Accipiter gentilis


Table of Contents


INTRODUCTORY

Photo by Nathan Stone.

AUTHORSHIP AND CITATION:
Stone, Katharine R. 2013. Accipiter gentilis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [ ].

FEIS ABBREVIATION:
ACGE

COMMON NAMES:
northern goshawk

TAXONOMY:
The scientific name of northern goshawk is Accipiter gentilis Linnaeus (Accipitridae) [1,2]. Subspecies recognized by the American Ornithologists' Union (5th edition) [1] include:

Accipiter gentilis atricapillus (Wilson), northern goshawk
Accipiter gentilis laingi (Taverner), Queen Charlotte goshawk

Some scientists recognize an additional subspecies, Accipiter gentilis apache Van Rossem, as inhabiting parts of the southwestern United States and Mexico, though this subspecies is not recognized by the American Ornithologists' Union or the US Fish and Wildlife Service [10,26,48].

SYNONYMS:
None

ORDER:
Accipitriformes

CLASS:
Bird

DISTRIBUTION AND OCCURRENCE

SPECIES: Accipiter gentilis
GENERAL DISTRIBUTION:
All About Birds provides a distributional map of the northern goshawk.

States and provinces:
United States: AK, AZ, CA, CO, CT, DE, IA, ID, IL, IN, KS, KY, MA, MD, ME, MI, MN, MT, NC, ND, NE, NH, NJ, NM, NN, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, UT, VT, WA, WI, WV, WY
Canada: AB, BC, MB, NB, NF, NL, NS, NT, NU, ON, PE, QC, SK, YT (as of 2012 [34])
Mexico [48]

PLANT COMMUNITIES:
Northern goshawks breed in most forested plant communities available throughout their range, including coniferous, deciduous, and mixed forest types. In addition to forested areas, they may also use shrublands and open areas while foraging, migrating, or overwintering [48]. Several reviews contain additional information on plant communities used by northern goshawks throughout their range [10,48] and in the western United States [3,10,23,24,26], the Pacific Northwest [17], the Southwest [40,46,53], the Great Lakes region [7,43], and New England [15]. See the Fire Regime Table for a list of plant communities in which the northern goshawk may occur and information on the fire regimes associated with those communities.

BIOLOGICAL DATA AND HABITAT REQUIREMENTS

SPECIES: Accipiter gentilis
BIOLOGICAL DATA: This review includes information covering many aspects of northern goshawk life history but focuses on those most relevant to fire. The information presented here relies heavily on syntheses material from several sources, including "The birds of North America Online" [48] species account for the northern goshawk and reviews of the northern goshawk's status and/or habitat needs throughout its range [10] and in the following regions: New England [15], Great Lakes [7,43], central Rocky Mountains [26], Rocky Mountains [23], western United States [3,10,24], the Pacific Northwest [17], and the Southwest [40,53].

Life history:
Description: The northern goshawk is a large forest hawk with long, broad wings and a long, rounded tail. Females average 24 inches (61 cm) in length, 41 to 45 inches (105-115 cm) in wingspan, and 30 to 45 ounces (860-1,264 g) in mass, while the smaller males average 22 inches (55 cm) in length, 39 to 41 inches (98-104 cm) in wingspan, and 22 to 39 ounces (631-1,099 g) in mass [48].

Adult northern goshawks are brown-gray to slate-gray on top. The head has a black cap and a pronounced white superciliary line. Underparts are light gray with some black streaking. The tail is dark gray above with 3 to 5 inconspicuous broad, dark bands, and sometimes a thin white terminal band. Juveniles are generally brown on top and have brown streaking on the chest [48].

Adult (left) and juvenile (right) northern goshawks. Photos by Jack Kirkley.

Life span: Based on band recoveries at trapping sites, the maximum life span of wild northern goshawks is at least 11 years [48]. One review reports a captive northern goshawk living 19 years [26].

Age at first breeding: Northern goshawks may breed as subadults (1-2 years old), young adults (2-3 years old), or adults (≥3 years old). Females are more likely than males to breed at a young age [48].

Home range: In North America, home range in the breeding season ranges from 1,400 to 8,600 acres (570-3,500 ha) [48]. Home range size varies depending on sex [26,48], season [48], local prey availability, climate [7], and habitat characteristics [7,26,48]. The male's home range is generally larger than the female's. Within a home range, individuals often have core-use areas that include the nest and primary foraging areas. Outside of a nesting area, the home range of a breeding pair may not be defended and may overlap with the home range of adjacent pairs. The shape of a home range may vary from circular to linear or may be discontinuous, depending on local habitat characteristics [48].

Nesting phenology: Northern goshawk pairs occupy nesting areas from February to early April. Some pairs may remain in their nesting areas year-round. Nest construction may begin as soon as individuals return to their territories. Eggs are laid anywhere from mid-April to early May. Cold, wet springs may delay incubation. Incubation varies from 28 to 37 days. Nestlings move from nests to nearby branches when they are around 34 to 35 days of age. Their first flight from the nest tree ranges from 35 to 36 days for males and 40 to 42 days for females. They reach independence approximately 70 days from hatching. Most fledglings disperse from the nest area between 65 and 90 days after hatching, with females dispersing later than males [48].

Clutch size: Northern goshawks usually produce one clutch per year. Clutch size is usually 2 to 4, but occasionally 1 or 5 eggs. Because northern goshawk chicks hatch asynchronously, older, larger nestlings may attack smaller, younger nestlings [48].

Northern goshawk female with young. Photo by Jack Kirkley.

Nest success and productivity: Northern goshawk nest success and productivity vary and may be limited by prey availability [6,46,48], weather [26,48], predation [7,26], disease [26], habitat features [24], and disturbance from timber harvest or other human activities [26,48].

In North America, nest success usually ranges from 80% to 94%, with most successful nests producing an average of 2.0 to 2.8 fledglings. Unsuccessful nests usually fail early in the breeding season, before or soon after laying. Weather, particularly cold temperatures in the spring and exposure to low temperatures and rain, may cause egg and chick mortality. Once chicks reach 3 weeks of age, nests rarely fail. Productivity may differ between years in the same study area and among landscapes within a limited geographic area. The availability of prey strongly affects nest occupancy and productivity. The age of the female may also affect productivity; pairs with a younger female may produce fewer fledglings than pairs with an older female. If food resources are low, siblicide and cannibalism may occur [48].

Nest description: The northern goshawk constructs a nest of thin sticks, forming a bowl lined with tree bark and greenery. Nests are usually placed on large horizontal limbs against the trunk, or occasionally on large limbs away from the bole. A variety of tree species is used for nesting [48].

Northern goshawk nest in western Montana. Photo by Jack Kirkley.

Nest site: Northern goshawks build nests in both deciduous and coniferous trees. They typically use the largest tree in a nest stand. Nest height varies by tree species and regional tree characteristics. The size and structure of a nest tree may be more important than species. Northern goshawks occasionally build nests on dwarf mistletoe (Arceuthobium spp.) clumps and rarely in dead trees [48]. Several reviews provide lists of specific tree species used by northern goshawks for nesting throughout their range [48] and in the Great Lakes region [7] and central Rocky Mountains [26].

Nest and nest site fidelity: Northern goshawks may use the same nest for consecutive years, but they usually alternate between 2 or more nests within a nest area. They may maintain as many as 8 alternate nests within a nest area. It is thought that most nest sites are occupied from 1 to 3 years, though some may be occupied much longer. Though the importance of alternate nest maintenance is not completely understood, it is hypothesized that nest switching reduces exposure to diseases and parasites. This behavior complicates the determination of nest-site fidelity because it is difficult for biologists to locate all alternative nests [48]. A synthesis of 5 studies correlating nest occupancy with habitat features found a consistently positive relationship between closed-canopy forests with large trees and northern goshawk nest occupancy. Occupancy rates were reduced by removing forest cover in the home range, which thereby resulted in reduced productivity because there were fewer active breeding territories [24].

Dispersal: Natal dispersal of the northern goshawk had not been well studied as of this writing (2012). One review notes that very few (24 of 452) fledglings in an Arizona study were recruited into the local breeding population, and mean natal dispersal distance was 9.1 (SD 5.1) miles (14.7 (SD 8.2) km) (range 2.1-22.6 miles (3.4-36.3 km)) [26]

Mate fidelity: Northern goshawks may show high mate fidelity. A study from northern California found that over 9 years, 72% of the adults located in subsequent years (18 of 25 instances) retained the mate from the previous year [18].

Density: Northern goshawk populations occur at low densities compared to many bird species [43]. One review reports that regular territory dispersion is a consistent characteristic of northern goshawk populations that likely results from territorial behavior. In North America, mean nearest neighbor distances range from 1.9 to 3.5 miles (3.0-5.6 km) [26], and density estimates range from less than 1 to 11 pairs per 100 km². Densities in the range of 10 to 11 occupied nests per 100 km² were reported for 3 study areas in Arizona, California, and the Yukon. However, nest density across a landscape is difficult to determine and often based on either assumed censuses of breeding pairs or the distribution of nearest neighbor distances. Because most searches for nests are conducted in what is predetermined to be "suitable" habitat, reported densities may not accurately reflect the number of territories per unit area. Surveys may also be incomplete or inaccurate [26].

Migration: The northern goshawk is considered a partial migrant. Some individuals, particularly those that inhabit northern latitudes, may migrate long distances. Other individuals make short winter movements to lower elevations and/or more open plant communities. Food availability in the winter may influence the degree to which individuals or populations migrate [40,48].

Predation and mortality: Northern goshawks are vulnerable to predation from red-tailed hawks (Buteo jamaicensis), short-eared owls (Asio flammeus), great horned owls (Bubo virginianus), American martens (Martes americana) [48], fishers (M. pennanti) [7], wolverines (Gulo gulo) [48], coyotes (Canis latrans), bobcats (Lynx rufus), and northern raccoons (Procyon lotor) [40]. It is likely that other mammals prey on nestlings and/or adults [48]. In the Great Lakes region, great horned owls were the most common nest predator [7]. Other potential sources of northern goshawk mortality include starvation, disease, shooting, trapping, poisoning, and collisions with vehicles [48].

Interspecific competition: Reduction and fragmentation of mature forest habitat may favor early-successional competitors such as red-tailed hawks and great horned owls and reduce occupancy of an area by northern goshawks [26]. One study from California found great horned owls, long-eared owls (Asio otus), spotted owls (Strix occidentalis), red-tailed hawks, and Cooper's hawks (Accipiter cooperii) occupying traditional northern goshawk nests or nest stands, but the territories were usually not abandoned entirely by northern goshawks. In 3 instances, however, northern goshawks moved out of their traditional nest stand after it was occupied by spotted owls [51].

Great gray owls (Strix nebulosa) using a nest formerly used by northern goshawks. Photo by Jack Kirkley.

Population dynamics: Factors limiting northern goshawk populations may include food availability [10,26,40,48], availability of nest sites [40], and territoriality [26]. Food availability is more of an issue in northern latitudes, where northern goshawks are more dependent on populations of few species (e.g., snowshoe hare (Lepus americanus)). There is less evidence of population fluctuations in response to food in lower latitudes, where a greater variety of prey species are available [40,43]. See Population status for more information on how stand and landscape characteristics may influence northern goshawk populations.

Diet: The northern goshawk opportunistically feeds on a wide diversity of prey items that varies by region, season, and availability. Though the list of potential prey species is extensive, a few taxa are particularly prevalent in most diets [48]. Diet options may be narrower in northerly latitudes, where fewer prey species are available, than in lower latitudes [40,43].

Prey species prevalent in the diet of northern goshawks throughout their range [48]
Mammals Tree squirrels Abert's squirrel (Sciurus aberti), eastern gray squirrel (S. carolinensis), Douglas's squirrel (Tamiasciurus douglasii), red squirrel (T. hudsonicus), northern flying squirrel (Glaucomys sabrinus)

Ground squirrels

Belding's ground squirrel (Spermophilus beldingi), golden-mantled ground squirrel (S. lateralis), Richardson's ground squirrel (S. richardsonii), Townsend's ground squirrel (S. townsendii)
Lagomorphs cottontails (Sylvilagus spp.), jackrabbits (Lepus spp.), snowshoe hare
Birds Phasianidae dusky grouse (Dendragapus obscurus), ruffed grouse (Bonasa umbellus), spruce grouse (Falcipennis canadensis)
Corvidae American crow (Corvus brachyrhynchos), blue jay (Cyanocitta cristata), Steller's jay (C. stelleri), gray jay (Perisoreus canadensis),
Picidae American three-toed woodpecker (Picoides dorsalis), black-backed woodpecker (P. arcticus), hairy woodpecker (P. villosus), northern flicker (Colaptes auratus), pileated woodpecker (Dryocopus pileatus),Williamson's sapsucker (Sphyrapicus thyroideus)
Turdidae American robin (Turdus migratorius)

Regional diet summaries are available from the Great Lakes [7,43], South Dakota [47], the central Rocky Mountains [26], and eastern Oregon [17].

Prey habitat and availability: Managing for prey species is a major component of habitat recommendations for the northern goshawk (e.g., see [40]). Northern goshawk populations may experience reduced fitness and reproduction, greater interspecific competition for food, and greater susceptibility to predators when food resources are limited [26]. Several reviews emphasize the importance of both prey abundance and availability when determining suitable northern goshawk habitat. In other words, prey need to be both present and huntable, with availability determined by stand structure [24,26].

For information on habitat preferences of northern goshawk prey species, see the following reviews from the Southwest [10,40,53] and central Rocky Mountains [26] or FEIS reviews for the following species: Abert's squirrel, Townsend's ground squirrel, eastern cottontail, black-tailed jackrabbit, snowshoe hare, ruffed grouse, gray jay, and black-backed woodpecker.

HABITAT:
Northern goshawk habitat includes a variety of forest types and stand structures, depending on geographic location and life history activities. The northern goshawk's large home ranges and ability to move great distances mean that it may encounter a variety of habitats over a short period. In addition to nesting habitat, northern goshawks need foraging habitat in both the breeding and nonbreeding seasons and in postfledging areas where young learn to hunt but are protected from predators [43]. Habitat selection may be shaped by landscape structure and pattern and/or occupancy by other raptors [43]. In general, as the scale of analysis increases (i.e., from stand to landscape), northern goshawks use more diverse habitats and show less preference for specific habitat features [3,10,17,43]. Northern goshawks appear to use a wider range of habitats during the nonbreeding season than the breeding season [3].

In general, northern goshawks appear to prefer relatively dense forests [24,25,47] with large trees [3,24] and relatively high canopy closures [3,24,25,47]. A review noted that 9 of 12 radio telemetry studies from the western United States found northern goshawks selected stands with higher canopy closures, larger trees, and more large trees than found in random stands. But northern goshawks still used stands with a wide range of structural conditions [24]. The use of forests with relatively large trees and high canopy closures may be related to increased protection from predators, increased food availability, limited exposure to cold temperatures and precipitation early in the breeding season, limited exposure to high temperatures in the summer nestling period, high mobility due to a lack of understory structure, and less competition from other raptor species that inhabit more open habitats [3].

The relatively large body size and wingspan of the northern goshawks limit its use of young, dense forests where there is insufficient space in and below the canopy to facilitate flight and capture of prey. There are also few suitably large trees for nesting in young, dense forests [40].

Breeding habitat: Northern goshawk habitat use may be most selective during the breeding season, mostly due to strong preferences for nest placement [43,48].

Nest stand: Forest stands containing nests are often small, ranging from approximately 24 to 247 acres (10-100 ha) [48]. Tree species composition is highly variable among nest sites both within a region and a across the range of the northern goshawk [40]. Northern goshawks nests are often found in mature or late-successional forests [3,15,17,43,48] with high canopy closures [9,17,43,47,48] and large trees [43,48] but relatively open understories [26,43,48]. However, due to frequent bias in northern goshawk nest detection methods, the selection of mature forest over other forest successional stages has been demonstrated in only a few studies [43].

Northern goshawks nested in this conifer forest in western Montana.
Photo by Jack Kirkley.

Though northern goshawks are most often documented nesting in late-successional forests, they sometimes nest in younger, more open forests. For example, in dry areas of the West such as the Great Basin, northern goshawks nested in high-elevation shrubsteppe habitats supporting small, highly fragmented stands of quaking aspen (Populus tremuloides) [52]. In a conifer plantation in western Washington, 3 northern goshawk pairs nested in younger, denser stands than previously reported for the region; nest sites were composed of 40- to 54-year-old, second-growth conifer stands with high live tree and snag densities [9].

Northern goshawk nest sites are often located near water [43,47,52], though some studies have shown no association between nest sites and water [26,43] and the presence of water is not considered a habitat requirement [48]. The function of open water during nesting is unknown [43].

Nest sites often are located close to forest openings or other open areas [12,15,26,43,47], which may increase nest access, serve as travel corridors, support open-habitat prey species, or reduce flight barriers to fledglings [48]. However, one study from west-central Montana noted that the number of young fledged per nest was negatively correlated with the size of the nonforested openings near the nest (P≤0.05) [12].

Slope and aspect may influence microclimate conditions important to northern goshawk nesting. Northern goshawk nests are often located at the base of moderate slopes [48] and tend to be on gentle rather than steep terrain [15]. However, there may be no relationship between nesting and slope in areas with low topographic relief, like the Great Lakes region [7]. One study from west-central Montana found that 82.6% of occupied nests were located on north slopes [12]. Preferred aspects may vary regionally; one review noted that in southern parts of the range, northern goshawks nest areas typically had northerly aspects, while nest areas in interior Alaska had southerly aspects [26].

Postfledging family areas: A postfledging area represents the area of concentrated use for a northern goshawk family from the time the young leave the nest until they are no longer dependent on the adults for food. Northern goshawks typically defend this area as a territory. Postfledging family areas provide hiding cover and prey for fledglings to develop hunting skills. They typically contain patches of dense trees, developed herbaceous and/or shrubby understories, and habitat attributes that support prey, such as snags, downed logs, and small openings. Postfledging family areas range in size from 300 to 600 acres (120-240 ha) [40].

Wintering habitat: Northern goshawk breeding habitat has been studied much more intensively than nonbreeding habitat. In general, northern goshawks use a wider range of habitats during the nonbreeding season than during the breeding season [48]. One review reports that northern goshawks in northern Arizona may select winter foraging sites based on forest structure rather than prey abundance, similar to selection in the breeding season [26] (see Foraging habitat). In some regions, northern goshawks appear to remain near breeding areas throughout the year [3,7,43], though there is considerable annual variation and variation between sexes in nonbreeding habitat use [3]. In at least some landscapes, northern goshawks forage in late-successional forest habitats throughout the year [3,24]. However, some northern goshawks move to low-elevation, open plant communities (e.g., woodlands) in the winter [3,24].

Foraging habitat: Northern goshawks forage by ambush and perching in vegetation to scan for prey items. They occasionally hunt by flying rapidly along forest edges and across openings [26]. Ideal foraging habitat includes space under the canopy to allow for flight, abundant trees perches, and available prey [53]. Preferred perches while hunting are low (usually <3 feet (1 m)), bent-over trees or saplings. Plucking perches where northern goshawks consume prey are usually located in dense vegetation below the main forest canopy and are often upslope and fairly close to the nest in the breeding season [48].

Northern goshawks forage over large areas and encounter a variety of forest structures [23,26] and plant communities [48] when foraging. In the breeding season, a foraging area may encompass 5,400 acres (2,200 ha) surrounding the postfledging family area [40]. Northern goshawks may rely heavily on mature forest while foraging [3,10,17] but may also forage in younger forests, edges, and openings [10,17,26,43]. An open understory may enhance the detection of potential prey [3,40,43].

Prey abundance may be an important feature of foraging habitat, but several sources stress the importance of prey availability [3,5,22,26,40,53], which is often linked to vegetative structure that allows northern goshawks to hunt successfully [3]. For example, over 2 breeding seasons in ponderosa pine (Pinus ponderosa) forests in northern Arizona, 20 adult northern goshawks did not select foraging sites based on prey abundance; abundance of some prey was lower in selected sites than what was generally available. Northern goshawks instead selected foraging sites that had higher canopy closure (P=0.006), greater tree density (P=0.001), and greater density of trees >16.0 inches (40.6 cm) DBH (P<0.0005) than what was generally available. The authors concluded that above a minimal prey threshold, northern goshawks may select sites with favorable structure over those with abundant prey. However, they also suggested that their results only apply to foraging habitat selection within an established home range. Prey abundance may be an important factor when northern goshawks initially establish a home range [5].

In the Great Lakes region, male northern goshawks primarily foraged in mature upland conifer and upland deciduous stands, but other stand types were used and may be important to prey production [7]. In lodgepole pine (P. contorta) and quaking aspen forest in south-central Wyoming, the kill sites of male northern goshawks in the breeding season were more related to stand structure and aspect than prey abundance. Males returned most often to sites with more mature forests (P=0.0), gentler slopes (P=0.011), lower ground cover of woody plants (P=0.023), and greater densities of trees (P<0.089) and conifers (P<0.14) ≥9 inches (23 cm) but ≤15 inches (38 cm) DBH. Average canopy closure at kill sites was 52.8%. Kill sites were often associated with small openings; average distance to the nearest open area was 152.2 feet (46.4 m). The author noted that several prey species were often associated with forest edges. The results of this study suggest that the high density of large trees allowed northern goshawks to approach prey unseen, while the low density of understory vegetation allowed northern goshawks to see potential prey items. At the landscape scale, male northern goshawks intensively used large areas of conifer forests interspersed with small openings in proximity to nests. They used a variety of habitats, from narrow patches of quaking aspen in drainages surrounded by sagebrush (Artemisia) and grassland to areas dominated by conifer forests [22].

Roosting habitat: Northern goshawks roost alone in the tree canopy and may use several sites for roosting. In the early nesting phase, female northern goshawks roost on the nest while brooding young [48]. In California, roost tree species and roosting stand characteristics varied by season, which the authors hypothesized was in response to changes in prey abundance and availability [42].

Landscape features: Northern goshawks use large landscapes for many life history activities, though it is difficult to make broad generalizations about the importance of landscape features to northern goshawk populations. Studies and reviews highlight the importance of landscape features such as the presence of large areas of mature forest [10,15,26,40], a mosaic of forest structural stages [17,25,26,40], limited forest fragmentation [26,51], and large patch sizes [9,43,51].

MANAGEMENT CONSIDERATIONS:
Federal legal status: The Queen Charlotte subspecies of the northern goshawk is listed as Threatened [50].

Other status: Information on state- and province-level protection status of animals in the United States and Canada is available at NatureServe, though recent changes in status may not be included.

Other management information:
Population status: Trends in northern goshawk populations are difficult to assess for several reasons. Northern goshawks are secretive and consequently difficult to survey. Many studies have small sample sizes and are temporally and/or spatially limited in scope. Methodology in some studies may be biased and methods, analyses, and interpretation vary between studies [43]. Attempts to assess the status of northern goshawk populations have not found strong evidence supporting population declines, though most studies were not designed to detect population changes [10,26]. Populations may also vary regionally; some managers in New England suspect northern goshawk populations may be increasing due to widespread reforestation in the region, but they lack definitive data to support this hypothesis [15].

Management considerations: Northern goshawks exhibit some life history characteristics that facilitate adaptation to landscape change. They maintain a large breeding territory that contains several nest sites, so if one nest site is altered or destroyed, they may have other nearby options (see Nest and nest site fidelity). Though most sources report the use of mature forests for nesting, northern goshawks occasionally nest in areas with few trees or in small forest patches [10]. Similarly, they forage over large areas, using open areas and a variety of forest structures (see Foraging habitat). Several sources suggest that they adjust to changing environmental conditions [10,26]. Northern goshawks also show plasticity in migration strategy, allowing individuals to seasonally avoid areas where habitat has been degraded [26].

Landscape management decisions can influence the success of individuals or pairs of northern goshawks and northern goshawk populations. One review asserts that the primary threat to northern goshawk populations is the modification of forest habitats by management and natural disturbances [10]. Though it is difficult to assess the population status of northern goshawks, managers have raised concerns over destruction and/or modification of northern goshawk habitat via natural and anthropogenic disturbances. Natural disturbances that may impact northern goshawk habitat include severe wildfires [10], insect outbreaks [17], and drought [40]. Diseases, parasites, exposure, and predation tend to impact individuals rather than populations [10]. Potential anthropogenic threats to northern goshawk habitat include silvicultural treatments that result in forest fragmentation, creation of even-aged and/or monotypic stands, potential increase in acreage of young age classes, and loss of tree species diversity [43]. Other anthropogenic threats to northern goshawk populations include fire suppression activities [17,40], livestock grazing, exposure to toxins and chemicals [40], and timber harvest [10,17,26,40].

Timber harvest: The impact of timber harvest on northern goshawks is much debated in the literature, and centers mostly on the loss of mature forest. Though many believe that extensive habitat modification due to timber harvest is detrimental to northern goshawk populations, a lack of research across a gradient of tree-harvest intensities precludes a clear demonstration of negative effects [10]. Furthermore, few studies have investigated northern goshawk habitats in forests not managed for timber harvest [26].

Forest management for timber extraction can directly impact the structure, function and quality of both nesting and foraging habitat by removing nests and nest trees, modifying or removing entire nest stands, and removing the canopy and mature trees, snags, and downed wood that support prey populations [26]. The loss of important habitat features could impact both the ability of northern goshawks to access prey items (e.g., inability to hunt in areas of dense tree regeneration) and limit prey populations [40]. Reduction and fragmentation of habitat may also favor early-successional competitors and predators such as red-tailed hawks and great horned owls [26]. Indirect impacts of timber harvest on nesting may vary; breeding densities may be lowered or individuals may move to adjacent, undisturbed areas [48]. The threshold at which landscape-altering projects render an area unsuitable to northern goshawks likely varies spatially and/or temporally [26]. However, one source suggests that in some cases (e.g., the inland Pacific Northwest), nonharvest forestry may be just as detrimental to northern goshawk nesting habitat as aggressive, maximum-yield forestry [17].

The following sources provide information on reducing potential negative impacts of timber harvest on northern goshawk individuals and populations: [9,48].

Management actions to benefit northern goshawks: Managers and researchers offer many suggestions for managing forested landscapes to benefit northern goshawk populations. These recommendations include stand-level treatments like maintaining large trees, snags, and large downed logs [40] and larger-scale suggestions such as maintaining and enhancing mature forests [10,15,26,40], limiting forest fragmentation [26], and maintaining a mosaic of structural stages [17,26,40]. Several authors suggest managing at multiple scales [17,26,40]. However, because stand and landscape characteristics, as well as management objectives, vary throughout the range of northern goshawks, no management plan or prescription can encompass the variety of conditions northern goshawks might encounter [40]. For example, in the western United States, 78% of the habitat occupied by nesting northern goshawks occurs on federally managed lands, while in the eastern United States, most forested areas are privately owned [10]. Several sources offer regional recommendations for managing forests for northern goshawk habitat, including recommendations for New England [15], the Great Lakes [7], the Black Hills region of South Dakota [47], the central Rocky Mountains [26], west-central Montana [12], the western United States [24], the southwestern United States [40], the inland Pacific Northwest [17], and California [42]. Several sources offer recommendations for silvicultural and other physical treatments (e.g., forest restoration, understory thinning, prescribed fire) to increase the availability of mature forest and/or restore historical stand conditions to improve habitat for northern goshawks and their prey [10,26,32,40,48]. See Fire Management Considerations for more information on this topic.

FIRE EFFECTS AND MANAGEMENT

SPECIES: Accipiter gentilis
DIRECT FIRE EFFECTS:
A review of the effects of fire on raptor populations suggests that direct mortality from fire is rare [30]. Adult northern goshawks are highly mobile and consequently are probably able to flee an approaching fire. Mortality from fire is most likely to occur during the breeding season when nestlings are unable to flee an approaching fire [30]. One wildlife biologist in western Montana thought a high-severity wildfire in August might have killed 2 northern goshawk nestlings observed 2 weeks prior to the fire [31].

Fire in the spring and summer may disrupt the breeding of northern goshawks.

INDIRECT FIRE EFFECTS:
As of this writing (2012), there was little documentation of the indirect effects of fire on northern goshawk individuals or populations. Presumably, the occurrence, extent, and severity of fire could have major impacts on small- and large-scale forest structure which in turn may affect the suitability of an area for life history activities such as breeding and foraging. Effects may be positive or negative and could vary regionally.

A review of the effects of fire on raptor populations suggests that the most significant effect is the modification and/or destruction of habitat. Habitat losses can include small-scale losses like an individual nest tree or a roost site or large-scale losses like the elimination of a foraging area [30]. However, fire may also modify the landscape in ways that improve habitat for northern goshawks (e.g., the creation of a mosaic of stand structures).

Northern goshawk populations have long been exposed to wildfire as a natural disturbance process [23], and some sources suggest that northern goshawks can adjust to changing environmental conditions [10,26]. Northern goshawks exhibit some life history characteristics that make them adaptable to landscape disturbances such as fire. They maintain a large breeding territory that contains several nest sites, so if one nest site is altered or destroyed, they may have other nearby options (see Nest and nest site fidelity). Though most sources report the use of mature forests for nesting, northern goshawks occasionally nest in areas with few trees or in small forest patches [10]. Northern goshawks use a variety of forest structures when foraging [23,26], and though they often rely heavily on mature forest while foraging [3,10,17], they also forage in young forests, edges, and openings [10,17,43] (see Foraging habitat).

Indirect fire effects on nesting: Fire may consume northern goshawk nests, nest stands, and/or breeding territories. A review suggests that stand-replacement wildfire could reduce the suitability of an area for northern goshawk nesting and create forest openings larger than what occurred historically [19].

Two biologists working with northern goshawks in Montana provided observations of fire effects on northern goshawk nesting. It should be noted that these observations are anecdotal and may not be representative of northern goshawk response to fire throughout its range.

One biologist studied northern goshawk nest and territory occupancy over many years in lodgepole pine forests on the Beaverhead-Deerlodge National Forest, southwestern Montana. A stand-replacing wildfire in 2007 burned 2 historical northern goshawk territories, though the territories were not occupied in the years prior to the fire. The fire resulted in a reduction of suitable nesting habitat, leaving a patchy distribution of unburned forest amidst largely open meadows. Three and 4 years after the fire, northern goshawks nested in an unburned patch of forest midway between the historical territories. These observations show that northern goshawks can shift to remaining suitable nesting stands even when stand-replacing fire has consumed most of the vegetation in an area [27].

A 2nd biologist observed that high-severity wildfires occurring in mixed-conifer forests on the Bitterroot National Forest, western Montana, in August of 2000 consumed 2 known northern goshawk territories and several nests, 1 of which was active 2 weeks prior to the fire. The young in this nest were presumed dead, though it is possible they were able to fly well enough to escape the area. The landscapes surrounding both territories experienced extensive stand-replacement fire, and local biologists described the territories as unsuitable for northern goshawk nesting in the years following fire [31].

Low-severity fires may result in nest abandonment, though not always immediately. In one area on the Bitterroot National Forest, western Montana, a low-severity fire in August of 2000 consumed most of the forest understory but left the overstory intact. The fire killed most of the trees in the sapling and intermediate layers as well as many Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in the overstory via bole scorch, but almost all of the Douglas-fir (Pseudotsuga menziesii) survived. Douglas-fir beetles (Dendroctonus pseudotsugae) began causing overstory canopy mortality by 2002, with many trees exhibiting red needles by the summer of 2003. Northern goshawks nested in the stand prior to fire and continued to nest and successfully fledge young in the stand for several years after the fire, though biologists found a new and different active nest each year from 2001 to 2004. The nesting area was eventually abandoned; none of the 4 known nests were active in 2005, 2006, or 2007, though it is possible that other nests were constructed in the area and not found. Local biologists suspected the area was abandoned because canopy closure decreased as overstory mortality increased [31].

In another area on the Bitterroot National Forest, western Montana, burned by low-severity fire in 2000, a northern goshawk nest tree was killed, but much of the surrounding nest stand was not killed. The nest was abandoned and eventually fell out of the tree. In other instances where nest stands were burned by low-severity fire in 2000, the canopies around the nests gradually thinned out as surrounding trees died, and the nests were not used again. However, in all instances, biologists were unable to determine if northern goshawks left the area completely or if they shifted to unlocated nests within the territory [31].

Indirect fire effects on foraging: The effect of fire on foraging habitat likely varies with fire severity and extent across a landscape. For example, an extensive, high-severity fire that results in major canopy and understory mortality may result in poor habitat for some prey species for many years after fire. The dense regeneration that may follow stand-replacing fire in some forest types (e.g., lodgepole pine) may inhibit the ability of northern goshawks to detect prey. A fire that creates a mosaic of forest structures and openings may offer northern goshawks a variety of foraging opportunities and provide habitat for a wide range of prey species. Since open understories may enhance the detection of prey items, low-severity fires that consume the understory but maintain a live overstory may create foraging opportunities [3,40,43]. The impact of fire on foraging habitat may be greater in the breeding season, when northern goshawks are tied to a nest and breeding territory, than in the winter, when individuals are more flexible in how far and where they travel to forage and use a wider range of habitats (see Foraging habitat).

Northern goshawk occurrence in burned areas: To date (2012), the documentation of northern goshawks occurring in burned areas is rare and largely incidental, making generalizations difficult. Between 1 and 3 years after a low- to moderate-severity prescribed fire in northern Arizona, one northern goshawk was detected during winter point counts [38,39]. One northern goshawk was detected on the ecotone between burned and unburned lodgepole pine forest 8 years after a high-severity wildfire in north-central Colorado [44]. In mixed-conifer forests on the Lolo National Forest, western Montana, one northern goshawk responded to a playback call in the breeding season in an area treated approximately 10 years previously by a low-severity "ecosystem burn" aimed at retaining the stand's old growth characteristics [11]. In central Alaska, a northern goshawk was killed by an American marten in boreal forest burned approximately 25 years previously. The forest was in a midsuccessional stage of dense tree regeneration, though some severely burned lowlands were in an earlier shrub-sapling stage. Mature forest in the area was primarily black spruce (Picea mariana) and tamarack (Larix laricina) [36]. Three years after mixed-severity wildfires in a ponderosa pine forest in Arizona, researchers detected 2 northern goshawks in an unburned area adjacent to burned forest while conducting point counts in the nonbreeding season. Northern goshawks were not detected in any area (unburned, moderately burned, severely burned) in the breeding season or in severely or moderately burned forest in the nonbreeding season [8].

FIRE REGIMES:
Because of their broad distribution, northern goshawks occur in plant communities that experience a wide range of fire regimes, including fire regimes characterized by low-severity, mixed-severity, or stand-replacement fire. Return intervals may be short to long. In the western United States, fire creates a landscape mosaic capable of supporting northern goshawk populations. Northern goshawks and their prey have historically had exposure and adapted to forest conditions maintained by a variety of fire regimes, including nonlethal surface, mixed-severity, mosaic, and stand-replacement fire [23]. However, several reviews discuss how fire regimes within the range of the northern goshawks have shifted away from historic patterns due to fire exclusion and other anthropogenic practices [10,12,23,30,32,40,51]. Changes in the frequency and severity of fire have resulted in shifts in forest composition and structure, which may impact northern goshawks and their prey [26]. Documented forest changes that may result from fire exclusion and other anthropogenic practices include reduced stand structural diversity [32], increased stand density [12,32,40,51], increased understory density [12,40], and changes in species composition [40,51]. Such forest structural and compositional changes may limit the mobility and hunting success of northern goshawks [19] and cause changes to prey populations and diversity [12,19,40]. In some cases, forest structural and compositional changes may increase the probability of high-severity fires [40,51], which would reduce the amount of mature forest on the landscape [10,40], eliminate nesting habitat, and create forest openings larger than what occurred historically [19]. Though these forest changes are generally discussed in the literature as reducing habitat for northern goshawks, it is possible that forest changes in some areas may improve habitat for northern goshawks.

One review discusses how several fire regimes typical of Southwestern forests may have influenced northern goshawk populations in the region. Nonlethal, low-severity surface fires in ponderosa pine forests would "clean" the forest, providing suitable foraging habitat and open canopies that enabled northern goshawks to successfully access prey. Large trees would eventually die from lightning, disease, or insects and provide snags or coarse woody debris, habitat features important to northern goshawk prey. These fires would gradually consume downed logs, but not before the logs contributed to habitat for prey species and added organic matter to the soil. The small openings left would allow for the regeneration of new trees. Mixed-severity fire regimes in relatively moist coniferous forests would create larger openings (>4 acres (2 ha)), greater amounts of coarse woody debris, and multiple canopy layers compared to less severe fires. These fires could create openings of all sizes, leading to a mosaic of forest structural conditions across the landscape. Large openings would likely not provide ideal northern goshawk foraging habitat, but the edges of these openings might be used. Large forest openings may have been historically important for maintaining seral quaking aspen stands, an important component of many northern goshawk home ranges in this region. Forests maintained by high-severity fires may have limited value as northern goshawk habitat because they result in large (>24 acres (10 ha)) openings and/or an even-aged structure across a large landscape [23]. For management recommendations pertaining to these and other fire regimes throughout the range of the northern goshawk, see Fire Management Considerations.

The Fire Regime Table summarizes characteristics of fire regimes for vegetation communities in which northern goshawks may occur. Follow the links in the table to documents that provide more detailed information on these fire regimes. Northern goshawks also occur in geographic areas not covered by the Fire Regime Table, including a variety of boreal plant communities in Alaska and Canada, as well as forested plant communities in Mexico.

FEIS also provides reviews of many of the prey species important to the life history and habitat use of northern goshawks. See FEIS reviews for additional information—including information on fire regimes and fire effects on species including: Abert's squirrel, Townsend's ground squirrel, eastern cottontail, black-tailed jackrabbit, snowshoe hare, ruffed grouse, gray jay, and black-backed woodpecker.

FIRE MANAGEMENT CONSIDERATIONS:
The lack of scientific information predicting the positive or negative consequences of fire management on the northern goshawk has legal, scientific, and social ramifications for land management agencies attempting to implement national fire programs [45]. Managers may not have many action options to protect northern goshawks in wildfire situations, but forest management activities (e.g., prescribed fire, thinning) aimed at fuels reduction and restoring historic stand structure are widespread in areas inhabited by northern goshawks. Many agencies suggest or require the designation of a buffer around nest trees when treatments occur, but there is some debate over the appropriate buffer size and the effectiveness of this approach, particularly because northern goshawks rely on a large landscape to meet life history needs [17,26,48]. One review critiques the buffer concept because the designation of buffers of a specific size around nests forces a predetermined restriction on all forest types—which may not be appropriate—gives the impression that management is not required beyond the buffer, and ignores the multiple scales at which northern goshawks use a landscape [17]. Reynolds and others [40] recommend avoiding or minimizing direct negative impacts on individual northern goshawks by restricting treatments or activities in the breeding season, particularly when females are incubating and/or young are immobile.

Because current fire regimes and forest conditions may fall outside of the range of historic variability in some parts of the range of northern goshawks, several sources suggest thinning and/or prescribed fire to restore historical stand characteristics and/or improve habitat for northern goshawks and their prey [13,14,26,35,40,53] and to make forests more resilient to high-severity wildfires [35]. In some cases, there is concern that mechanical and/or prescribed fire treatments aimed at converting dense forests to more open stands may result in a loss of habitat for species that use mature forest, like the northern goshawk [10,49]. On the other hand, some evidence suggests that avoiding treatment in areas to protect habitat for northern goshawks may have unintended negative consequences, particularly in the presence of high-severity fire. For example, in a mixed-conifer forest on the Plumas National Forest, northern California, managers left areas designated as protected northern goshawk habitat untreated during a fuels reduction treatment. When a wildfire burned through the region, fire severity in untreated areas was higher than in treated areas, resulting in significantly higher mortality of canopy trees (P<0.001) [21].

One review offers management recommendations for maintaining northern goshawk habitat in several Southwest fire regimes. In areas that experience infrequent fire, managers could create small openings that mimic wind events and other small-scale disturbances that historically maintained a diverse stand structure across the landscape. Such actions would provide a variety of interspersed stand structures that would support habitat for a wide range of prey species. In areas experiencing mixed-severity fire regimes, limiting large openings to small portions of a home range can help prevent fragmentation and ensure that enough mature forest habitat and canopy cover are available for both northern goshawks and their prey. In areas experiencing high-severity fire, northern goshawks may require relatively large home ranges (>9,900 acres (4,000 ha)) to ensure enough mature forest is available to provide adequate prey. Northern goshawks may also benefit from a range of seral to climax plant communities. Given the creation of large openings, rate of forest development, and tree longevity in areas experiencing high severity fire, the proportion of the landscape in various structural stages would likely vary. Management plans in these areas would require a scope of hundreds of years and landscape-level planning [23].

For information on combining management goals to include both habitat for the northern goshawk and fuels reduction projects that improve overall ecosystem function and resiliency to high-severity wildfire, see the following sources: [13,14,23,26,35,40,53]. For information regarding using fire and silvicultural techniques to restore fire-adapted ecosystems in the Southwest, see: [23,40,53].

Northern goshawk use of treated areas: Northern goshawks have been documented occurring and breeding in areas treated for fuels reduction and/or restoration, but their response to these treatments has not been well studied. The anecdotal information presented below suggests that northern goshawks may tolerate fuels reduction activities taking place in the breeding season, but use of treated areas is variable in subsequent years. It is not clear if non-use of a treated area is due to the physical disturbance during the breeding season or the resulting changes in local stand structure. It should also be noted that the lack of northern goshawk detections at particular nests does not mean territory abandonment; use of multiple nests in a territory is common and nests may not be detected by biologists (see Nest and nest side fidelity). The information presented here is largely anecdotal and limited in scope, and may not be representative of northern goshawk response to fuels reduction and restoration treatments throughout their range.

Two fuels reduction treatments occurred in northern goshawk territories in mixed ponderosa pine and Douglas-fir forests on the Bitterroot National Forest, western Montana. The prescriptions for both treatments left 30 to 40 acres (12-16 ha) untreated immediately surrounding known northern goshawk nests. The prescription also retained 80 to 100 feet²/acre basal area of canopy trees in the postfledging family area. Thinning in one territory containing 3 known nests occurred in 2006 and 2007. A nest successfully fledged young during the 2 years of treatments. No known nesting occurred in the territory in 2008 or 2011, but young were fledged from the territory in 2009, 2010, and 2012, with 2 different nests used. Thinning in a 2nd northern goshawk territory occurred after the northern goshawk breeding season in 2011. Northern goshawks successfully fledged young in 2011 prior to thinning, and in 2012 after thinning [31].

In southwestern Montana, the US Bureau of Land Management conducted a major thinning project to remove ladder fuels in Douglas-fir forest. Low-severity surface fires and pile burning were used to consume slash on the ground. Prior to treatment, the area consisted of a structurally diverse, multiaged stand with a large component of large, mature trees. The treatment resulted in a more "park-like" and open structure, though most of the mature trees were left standing. One female goshawk twice tolerated the activities associated with this project, continuing to incubate despite the presence of an active skid trail within 98 feet (30 m) of her nest the 1st year of treatment, and a burning slash pile within 66 feet (20 m) of her nest the 2nd year of treatment. In both instances, the female did not abandon incubation duties and young were successfully fledged. However, nest location shifted between the 2 years, with the pair building a new nest in a "leave" tree remaining after the thinning occurred. Northern goshawks were not detected nesting in the treated area again, though an adjacent, untreated territory was occasionally occupied [27].

One active northern goshawk nest was discovered during a selection-harvest fuels reduction treatment in 1993 in a mixed-conifer forest on the Bitterroot National Forest, western Montana. After this discovery, a small island of trees was left surrounding the nest, and approximately 100 feet²/acre basal area of canopy trees was left in the surrounding unit. The female continued incubating, and 2 young hatched while the treatments were conducted. Though the nest successfully fledged young that year, it was not used by northern goshawks in subsequent years, presumably because of the reduction in overstory canopy cover. The nest was used by great horned owls and Cooper's hawks after treatment [31].

In mixed-conifer forests on the Lolo National Forest, western Montana, northern goshawks were detected in treated (low-severity fires and selection harvest) and untreated "old growth" stands at frequencies similar to those found throughout the area [11]. One biologist observed northern goshawks nesting for 2 years within thinned lodgepole pine forests on the Beaverhead-Deerlodge National Forest, southwestern Montana [27].

APPENDIX: FIRE REGIME TABLE

SPECIES: Accipiter gentilis
The following table provides fire regime information that may be relevant to northern goshawk habitats. Follow the links in the table to documents that provide more detailed information on these fire regimes.

Fire regime information on vegetation communities in which northern goshawks may occur. This information is taken from the LANDFIRE Rapid Assessment Vegetation Models [29], which were developed by local experts using available literature, local data, and/or expert opinion. This table summarizes fire regime characteristics for each plant community listed. The PDF file linked from each plant community name describes the model and synthesizes the knowledge available on vegetation composition, structure, and dynamics in that community. Cells are blank where information is not available in the Rapid Assessment Vegetation Model.
Pacific Northwest California Southwest Great Basin
Northern and Central Rockies Northern Great Plains Great Lakes Northeast
South-central US Southern Appalachians    
Pacific Northwest
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Pacific Northwest Grassland
Alpine and subalpine meadows and grasslands Replacement 68% 350 200 500
Mixed 32% 750 500 >1,000
Pacific Northwest Shrubland
Wyoming big sagebrush semidesert Replacement 86% 200 30 200
Mixed 9% >1,000 20  
Surface or low 5% >1,000 20  
Wyoming sagebrush steppe Replacement 89% 92 30 120
Mixed 11% 714 120  
Low sagebrush Replacement 41% 180    
Mixed 59% 125    
Mountain big sagebrush (cool sagebrush) Replacement 100% 20 10 40
Pacific Northwest Woodland
Western juniper (pumice) Replacement 33% >1,000    
Mixed 67% 500    
Oregon white oak-ponderosa pine Replacement 16% 125 100 300
Mixed 2% 900 50  
Surface or low 81% 25 5 30
Pine savannah (ultramafic) Replacement 7% 200 100 300
Surface or low 93% 15 10 20
Ponderosa pine Replacement 5% 200    
Mixed 17% 60    
Surface or low 78% 13    
Oregon white oak Replacement 3% 275    
Mixed 19% 50    
Surface or low 78% 12.5    
Subalpine woodland Replacement 21% 300 200 400
Mixed 79% 80 35 120
Pacific Northwest Forested
Sitka spruce-western hemlock Replacement 100% 700 300 >1,000
Douglas-fir (Willamette Valley foothills) Replacement 18% 150 100 400
Mixed 29% 90 40 150
Surface or low 53% 50 20 80
Oregon coastal tanoak Replacement 10% 250    
Mixed 90% 28 15 40
Ponderosa pine (xeric) Replacement 37% 130    
Mixed 48% 100    
Surface or low 16% 300    
Dry ponderosa pine (mesic) Replacement 5% 125    
Mixed 13% 50    
Surface or low 82% 8    
Douglas-fir-western hemlock (dry mesic) Replacement 25% 300 250 500
Mixed 75% 100 50 150
Douglas-fir-western hemlock (wet mesic) Replacement 71% 400    
Mixed 29% >1,000    
Mixed conifer (southwestern Oregon) Replacement 4% 400    
Mixed 29% 50    
Surface or low 67% 22    
California mixed evergreen (northern California and southern Oregon) Replacement 6% 150 100 200
Mixed 29% 33 15 50
Surface or low 64% 15 5 30
Mountain hemlock Replacement 93% 750 500 >1,000
Mixed 7% >1,000    
Lodgepole pine (pumice soils) Replacement 78% 125 65 200
Mixed 22% 450 45 85
Pacific silver fir (low elevation) Replacement 46% 350 100 800
Mixed 54% 300 100 400
Pacific silver fir (high elevation) Replacement 69% 500    
Mixed 31% >1,000    
Subalpine fir Replacement 81% 185 150 300
Mixed 19% 800 500 >1,000
Mixed conifer (eastside dry) Replacement 14% 115 70 200
Mixed 21% 75 70 175
Surface or low 64% 25 20 25
Mixed conifer (eastside mesic) Replacement 35% 200    
Mixed 47% 150    
Surface or low 18% 400    
Red fir Replacement 20% 400 150 400
Mixed 80% 100 80 130
Spruce-fir Replacement 84% 135 80 270
Mixed 16% 700 285 >1,000
California
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
California Grassland
Wet mountain meadow-Lodgepole pine (subalpine) Replacement 21% 100    
Mixed 10% 200    
Surface or low 69% 30    
California Woodland
California oak woodlands Replacement 8% 120    
Mixed 2% 500    
Surface or low 91% 10    
Ponderosa pine Replacement 5% 200    
Mixed 17% 60    
Surface or low 78% 13    
California Forested
California mixed evergreen Replacement 10% 140 65 700
Mixed 58% 25 10 33
Surface or low 32% 45 7  
Coast redwood Replacement 2% ≥1,000    
Surface or low 98% 20    
Mixed conifer (north slopes) Replacement 5% 250    
Mixed 7% 200    
Surface or low 88% 15 10 40
Mixed conifer (south slopes) Replacement 4% 200    
Mixed 16% 50    
Surface or low 80% 10    
Aspen with conifer Replacement 24% 155 50 300
Mixed 15% 240    
Surface or low 61% 60    
Jeffrey pine Replacement 9% 250    
Mixed 17% 130    
Surface or low 74% 30    
Mixed evergreen-bigcone Douglas-fir (southern coastal) Replacement 29% 250    
Mixed 71% 100    
Interior white fir (northeastern California) Replacement 47% 145    
Mixed 32% 210    
Surface or low 21% 325    
Red fir-white fir Replacement 13% 200 125 500
Mixed 36% 70    
Surface or low 51% 50 15 50
Red fir-western white pine Replacement 16% 250    
Mixed 65% 60 25 80
Surface or low 19% 200    
Sierra Nevada lodgepole pine (cold wet upper montane) Replacement 23% 150 37 764
Mixed 70% 50    
Surface or low 7% 500    
Sierra Nevada lodgepole pine (dry subalpine) Replacement 11% 250 31 500
Mixed 45% 60 31 350
Surface or low 45% 60 9 350
Southwest
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Southwest Grassland
Montane and subalpine grasslands Replacement 55% 18 10 100
Surface or low 45% 22    
Montane and subalpine grasslands with shrubs or trees Replacement 30% 70 10 100
Surface or low 70% 30    
Southwest Shrubland
Southwestern shrub steppe Replacement 72% 14 8 15
Mixed 13% 75 70 80
Surface or low 15% 69 60 100
Southwestern shrub steppe with trees Replacement 52% 17 10 25
Mixed 22% 40 25 50
Surface or low 25% 35 25 100
Low sagebrush shrubland Replacement 100% 125 60 150
Interior Arizona chaparral Replacement 100% 125 60 150
Mountain sagebrush (cool sage) Replacement 75% 100    
Mixed 25% 300    
Gambel oak Replacement 75% 50    
Mixed 25% 150    
Mountain-mahogany shrubland Replacement 73% 75    
Mixed 27% 200    
Southwest Woodland
Mesquite bosques Replacement 32% 135    
Mixed 67% 65    
Madrean oak-conifer woodland Replacement 16% 65 25  
Mixed 8% 140 5  
Surface or low 76% 14 1 20
Pinyon-juniper (mixed fire regime) Replacement 29% 430    
Mixed 65% 192    
Surface or low 6% >1,000    
Pinyon-juniper (rare replacement fire regime) Replacement 76% 526    
Mixed 20% >1,000    
Surface or low 4% >1,000    
Ponderosa pine/grassland (Southwest) Replacement 3% 300    
Surface or low 97% 10    
Bristlecone-limber pine (Southwest) Replacement 67% 500    
Surface or low 33% >1,000    
Southwest Forested
Riparian forest with conifers Replacement 100% 435 300 550
Riparian deciduous woodland Replacement 50% 110 15 200
Mixed 20% 275 25  
Surface or low 30% 180 10  
Ponderosa pine-Gambel oak (southern Rockies and Southwest) Replacement 8% 300    
Surface or low 92% 25 10 30
Ponderosa pine-Douglas-fir (southern Rockies) Replacement 15% 460    
Mixed 43% 160    
Surface or low 43% 160    
Southwest mixed conifer (warm, dry with aspen) Replacement 7% 300    
Mixed 13% 150 80 200
Surface or low 80% 25 2 70
Southwest mixed conifer (cool, moist with aspen) Replacement 29% 200 80 200
Mixed 35% 165 35  
Surface or low 36% 160 10  
Aspen with spruce-fir Replacement 38% 75 40 90
Mixed 38% 75 40  
Surface or low 23% 125 30 250
Stable aspen without conifers Replacement 81% 150 50 300
Surface or low 19% 650 600 >1,000
Lodgepole pine (Central Rocky Mountains, infrequent fire) Replacement 82% 300 250 500
Surface or low 18% >1,000 >1,000 >1,000
Spruce-fir Replacement 96% 210 150  
Mixed 4% >1,000 35 >1,000
Great Basin
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Great Basin Grassland
Mountain meadow (mesic to dry) Replacement 66% 31 15 45
Mixed 34% 59 30 90
Great Basin Shrubland
Basin big sagebrush Replacement 80% 50 10 100
Mixed 20% 200 50 300
Wyoming big sagebrush semidesert Replacement 86% 200 30 200
Mixed 9% >1,000 20 >1,000
Surface or low 5% >1,000 20 >1,000
Wyoming big sagebrush semidesert with trees Replacement 84% 137 30 200
Mixed 11% >1,000 20 >1,000
Surface or low 5% >1,000 20 >1,000
Wyoming sagebrush steppe Replacement 89% 92 30 120
Mixed 11% 714 120  
Mountain big sagebrush Replacement 100% 48 15 100
Mountain big sagebrush with conifers Replacement 100% 49 15 100
Mountain sagebrush (cool sage) Replacement 75% 100    
Mixed 25% 300    
Montane chaparral Replacement 37% 93    
Mixed 63% 54    
Gambel oak Replacement 75% 50    
Mixed 25% 150    
Mountain shrubland with trees Replacement 22% 105 100 200
Mixed 78% 29 25 100
Black and low sagebrushes Replacement 33% 243 100  
Mixed 67% 119 75 140
Black and low sagebrushes with trees Replacement 37% 227 150 290
Mixed 63% 136 50 190
Curlleaf mountain-mahogany Replacement 31% 250 100 500
Mixed 37% 212 50  
Surface or low 31% 250 50  
Great Basin Woodland
Juniper and pinyon-juniper steppe woodland Replacement 20% 333 100 >1,000
Mixed 31% 217 100 >1,000
Surface or low 49% 135 100  
Ponderosa pine Replacement 5% 200    
Mixed 17% 60    
Surface or low 78% 13    
Great Basin Forested
Interior ponderosa pine Replacement 5% 161   800
Mixed 10% 80 50 80
Surface or low 86% 9 8 10
Ponderosa pine-Douglas-fir Replacement 10% 250   >1,000
Mixed 51% 50 50 130
Surface or low 39% 65 15  
Great Basin Douglas-fir (dry) Replacement 12% 90   600
Mixed 14% 76 45  
Surface or low 75% 14 10 50
Aspen with conifer (low to midelevations) Replacement 53% 61 20  
Mixed 24% 137 10  
Surface or low 23% 143 10  
Douglas-fir (warm mesic interior) Replacement 28% 170 80 400
Mixed 72% 65 50 250
Aspen with conifer (high elevations) Replacement 47% 76 40  
Mixed 18% 196 10  
Surface or low 35% 100 10  
Stable aspen-cottonwood, no conifers Replacement 31% 96 50 300
Surface or low 69% 44 20 60
Spruce-fir-pine (subalpine) Replacement 98% 217 75 300
Mixed 2% >1,000    
Aspen with spruce-fir Replacement 38% 75 40 90
Mixed 38% 75 40  
Surface or low 23% 125 30 250
Stable aspen without conifers Replacement 81% 150 50 300
Surface or low 19% 650 600 >1,000
Northern and Central Rockies
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Northern and Central Rockies Grassland
Mountain grassland Replacement 60% 20 10  
Mixed 40% 30    
Northern and Central Rockies Shrubland
Riparian (Wyoming) Mixed 100% 100 25 500
Wyoming big sagebrush Replacement 63% 145 80 240
Mixed 37% 250    
Basin big sagebrush Replacement 60% 100 10 150
Mixed 40% 150    
Low sagebrush shrubland Replacement 100% 125 60 150
Mountain shrub, nonsagebrush Replacement 80% 100 20 150
Mixed 20% 400    
Mountain big sagebrush steppe and shrubland Replacement 100% 70 30 200
Northern and Central Rockies Woodland
Ancient juniper Replacement 100% 750 200 >1,000
Northern and Central Rockies Forested
Ponderosa pine (Northern Great Plains) Replacement 5% 300    
Mixed 20% 75    
Surface or low 75% 20 10 40
Ponderosa pine (Northern and Central Rockies) Replacement 4% 300 100 >1,000
Mixed 19% 60 50 200
Surface or low 77% 15 3 30
Ponderosa pine (Black Hills, low elevation) Replacement 7% 300 200 400
Mixed 21% 100 50 400
Surface or low 71% 30 5 50
Ponderosa pine (Black Hills, high elevation) Replacement 12% 300    
Mixed 18% 200    
Surface or low 71% 50    
Ponderosa pine-Douglas-fir Replacement 10% 250   >1,000
Mixed 51% 50 50 130
Surface or low 39% 65 15  
Western redcedar Replacement 87% 385 75 >1,000
Mixed 13% >1,000 25  
Douglas-fir (xeric interior) Replacement 12% 165 100 300
Mixed 19% 100 30 100
Surface or low 69% 28 15 40
Douglas-fir (warm mesic interior) Replacement 28% 170 80 400
Mixed 72% 65 50 250
Douglas-fir (cold) Replacement 31% 145 75 250
Mixed 69% 65 35 150
Grand fir-Douglas-fir-western larch mix Replacement 29% 150 100 200
Mixed 71% 60 3 75
Mixed conifer-upland western redcedar-western hemlock Replacement 67% 225 150 300
Mixed 33% 450 35 500
Western larch-lodgepole pine-Douglas-fir Replacement 33% 200 50 250
Mixed 67% 100 20 140
Grand fir-lodgepole pine-western larch-Douglas-fir Replacement 31% 220 50 250
Mixed 69% 100 35 150
Persistent lodgepole pine Replacement 89% 450 300 600
Mixed 11% >1,000    
Whitebark pine-lodgepole pine (upper subalpine, Northern and Central Rockies) Replacement 38% 360    
Mixed 62% 225    
Lower subalpine lodgepole pine Replacement 73% 170 50 200
Mixed 27% 450 40 500
Lower subalpine (Wyoming and Central Rockies) Replacement 100% 175 30 300
Upper subalpine spruce-fir (Central Rockies) Replacement 100% 300 100 600
Northern Great Plains
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Northern Plains Grassland
Oak savanna Replacement 7% 44    
Mixed 17% 18    
Surface or low 76% 4    
Northern Plains Woodland
Oak woodland Replacement 2% 450    
Surface or low 98% 7.5    
Northern Great Plains wooded draws and ravines Replacement 38% 45 30 100
Mixed 18% 94    
Surface or low 43% 40 10  
Great Plains floodplain Replacement 100% 500    
Great Lakes
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Great Lakes Grassland
Mosaic of bluestem prairie and oak-hickory Replacement 79% 5 1 8
Mixed 2% 260    
Surface or low 20% 2   33
Great Lakes Woodland
Great Lakes pine barrens Replacement 8% 41 10 80
Mixed 9% 36 10 80
Surface or low 83% 4 1 20
Jack pine-open lands (frequent fire-return interval) Replacement 83% 26 10 100
Mixed 17% 125 10  
Northern oak savanna Replacement 4% 110 50 500
Mixed 9% 50 15 150
Surface or low 87% 5 1 20
Great Lakes Forested
Northern hardwood maple-beech-eastern hemlock Replacement 60% >1,000    
Mixed 40% >1,000    
Conifer lowland (embedded in fire-prone ecosystem) Replacement 45% 120 90 220
Mixed 55% 100    
Conifer lowland (embedded in fire-resistant ecosystem) Replacement 36% 540 220 >1,000
Mixed 64% 300    
Great Lakes floodplain forest Mixed 7% 833    
Surface or low 93% 61    
Great Lakes spruce-fir Replacement 100% 85 50 200
Minnesota spruce-fir (adjacent to Lake Superior and Drift and Lake Plain) Replacement 21% 300    
Surface or low 79% 80    
Great Lakes pine forest, jack pine Replacement 67% 50    
Mixed 23% 143    
Surface or low 10% 333    
Maple-basswood Replacement 33% >1,000    
Surface or low 67% 500    
Maple-basswood mesic hardwood forest (Great Lakes) Replacement 100% >1,000 >1,000 >1,000
Maple-basswood-oak-aspen Replacement 4% 769    
Mixed 7% 476    
Surface or low 89% 35    
Northern hardwood-eastern hemlock forest (Great Lakes) Replacement 99% >1,000    
Oak-hickory Replacement 13% 66 1  
Mixed 11% 77 5  
Surface or low 76% 11 2 25
Pine-oak Replacement 19% 357    
Surface or low 81% 85    
Red pine-eastern white pine (frequent fire) Replacement 38% 56    
Mixed 36% 60    
Surface or low 26% 84    
Red pine-eastern white pine (less frequent fire) Replacement 30% 166    
Mixed 47% 105    
Surface or low 23% 220    
Great Lakes pine forest, eastern white pine-eastern hemlock (frequent fire) Replacement 52% 260    
Mixed 12% >1,000    
Surface or low 35% 385    
Eastern white pine-eastern hemlock Replacement 54% 370    
Mixed 12% >1,000    
Surface or low 34% 588    
Northeast
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Northeast Woodland
Eastern woodland mosaic Replacement 2% 200 100 300
Mixed 9% 40 20 60
Surface or low 89% 4 1 7
Rocky outcrop pine (Northeast) Replacement 16% 128    
Mixed 32% 65    
Surface or low 52% 40    
Pine barrens Replacement 10% 78    
Mixed 25% 32    
Surface or low 65% 12    
Oak-pine (eastern dry-xeric) Replacement 4% 185    
Mixed 7% 110    
Surface or low 90% 8    
Northeast Forested
Northern hardwoods (Northeast) Replacement 39% >1,000    
Mixed 61% 650    
Eastern white pine-northern hardwood Replacement 72% 475    
Surface or low 28% >1,000    
Northern hardwoods-eastern hemlock Replacement 50% >1,000    
Surface or low 50% >1,000    
Northern hardwoods-spruce Replacement 100% >1,000 400 >1,000
Appalachian oak forest (dry-mesic) Replacement 2% 625 500 >1,000
Mixed 6% 250 200 500
Surface or low 92% 15 7 26
Beech-maple Replacement 100% >1,000    
Northeast spruce-fir forest Replacement 100% 265 150 300
Southeastern red spruce-Fraser fir Replacement 100% 500 300 >1,000
South-central US
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
South-central US Grassland
Oak savanna Replacement 3% 100 5 110
Mixed 5% 60 5 250
Surface or low 93% 3 1 4
South-central US Shrubland
Southwestern shrub steppe Replacement 76% 12    
Mixed 24% 37    
Shinnery oak-mixed grass Replacement 96% 7    
Mixed 4% 150    
Shinnery oak-tallgrass Replacement 93% 7    
Mixed 7% 100    
South-central US Woodland
Mesquite savanna Replacement 5% 100    
Mixed 4% 150    
Surface or low 91% 6    
Oak-hickory savanna (East Texas) Replacement 1% 227    
Surface or low 99% 3.2    
Interior Highlands dry oak/bluestem woodland and glade Replacement 16% 25 10 100
Mixed 4% 100 10  
Surface or low 80% 5 2 7
Oak woodland-shrubland-grassland mosaic Replacement 11% 50    
Mixed 56% 10    
Surface or low 33% 17    
Interior Highlands oak-hickory-pine Replacement 3% 150 100 300
Surface or low 97% 4 2 10
South-central US Forested
Interior Highlands dry-mesic forest and woodland Replacement 7% 250 50 300
Mixed 18% 90 20 150
Surface or low 75% 22 5 35
Southern floodplain Replacement 42% 140    
Surface or low 58% 100    
Southern floodplain (rare fire) Replacement 42% >1,000    
Surface or low 58% 714    
Cross Timbers Replacement 3% 170    
Mixed 2% 250    
Surface or low 94% 6    
Southern Appalachians
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Southern Appalachians Woodland
Appalachian shortleaf pine Replacement 4% 125    
Mixed 4% 155    
Surface or low 92% 6    
Table Mountain-pitch pine Replacement 5% 100    
Mixed 3% 160    
Surface or low 92% 5    
Oak-ash woodland Replacement 23% 119    
Mixed 28% 95    
Surface or low 49% 55    
Southern Appalachians Forested
Bottomland hardwood forest Replacement 25% 435 200 >1,000
Mixed 24% 455 150 500
Surface or low 51% 210 50 250
Mixed mesophytic hardwood Replacement 11% 665    
Mixed 10% 715    
Surface or low 79% 90    
Appalachian oak-hickory-pine Replacement 3% 180 30 500
Mixed 8% 65 15 150
Surface or low 89% 6 3 10
Eastern hemlock-eastern white pine-hardwood Replacement 17% >1,000 500 >1,000
Surface or low 83% 210 100 >1,000
Red pine-eastern white pine (frequent fire) Replacement 38% 56    
Mixed 36% 60    
Surface or low 26% 84    
Eastern white pine-northern hardwood Replacement 72% 475    
Surface or low 28% >1,000    
Oak (eastern dry-xeric) Replacement 6% 128 50 100
Mixed 16% 50 20 30
Surface or low 78% 10 1 10
Appalachian Virginia pine Replacement 20% 110 25 125
Mixed 15% 145    
Surface or low 64% 35 10 40
Appalachian oak forest (dry-mesic) Replacement 6% 220    
Mixed 15% 90    
Surface or low 79% 17    
Southern Appalachian high-elevation forest Replacement 59% 525    
Mixed 41% 770    
*Fire Severities—
Replacement: Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants.
Mixed: Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects.
Surface or low: Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area [4,28].

REFERENCES:


1. American Ornithologists' Union. 1957. Checklist of North American birds. 5th ed. Baltimore, MD: The Lord Baltimore Press. 691 p. [21235]
2. American Ornithologists' Union. 2013. The A.O.U. check-list of North American birds, 7th ed., [Online]. American Ornithologists' Union (Producer). Available: http://checklist.aou.org/. [50863]
3. Andersen, David E.; DeStefano, Stephen; Goldstein, Michael I.; Titus, Kimberly; Crocker-Bedford, Cole; Keane, John J.; Anthony, Robert G.; Rosenfield, Robert N. 2005. Technical review of the status of northern goshawks in the western United States. Journal of Raptor Research. 39(3): 192-209. [84132]
4. Barrett, S.; Havlina, D.; Jones, J.; Hann, W.; Frame, C.; Hamilton, D.; Schon, K.; Demeo, T.; Hutter, L.; Menakis, J. 2010. Interagency Fire Regime Condition Class Guidebook. Version 3.0, [Online]. In: Interagency Fire Regime Condition Class (FRCC). U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; The Nature Conservancy (Producers). Available: http://www.frcc.gov/. [85876]
5. Beier, Paul; Drennan, Joseph E. 1997. Forest structure and prey abundance in foraging areas of northern goshawks. Ecological Applications. 7(2): 564-571. [62226]
6. Beier, Paul; Rogan, Erik C.; Ingraldi, Michael F.; Rosenstock, Steven S. 2008. Does forest structure affect reproduction of northern goshawks in ponderosa pine forests? Journal of Applied Ecology. 45: 342-350. [84189]
7. Boal, Clint W.; Andersen, David E.; Kennedy, Patricia L.; Roberson, Aimee M. 2006. Northern goshawk ecology in the western Great Lakes region. Studies in Avian Biology. 31: 126-134. [84224]
8. Bock, Carl E.; Block, William M. 2005. Response of birds to fire in the American Southwest. In: Ralph, C. John; Rich, Terrell D., eds. Bird conservation implementation and integration in the Americas: proceedings of the 3rd international Partners in Flight conference: Vol. 2; 2002 March 20-24; Asilomar, CA. Gen. Tech. Rep. PSW-GTR-191. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 1093-1099. [61162]
9. Bosakowski, Thomas; McCullough, Bruce; Lapsansky, Frank J.; Vaughn, Martin E. 1999. Northern goshawks nesting on a private industrial forest in western Washington. Journal of Raptor Research. 33(3): 240-244. [84254]
10. Boyce, Douglas A., Jr.; Reynolds, Richard T.; Graham, Russell T. 2006. Goshawk status and management: what do we know, what have we done, where are we going? Studies in Avian Biology. 31: 312-325. [84260]
11. Brewer, Lorraine; Erickson, Bruce; Kennedy, Beth; Partyka, Chris; Slaughter, Steve; Wrobleski, Dave. 2008. Effects of silvicultural treatments on old growth characteristics and associated wildlife habitat: Preliminary findings of the Lolo National Forest's 2006-2010 old growth monitoring study. Monitoring Paper. Missoula, MT: U.S. Department of Agriculture, Forest Service, Lolo National Forest. 25 p. [+ appendices]. [82402]
12. Clough, Lorraine T. 2000. Nesting habitat selection and productivity of northern goshawks in west-central Montana. Missoula, MT: University of Montana. 87 p. Thesis. [84583]
13. Converse, Sarah J.; Block, William M.; White, Gary C. 2006. Small mammal population and habitat responses to forest thinning and prescribed fire. Forest Ecology and Management. 228(1-3): 263-273. [62635]
14. Converse, Sarah J.; White, Gary C.; Farris, Kerry L.; Zack, Steve. 2006. Small mammals and forest fuel reduction: national-scale responses to fire and fire surrogates. Ecological Applications. 16(5): 1717-1729. [65278]
15. DeStefano, Stephen. 2005. A review of the status and distribution of northern goshawks in New England. Journal of Raptor Research. 39(3): 324-332. [84390]
16. DeStefano, Stephen; Daw, Sonya K.; Desimone, Steven M.; Meslow, E. Charles. 1994. Density and productivity of northern goshawks: implications for monitoring and management. Studies in Avian Biology. 16: 88-91. [84221]
17. DeStefano, Stephen; McGrath, Michael T.; Daw, Sonya K.; Desimone, Steven M. 2006. Ecology and habitat of breeding northern goshawks in the inland Pacific Northwest: a summary of research in the 1990s. Studies in Avian Biology. 31: 75-84. [84387]
18. Dietrich, Phillip J.; Woodbridge, Brian. 1994. Territory fidelity, mate fidelity, and movements of color-marked northern goshawks in the southern Cascades of California. Studies in Avian Biology. 16: 130-132. [84220]
19. Dodd, Norris L. 1988. Fire management and southwestern raptors. In: Glinski, Richard L.; Pendleton, Beth Giron; Moss, Mary Beth; LeFranc, M. N., Jr.; Millsap, B. A.; Hoffman, S. W., eds. Proceedings of the southwest raptor management symposium and workshop; 1986 May 21-24; Tucson, AZ. NWF Scientific and Technical Series No. 11. Washington, DC: National Wildlife Federation: 341-347. [22648]
20. Engstrom, R. Todd. 2010. First-order fire effects on animals: review and recommendations. Fire Ecology. 6(1): 115-130. [82000]
21. Fites, Jo Ann; Campbell, Mike; Reiner, Alicia; Decker, Todd. 2007. Fire behavior and effects relating to suppression, fuel treatments, and protected areas on the Antelope Complex Wheeler Fire. Sacramento, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Region. 41 p. [74740]
22. Good, Rhett E. 1998. Factors affecting the relative use of northern goshawk (Accipiter gentilis) kill areas in southcentral Wyoming. Laramie, WY: University of Wyoming. 153 p. Thesis. [84092]
23. Graham, Russell T; Jain, Theresa B.; Reynolds, Richard T.; Boyce, Douglas A. 1997. The role of fire in sustaining northern goshawk habitat in Rocky Mountain forests. In: Greenlee, Jason M., ed. Proceedings, 1st conference on fire effects on rare and endangered species and habitats; 1995 November 13-16; Coeur d'Alene, ID. Fairfield, WA: International Association of Wildland Fire: 69-76. [28124]
24. Greenwald, D. Noah; Crocker-Bedford, D. Coleman; Broberg, Len; Suckling, Kieran; Tibbitts, Timothy. 2005. A review of northern goshawk habitat selection in the home range and implications for forest management in the western United States. Wildlife Society Bulletin. 33(1): 120-129. [84508]
25. Hargis, C. D., C. McCarthy, and R. D. Perloff. 1994. Home ranges and habitats of northern goshawks in eastern California. Studies in Avian Biology. 16: 66-74. [84191]
26. Kennedy, Patricia L. 2003. Northern goshawk (Accipiter gentiles atricapillus): a technical conservation assessment, [Online]. Golden, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Region (Producer). 142 p. Available: http://www.fs.fed.us/r2/projects/scp/assessments/northerngoshawk.pdf [2012, February 9]. [84509]
27. Kirkley, Jack. 2012. [Email to Kate Stone]. July 5. Regarding northern goshawk responses to fire and fuels treatments. Dillon, MT: University of Montana--Western, Biology Department. On file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT; FEIS files. [86301]
28. LANDFIRE Rapid Assessment. 2005. Reference condition modeling manual (Version 2.1), [Online]. In: LANDFIRE. Cooperative Agreement 04-CA-11132543-189. Boulder, CO: The Nature Conservancy; U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior (Producers). 72 p. Available: http://www.landfire.gov/downloadfile.php?file=RA_Modeling_Manual_v2_1.pdf [2007, May 24]. [66741]
29. LANDFIRE Rapid Assessment. 2007. Rapid assessment reference condition models, [Online]. In: LANDFIRE. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: http://www.landfire.gov/models_EW.php [2008, April 18] [66533]
30. Lehman, Robert N.; Allendorf, John W. 1989. The effects of fire, fire exclusion and fire management on raptor habitats in the western United States. In: Pendleton, B. G., ed. Proceedings of the western raptor management symposium and workshop; 1987 October 26-28; Boise, ID. Scientific and Technical Series No. 12. Washington, DC: National Wildlife Federation: 236-244. [22324]
31. Lockman, Dave. 2012. [Email to Kate Stone]. November 1. Regarding northern goshawk response to fire and fuels treatment. Hamilton, MT: U.S. Department of Agriculture, Forest Service, Bitterroot National Forest, North Zone Biologist. On file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT; FEIS files. [86300]
32. Long, James N.; Smith, Frederick W. 2000. Restructuring the forest: Goshawks and the restoring of southwestern ponderosa pine. Journal of Forestry. 98(8): 25-30. [38866]
33. Mahon, Todd; Doyle, Frank I. 2005. Effects of timber harvesting near nest sites on the reproductive success of northern goshawks (Accipiter gentilis). Journal of Raptor Research. 39(3): 335-341. [84979]
34. NatureServe. 2013. NatureServe Explorer: An online encyclopedia of life, [Online]. Version 7.1. Arlington, VA: NatureServe (Producer). Available http://www.natureserve.org/explorer. [69873]
35. North, Malcolm; Stine, Pete; Zielinski, William; O'Hara, Kevin; Stephens, Scott. 2010. Harnessing fire for wildlife. The Wildlife Professional. 4(1): 30-33. [81864]
36. Paragi, Thomas F.; Johnson, W. N.; Katnik, Donald D.; Magoun, Audrey J. 1996. Marten selection of postfire seres in the Alaskan taiga. Canadian Journal of Zoology. 74: 2226-2237. [28567]
37. Patton, David R.; Gordon, Janet. 1995. Fire, habitats, and wildlife. Final report. Flagstaff, AZ: U.S. Department of Agriculture, Forest Service, Coconino National Forest. 85 p. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. [61019]
38. Pope, Theresa L. 2006. Effects of prescribed fire on wintering bark-foraging birds in northern Arizona. Flagstaff, AZ: Northern Arizona University. 70 p. Thesis. [73498]
39. Pope, Theresa L.; Block, William M. 2010. Effects of prescribed fire on winter assemblages of birds in pondersa pine forests of northern Arizona. The Southwestern Naturalist. 55(1): 22-28. [80632]
40. Reynolds, Richard T.; Graham, Russel T.; Reiser, M. Hildegard; Bassett, Richard L.; Kennedy, Patricia L.; Boyce, Douglas A., Jr.; Goodwin, Greg; Smith, Randall; Fisher, E. Leon. 1992. Management recommendations for the northern goshawk in the southwestern United States. Gen. Tech. Rep. RM-217. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 90 p. [27983]
41. Reynolds, Richard T.; Joy, Suzanne M.; Leslie, Douglas G. 1994. Nest productivity, fidelity, and spacing of northern goshawks in Arizona. Studies in Avian Biology. 16: 106-113. [84222]
42. Rickman, Tom H.; Jones, Bobette E.; Cluck, Danny R.; Richter, David J.; Tate, Kenneth W. 2005. Night roost habitat of radiotagged northern goshawks on Lassen National Forest, California. Journal of Wildlife Management. 69(4): 1737-1742. [84981]
43. Roberson, Aimee M.; Andersen, David E.; Kennedy, Patricia L. 2003. The northern goshawk (Accipiter gentilis) in the western Great Lakes region: a technical conservation assessment. St. Paul, MN: University of Minnesota, Minnesota Cooperative Fish & Wildlife Research Unit. 91 p. [84982]
44. Roppe, Jerry A.; Hein, Dale. 1978. Effects of fire on wildlife in a lodgepole pine forest. The Southwestern Naturalist. 23(2): 279-287. [261]
45. Saab, Victoria; Block, William; Russell, Robin; Lehmkuhl, John; Bate, Lisa; White, Rachel. 2007. Birds and burns of the interior West: descriptions, habitats, and management in western forests. Gen. Tech. Rep. PNW-GTR-712. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 23 p. [69754]
46. Salafsky, Susan Rebecca. 2004. Covariation between prey abundance and northern goshawk fecundity on the Kaibab Plateau, Arizona. Fort Collins, CO: Colorado State University. 39 p. Thesis. [61352]
47. Shepperd, Wayne D.; Battaglia, Michael A. 2002. Ecology, silviculture, and management of Black Hills ponderosa pine. Gen. Tech. Rep. RMRS-GTR-97. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 112 p. [44794]
48. Squires, John R.; Reynolds, Richard T. 1997. Northern goshawk (Accipiter gentilis), [Online]. Issue No. 298. In: Poole, A., ed. The birds of North America Online. Ithaca, NY: Cornell Lab of Ornithology (Producer). Available: http://bna.birds.cornell.edu/bna/species/298 [2012, November 30]. [84032]
49. Tiedemann, Arthur R.; Klemmedson, James O.; Bull, Evelyn L. 2000. Solution of forest health problems with prescribed fire: are forest productivity and wildlife at risk? Forest Ecology and Management. 127(1-3): 1-18. [36435]
50. U.S. Department of the Interior, Fish and Wildlife Service, Division of Endangered Species. 2013. Threatened and endangered animals and plants, [Online]. Available: http://ecos.fws.gov/tess_public/pub/listedAnimals.jsp. [62042]
51. Woodbridge, Brian; Detrich, Phillip J. 1994. Territory occupancy and habitat patch size of northern goshawks in the southern Cascades of California. Studies in Avian Biology. 16: 83-87. [84190]
52. Younk, James V.; Bechard, Marc J. 1994. Breeding ecology of the northern goshawk in high-elevation aspen forests of northern Nevada. Studies in Avian Biology. 16: 119-121. [84223]
53. Youtz, James A.; Graham, Russell T.; Reynolds, Richard T.; Simon, Jerry. 2007. Implementing northern goshawk habitat management in southwestern forests: a template for restoring fire-adapted forest ecosystems. In: Deal, R. L., ed. Proceedings of the 2007 national silviculture workshop. Gen. Tech. Rep. PNW-GTR-733. Portland, OR: U.S. Department of Agriculture, Forest Service, Northern Research Station: 173-191. [73716]

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