Index of Species Information
WILDLIFE SPECIES: Buteo swainsoni
Introductory
WILDLIFE SPECIES: Buteo swainsoni
AUTHORSHIP AND CITATION :
Tesky, Julie L. 1994. Buteo swainsoni. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: www.fs.usda.gov/database/feis/animals/bird/busw/all.html [].
ABBREVIATION :
BUSW
COMMON NAMES :
Swainson's hawk
TAXONOMY :
The currently accepted scientific name for the Swainson's hawk is Buteo
swainsoni Bonaparte [1]. There are no recognized subspecies or races.
ORDER :
Falconiformes
CLASS :
Bird
FEDERAL LEGAL STATUS :
Not listed [43]
OTHER STATUS :
Information on state-level protected status of animals in the
United States and Canada is available at NatureServe.
WILDLIFE DISTRIBUTION AND OCCURRENCE
WILDLIFE SPECIES: Buteo swainsoni
GENERAL DISTRIBUTION :
The breeding range of the Swainson's hawk is restricted primarily to
western North America from interior Alaska and western Canada south
into northern Mexico [12,21]. The Swainson's hawk winters primarily on
the pampas of southern South America, irregularly north to Costa Rica
and Panama, and sometimes north to the southwestern United States and
southern Florida [1,12,21]. During migration the Swainson's hawk occurs
regularly in most of the central states and Canadian provinces, and
rarely, east along the Gulf Coast to Florida. It is occasionally a fall
migrant through the Florida Keys. The Swainson's hawk is occasionally
found in northeastern North America from southern Ontario, southern
Quebec, New York, and Massachusetts south to Virginia [1].
ECOSYSTEMS :
FRES28 Western hardwoods
FRES29 Sagebrush
FRES30 Desert shrub
FRES31 Shinnery
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES35 Pinyon-juniper
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES39 Prairie
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
STATES :
| AK |
AZ |
CA |
CO |
CT |
DE |
FL |
ID |
IL |
| IA |
KS |
LA |
MD |
MA |
MT |
NE |
NV |
NH |
| NJ |
NM |
NY |
ND |
OH |
OK |
OR |
PA |
RI |
| SD |
TN |
TX |
UT |
VA |
WA |
WY |
BLM PHYSIOGRAPHIC REGIONS :
1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS :
K023 Juniper - pinyon woodland
K024 Juniper steppe woodland
K026 Oregon oakwoods
K027 Mesquite bosque
K030 California oakwoods
K031 Oak - juniper woodlands
K032 Transition between K031 and K037
K033 Chaparral
K034 Montane chaparral
K035 Coastal sagebrush
K037 Mountain-mahogany - oak scrub
K038 Great Basin sagebrush
K039 Blackbrush
K040 Saltbush - greasewood
K041 Creosotebush
K042 Creosotebush - bursage
K043 Paloverde - cactus shrub
K044 Creosotebush - tarbush
K045 Ceniza shrub
K047 Fescue - oatgrass
K048 California steppe
K050 Fescue - wheatgrass
K051 Wheatgrass - bluegrass
K053 Grama - galleta steppe
K054 Grama - tobosa prairie
K055 Sagebrush steppe
K056 Wheatgrass - needlegrass shrubsteppe
K057 Galleta - three-awn shrubsteppe
K058 Grama - tobosa shrubsteppe
K059 Trans-Pecos shrub savanna
K060 Mesquite savanna
K061 Mesquite - acacia savanna
K062 Mesquite - live oak savanna
K063 Foothills prairie
K064 Grama - needlegrass - wheatgrass
K065 Grama - buffalograss
K066 Wheatgrass - needlegrass
K067 Wheatgrass - bluestem - needlegrass
K068 Wheatgrass - grama - buffalograss
K069 Bluestem - grama prairie
K070 Sandsage - bluestem prairie
K071 Shinnery
K072 Sea oats prairie
K074 Bluestem prairie
K075 Nebraska Sandhills prairie
K076 Blackland prairie
K077 Bluestem - sacahuista prairie
K083 Cedar glades
K085 Mesquite - buffalograss
K086 Juniper - oak savanna
K087 Mesquite - oak savanna
K088 Fayette prairie
SAF COVER TYPES :
66 Ashe juniper - redberry (Pinchot) juniper
67 Mohrs (shin) oak
68 Mesquite
203 Balsam poplar
217 Aspen
220 Rocky Mountain juniper
221 Red alder
222 Black cottonwood - willow
233 Oregon white oak
235 Cottonwood - willow
236 Bur oak
238 Western juniper
239 Pinyon - juniper
240 Arizona cypress
241 Western live oak
242 Mesquite
246 California black oak
249 Canyon live oak
250 Blue oak - gray pine
252 Paper birch
255 California coast live oak
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
PLANT COMMUNITIES :
The Swainson's hawk breeds in open grasslands, sagebrush (Artemisia
spp.), shrub-steppe, oak (Quercus spp.) woodlands, open pine (Pinus
spp.)-oak woodlands, pinyon-juniper (Pinus spp.-Juniperus spp.)
woodlands, and cultivated lands [1,3,6,16,40]. In California the
Swainson's hawk favors open blue oak (Quercus douglasii) savannahs and
gray pine (Pinus sabiniana)-oak woodlands [35]. In the Central Valley
of California, populations of Swainson's hawks frequently nest and roost
in riparian communities dominated by valley oak (Quercus lobata),
cottonwoods (Populus spp.), California sycamore (Platanus racemosa), and
willows (Salix spp.) [22,33]. Foraging habitat for Swainson's hawks in
California includes native grassland communities of oat (Avena spp.),
brome grass (Bromus spp.), ryegrass (Elymus spp. and Lolium spp.), and
barley (Critesion spp.) [33]. West of Laramie, Wyoming, Dunkle [15]
reported that breeding habitat of the Swainson's hawk included irrigated
sedge meadows, shortgrass plains with some sagebrush, and black
greasewood (Sarcobatus vermiculatus) [15].
In the Great Basin, the Swainson's hawk is often found nesting in
juniper-sagebrush and prairie habitats [33]. In Arizona, the Swainson's
hawk generally occurs in sparse semidesert grasslands, plains
grasslands, Great Basin grasslands, and Chihuahuan Desert scrub often
mixed with a few species of shrubs including yucca (Yucca spp.),
creosotebush (Larrea tridentata), mesquite (Prosopis spp.), and fourwing
saltbrush (Atriplex canescens). In New Mexico and Texas, breeding
Swainson's hawk occur in various types of grasslands including
grasslands with sand shinnery oak (Q. havardii), and are occasionally
found in Chihuahuan Desert scrub. In Oklahoma, Swainson's hawk breed
primarily in grasslands [6].
The Swainson's hawk sometimes nests in intensively cultivated areas
[4,5,20]. Of the large raptors breeding in northern Colorado, only the
Swainson's hawk regularly nested near cultivated lands [20].
BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Buteo swainsoni
TIMING OF MAJOR LIFE HISTORY EVENTS :
Age at sexual maturity - Swainson's hawk are generally sexually mature
at 2 years of age [31].
Nesting season - The Swainson's hawk arrives on its breeding grounds
later than most raptors [31]. The nesting season generally occurs from
March to October depending on geographic area [14,21,35]. In
California, the Swainson's hawk breeds from late March to mid-August,
with peak activity from late May to late July. In Nevada, it breeds
from April to October [21]. In Montana, the breeding season is from May
to September [14].
Clutch size and incubation - The Swainson's hawk lays two to four eggs,
with two most common [14,21,31,35]. The eggs are incubated for 28 to 35
days [14,21,31]. The Swainson's hawk may lay a replacement clutch if
the first clutch is destroyed [31].
Fledging - Nestlings fledge in 35 to 44 days [21,31]. Fledglings
continue to be fed by the adults and remain within the nesting territory
for 14 to 21 days after fledging; they often return to the nest tree to
roost [21].
Migration - The Swainson's hawk travels in large flocks (sometimes
containing over 100 individuals) from the nesting areas south to their
winter grounds in South America [6,21,31].
Peak fall migration clears the southern plains states and southern Texas
by early October. The Swainson's hawk arrives in Central America the
last 3 weeks of October to early November; arrival in Argentina is
reported as late November. Average dates for spring migration of the
Swainson's hawk are mid-March in Panama, the last 3 week of March in
Costa Rica, the last half of March and first week of April in the state
of Veracruz, Mexico, and early April in southern Texas [31].
Longevity - The Swainson's hawk probably seldom lives longer than 16
years [31].
PREFERRED HABITAT :
The Swainson's hawk inhabits mostly semiopen to open areas in tundra,
valleys, plains, dry meadows, foothills, and level uplands at low to
middle elevations [1,31,40].
Nesting habitat - The Swainson's hawk nests almost exclusively in trees
[37] and will nest in almost any tree species of suitable size (taller
than 10 feet [3 m] with a d.b.h. of 2 inches [5 cm] or more) [6,7].
Nests are constructed in isolated trees (dead or live), in trees in
wetlands and along drainages, or in windbreaks in fields and around
farmsteads [6,12,31]. The Swainson's hawk builds nests from 4 to 100
feet (1.2-30.4 m) above the ground [12,14,35]. They sometimes add to an
existing black-billed magpie (Pica pica) nest [31]. The Swainson's hawk
occasionally nests in shrubs, on the crossbars of telephone poles, or on
the ground, low cliffs, rocky pinnacles, or cutbanks [6,12,31].
In the Central Valley of California, the majority of Swainson's hawk
nests and territories are located in or near riparian systems. Nests
are found most often in cottonwoods and oaks [33]. In Whitman County,
Washington, Swainson's hawk nests were constructed in black locust
(Robinia pseudoacacia), cherry (Prunus spp.) and hawthorn (Crataegus
spp.) trees [5]. Of 48 Swainson's hawk nests on the Laramie Plains,
Wyoming, 43 were in narrowleaf cottonwood (Populus angustifolia),
peachleaf willow (Salix amygdaloides), or other willows. None of the
few buttes in the area were used for nesting [15]. In the Centennial
Valley of Montana, Swainson's hawks nest extensively in willows [32].
At 234 Swainson's hawk nest sites in North Dakota, eastern cottonwood
(Populus deltoides) was the most common tree species used (45%). Other
species included Chinese elm (Ulmus parvifolia), 22 percent; peachleaf
willow, 13 percent; boxelder (Acer negundo), 12 percent; and green ash
(Fraxinus pennsylvanica), 7 percent. American elm (U. americana) and
Russian olive (Elaeagnus angustifolia) accounted for the remaining 1
percent [20]. In the Lower Sonoran Desert of New Mexico, the Swainson's
hawk often nests and roosts on large yucca plants [30]. In the
southwestern United States, mesquite is commonly used [6].
Foraging habitat - The Swainson's hawk generally forages in open
habitats with short vegetation containing small mammals, reptiles,
birds, and insects [6,40,38]. During the nesting season the Swainson's
hawk usually forages within 1.9 miles (3 km) of the nest. The
Swainson's hawk has a home range of approximately 3.5 square miles (9 sq
km) [40]. Although the Swainson's hawk does search for prey from
elevated perches, it relies much more on aerial foraging. Consequently,
it is not tied to habitats containing an abundance of perches, and often
occupy habitats with few or no perches except the nest tree [23].
Winter habitat - The Swainson's hawk generally spends the winter south
of the United States [1,12,31]; no information is available in the
English literature on its habitat in Central and South America.
COVER REQUIREMENTS :
Swainson's hawk nests are often built in trees that provide shade for
the nest but also afford a good view of the surrounding terrain [33].
The Swainson's hawk is a more efficient predator in open areas than in
areas with high vegetative cover [5]. Bechard [5] found that vegetative
cover is more important than prey abundance in the selection of hunting
sites by the Swainson's hawk. In Whitman County, Washington, the
Swainson's hawk foraged at sites where vegetative height and density had
been reduced, even though other areas had higher prey density [5].
Alfalfa field use by Swainson's hawk in northern California increased
dramatically during monthly harvests that reduced vegetative heights
[38].
FOOD HABITS :
The Swainson's hawk is a versatile and opportunistic predator on
relatively small prey [6]. The Swainson's hawk feeds on small mammals,
large insects, birds, and reptiles [9,14,31,35]. During the breeding
season, the Swainson's hawk primarily preys on small mammals, especially
young ground squirrels (Spermophilus spp.), pocket gophers (Thomomys
spp.), and some microtines [15,20,31,32]. During migration
invertebrates often make up over 90 percent of the Swainson's hawk's
diet [31].
In a North Dakota study, Swainson's hawks preyed primarily on northern
pocket gopher (Thomomys talpoides), Richardson's ground squirrel
(Spermophilus richardsonii), meadow vole (Microtus pennsylvanicus), and
thirteen-lined ground squirrel (S. tridecemlineatus) [20]. To a lesser
extent Swainson's hawks also ate western meadow lark (Sturnella
neglecta), chestnut-collared longspur (Calcarius ornatus), sharp-tailed
grouse (Tympanuchus phasianellus), short-eared owl (Asio flammeus),
American kestrel (Falco sparverius), blue jay (Cyanocitta cristata),
and rock dove (Columba livia) [20]. Toads (Bufo spp.) and various
lizards, mostly desert grassland whiptail (Cnemidophorous uniparens)
and spiny lizards (Sceloporus spp.), were commonly taken by nesting
Swainson's hawk in Arizona. Mammals, particularly cottontails
(Sylvilagus spp.), ground squirrels, and kangaroo rats (Dipodomys spp.),
were the most common food items brought to Swainson's hawk nestlings in
New Mexico [6]. Rabbits comprised between 40 and 80 percent of the diet
of Swainson's hawk nestlings in New Mexico [7].
PREDATORS :
Large raptors including great horned owl (Buteo virginianus) and golden
eagle (Aquila chrysaetos), and coyote (Canis latrans), bobcat (Lynx
rufus), and striped skunk (Mephitis mephitis) have been known to kill
Swainson's hawk nestlings and fledglings or destroy clutches
[7,11,15,31,38]. Crows (Corvus spp.) sometimes destroy clutches
[15,31].
MANAGEMENT CONSIDERATIONS :
Swainson's hawk populations have declined over much of their breeding
range due to habitat loss from cultivation, removal of riparian areas,
and removal of shelterbelts [14,31]. Nest site availability may limit
occurrence and breeding density of Swainson's hawk [6]. Schmutz and
others [34] reported that the nesting density of the Swainson's hawk
increased significantly following the erection of 98 artificial nest
platforms in an experimental study plot. When roads, pipelines, or
other surface facilities are constructed, trees taller than 10 feet (3
m) with a d.b.h. of 2 inches (5 cm) or more should be conserved. If
destruction of potential nest trees cannot be avoided, they should be
replaced with artificial nest platforms [7]. Within treeless expanses,
constructing artificial nest platforms or planting trees may also benefit
Swainson's hawk populations [6]. Additionally, establishing and
enhancing small wooded areas in the nesting habitat, and protecting
habitat used by the prey base, may benefit the Swainson's hawk [10,39].
The Swainson's hawk is more tolerant of human disturbance than other
hawks and will often nest close to occupied houses [7,14]. However,
intensive human activity in a small area near an active Swainson's hawk
nest would likely result in nest abandonment and breeding failure at
that site [7].
Swainson's hawk is sometimes eaten by people in South America. Large
numbers are taken from communal roosting areas and killed. This
activity could have a significant effect on populations that nest in
North America [21]. Additionally, the use of biocides in North,
Central, and South America may have an effect on Swainson's hawk
populations. The Swainson's hawk may accumulate high pesticide levels
via food-chain concentration [31].
FIRE EFFECTS AND USE
WILDLIFE SPECIES: Buteo swainsoni
DIRECT FIRE EFFECTS ON ANIMALS :
Fire directly reduces Swainson's hawk reproductive success if the fire
crowns in occupied nest trees [25]. Fires that kill or otherwise alter
unoccupied nest trees may disrupt reproduction if acceptable nest trees
are scarce. The Swainson's hawk arrives on breeding grounds
comparatively late and so must establish or reestablish a nest site
among earlier migrant and resident raptors [31]. Low-severity fires
probably have little direct effect on Swainson's hawks. Landers [25]
commented that light winter burning probably does no substantial harm to
raptors.
HABITAT RELATED FIRE EFFECTS :
The Swainson's hawk occurs in the following four major fire-dependent
plant associations in the western United States: grassland, semidesert
grass-shrub, sagebrush grass, and pinyon-juniper [26].
Although fire may reduce potential nest trees, it may enhance the
foraging habitat of Swainson's hawks. Fires that reduce vegetation
height and create open areas probably increase hunting efficiency by
Swainson's hawks. Open-habitat raptors such as the Swainson's hawk use
scattered patches of woody vegetation near open foraging areas for
nesting and perching. However, where extensive invasion of woody
species has occurred, Swainson's hawk foraging habitat may be reduced.
The Swainson's hawk is favored by fires that reduce pinyon-juniper
woodlands [26]. Raptors associated with pinyon-juniper woodlands depend
upon edges of openings created by fire and scattered islands of unburned
woodlands [13]. Fire suppression in pinyon-juniper habitats of the
Great Basin of California may have reduced suitable Swainson's hawk
habitat in this area [26].
Regular burning helps to maintain habitat for many prey species of
Swainson's hawk [13,25]. Several studies indicate that many prey
populations increase rapidly subsequent to burning in response to
increased food availability [13]. Fire suppression in grasslands was
detrimental to small bird and mammal populations due to organic matter
accumulation and reduced plant vigor [36]. The Swainson's hawk has been
observed hunting on recently burned areas in Colorado county, Texas [2].
On the Bridger Teton National Forest, Swainson's hawks were more
commonly observed using a high-severity fall burn than a low-severity
spring burn in the same area [27].
FIRE USE :
Prescribed fire can be beneficial to Swainson's hawk populations by
enhancing habitat and increasing the prey base [13,25]. Burning in
grasslands where scattered trees are retained benefits Swainson's hawk
populations, particularly in areas where nesting sites are limited.
Prescribed burning plans should strive for creation of maximum
interspersion of openings and edge, with high vegetative diversity.
Habitats should be maintained in a random mosaic. In most cases,
burning plans must be integrated with proper range management.
Reseeding of perennial grasses as well as rest from livestock grazing
may be necessary to achieve desired goals. Burning should be deferred
until nesting is completed in areas where impact to breeding Swainson's
hawk may occur [13].
An extensive body of research has been published on fire effects on animals
in semidesert grassland, oak savanna, and Madrean oak woodlands of southeastern
Arizona, including the response of Swainson's hawk to fire. See the
Research Project Summary of this work for more information on
Swainson's hawk and more than 100 additional species of birds, small
mammals, grasshoppers, and herbaceous and woody plant species.
FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find Fire Regimes".
REFERENCES
WILDLIFE SPECIES: Buteo swainsoni
REFERENCES :
1. American Ornithologists' Union. 1983. Checklist of North American birds.
6th ed. Lawrence, KS: Allen Press, Inc. 877 p. [21234]
2. Baker, R. H. 1940. Effects of burning and grazing on rodent populations.
Journal of Mammalogy. 21: 223. [2849]
3. Balda, Russell P.; Masters, Nancy. 1980. Avian communities in the
pinyon-juniper woodland: a descriptive analysis. In: DeGraaf, Richard
M., technical coordinator. Management of western forests and grasslands
for nongame birds: Workshop proceedings; 1980 February 11-14; Salt Lake
City, UT. Gen. Tech. Rep. INT-86. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Forest and Range Experiment
Station: 146-169. [17903]
4. Bechard, M. J. 1980. Factors affecting the productivity of Swainson's
hawk nesting in southeastern Washington. Pullman, WA: Washington State
University. [Pages unknown]. Dissertation. [25334]
5. Bechard, Marc J. 1982. Effect of vegetative cover on foraging site
selection by Swainson's hawk. Condor. 84(2): 153-159. [22656]
6. Bednarz, James C. 1988. Swainson's hawk. In: Glinski, Richard L.;
Pendleton, Beth Giron; Moss, Mary Beth; [and others], 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: 87-96. [22650]
7. Bednarz, James C.; Hoffman, Stephen W. 1988. The status of breeding
Swainson's hawks in southeastern New Mexico. In: Glinski, Richard L.;
Pendleton, Beth Giron; Moss, Mary Beth; [and others], 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: 253-259. [22651]
8. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals,
reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's
associations for the eleven western states. Tech. Note 301. Denver, CO:
U.S. Department of the Interior, Bureau of Land Management. 169 p.
[434]
9. Burleigh, Thomas D. 1950. "Give Idaho hawks a break" biologist asks
nimrods; some species helpful to wildlife. Idaho Wildlife Review.
February: 6-7. [21497]
10. Call, Mayo. 1979. Habitat management guides for birds of prey. Techical
Note 338. Denver, CO: U.S. Department of the Interior, Bureau of Land
Management, Denver Service Center. 70 p. [22451]
11. Cowart, Linda. 1975. The desert hunters. Pacific Discovery. 28(1): 5-9.
[22655]
12. DeGraaf, Richard M.; Scott, Virgil E.; Hamre, R. H.; [and others]. 1991.
Forest and rangeland birds of the United States: Natural history and
habitat use. Agric. Handb. 688. Washington, DC: U.S. Department of
Agriculture, Forest Service. 625 p. [15856]
13. Dodd, Norris L. 1988. Fire management and southwestern raptors. In:
Gliski, R. L.; Pendleton, Beth Giron; Moss, Mary Beth; [and others],
eds. Proceedings of the southwest raptor symposium and workshop; 1986
May 21-24; Tucson, AZ. NWF Scientific and Technology Series No. 11.
Washington, DC: National Wildlife Federation: 341-347. [22648]
14. DuBois, Kristi; Becker, Dale; Thornbrugh, Joe. 1987. Identification of
Montana's birds of prey. Montana Outdoors. 18(6): 11-31. [3606]
15. Dunkle, Sidney W. 1977. Swainson's hawks on the Laramie Plains, Wyoming.
Auk. 94: 65-71. [22654]
16. Emmerich, John M.; Vohs, Paul A. 1982. Comparative use of four woodland
habitats by birds. Journal of Wildlife Management. 46(1): 43-49.
[19283]
17. Estep, J. A. 1989. Biology, movements, and habitat relationships of the
Swainson's hawk in the Central Valley of California. Sacramento, CA:
California Department of Fish and Game. 70 p. [23124]
18. Eyre, F. H., ed. 1980. Forest cover types of the United States and
Canada. Washington, DC: Society of American Foresters. 148 p. [905]
19. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others].
1977. Vegetation and environmental features of forest and range
ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of
Agriculture, Forest Service. 68 p. [998]
20. Gilmer, David S.; Stewart, Robert E. 1984. Swainson's hawk nesting
ecology in North Dakota. Condor. 86: 12-18. [22653]
21. Herron, Gary B.; Mortimore, Craig A.; Rawlings, Marcus S. 1985.
Red-tailed hawk. In: Nevada raptors: Their biology and management.
Biological Bulletin No. 8. Reno, NV: Nevada Department of Wildlife:
29-30. [22694]
22. Holland, Robert F.; Roye, Cynthia L. 1989. Great Valley riparian
habitats and the National Registry of Natural Landmarks. In: Abell, Dana
L., technical coordinator. Proceedings of the California riparian
systems conference: Protection, management, and restoration for the
1990's; 1988 September 22-24; Davis, CA. Gen. Tech. Rep. PSW-110.
Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific
Southwest Forest and Range Experiment Station: 69-73. [13511]
23. James, Paul C. 1992. Urban-nesting of Swainson's hawks in Saskatchewan.
Condor. 94: 773-774. [23120]
24. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation
of the conterminous United States. Special Publication No. 36. New York:
American Geographical Society. 77 p. [1384]
25. Landers, J. Larry. 1987. Prescribed burning for managing wildlife in
southeastern pine forests. In: Dickson, James G.; Maughan, O. Eugene,
eds. Managing southern forests for wildlife and fish: a proceedings;
[Date of conference unknown]; [Location of conference unknown]. Gen.
Tech. Rep. SO-65. New Orleans, LA: U.S. Department of Agriculture,
Forest Service, Southern Forest Experiment Station: 19-27. [11562]
26. 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: 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]
27. McGee, John Michael. 1976. Some effects of fire suppression and
prescribed burning on birds and small mammals in sagebrush. Laramie, WY:
University of Wyoming. 114 p. Dissertation. [16998]
28. Montana Natural Heritage Program. 1990. Animal species of special
concern. Helena, MT: Montana Natural Heritage Program. 5 p. [13751]
29. Moseley, Robert; Groves, Craig, compilers. 1990. Rare, threatened and
endangered plants and animals of Idaho. Boise, ID: Idaho Department of
Fish and Game, Nongame and Endangered Wildlife Program, Natural Heritage
Section. 33 p. [19328]
30. Olendorff, Richard R.; Kochert Michael N. 1977. Land management for the
conservation of birds of prey. In: Chancellor, R. D., ed. World
conference on birds of prey; Report of proceedings; [Date unknown];
[Location unknown]. [Place of publication unknown]: International
Council on Bird Preservation: 294-307. On file with: U.S. Department of
Agriculture, Forest Service, Intermountain Research Station, Fire
Sciences Laboratory, Missoula, MT. [22699]
31. Palmer, Ralph S., editor. 1988. Handbook of North American birds. Volume
5. New Haven, CT: Yale University Press. 463 p. [22303]
32. Restani, Marco. 1991. Resource partitioning among three Buteo species in
the Centennial Valley, Montana. Condor. 93: 1007-1010. [20663]
33. Schlorff, Ronald W.; Bloom, Peter H. 1984. Importance of riparian
systems to nesting Swainson's hawks in the Central Valley of California.
In: Warner, Richard E.; Hendrix, Kathleen M., eds. California riparian
systems: Ecology, conservation, and productive management: Proceedings
of a conference; 1981 September 17-19; Davis, CA. Berkeley, CA:
University of California Press: 612-618. [5863]
34. Schmutz, Josef K.; Fyfe, Richard W.; Moore, David A.; Smith, Alan R.
1984. Artificial nests for ferruginous and Swainson's hawks. Journal of
Wildlife Management. 48(3): 1009-1013. [23122]
35. Verner, Jared; Boss, Allan S., tech. coords. 1980. California wildlife
and their habitats: western Sierra Nevada. Gen. Tech. Rep. PSW-37.
Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific
Southwest Forest and Range Experiment Station. 439 p. [10237]
36. Wagle, R. F. 1981. Fire: its effects on plant succession and wildlife in
the Southwest. Tucson, AZ: University of Arizona. 82 p. [4031]
37. Schmutz, Josef K.; Fyfe, Richard W.; Moore, David A.; Smith, Alan R.
1984. Artificial nests for ferruginous and Swainson's hawks. Journal of
Wildlife Management. 48(3): 1009-1013. [23122]
38. Woodbridge, B. 1991. What do Swainson's hawks really eat?. Journal of
Raptor Research. 25(4): 163. [Abstract]. [22652]
39. Young, Leonard S. 1989. Effects of agriculture on raptors in the western
United States: an overview. In: Proceedings of the western raptor
symposium and workshop; 1987 October 26-28; Boise, ID. NWF Scientific
and Technical Series No. 12. Washington, DC: National Wildlife
Federation: 209-218. [22649]
40. Kochert, Michael N. 1986. Raptors. In: Cooperrider, Allan Y.; Boyd,
Raymond J.; Stuart, Hanson R., eds. Inventory and monitoring of wildlife
habitat. Denver, CO: U.S. Department of the Interior, Bureau of Land
Management, Denver Service Center: 313-349. [13527]
41. Herkert, J. R., ed. 1992. Endangered and threatened species of Illinois:
status and distribution. Volume 2--Animals. Springfield, IL: Illinois
Endangered Species Protection Board. 142 p. [23799]
42. Tate, James, Jr. 1986. The Blue List for 1986. American Birds. 40(2):
227-235. [24324]
43. U.S. Fish and Wildlife Service. 2013. Listed animals. In: Environmental
Conservation Online System, [Online]. In: Species reports. Available:
http://ecos.fws.gov/tess_public/pub/listedAnimals.jsp. [86534]
FEIS Home Page
https://www.fs.usda.gov/database/feis/animals/bird/busw/all.html
