel and others 2010). Other 

flying squirrel foods include seeds, nuts, bird eggs, nestlings, insects, tree sap, buds, 

berries, and tree cones (Weigl 2007; Wells-Gosling and Heaney 1984).

Home range

Northern flying squirrel home range size is limited by food abundance and, to 

a lesser extent, den site availability (Hough 2008). In Wind Cave National Park the 

average size of female flying squirrel home ranges was 11.4 acres (4.6 ha) (Duckwitz 

2001). Also in the Black Hills, Hough and Dieter (2009a) reported home range sizes 

for males of 27.7 acres (11.2 ha) and 17.1 acres (6.9 ha) for females. They indicated 
USDA Forest Service RMRS-GTR-339. 2015. 157

that home ranges in the mesic and more structurally complex forest of the northern 

Black Hills were more than twice as large as those located in the drier southern hills. 

Male home ranges are generally two to three times as large as females and often 

overlap with those of several females, presumably to increase breeding potential 

(Carey and others 1997; Holloway and Malcolm 2007; Hough and Dieter 2009a; 

Martin and Anthony 1999). In ponderosa pine forests with 40 percent canopy cover in 

Washington, home range size was 11.4 acres (4.6 ha ) and 85 percent larger than those 

located in nearby mixed-conifer forests (Lehmkuhl and others 2006). Core areas were 

generally centered on food patches, while nest sites were often located near home 

range perimeters (Holloway and Malcolm 2007; Smith 2007).

Populations 

Estimated flying squirrel densities in coniferous forests of the Pacific Northwest 

ranged from 0.4 to 1.2 animals/acre (1 to 3/ha) and did not show trends relative to 

habitat, geographic location, or elevation (Thomas and others 1990). However, Gomez 

and others (2005) reported that squirrel density increased with increased mushroom 

biomass, large logs, and conifers with DBHs greater than 19.7 inches (50 cm). In 

southwestern Oregon mean density of flying squirrels was 0.8 squirrels/acre (2/ha) 

in old Douglas-fir forests and 0.4 squirrels/acre (1/ha) in mid-aged forests (Carey 

and others 1992). Witt (1992) reported 2.47 flying squirrels/acre (0.85/ha) in an old 

hemlock-fir forest, which was six times the number found in a 65-year-old forest. 

However, the occurrence of flying squirrels was far less in mature forests if their range 

was less than 50 acres (20 ha) in size (Rosenberg and Raphael 1986). 

Doyle (1990) reported similar densities of flying squirrels in riparian and upland 

habitats but found a larger proportion of juveniles in upland habitats, suggesting that 

riparian habitats may serve as population sources, whereas upland habitats may be 

population sinks for dispersing juveniles. Waters and Zabel (1995) observed highest 

squirrel densities in old forest, intermediate densities in young forest, and lowest 

densities in forests with scattered overstory trees. Structure (e.g., young, mid-aged, 

and old) appears to be more influential on flying squirrel populations than seral stage 

(e.g., pioneer, mid-seral, and climax) (Rosenberg and Anthony 1992; Carey and others 1999). Therefore, squirrel abundance usually increases in a forest from the time 

it is disturbed (e.g., harvested and burned) as it progresses to old forest (Fisher and 

Wilkinson 2005). Lehmkuhl and others (2006) found 0.5 squirrels/acre (1.2/ha) in 

open ponderosa pine forests and 0.9 squirrels/acre (2.2/ha) in mixed-conifer forest and 

they postulated that a threshold of 55 percent canopy cover separated low- from highdensity flying squirrel populations.

Tree harvesting that removes snags, defective trees, mature forests, and 

mistletoe-infected trees will likely reduce the quality of flying squirrel habitat (Carey 

and others 2002; Lehmkuhl and others 2006; Smith 2007). Clearcut and partial cut 

harvesting resulting in tree spacings greater than 120 ft may limit flying squirrel 

gliding and increase their predation risk. Carey (1995) found that forest treatments 

that produce heterogeneous canopy cover negatively affected population abundance. 

However, he reported that population levels rebounded to pre-thinning levels after 

5 years. In contrast, other studies showed that thinning of mid-aged forests showed 

no negative short-term effects on squirrel survival rates, densities, or mushroom 
158 USDA Forest Service RMRS-GTR-339. 2015.

production (Carey and others 2002; Gomez and others 2005; Ransome and Sullivan 

2002). However, Carey (2001) indicated that where squirrel densities were low, effects 

of thinning may be hard to detect. Squirrel populations in young forests containing a 

legacy of old trees, snags, down logs, and developed understory can equal the populations found in old forests (Carey 1995). 

Isolated northern flying squirrel populations, such as those at the southern extension of the species’ range, are highly susceptible to decline as a result of timber harvest 

(Koprowski 2005; Weigl 2007). Flying squirrels in the Black Hills are at risk simply 

because they are rare and their range being restricted to the mesic northern portion of 

the Hills. Because of this, the Black Hills National Forest considers the northern flying 

squirrel a species of special concern (USDA Forest Service 2005).

Red-Headed Woodpecker

The red-headed woodpecker (Melanerpes erythrocephalus) is a medium-sized 

bird being 7.9 to 9.4 inches (20 to 24 cm) long and weighing 2.0 to 3.2 ounces (56 to 

91 g) (Smith and others 2000). This woodpecker is one of five Melanerpes species 

living in the United States, and although members of this genus regularly occur in the 

diet of goshawks the red-headed woodpecker has yet to be recorded (Reynolds and 

Meslow 1984).

Distribution

Red-headed woodpeckers range from southern New England west to eastern 

Saskatchewan and the eastern slope of the Rocky Mountains, south to central New 

Mexico, and east to the Gulf Coast (Smith and others 2000). They are common summer residents within most of South Dakota, except in the Black Hills where they 

occur primarily at lower elevations (Pettingill and Whitney 1965; South Dakota 

Ornithologists’ Union 1991). Recent monitoring in the Black Hills found this species 

mostly in the Jasper Fire area but also in ponderosa pine and riparian habitats, especially where they were associated with burned areas (Panjabi 2003; White and others 

2010).

Habitat

Red-headed woodpeckers use open forests with uncluttered understories 

containing mature hardwoods, snags, stumps, and trees with dead limbs (Bent 1939; 

Smith and others 2000). They use vegetative edges, upland forests, woodlots, and 

shelterbelts along agricultural fields (Luensmann 2006). Riparian areas, upland meadows, forest bottomlands, beaver ponds, and open wooded swamps are favored by this 

woodpecker. Red-headed woodpeckers also use forests disturbed by harvesting, wind, 

ice, flooding, insects, fire, and especially those that remove tree leaves. Also orchards, 

residential areas, isolated trees, roadside fence posts, utility poles, and golf courses are 

frequented by red-headed woodpeckers (Anderson 2003; Pettingill and Whitney 1965; 

Smith and others 2000; South Dakota Ornithologists’ Union 1991). 

Red-headed woodpeckers nest in snags, stumps, dead limbs, and dead portions of pine, birch, oak, elm, maple, cottonwood, willow, box elder, and white ash 

(Fraxinus americana) (Johnsgard 1986; Twomey 1945; Smith and others 2000). They 

prefer nest trees to be grouped (Sedgwick and Knopf 1990). In addition, they tend to 
USDA Forest Service RMRS-GTR-339. 2015. 159

avoid pure live forests, as exemplified in the Black Hills, as no red-headed woodpeckers were detected in 272 samples of live forests (Spiering and Knight 2005). They also 

use telephone poles, nest boxes, split-rail fence rails, and buildings for nesting and 

they often reuse the same cavity for several years. They prefer well-worn and smoothsurfaced nest sites compared to those with bark and as weak excavators, they often 

use existing cavities (Bent 1939; Smith and others 2000). In riparian areas of South 

Dakota red-headed woodpeckers nested in cottonwood trees and they also nested 

in burned ponderosa pine trees (Gentry and Vierling 2008; Sharp and Uresk 1990). 

Within the Jasper Fire that burned in the Black Hills in 2000, 53 percent of red-headed 

woodpecker nests were in the few quaking aspen snags that remained and the other 

47 percent were in dead ponderosa pine trees (Vierling and Lentile 2006). 

In the Jasper Fire area, nest trees averaged 10.8 inches (27.4 cm) DBH while 

random trees averaged 8 inches (20.4 cm) DBH and in areas in the Hills near the fire, 

nest snags averaged 28.5 ft (8.7 m) tall and 15 inches (38.2 cm) DBH (Gentry and 

Vierling 2008; Vierling and Lentile 2006). Also within the Jasper Fire area red-headed 

woodpecker nest snags averaged 14.9 inches (37.8 cm) DBH and nest height averaged 

35.1 ft (10.7 m) (Vierling and others 2009). Across the Wyoming border in the Bear 

Lodge, the average height of two nests located in ponderosa pine snags was 30 ft 

(9.1 m) (Pettingill and Whitney 1965). Elsewhere in South Dakota, the average height 

of a nest located in a dead branch of an ornamental poplar and one in a utility pole was 

60 ft (18.3 m) (Pettingill and Whitney 1965). 

Diet

Red-headed woodpeckers forage by fly-catching insects on the ground, on dead 

trees, utility poles, and dead branches (Beal 1911; Smith and others 2000). Based on 

the analysis of 443 stomachs collected throughout the year, approximately 34 percent 

of their diet was animal matter consisting of grasshoppers, bees, wasps, crickets, 

beetles, and caterpillars with the remainder being plant material (Beal 1911). These 

woodpeckers also consume birds, bird eggs, nestlings, mice, and lizards. Red-headed 

woodpeckers also eat seeds, acorns, sap, nuts, berries, fruit, and corn (Smith and others 2000). Acorns are an important food, especially during the winter, making these 

woodpeckers somewhat nomadic as they search for oak forests (Smith and others 

2000; South Dakota Ornithologists’ Union 1991; Vierling and others 2009). They store 

many of these foods such as grasshoppers, corn, and acorns in tree crevices and under 

tree bark for later consumption (Beal 1911). 

Home range

Red-headed woodpecker territories vary in size with habitat and winter territories generally smaller. Home ranges in the Black Hills were estimated to be 3 to 

6 acres (1.2 to 2.4 ha) in size (Haldeman 1980). 

Populations

Due to population declines, red-headed woodpeckers are considered a species of conservation concern among the Badlands, Prairies, and several other Bird 

Conservation Regions, (USFWS 2008). Historically, red-headed woodpecker populations increased when forests were cleared for agriculture, years with abundant acorn 
160 USDA Forest Service RMRS-GTR-339. 2015.

production, and outbreaks of Rocky Mountain grasshoppers. Population declines have 

occurred when forests recovered after disturbance and seed producing beech, elm, and 

oak forests declined. Tree harvesting that removes snags, dead tree limbs, broken tree 

stumps, and acorn producing oaks, along with the loss of cottonwoods in riparian areas 

can negatively impact populations (Sedgwick and Knopf 1990). Also populations can 

be threatened by the expansion of European starlings (competitor for cavity nests) and 

fire suppression (Smith and others 2000).

Grinnell (1875), who accompanied General Custer to the Black Hills 1874, 

described red-headed woodpeckers as “especially abundant and seen where ever there 

was timber” and Cary (1901) described them as “the most abundant woodpecker in the 

Hills.” However, today (2014) they are uncommon in the Black Hills and bird monitoring conducted from 2001 through 2009 detected only a handful of individuals in a 

variety of riparian, grassland, shrubland, and ponderosa pine habitats (Panjabi 2001, 

2003; White and Giroir 2008). However, the majority of red-headed woodpeckers 

were seen in burned forests where densities averaged 5.14 woodpeckers/mile2 (1.99/km2) 

(White and others 2010).

Red-Naped Sapsucker

The red-naped sapsucker (Sphyrapicus nuchalis) is a medium-sized woodpecker 

that averages 7.5 to 8.3 inches (19 to 21 cm) long and weighs approximately 1.1 to 

2.3 ounces (32 to 66 g) (Walters and others 2002). The red-naped sapsucker is one of 

four Sphyrapicus species that occupy forests of North America and they are regularly 

consumed by goshawks (Bloom and others 1986; Lewis and others 2006; Patla 1997; 

Reynolds and Meslow 1984; Squires 2000). 

Distribution

Red-naped sapsuckers reside in forests of southeast Alaska, British Columbia, 

Alberta, Rocky Mountains (i.e., Idaho, Nevada, Montana, Utah, Colorado, Arizona 

and New Mexico), California, and the Black Hills. They winter in Arizona, New 

Mexico, Baja California, and northwestern Mexico (Walters and others 2002). In the 

Black Hills, red-naped sapsuckers are considered uncommon summer residents at all 

elevations (Pettingill and Whitney 1965; South Dakota Ornithologists’ Union 1991). 

Recent surveys found them in low to moderate abundance across the Hills, but they 

were most abundant in the northern Black Hills (Panjabi 2001, 2003; White and others 

2010). 

Habitat

Red-naped sapsuckers use deciduous and mixed woodlands containing mature 

and dead trees. They are found in ponderosa pine, quaking aspen, mixed-conifer, 

lodgepole pine, and mixed Douglas-fir/western larch/ponderosa pine forests. They 

were also found in riparian areas containing quaking aspen, birch, and willow (Scott 

and others 1977; Walters and others 2002). In the Rocky Mountains, sapsuckers used 

pure quaking aspen forests or quaking aspen mixed with open conifer forests. In 

Montana, red-naped sapsuckers used mature mixed-conifer forests of western larch, 

Douglas-fir, and paper birch (McClelland and McClelland 2000). In Utah and Idaho, 

sapsuckers were strongly associated with quaking aspen and mature Douglas-fir 
USDA Forest Service RMRS-GTR-339. 2015. 161

forests (Smith 1982). They also used harvested forests where groves of quaking aspen 

were retained (Walters and others 2002). In the Black Hills, red-naped sapsuckers 

mainly used ponderosa pine and quaking aspen forests but were also found in riparian areas and white spruce forests (Pettingill and Whitney 1965; Panjabi 2001, 2003; 

White and others 2010). Although nests have been found in a variety of deciduous 

and coniferous forests, red-naped sapsuckers nest almost exclusively in mature and 

diseased quaking aspen forests that incorporate foraging areas. In addition to nesting 

in mature quaking aspen trees in Colorado, sapsuckers used mixed cottonwood-willow 

forests in riparian areas especially when they were associated with foraging areas 

(Vasquez 2005). 

Red-naped sapsuckers are cavity nesters and they occasionally reuse a nest, but 

typically they excavate a new cavity each year. For example, in Montana, 22 of 42 nest 

trees were used for 2 consecutive years and only 6 were reused for more than 2 years 

(McClelland and McClelland 2000). Similarly, in Colorado, only 3 of 33 cavities were 

reused, but 22 of the 33 nests were located in the same trees as the previous year’s 

cavities (Daily 1993). Quaking aspen trees are preferred by sapsuckers for nesting and 

they select trees infected with stem rots (fungi) to ease nest excavation. In Colorado 

and Wyoming, 51 nests were located in quaking aspen trees and most were infected 

with the shelf fungus (Phellinus igniarius) (Crockett and Hadow 1975). Similarly, 

13 nests were located in Wyoming and all were in quaking aspen also infected with 

a stem rot (Loose and Anderson 1995). The DBH of quaking aspen trees used for 

nesting tend to be larger than the average quaking aspen tree available and the number 

of nests located in a stand was strongly associated with the number of quaking aspen 

trees greater than 7.1 inches (18 cm) DBH (Crockett and Hadow 1975). Nest stands 

had 36 overstory trees per acre (90/ha) and when compared to other stands had greater 

ground cover (73 percent versus 35 percent) and greater grass cover (39 percent versus 

10 percent) (Loose and Anderson 1995). Scott and others (1980) characterized 6 nests 

located in ponderosa pine, spruce-fir, and quaking aspen forests within in the Rocky 

Mountains. Five nests were located in live quaking aspen trees and the other was in a 

conifer snag.

Sapsuckers excavate cavities relatively low on a tree, especially if the tree has no 

nests. New nests are located above older ones as stem rots usually begin near a tree’s 

base and progresses upward with time (Daily 1993). In Colorado, the average nest 

tree was 62 ft (19 m) tall and nest height averaged 39 ft (12 m) with the DBH of nest 

trees averaging 16 inches (40.6 cm) (Scott and others 1980). Of 20 nests discovered 

in Arizona, all were located in quaking aspen trees (20 percent snags, 25 percent dead 

portions of live trees, and 55 percent live trees), average nest tree height was 43.6 ft 

(13.3 m), and average nest tree DBH was 14.6 inches (37.1 cm) (Li and Martin 1991). 

An average of 1.7 (4.2/ha) quaking aspen and 0.6 (1.5/ha) conifer snags per acre were 

located around the nests. Conifers containing sapsucker nests tend to have larger 

DBHs than quaking aspen nest trees allowing nests to be located high in the tree where 

the tree bark is thinner and the cavity is better protected from predators (Crockett and 

Hadow 1975).

In Colorado red-naped sapsuckers foraged in quaking aspen, willow, conifer, and 

cottonwood trees close to their nests (Crockett and Hadow 1975). In Wyoming, they 

foraged in young and mature lodgepole pine, multi-story lodgepole pine, spruce-fir, 
162 USDA Forest Service RMRS-GTR-339. 2015.

and quaking aspen forests. Trees and snags used for foraging averaged 11 inches 

(28 cm) DBH and random trees averaged 4.5 inches (11.4 cm) DBH. Logs used for 

foraging were no larger than others available (Loose and Anderson 1995). 

Diet

Red-naped sapsuckers feed on tree sap throughout the year, but the amount 

taken, tree species used, and location of the sap wells on a tree vary seasonally (Bock 

and Larson 1986; Scott and others 1977; Walters and others 2002). Rocky Mountain 

juniper (Juniperus scopulorum), Douglas-fir, lodgepole pine, white spruce, willow, 

quaking aspen, and cottonwood trees are frequently drilled by sapsuckers (Loose and 

Anderson 1995). During the breeding season, red-naped sapsuckers in Colorado and 

Wyoming used a variety of conifers and deciduous trees and shrubs for sap-sucking 

(Crockett and Hadow 1975). In early spring, sap wells are drilled into tree boles using 

a series of parallel holes. Exploratory wells are made initially but they are enlarged 

into a single well when sap starts to flow. Occasionally, sapsucker drilling can girdle 

and kill tree branches and a family foraging on willow trees was known to do sufficient damage that it may take years for the trees to recover (Ehrlich and Daily 1988). 

Although sap constitutes the majority of plant material eaten by sapsuckers, tree fruit 

often makes up a small proportion of their diet (Bock and Larson 1986; Scott and others 1977). Most (80 percent) of the animal material consumed by sapsuckers are ants, 

but they also consume beetles, wasps, and other insects that get trapped in sap wells, 

gleaned from trees, or by fly-catching(Scott and others 1977; Walters 1996). 

Home range

Territories of red-naped sapsuckers include both nest and sap-well trees. In 

British Columbia, average territory size was 13.2 acres (2.47 ha). Most movements 

were less than 1,640 ft (500 m) from the nest, although some sapsuckers traveled 

nearly a mile (1.6 km) to maintain sap wells in willow trees. In Colorado, territory size 

averaged 4.1 acres (1.67 ha) (Walters 1996). 

Populations

Breeding Bird Survey data indicate red-naped sapsucker populations are increasing in the United States, and there is an increasing population trend in South Dakota 

(Sauer and others 2011a). In the Black Hills, they are considered quaking aspen-paper 

birch obligates, and their highest abundance was associated with forest compositions 

that included at least 4 quaking aspen-paper birch snags/acre (1/ha) that had DBHs 

greater than 5.9 inches (15 cm) (Mills and others 2000). From 2001 to 2009, the 

total number of red-naped sapsuckers observed in the Hills ranged from 306 in 2001 

to 118 in 2006 (White and others 2010). Densities for the same period in mid-aged 

ponderosa pine forests were 42.5 birds/mile2 (16.4 /km2), in old ponderosa pine forests 

densities were 32.9 birds/mile2 (12.7/km2), and in white spruce forests densities were 

32.4 birds/mile2 (12.5/km2) (White and others 2010). All three forest types included 

quaking aspen. Populations of sapsuckers in quaking aspen forests were nearly twice 

as high, ranging from 73.8 birds/mile2 (28.5/km2) in 2001 to 125.3/mile2 (48.4/km2) in 

2004 (White and Giroir 2008).
USDA Forest Service RMRS-GTR-339. 2015. 163

Red Squirrel

The red squirrel (Tamiasciurus hudsinicus) is a small tree squirrel ranging in 

length from 10.8 to 15.0 inches (27.0 to 38.5 cm) and weighs from 6.9 to 9.9 ounces 

(197 to 282 g) (Steele 1998). Black Hills red squirrels (T. h. dakotensis) are larger than 

those living to the west and southwest of the Hills and average 13.7 inches (34.8 cm) 

long and they weigh an average of 10.3 ounces (292 g) (Turner 1974). 

The red squirrel is a common year-round prey of goshawks in the Black Hills, 

which makes the species especially important. During three breeding seasons in 

Alberta, Canada an estimated 306 red squirrels were captured by a pair of goshawks 

and during the winter, when less prey is available, they likely captured many more 

(Rusch and Reeder 1978). In New York red squirrels comprised 12 percent of the 

goshawk’s diet, in Minnesota, 31 percent, and in California they comprised 21 percent 

(Bloom and others 1986; Grzybowski and Eaton 1976; Meng 1959; Smithers and others 2005). In Arizona, 29 percent of the prey captured by goshawks was red squirrels 

in 1991 and 12 percent from 1999 to 2003 (Reynolds and others 1994; Salafsky and 

others 2005). In Idaho, red squirrels comprised 17.8 percent of the goshawk’s diet and 

in Wyoming, 50 percent of 793 fecal pellets collected contained red squirrel remains 

(Patla 1997; Squires 2000). In the Black Hills, red squirrel remains were found at all 

of nests located by Bartelt (1977), Erickson (1987), and Knowles and Knowles (2009). 

Distribution

Red squirrels live in the forests of Alaska, the boreal of Canada, and the hardwood and coniferous forests of the upper midwestern, northeastern, and Appalachian 

states. They range throughout coniferous forests of the Rocky Mountains and south 

into the mountains and higher elevation plateaus of Arizona and New Mexico 

(Hoffmeister 1986; Steele 1998). In the Black Hills, red squirrels are most common above 5,200 ft (1585 m), especially in the white spruce forests, but they occur 

throughout the Hills above 3,800 ft (1158 m) (Turner 1974).

Habitat

In the western United States, red squirrels are found most often in mature 

spruce-fir, Douglas-fir, and lodgepole pine forests. Mature forests appear to offer 

excellent breeding conditions and have higher squirrel survival rates than do younger 

stands. However, young forests offer yearling and young squirrels areas to move 

to (Sullivan and Moses 1986). Red squirrels are less common in mixed ponderosa 

pine and Douglas-fir forests and are rare in pure ponderosa pine (Gurnell 1984; 

Hoffmeister 1986; Rasmussen 1941; Sullivan and Moses 1986). Uphoff (1990) found 

high densities of red squirrels in low elevation mixed-coniferous and deciduous forests 

in Arizona. In the Black Hills, red squirrels live in white spruce, often mixed with 

ponderosa pine, pure and mixed quaking aspen forests, and oak woodlands (Higgins 

and others 2002; Turner 1974). 

Large and centrally located food caches (middens) are critically important for 

red squirrels. Over the winter, this stored food is consumed and during the summer 

it is consumed by juveniles as they learn to forage (Gurnell 1984; Kemp and Keith 

1970; Patton and Vahle 1986; Rusch and Reeder 1978; Smith 1968b; Uphoff 1990). 

Seed crops can fluctuate widely from year to year, often making cached cones an 
164 USDA Forest Service RMRS-GTR-339. 2015.

important food source for several winters (Smith 1968b). Caches located in moist and 

well shaded areas provide optimal conditions for cone storage (Rothwell 1979). Shade 

from groups of mature trees and from mid and lower vegetation maintain temperature 

and humidity at levels sufficient to prevent cones from opening and minimize the 

drying of mushrooms, conifer buds, grasses, berries, and insects that are also cached. 

In Arizona, Vahle and Patton (1983) found that 90 percent of 141 caches had canopy 

cover greater than 60 percent and also in Arizona canopy cover over and within 33 ft 

(10.1 m) of middens averaged 89 percent (Mannan and Smith 1991). Very often one or 

more snags, fallen logs, and/or live trees greater than 20 inches (50.8 cm) DBH provide support for primary caches (Vahle and Patton 1983). In old mixed conifer forests, 

density measured by basal area averaged 197 ft2/acre (45.2 m2/ha) at cache sites and at 

random sites averaged 142 ft2/acre (32.6/m2). Cache sites also had more than 3 trees/

acre (7.4/ha) with 20 inch (50.8 cm) DBHs (Patton and Vahle 1986; Vahle and Patton 

1983). Similarly, Mannan and Smith (1991) found an average of 4 trees/acre (9.9/ha) 

with DBHs greater than 16 inches (40.6 cm) at middens.

Old-trees tend to produce 20 to 30 times more cones than trees that are 50 to 100 

years old (Hermann and Lavender 1990). For example Douglas-fir trees 200 to 300 

years old are far better at producing cones than younger trees. White fir begins producing cones approximately at 40 years of age and continues well beyond 300 years. 

Dominant white fir trees 12 to 35 inches (30.5 to 88.9 cm) DBH tend to be the best 

and most reliable cone producers (Laacke 1990). Engelmann spruces begin producing 

abundant cones at DBHs greater than 15 inches (38.1 cm) and that are 150 to 200 

years old and blue spruce’s (Picea pungens) best seed-producing years are from age 50 

to 150 years (Alexander and Shepperd 1990; Fechner 1990). 

Red squirrels prefer to nest in trees located within groups of trees with interlocking crowns (Vahle and Patton 1983). In Wyoming, 48 percent of 65 nest trees 

had crowns with greater than 75 percent overlap with other trees and the remaining 

nest trees had 15 to 75 percent overlap (Rothwell 1979). In a mixed species forest in 

Arizona, nest trees averaged 14 inches (35.6 cm) DBH and the largest nest trees were 

found at cache sites. Nest trees on average were located within 15 ft (4.6 m) of the 

cache center (Vahle and Patton 1983). Layne (1954) found leaf nests in trees with 4- to 

16-inch (10.2- to 40.6-cm) DBHs located in a mixed hardwood forest of New York 

and cavity nests were located in trees with 12- to 36-inch (30.5- to 91.4-cm) DBHs.

Diet

In coniferous forest, seeds are the year-round food of red squirrels. The number 

of cones required to sustain a single red squirrel for a year ranges from 42,000 to 

100,000. It has been estimated that 9 to 25 large cone-producing trees per territory 

would be necessary to support a red squirrel or 3 to 4 trees trees/acre (7.4 to 9.9/ha) 

with DBHs greater than 18 inches (45.7 cm) DBH (Gurnell 1984; Patton and Vahle 

1986; Rusch and Reeder 1978; Smith 1968a; Vahle 1978;). Common seeds eaten by 

red squirrels in the Southwest are from Douglas-fir, blue spruce, Engelmann spruce, 

and white fir (Gurnell 1984; Patton and Vahle 1986; Rusch and Reeder 1978; Smith 

1968a; Sullivan and Moses 1986). On the Kaibab Plateau in northern Arizona, ponderosa pine seeds were occasionally consumed by red squirrels and in feeding trials 
USDA Forest Service RMRS-GTR-339. 2015. 165

they were second most preferred and were the most nutritious out of seven species 

tested (Rasmussen 1941; Smith 1968a). 

Tree buds, fruits, sap, acorns, insects, and bird eggs are also consumed by red 

squirrels, especially if conifer seed supplies are low (Brink and Dean 1966; Hatt 1929; 

Layne 1954; Rusch and Reeder 1978; Smith 1968a, 1968b; Uphoff 1990). Depending 

on location, conifer pollen is consumed for 2 or 3 weeks, while mushrooms are usually available throughout the summer. After being dried, they are cached along with 

cones (Hatt 1929; Rusch and Reeder 1978; Smith 1968a, 1968b). Mushrooms of 

42 fungi species have been eaten by squirrels in the Cascade Mountains of southern 

British Columbia, with false truffles (Rhizopogon), pine spike (Chroogumphus), and 

butter (Suillus) mushrooms being preferred (Smith 1968a). In the northern Hills, 

Oregon mushrooms (basidiomycetes) were eaten most frequently by red squirrels 

and made up 77 percent of the diet (Maser and others 1978). In Arizona, the most 

common mushrooms gathered were the beef steak (Fistulina hepatica), brown 

(Cortinarius rufolivuccus), and angle wing (Pleurotus porrigens), which were dried 

and cached (Uphoff 1990). However pine truffles (Geopora cooperi) and puffballs 

(Basidiomycota) would be eaten immediately upon discovery and were the most common summer food eaten by females in Arizona (Uphoff 1990).

Home range

Adult red squirrels used 0.7 to 2.0 acres (0.3 to 0.8 ha) in a lodgepole pine forest 

and from 0.5 to 11 acres (1.3 to 4.5 ha) in a mixed hardwood-conifer forest (Gurnell 

1984; Layne 1954). In British Columbia, adult territories were contiguous and nonoverlapping and averaged 1.3 acres (0.5 ha) at high elevation sites and 2.2 acres 

(0.9 ha) at low elevation sites. Territories estimated for 23 marked red squirrels in 

mixed white spruce, black spruce, jack pine, quaking aspen, and poplar forests ranged 

from 0.6 to 2.0 acres (0.2 to 0.8 ha) (Kemp and Keith 1970; Rusch and Reeder 1978). 

Populations

Red squirrels are generally more abundant in mature and unharvested forests 

than in treated and young forests (Thompson and others 1989). Densities of red 

squirrels spanning 50 years averaged 1.1/acre (2.7/ha) in spruce forests, 0.7 squirrels/

acre (1.7/ha) in mixed conifer forests, and 0.4 squirrels/acre (1.0/ha) in pine forests 

(Rusch and Reeder 1978). Vahle and Patton (1983) found red squirrel population 

densities in old mixed species stands to be 0.4 to 1 squirrels/acre (1.0 to 2.5/ha), while 

Ward (2001) estimated densities of 0.03 to 0.32 squirrels/acre (0.1 to 0.8/ha) in mixed 

species forests. Also, Ward (2001) found an average of 1.7 squirrels/acre (4.2/ha) in 

45-foot wide corridors along drainages (primarily occupied by females), but only 

0.61 squirrels/acre (1.5/ha) were found in corridors on the upper slope drainages. In a 

natural 20-year-old lodgepole pine forest, red squirrel densities were 0.5/acre (1.2/ha), 

and in areas that had been thinned densities were 0.2 squirrels/acre (0.5/ha). 

Ruffed Grouse

Ruffed grouse (Bonasa umbellus) are medium-sized birds living in deciduous 

and coniferous forests and woodlands. Adult males average 16.9 to 19.7 inches (43 to 

50 cm) tall are slightly larger than the 15.7 to 18.5 (40 to 47 cm) inch tall females. 
166 USDA Forest Service RMRS-GTR-339. 2015.

Weighing from 15.8 to 26.5 ounces (450 to 750 g), ruffed grouse are high value prey 

for goshawks (Rusch and others 2000). Of 39 prey remains found at two goshawk 

nests in the Oregon Coast Range, 45 percent were ruffed grouse (Thrailkill and others 2000). Less than 1 percent of the prey remains collected from nests in Oregon 

and Washington were ruffed grouse and in Idaho, they comprised 18.8 percent of the 

goshawk’s diet (Patla 1997; Reynolds and Meslow 1984; Watson and others 1998;). 

In Minnesota, using video recordings of goshawks delivering prey to nests, Smithers 

and others (2005) estimated that ruffed grouse comprised 5 percent of the prey and 

11 percent of the biomass. Over the course of 10 years, 18.2 percent of prey remains 

found at 10 nests in New York were ruffed groused (Grzybowski and Eaton 1976). In 

the Black Hills, ruffed grouse remains were found underneath 4 of 5 of goshawk nests 

Bartelt (1977) visited.

Distribution

Ruffed grouse are widely distributed across Canadian and northern U.S. forests, 

occurring south into the higher elevations of the Pacific Coastal region, north-central 

Utah, and northwestern Colorado and into the southern Appalachian Mountains. 

Isolated populations also occur in the Black Hills and populations have been restored 

across the Midwestern states and in northeastern Nevada. Ruffed grouse were abundant residents in the Black Hills when Custer came to the Hills in 1874 and into the 

beginning of the 20th century (Grinnell 1875; Knight 1902; Over and Thomas 1921). 

More recent accounts suggest that ruffed grouse are rare in the Hills and only small 

populations live in the northern portion (Pettingill and Whitney 1965; South Dakota 

Ornithologists’ Union 1991; White and others 2010). 

Habitat

Across most of their range, ruffed grouse are strongly associated with quaking 

aspen forests (Rusch and Keith 1971a; Rusch and others 2000; Wiggins 2006). In 

Minnesota, ruffed grouse used pure quaking aspen, mixed quaking aspen hardwood, 

and mixed quaking aspen conifer forests but avoided forests without a quaking aspen 

overstory (Svoboda and Gullion 1972). Also in Utah and Wyoming ruffed grouse were 

found primarily in quaking aspen forests (Dorn and Dorn 1990; Hayward and others 

1976). Ruffed grouse live in boreal forests but dense mature forests are rarely used 

(Gullion 1970; Gullion and Marshall 1968; Rusch and Keith 1971b). In the Black 

Hills, ruffed grouse lived in deciduous woodlands, quaking aspen groves, and mixedconifer woodlands (Pettingill and Whitney 1965). Also in the Hills, the species uses 

mesic ponderosa pine forests interspersed with small groves of quaking aspen, paper 

birch, and bur oak along with riparian areas (White and others 2010). 

Because grouse are non-migratory, a structural stage mosaic of young to old 

forests that provides both cover (e.g., thermal, hiding) and foraging (e.g., herbs, forbs, 

and fruit bearing shrubs) were used year-round (Bump and others 1947; Gullion 

and Alm 1983; Sharp 1963; Rusch and others 2000). However, in Minnesota, ruffed 

grouse selected home ranges with high densities of small and uniform vegetative 

patches and home ranges were centered on areas with abrupt vegetative edges 

(Svoboda and Gullion 1972). Patches of young quaking aspen and mixed vegetative 

patches containing tens of thousands of stems per acre (ha) are frequently used by 
USDA Forest Service RMRS-GTR-339. 2015. 167

ruffed grouse and can be sustained by light burning (Gullion and Alm 1983; Jones and 

DeByle 1985; Stauffer and Peterson 1985b). Also, such burning may reduce the invasion or succession of quaking aspen to conifers (Mueggler 1985). 

Male ruffed grouse are particularly territorial and express their presence by 

“drumming” (i.e., opening and closing their wings in rapid succession) on elevated 

rocks, stumps, exposed roots, snow banks, mounds of dirt, and piles of logs (Rusch 

and others 2000). Drumming sites are the center of a male’s territory during late 

winter to early spring and their presence may determine site occupancy (Archibald 

1975; Hansen and others 2011b; Zimmerman and Gutierrez 2008). Male grouse 

are particularly conspicuous at this time and vulnerable to predators (Tirpak and 

others 2010). They select drumming, and alternate drumming sites, in deciduous 

forests that afford aerial cover while providing horizontal visibility and avoid conifer 

forests and those with dense understories for drumming (Gullion 1970; Gullion and 

Marshall 1968; Hansen and others 2011b; Rusch and Keith 1971a; Rusch and others 

2000; Zimmerman and Gutierrez 2008). In 8- to 25-year-old quaking aspen stands 

of Minnesota, 40 percent of the male grouse observed, used drumming logs at least 

7.9 inches (20 cm) in diameter and greater than 6.6 ft (2 m) in length. Similar sites 

were chosen by ruffed grouse for drumming in the Black Hills (Gullion and Alm 1983; 

Hansen and others 2011b; Rusch and others 2000). 

Quaking aspen and other hardwood forests with open understories are used by 

ruffed grouse for nesting. Nests located in moist riparian areas provide broods a cool 

setting during the heat of late summer (Wiggins 2006). Nests were placed in shallow 

depressions, usually at the base of trees but also at the base of stumps, under slash 

piles, or in shrubs (Bump and others 1947; Rusch and others 2000). Most often, nests 

were located in mature quaking aspen stands, allowing incubating females to feed on 

emerging quaking aspen leaves (Cade and Sousa 1985; Maxson 1978; Rusch and others 2000). 

Suitable winter habitat is critical for long-term population stability of ruffed 

grouse (Gullion and Alm 1983). Ruffed grouse frequently roost within snow banks 

where temperatures rarely dip below 20 °F (-6.6 °C), which allow them to maintain 

body heat even though air temperatures are much colder (Gullion 1970). Quaking 

aspen and, in particular, young quaking aspen stands with minimal canopy cover 

(rather than conifer stands) can provide adequate snow for burrows and protection 

from predators (Gullion 1970; Rusch and Keith 1971a; Stauffer and Peterson 1985a; 

Thompson and Fritzell 1989). Also, in the winter, young quaking aspen stands provide 

buds upon which ruffed grouse can forage (Svoboda and Gullion 1972). In areas with 

mild winters and wet or icy snow conditions that preclude snow roosting, grouse 

selected areas with moderate to high canopy cover. For example, in Missouri, grouse 

used dense coniferous forests for winter roosting and avoided areas with deciduous 

cover (Rusch and others 2000; Thompson and Fritzell 1989).

Diet

Ruffed grouse consume a variety of plant and animal foods, which varies 

seasonally, regionally, and with grouse age. Missouri grouse relied heavily on high 

protein foods during the summer, high fat and carbohydrate foods during the winter, 

and high mineral foods during the spring (Johnsgard 1973; Korschgen 1966). In 
168 USDA Forest Service RMRS-GTR-339. 2015.

winter, adults rely on buds, twigs, and especially quaking aspen catkins (Rusch and 

others 2000). Where quaking aspen co-occurs with bigtooth aspen (Populus grandidentata) and paper birch, ruffed grouse prefer quaking aspen catkins (Svoboda and 

Gullion 1972). In Virginia, principal December foods were soft fruits (69 percent; 

e.g., greenbrier, Smilax spp., grape Vitis spp., cranberry, Viburnum spp., dogwood, 

Cornus spp., and rose) followed by hard fruits (18 percent; e.g., oaks, Quercus alba, 

Q. ilicifolia, Q. rubra, and sumac Rhus spp.). In January through April, the species 

switched to mostly eating leaves (Norman and Kirkpatrick 1984). Wintering ruffed 

grouse in Idaho, fed primarily on buds and leaves of mountain ash (Sorbus scopulina), 

serviceberry (Amelanchier alnifolia), mountain maple (Acer glabrum), chokecherry, 

willow, black cottonwood, snowberry (Symphoricarpus albus), and buck brush 

(Ceanothus velutinus) (Marshall 1946). In Utah, grouse ate rose; quaking aspen buds, 

twigs, and leaves; chokecherries; and meadow-rue (Thalictrum alpinum) fruit (Phillips 

1967). Ruffed grouse less than 5 weeks old primarily feed on insects and other invertebrates (50 to 75 percent) and switch to leaves throughout the summer (Bump and 

others 1947; Cade and Sousa 1985; Johnsgard 1973; Rusch and others 2000).

Home range

In general, home range sizes of adult ruffed grouse males are larger in winter 

than in summer when their movements are restricted to central drumming areas. 

However, their home ranges are smaller than juvenile male and brooding female home 

ranges (Archibald 1975; Fearer and Stauffer 2003). In Minnesota, 15 radio-tagged 

female ruffed grouse had home ranges that averaged 29.9 acres (12.1 ha) in size before 

they laid eggs when they likely visited several drumming males. During egg-laying 

home range sizes averaged 20.8 acres (8.4 ha) and during incubation they averaged 

2.2 acres (0.9 ha) (Maxson 1978). During the first three weeks post-incubation, 

females with broods had home range sizes from 7.4 to 24.7 acres (3 to 10 ha) and 

those without broods had home ranges that averaged 3.7 acres (1.5 ha) in size. After 

5 weeks, home range size decreased when broods switched to feeding primarily 

on vegetation (Bump and others 1947; Maxson 1978). Also in Minnesota, summer 

home range size for six broods averaged 31.9 acres (12.9 ha), but they decreased in 

size as the summer progressed (Godfrey 1975). In Virginia, home range size for both 

males and females averaged 82.3 acres (33.3 ha) and in Missouri, home range sizes 

for 32 radio-tagged males averaged 168 acres (68 ha) in the spring and summer and 

257 acres (104 ha) in the fall and winter (Fearer and Stauffer 2003; Thompson and 

Fritzell 1989).

Populations

Ruffed grouse populations vary among habitats, years, and regions. Spring 

density estimates in good habitats average, about 3.2 drumming males or 40 adults 

per 100 acres (8 drummers or 22 adults/100 ha) and densities would be lower in 

lesser quality habitats (Rusch and others 2000). Predicted occupancy estimates for 

ruffed grouse in the Black Hills were low because of quaking aspen scarcity and this 

prediction was validated during the 2001 to 2009 breeding bird monitoring found too 

few individuals to provide population estimates (Hansen and others 2011a; White and 

others 2010). Interestingly, the survey detected a drop from 36 grouse in 2001 and 
USDA Forest Service RMRS-GTR-339. 2015. 169

62 grouse in 2002 to fewer than 10 grouse observed from 2003 through 2010 (White 

and others 2010).

Thirteen-Lined Ground Squirrel 

Thirteen-lined ground squirrels (Spermophilus tridecemlineatus) are important goshawk prey and their remains were found at most nests in the Black Hills 

(Bartelt 1977; Erickson 1987; Promessi and others 2004; Rogers and others 2006; 

Squires 2000; Squires and Reynolds 1997). They are a small squirrel weighing 3.9 to 

4.9 ounces (110 to 140 g) and average 9.8 inches (25.0 cm) long (Petrella 1999). 

However individuals can gain substantial weight prior to hibernation with a male 

increasing 38 percent in body weight or 8.7 ounces (246 g) (Streubel and Fitzgerald 

1978). There are 9 or 10 subspecies of the thirteen-lined ground squirrel and S. t. pallidus lives in the Black Hills (Streubel and Fitzgerald 1978; Wilson and Ruff 1999).

Distribution

Once restricted to the plains states, thirteen-lined ground squirrels have 

expanded their range north and east as forested areas were cleared. They now range 

from south-central Canada south to the Texas Gulf Coast, and from the western slopes 

of the Rocky Mountains east to the Great Lakes States and as far east as central Ohio 

(Streubel and Fitzgerald 1978). They are most common below 5,500 ft (1676 m) in the 

Black Hills, but range up to 6,500 ft (1981 m) (Turner 1974).

Habitat

Throughout its range thirteen-lined ground squirrels use grasslands, especially 

native short-grasslands, golf courses, and highway borders preferring to occupy 

high points within these settings (Streubel and Fitzgerald 1978). In the Black Hills 

thirteen-lined ground squirrels inhabit similar areas, in addition to campgrounds and 

upland meadows (Higgins and others 2002; Turner 1974). In Colorado on the Pawnee 

National Grasslands, thirteen-lined ground squirrels used dry lands and avoided fertilized and irrigated fields and in Wyoming, they were found in short-grass communities 

and were transient in sagegrass and yucca-grass communities (Grant 1972; Maxwell 

and Brown 1968). Often in clay, loam, or sandy-loam soils, thirteen-lined ground 

squirrels build burrow systems that they use year-round for protection from predators 

and weather. Individuals may have several burrows which are usually shallow, temporary, and have secondary escape exits hidden in tall grass (Higgins and others 2002). 

Thirteen-lined ground squirrels hibernate from mid-September until early April using 

burrows that have steep entrances and extend to 20 ft (6 m) below ground, (Higgins 

and others 2002; Streubel and Fitzgerald 1978; Turner 1974). At the end of these tunnel systems is a grass-lined chamber used for resting and nesting while other chambers 

hold caches of seed and dry vegetation for consumption when food is scarce (Higgins 

and others 2002). 

Diet

Thirteen-lined ground squirrels consume seeds, grasses, leaves, and roots but 

also up to 50 percent of their diet can consist of birds, snakes, and small animals 

(Higgins and others 2002). For example, in Manitoba, Canada the diet of 80 squirrels 
170 USDA Forest Service RMRS-GTR-339. 2015.

was 54 percent insects, 44 percent plant material, and 2 percent unidentified (Banfield 

1974).

Home range

Female thirteen-lined ground squirrels tend to use the same home range every 

year while males do not (Rongstad 1965). In Manitoba, Canada, home range sizes for 

both males and females ranged between 1.62 (0.7 ha) and 11.7 acres (4.7 ha) while 

those of males usually were larger than those of females (Banfield 1974). In a tallgrass 

prairie of Kansas from 1983 to 1987, the average home range size for males was 1.38 

acres (0.56 ha) and the average for females was 0.9 acres (0.36 ha) (Clark and others 

1990). Ground squirrels can travel considerable distances, especially to and from grain 

fields, as exemplified by males in Wisconsin traveling 96 yards (88.2 m) and females 

99 yards (90.1 m) (Banfield 1974; Rongstad 1965). 

Populations

In Michigan, thirteen-lined ground squirrel density was estimated to be 2.2 

squirrels/acre (5.4/ha) and in Wisconsin, the average density was 8.9 to 10.7 squirrels/

acre (22.0 to 26.4/ha) (Banfield 1974; Rongstad 1965). In Wisconsin, squirrel density 

was estimated to be 1.2 to 8.0/acre (2.9 to 19.8/ha) and in dry lands of Colorado, the 

density was 20.8 squirrels/acre (51.4/ha) (Grant 1972; Jackson 1961). In the tallgrass 

prairie of Kansas, densities of squirrels from 1983 through 1987 ranged from 2.6 to 

5.6 squirrels/acre (6.4 to 13.8) (Clark and others 1990).

Western Tanager

The western tanager (Piranga ludoviciana) is a medium-sized songbird measuring 6.5 to 7.7 inches (16.5 to 19.5 cm) long and weighing 0.8 to 1.3 ounces (24 to 

36 g) (Hudon 1999). As summer residents in the Black Hills and because of their 

association with open ponderosa pine, they are potential prey for goshawks (Pettingill 

and Whitney 1965; South Dakota Ornithologists’ Union 1991; Squires and Reynolds 

1997). However, low frequencies of western tanager remains have been found at goshawk nests (Promessi and others 2004; Squires 2000).

Distribution

The breeding range of the western tanager extends from southeast Alaska, 

down the Pacific Coast, to northern Baja California, Mexico, east to western Texas, 

north through central New Mexico, central Colorado, eastern Nebraska, western 

South Dakota, and into the southern Northwest Territories, Canada and they migrate 

to Mexico and Central America (Hudon 1999; Isler and Isler 1999). Especially at the 

lower elevations and the south western portion, western tanagers inhabit most of the 

Hills. However, they are less common in the northern and Bear Lodge portions of the 

Hills (Panjabi 2001). 

Habitat

Western tanagers live in open coniferous and mixed woodlands. Individuals and 

nests are common in Douglas-fir, ponderosa pine, lodgepole pine, quaking aspen, and 

mixed coniferous-deciduous forests as well as in riparian and oak woodlands. They 

also use edges along roads, meadows, and other forest openings for nesting (Hudon 
USDA Forest Service RMRS-GTR-339. 2015. 171

1999). In the Colorado Front Range, 93 percent of 58 nests were in ponderosa pine 

and the remainder in Douglas-fir forests (Fischer and others 2002). In the Black Hills, 

western tanagers primarily used ponderosa pine forests and riparian woodlands but 

also used quaking aspen, white spruce, shrubland, and burned forests (Panjabi 2001; 

Pettingill and Whitney 1965; White and others 2010; South Dakota Ornithologists’ 

Union 1991).

Tanagers tend to nest in forests with high canopy cover and relatively open 

understories (Evans and others 1998). For example, in Colorado, nest stand canopy 

cover averaged 71 percent and was never less than 31 percent; in New Mexico, canopy 

cover averaged 77 percent; and in Arizona and New Mexico, nest stand canopy cover 

averaged 66 percent (Fischer and others 2002; Hudon 1999; Shy 1984). In Idaho, forests with tanager nests had 81 percent canopy cover and random sites had 74 percent 

canopy cover. In the Black Hills, western tanagers were most abundant in multi- storied 

ponderosa pine forests with greater than 40 percent canopy cover, especially those 

with bur oak and quaking aspen understories (Evans and others 1998; Mills and others 

2000). 

Western tanagers prefer forests with relatively large trees to nest in, and they 

typically place their open-cup nests near the end of a main branch surrounded by 

smaller branches. However, in deciduous trees, they often build their nest next to the 

tree bole (Evans and others 1998; Hudon 1999). In Colorado, nests were well hidden 

at the center of branches and typically located mid-crown (e.g., 54 percent of tree 

height), making tree height a good predictor of nest height (Fischer and others 2002). 

Nests were usually built within 30 ft (≈9 m) of the forest floor, but some have been 

located as high as 75 ft ( about 23 m) (Hudon 1999). 

Diet

Western tanagers glean and fly-catch wasps, ants, termites, stink bugs, cicadas, 

beetles, nut weevils, grasshoppers, dragonflies, caterpillars, scale insects, and sawflies during the breeding season (Hudon 1999). They also eat the fruits of hawthorn 

(Crataegus spp.), cherry, elderberry, Russian olive (Elaeagnus angustifolia), blackberry, mulberry (Morus spp.) serviceberry, and buds of several shrubs (Hudon 1999). 

Home range

Home range size for western tanagers is not well known. As measured by singing males, home ranges of 7 acres (2.83 ha) were estimated for western tanagers in 

Montana; however, this was likely an overestimate as 90 percent of the home ranges 

overlapped. Core areas, which did not overlap, averaged 2 acres (0.81 ha) in size and 

were used 59 percent of the time (Samuel and others 1985). In Idaho, telemetry data 

found the average size of territories to be 1.5 to 2.5 acres (0.6 to 1 ha) and average 

tanager home range size to be 9.6 acres (3.91 ha) (Evans and others 1998). 

Populations

Western tanager populations fluctuate during both summer and winter migrations. Across their range from 1966 to 1996, relative abundance estimated from 554 

Breeding Bird survey routes was 4.2 birds/route (Sauer and others 1997). In Idaho, 

densities averaged 22 pairs/100 acres (54/100 ha) (Medin 1985). In mixed conifer 
172 USDA Forest Service RMRS-GTR-339. 2015.

forests in Wyoming, western tanager densities averaged 12 birds/100 acres (30/100 ha) 

and were highest in lodgepole pine mixed with spruce compared to pure lodgepole 

pine or spruce-fir stands (Salt 1957). In Arizona, from 2007 to 2009, tanager densities varied little among years with an average of 161 birds/mile2 (62 birds/km2) 

found in mixed conifer forests, 62 birds/mile2 (24 birds/km2) found in ponderosa 

pine forests, and 23 birds/mile2 (9 birds/ km2) found in pinyon-juniper forests (Birek 

and others 2010). From 2001 through 2003 in the Black Hills 21 to 23 birds/mile2 (8 to 

9 birds/km2) were found in ponderosa pine forests but in 2009 the density increased to 

47 birds/mile2 (18.1 birds/km2) (Panjabi 2001, 2003; White and others 2010). Most of 

this increase was in the central and southern portions of Hills. In addition, tanagers were 

most abundant in burned forests where densities from 2001 to 2009 were greater than 

26 birds/mile2 (10 birds/km2) for all years except 2007 when 21 birds/mile2 (8 birds/

km2) were detected, and the highest density detected was 60 birds/mile2 (23 birds/km2) in 2003 

(White and others 2010). However, over a 3-year period in the Sierra Nevada mountains, an 

average of 5.6 pairs/100 acres (13.8/100 ha) nested in unburned forests while 0.8 pairs/100 acres 

(1.9/100 ha) nested in green trees that remained after a forest burned (Bock and Lynch 

1970).

White-Tailed Jackrabbit

The white-tailed jackrabbit (Lepus townsendii) is a large jackrabbit living in 

the North American plains and Intermountain West. White-tailed jackrabbits range 

from 22 to 26 inches (56 to 66 cm) long and weigh from 5.5 to 8.8 pounds (2.5 to 4 

kg), with females being slightly larger than males (Gosline 2001; Lim 1987). The L. t. 

townsendii subspecies lives west of the Continental Divide and L. t. campestris lives 

to the east (Lim 1987). Because of their relative abundance and large size, adult and 

young jackrabbits are important prey for goshawks (Lewis and others 2006; Promessi 

and others 2004; Smithers and others 2005; Squires 2000; Watson and others 1998) 

and their remains were found at 2 of the 5 nests Bartelt (1977) visited in the Hills. 

Distribution

White-tailed jackrabbits occur from the plains of west-central Canada (e.g., 

Saskatchewan and Alberta) south into the United States Great Plains, from Wisconsin 

west to the Rocky Mountains, as far south as New Mexico, and from the Great 

Basin region to the Oregon Cascades and Sierra Nevada mountains. They live from 

nearly sea level to locales over 14,000 ft (4250 m) and often co-occur with blacktailed jackrabbits (L. californicus). Some of their habitat was reduced when prairies 

were converted to agriculture lands but their range expanded where woodlands in 

Minnesota and Manitoba were converted to farmland (Gosline 2001; Lim 1987; 

Wilson and Ruff 1999).

Habitat

White-tailed jackrabbits use grasslands, forest openings, pastures, fields, and 

sage lands, and in Colorado, used grasslands more than meadows or sage lands 

(Higgins and others 2002; Bear and Hansen 1966). Also in Colorado, they used alfalfa 

and crested wheatgrass fields and avoided areas with four wing saltbush (Atriplex 

canescens) and sage where black-tailed jackrabbits lived (Flinders and Hansen 1973). 
USDA Forest Service RMRS-GTR-339. 2015. 173

During severe weather, white-tailed jackrabbits seek shelter in forests but they remain 

along the edges, and when the snow is 3 ft (1 m) or deeper, they may dig snow caves 

for added protection (Bailey 1926). Also in the winter, they are drawn to grassdominated ridge tops that have been cleared of snow by the wind (Bear and Hansen 

1966). In the Black Hills, white-tailed jackrabbits inhabit woodlands up to 6,000 ft 

(1829 m) in elevation, especially the prairies such as Reynolds, Gillette, Bald Hills, 

and those in Wind Cave National Park. At the higher elevations in the Hills, they use 

quaking aspen, ponderosa pine, and white spruce forests that border meadows, prairies, and pastures (Turner 1974).

Diet

White-tailed jackrabbits eat grasses and forbs throughout the spring, summer, 

and fall and prefer to eat succulent new growth (Bear and Hansen 1966; Lim 1987). 

In Colorado they ate sedges (Carex spp.), goosefoot (Chenopodium spp), dandelion 

(Taraxacum officinal), clover (Trifolium spp.), and in the winter (when they switched 

to shrubs) ate pasture sage (Artemisia frigid) and rabbitbrush (Chrysothamnus parryi). 

When feeding on shrubs, white-tailed jackrabbits tend to avoid leaves and eat mostly 

stems and the young tend to feed more on grasses than shrubs (Bear and Hansen 

1966).

Home range

Very little is known of home range size for white-tailed jackrabbits, but individuals likely restrict their activities to one large area (Jackson 1961). In the eastern 

portion of their range, circular home ranges from 246 to 566 acres (100 to 229 ha) in 

size were estimated but varied by sex, cover, water, and food availability (Lim 1987). 

Populations

White-tailed jackrabbits are not abundant within the Black Hills but frequent 

the surrounding plains (Bailey 1926). In Minnesota, during the early part of the 20th

century their densities ranged from 15.5 to 31.0 jackrabbits/mile2 (6 to 12/km2) with 

a high of 111.4 jackrabbits/mile2 (43/km2) (Mohr and Mohr 1936). In Wyoming, their 

density was 18.1 jackrabbits/mile2 (7/km2), and on the Pawnee National Grasslands 

in Colorado, their density was 3.5 jackrabbits/mile2 (1.35/km2) (Flinders and Hansen 

1973; Rogowitz and Wolfe 1991).

Merriam’s Wild Turkey

Wild turkeys (Meleagris gallopavo) are large birds whose size varies across 

their range and whose weight varies considerably with season and food availability. 

Adult males generally weigh from 15 to 24 pounds (6.8 to 11 kg) and females weigh 

about 8 to 12 pounds (3.6 to 5.4 kg) (McCullough 2001). Length of Merriam’s (M. g. 

Merriami) turkeys, the subspecies occurring in the Black Hills, ranged from 35 to 

50 inches (89 to 127 cm) for turkeys in Colorado (Bailey and Niedrach 1965). 

Goshawks do prey on adult-sized wild turkeys, as a female goshawk killed and 

consumed an adult wild turkey in Connecticut (Golet and others 2003). Juvenile wild 

turkey remains were found at goshawk nests in the New Jersey-New York Highlands 

area, and a goshawk was preying on an adult female wild turkey in south-central 

New York (Bosakowski and others 1992; Roberts and others 1995). Bartelt (1977) 
174 USDA Forest Service RMRS-GTR-339. 2015.

found adult hen feathers at two of five nests he visited in the Black Hills. However, 

goshawks are more likely to prey on young wild turkeys (poults), but protective hens 

are often an effective deterrent in preventing poults from being taken by goshawks 

(Lehman 2003).

Distribution 

Wild turkeys range across much of the eastern United States, from New England 

into Florida, and west to the Central Plains states. They also occur in all western states 

and south into northwestern Mexico. The Merriam’s subspecies lives in the western 

United States and in particular ponderosa pine forests (Eaton 1992). The historical 

range of Merriam’s turkeys was limited to southwestern Oklahoma, Colorado, New 

Mexico, northwest Texas, and northern Arizona but they were introduced throughout 

the western United States. In three separate releases from 1948 through 1951, a total 

of 29 Merriam’s turkeys trapped in Colorado and New Mexico were introduced to the 

Black Hills (Petersen and Richardson 1975). Since then, their population has grown 

and they are now a valued game bird and they are abundant throughout the Hills. 

Habitat 

Merriam’s turkeys use mixed conifer, ponderosa pine, Gamble’s oak, and pinyon-juniper forests and this use varies according to the time of year, sex, and breeding 

status. Turkeys use a variety of habitats during and among winters depending on food, 

snow conditions, and roosting opportunities (Hoffman and others 1993). They rely 

heavily on seed for food during the winter and mature ponderosa pine trees tend to be 

better cone and seed producers than younger trees, making them preferred winter habitat (Rumble and Anderson 1996). Also, seed availability is predicated on snow depth 

making closed forests more desirable for turkeys in the winter than open ones. Forests 

located on southern aspects tend to have less snow than those located on other aspects 

and they are inclined to become snow free earlier in the spring also making them 

favored turkey winter habitat (Petersen and Richardson 1975). When snow depths 

exceed 6 inches (15 cm), turkeys’ ability to scratch for seed is diminished and at snow 

depths greater than 14 inches (36 cm) they can become weakened and roost in trees 

until conditions improve (Austin and DeGraff 1975; Rumble and Anderson 1996). 

Turkeys often move to lower elevations in the winter and return to their breeding 

and nesting grounds in the spring. They often use well-established migration corridors 

which usually have contiguous canopy cover. For example in Colorado turkeys moved 

2.3 miles (3.7 km) from winter to breeding grounds and in Oregon, hens moved an 

average of 8 miles (12.8 km) (Crawford and Lutz 1984; Dickson 1992).

In the Black Hills, turkeys used ponderosa pine forests with moderate (41 to 

70 percent) canopy cover during the spring and summer with abundant shrubs and 

those with high (71 to 100 percent) canopy cover during the fall and winter, which 

provided turkeys protection from the weather. They avoided open forests (0 to 40 

percent canopy cover) but during the summer they may forage on grass seed in forests 

openings. Also in the Hills during spring and summer, turkeys foraged on insects and 

forbs in quaking aspen/paper birch forests located in riparian areas. Turkeys preferred 

such forests with 41 to 71 percent canopy cover and avoided those with 72 to 100 percent canopy cover (Rumble and Anderson 1993). 
USDA Forest Service RMRS-GTR-339. 2015. 175

Roosts provide turkeys with security, resting, and sleeping sites along with 

protection from wind, rain, and snow. In the Hills, turkeys tended to roost on ridge 

tops that contained all slope aspects but were more common on slopes with easterly 

aspects (Rumble 1992). Roost sites are typically located in mature to old conifer forests and usually range in size from 0.25 to 1.25 acres (0.1 to 0.5 ha) and contain 10 or 

more roost trees (Dickson 1992; Hoffman and others 1993). In some areas, turkeys 

form large flocks during the winter necessitating large roosting areas. However, in the 

Black Hills, turkeys do not congregate in the winter and their winter roost sites are 

similar to those used in the summer (Dickson 1992; Rumble 1992). In the ponderosa 

pine forests of the Black Hills winter, summer, and hens-with-poults roost sites had 

canopy cover greater than 50 percent, tree densities measured by basal area between 

83 and 109 ft2/acre (19 to 25m2/ha), and trees with an average of DBH greater than 

8.7 inches (22 cm). All roost trees averaged 14.5 inches (37 cm) DBH, but the range 

of tree sizes used by hens with poults was 10 to 22 inches (25 to 56 cm) DBH. Also 

in the Black Hills, forests with 242 trees/acre (598/ha) were used for winter roosting, 

forests with 216 trees/acre (534/ha) were used for summer roosting, and forests with 

394 trees/acre (973/ha) were used by hens with poults for roosting. One to nine roost 

trees were used by turkeys in the Black Hills, with winter areas having the most roost 

trees and hens with poults using the fewest roost trees, while summer roost sites were 

intermediate in the number of roost trees used. Turkeys used large trees for roosting 

that averaged 89 ft (27 m) tall with an average of 35 inches (89 cm) between branches, 

which allowed flight access for the turkeys. Roosting height averaged 41 ft (12.5 m) 

and roosting height for hens with poults during winter averaged 44 ft (13.4m) (Rumble 

1992).

Diet 

Merriam’s turkeys eat grass, leaves, seeds, forbs, pine seeds, acorns, invertebrates, cultivated crops, juniper berries, clover, kinnikinnick (Arctostaphylos uva-ursi), 

hawthorn, snowberry, and rose hips depending on the season and the region. When 

available, acorns and ponderosa pine seeds can comprise 80 to 90 percent of a turkey’s 

diet, while grasses are the most important and consistently available food. Poults 

rely heavily on insects and add plants and seeds to their diets as they age (Hoffman 

and others 1993). In the Black Hills from 1965 through 1969, turkeys consumed kinnikinnik seed, ponderosa pine seed, and bur oak acorns during the summer along with 

grasshoppers that were the most common animal food eaten. During the winter, Black 

Hills’ turkeys foraged in grain fields and livestock feeding areas where they ate oats 

and wheat, and in forested areas, they ate ponderosa pine seed and acorns (Petersen 

and Richardson 1975).

Home range

Spring home ranges of males can be large and may overlap (Dickson 1992). 

In Colorado, spring home range size for males averaged 2 mile2 (5.2 km2), winter 

home ranges for males in Oregon averaged 0.11 mile2 (0.28 km2), and spring home 

range sizes in Oregon averaged 1 mile2 (2.2 km2) (Crawford and Lutz 1984; Hoffman 

1991). The size of spring home ranges for male turkeys in the Black Hills averaged 1.7 

mile2 (4.4 km2) in 2005 and 5 mile2 (13.2 km2) in 2006. Also in the Black Hills, one 
176 USDA Forest Service RMRS-GTR-339. 2015.

male turkey had a 21.5 mile2 (55.8 km2) home range and two others had 11.6 mile2

(30.1 km2) spring home ranges (Steinke 2006).

Populations 

In 1992, the U.S. population of Merriam’s turkeys was estimated at 100,000 

(Eaton 1992). Breeding Bird Surveys indicated increasing populations but insufficient 

data make these estimates unreliable (Sauer and others 2011b). At the local scale, 

reproductive, survival, immigration, and emigration rates influence populations, however immigration and emigration minimally influence regional populations (Vangilder 

1992). Turkey longevity depends on habitat quality and hunting pressure, with 

≈50 percent mortality rates common their first year and much lower and relatively 

constant rates in subsequent years. The average life span of a turkey in the Black Hills 

is 4 years with one turkey living for over 8 years (Hoffman and others 1993; Rumble 

and others 2003). The 29 turkeys introduced to the Black Hills from 1948 through 

1951 grew to 7000 by 1960, and in 2012, tens of thousands of turkeys likely live in the 

Black Hills (Rumble and others 2003; South Dakota Department of Game, Fish, and 

Parks 2012). 

Nesting success strongly influences turkey populations, and adult nest success in 

the central and southern Black Hills from 1993 to 2005 ranged from 36 to 98 percent 

(Vangilder 1992; Rumble and Hodorff 1993; Lehman 2005). Nesting by juvenile hens 

is uncommon. However, in the central and southern Black Hills, nesting success of 

juveniles and yearlings ranged from 23 to 100 percent (Rumble and Hodorff 1993; 

Lehman 2005; Rumble and others 2003). Predators usually cause most nest failures 

but humans and livestock can make a nest fail (Ligon 1946). Also precipitation while 

a hen is incubating eggs increases their detection as wet feathers give off strong odors 

(Lehman 2005). As such, during the nesting season, hens experience their lowest 

survival rates of the year as they are frequently killed by coyotes, foxes, raptors, and 

other predators (Rumble and others 2003). 

In general, the survival rate for turkeys is quite good. For example the survival 

rate for hens in the southern Black Hills was 67 percent, 68 percent in the central 

Black Hills, 45 percent in Montana, and 75 percent in Arizona (Lehman 2005; Rumble 

and others 2003). The survival rate for male turkeys in the Black Hills was 42 percent, 

in Oregon 38 percent, and 83 percent in Arizona (Crawford and Lutz 1984; Steinke 

2006; Wakeling and Rogers 1998). Similar to survival rates of female turkeys in the 

Black Hills, the lowest survival rate of 47 percent for males occurred in the spring during hunting season (Huxoll 2010). Turkey hunting is very popular in the Black Hills 

with an unlimited number of hunting permits available. In 2000, 3374 spring hunting permits were sold and the number peaked at 6656 permits in 2006 but declined 

steadily to 4435 permits sold in 2012. Also, hunter success declined to 38 percent 

in 2012 with 1685 turkeys harvested (South Dakota Department of Game, Fish, and 

Parks 2012). 

Poult survival also has a strong effect on turkey populations with poult survival 

in the eastern United States during their first 14 days ranging from 27 to 44 percent 

(Kurzejeski and Vangilder 1992; Dickson 1992). First 4 week poult survival in 
USDA Forest Service RMRS-GTR-339. 2015. 177

Wyoming was 36 percent, 36 to 59 percent in Arizona, and 43 percent in the Black 

Hills (Hengel 1990; Wakeling 1991; Flake and Day 1996). Four week survival of 

poults raised by yearling females in the Black Hills was 11 percent (Lehman and others 2008). The survival of poults during the first 5 days after hatching can be greatly 

reduced when rain combined with air temperatures less than 52 °F (11 °C) occurs even 

with good care by hens (Lehman and others 2008). 


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