Index of Species Information
WILDLIFE SPECIES: Urocyon cinereoargenteus
WILDLIFE SPECIES: Urocyon cinereoargenteus
AUTHORSHIP AND CITATION :
Sullivan, Janet. 1996. Urocyon cinereoargenteus. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
18 July 2013: DeGraaf, Richard M.; Rudis, Deborah D. 2001 citation corrected to
DeGraaf, Richard M.; Yamasaki, Mariko. 2001.
COMMON NAMES :
common gray fox
The currently accepted scientific name of common gray fox is Urocyon
cinereoargenteus Schreber. It is a member of the dog family (Canidae).
There are 15 accepted subspecies; the 7 subspecies occurring north of
Mexico are as follows :
Urocyon cinereoargenteus borealis Merriam
Urocyon cinereoargenteus californicus Mearns
Urocyon cinereoargenteus cinereoargenteus (Schreber)
Urocyon cinereoargenteus floridanus Rhoads
Urocyon cinereoargenteus ocythous Bangs, prairie gray fox
Urocyon cinereoargenteus scottii Mearns
Urocyon cinereoargenteus townsendi Merriam
FEDERAL LEGAL STATUS :
Urocyon cinereoargenteus ocythous is Under Review for listing .
OTHER STATUS :
Information on state- and province-level protection status of animals in the
United States and Canada is available at NatureServe, although recent changes
in status may not be included.
WILDLIFE DISTRIBUTION AND OCCURRENCE
WILDLIFE SPECIES: Urocyon cinereoargenteus
GENERAL DISTRIBUTION :
The range of common gray fox extends from extreme southern Canada to northern
Venezuela and Columbia, excluding portions of the northern Rocky
Mountain region, the northern Great Plains, and eastern Central America
. Common gray fox range has expanded in the last 50 years to areas
formerly unoccupied and areas where common gray fox had been extirpated
including New England, Michigan, Minnesota, Iowa, Ontario, Manitoba,
North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and Utah .
Ranges of subspecies follow .
U. c. borealis occurs in New England and southern Ontario.
U. c. californicus occurs from southwestern California to northern Baja
U. c. cinereoargenteus occurs from southern Massachusetts and
Connecticut west to Lake Michigan and Illinois; south to central South
Carolina; and west to the Mississippi River.
U. c. floridanus occurs from southern South Carolina south to Florida
and west to eastern Texas; it occurs along the Gulf Coast excluding
U. c. ocythous occurs in Wisconsin and extreme western Illinois; from
Missouri and Arkansas west to Oklahoma, Kansas, Nebraska, South Dakota,
North Dakota, and extreme southern Manitoba and Quebec.
U. c. scottii occurs from western Texas north through northern Colorado
and Utah to the southern half of Nevada; and from California east of the
Sierra Nevada southeast in Mexico to Chihuahua.
U. c. townsendi occurs in northern California and western Oregon.
FRES10 White-red-jack pine
FRES12 Longleaf-slash pine
FRES13 Loblolly-shortleaf pine
FRES21 Ponderosa pine
FRES24 Hemlock-Sitka spruce
FRES26 Lodgepole pine
FRES28 Western hardwoods
FRES30 Desert shrub
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
BLM PHYSIOGRAPHIC REGIONS :
1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
4 Sierra Mountains
6 Upper Basin and Range
7 Lower Basin and Range
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
KUCHLER PLANT ASSOCIATIONS :
The common gray fox occurs in nearly every Kuchler plant association.
SAF COVER TYPES :
The common gray fox occurs in nearly every SAF cover type.
SRM (RANGELAND) COVER TYPES :
The common gray fox occurs in most SRM cover types.
PLANT COMMUNITIES :
Common gray foxes occur in a wide variety of forest types; they prefer
woodlands and woodland-brush ecotones over open habitat. They commonly
occur in eastern and southwestern deciduous forests, but are also found
in mixed and coniferous forests of the northeastern and western states .
Common gray foxes are ecologically important members of the oak (Quercus
spp.)-hickory (Carya spp.) ecosystem. In the Missouri Ozarks mature
oak-hickory stands were the most frequently used (of six habitat types)
by common gray foxes, both at night and during the day. Old fields were least
used . In North Carolina common gray fox habitats include evergreen redbay
(Persea borbonia) forests, deciduous forests, and streamhead forests.
Common gray foxes were common in the most densely wooded habitats, including
pocosins. They are often seen running along sandy rims and ridges
between bay and streamhead forests . In central Louisiana common gray foxes
occur in longleaf pine (Pinus palustris)-slash pine (P. elliottii)
stands . Common gray foxes are common in southwestern Wisconsin
oak-hickory forests dominated by white oak (Q. alba), northern red oak
(Q. rubra), black oak (Q. velutina), and shagbark hickory (C. ovata)
with lesser amounts of white ash (Fraxinus americana), green ash (F.
pennsylvanica), maples (Acer spp.), and basswood (Tilia americana) .
In Zion National Park, Utah, common gray foxes occur in blackbrush (Coleogyne
ramosissima), shrub-grassland dominated by fourwing saltbush (Atriplex
canescens), and pinyon (Pinus spp.)-juniper (Juniperus spp.) . In
Texas common gray foxes are found in post oak (Q. stellata) woodlands,
pinyon-juniper woodlands, and wooded sections of shortgrass prairie. In
western states common gray foxes are found in brushy habitat, woods, and
chaparral . In Arizona common gray foxes are relatively rare; they are
typically found in pine (Pinus spp.)-Gambel oak (Q. gambelii) woodlands
at 5,000 to 6,000 feet (1,500-1,800 m) elevation. They also occur in
pine-fir (Abies spp.), ponderosa pine (P. ponderosa), chaparral, and
desert grassland habitats [6,31]. In California common gray foxes are most
common in mature chaparral at elevations of 1,000 to 3,000 feet (300-900
m) and also occur in open chaparral, riparian areas, and other plant
communities . In riparian zones they have been found in communities
dominated by Fremont cottonwood (Populus fremontii)-northern California
black walnut (Juglans californica var. hindsii), and by large willow
(Salix laevigata) . In northwestern California common gray foxes were
present in Douglas-fir (Pseudotsuga menziesii) forests .
BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Urocyon cinereoargenteus
TIMING OF MAJOR LIFE HISTORY EVENTS :
Diurnal Activity: Common gray foxes are more active at night and at dusk than
during the day. Activity levels decrease sharply at sunrise, and
increase at sunset [17,18]. Common gray foxes usually leave their daytime rest
area shortly before sunset, investigate the immediate area, and then
move purposefully to a foraging area. Close to sunrise they usually
move back to a daytime resting area. Common gray foxes usually change resting
sites every day once vegetative cover is abundant in late spring; sites
are reused in winter .
Breeding Season: Common gray foxes usually breed from late winter to early
spring; dates of mating activity vary with latitude and elevation. In
southern Illinois breeding occurs from late January to February; in
Wisconsin breeding occurs from late January to March , and in Oregon
mating occurs from mid-February to March . Where common gray fox is
sympatric with red fox (Vulpes vulpes), common gray foxes breed 2 to 4 weeks
later than red foxes. Common gray foxes are assumed to be monogamous, but
direct evidence is lacking . There is only one litter per year .
Gestation and Development of Young: Gestation periods have been
variously reported as ranging from 53 to 63 days; Fritzell  reported
gestation in captivity lasted 59 days. Mean litter size is 3.8, ranging
from 1 to 7. Development has not been well studied . Young are born
blind and nearly naked. Eyes open about 9 days after birth. The pups
nurse for over 3 weeks. Solid food is fed to the pups before they are
completely weaned with the male beginning to bring food to the pups at
about 2 to 3 weeks. Pups begin to fend for themselves at about 3
months; families disperse in late summer and autumn .
Population Structure: Root and Payne  determined that the majority
of animals in a southwestern Wisconsin common gray fox population were under 1
year old. They concluded that common gray foxes are "an annual crop." The
majority of female common gray foxes breed their first year .
Mortality and Longevity: In the Central Valley of California, two of
four radiotracked common gray foxes were killed by cars . In east-central
Alabama, a population of common gray foxes was tagged and monitored for causes
of mortality. Canine distemper was the most frequent cause of death,
followed by trapping, automobile collision, and infectious canine
hepatitis. Canine distemper was probably a localized cause of mortality
in this area; it is not expected that most common gray fox populations suffer
the same rate of distemper deaths . Maser and others  stated
that collision with automobiles is rare in Oregon; the major causes of
common gray fox mortality are hunting and trapping. They listed a probable
maximum longevity in the wild of 6 years. The oldest captive common gray fox
lived less than 8 years .
PREFERRED HABITAT :
Common gray foxes are most closely associated with deciduous forest,
particularly where it is in contact with disturbed or brushy habitat
[9,23,35]. They are usually found near surface water . Preferred
habitat includes shrublands and brushy woodlands on hilly or rough
terrain. In areas where common gray foxes and red foxes occur together, common gray
foxes prefer mixed woods with dense underbrush. In the absence of red
foxes, common gray foxes prefer other habitats .
In New England common gray foxes are associated with dense northern hardwood or
mixed forests, thickets, and swamps. Preferred habitat includes a
mixture of fields and woods . In Wisconsin common gray foxes were most
abundant near brush-covered bluffs where woods and farmland were well
interspersed . From Virginia to southern Georgia optimal common gray fox
habitat consists of woodland-farmland edge; post oak woodlands are also
good common gray fox habitat . In southern Georgia common gray foxes are most
abundant in mixed woods and cultivated areas, less abundant in pine
savanna, and least common in mixed woods with dense underbrush . On
the Coastal Plain most common gray fox captures occurred in tall
weed-broomsedge (Andropogon virginicus)-dominated habitats and
cultivated areas. There were relatively few captures on forested sites;
this difference from common gray fox preferences in the majority of its range
was attributed to the absence of red foxes .
In the western states common gray fox habitats include rocky hillsides,
mountainsides, and washes . In Oregon common gray foxes prefer mixed
hardwood and mixed conifer-hardwood habitats; they are present in
riparian hardwood, headland prairie, headland shrub, and tanoak
(Lithocarpus densiflorus) habitats . In the Central Valley of
California, one common gray fox spent most of its time in old fields and
human-use areas, one spent most of its time in agricultural areas, and
two spent most of their time in riparian areas. None of the foxes used
areas of open dirt . In California common gray foxes were most abundant
from 3,800 to 5,000 feet (1,150-1,525 m) elevation . In
northwestern California Douglas-fir forests, common gray foxes were present in
similar abundances in all forest seres, but there were slightly fewer
common gray foxes in mature timber .
Home Range: Common gray foxes tracked from May through August, 1980 and
January through August, 1981, had a monthly average home range of 740
acres (299 ha), and an average composite home range of 1,700 acres (676
ha). Some individuals occupied the same general area for extended
periods, but home ranges tended to shift from month to month. Only a
fraction of the home range is used on a given night . The composite
home ranges of four radio-tracked common gray foxes varied from 262 to 425
acres (106-172 ha). Common gray foxes are apparently solitary in the
nonbreeding seasons . In Wisconsin common gray fox home ranges vary from
0.24 to 1.2 miles (0.40-2 km) in diameter . Lord  estimated
common gray fox home range diameter of 1.9 miles (3.2 km). Trapp  reported
an annual home range average of 0.2 square mile (0.52 sq km).
Territoriality: Common gray fox territoriality is not well defined.
Territories are marked with urine and feces, but in many areas home
ranges overlap considerably. Family aggregates are formed so that
individual territories overlap; family aggregates do not overlap .
COVER REQUIREMENTS :
Common gray foxes tend to escape their enemies by finding cover rather than
depending on speed (as do red foxes) . Dense vegetation is
important as diurnal resting and escape cover . They climb trees
for use as resting and escape cover . Their climbing ability
extends to saguaro (Carnegiea gigantea); one common gray fox was observed
resting 15 feet (4.6 m) above ground on a saguaro limb .
Den sites include hollow logs and trees, rock outcrops, underground
burrows (usually the abandoned den of some other species), cavities
under rocks, abandoned buildings, wood or sawdust piles, and brush
[9,23]. Dens have been found up to 20 feet (9.1 m) above ground in tree
hollows. Underground dens have usually been excavated by animals of
other species, but common gray foxes occasionally dig dens in loose soil .
Den Use: Dens are used throughout the year, but primary use is during
whelping season. Dens are usually located in brushy or wooded habitats.
In Wisconsin most common gray fox dens were on east-, southeast-, or
south-facing slopes . Leaves, grass, fur, and other soft materials
are added to dens .
FOOD HABITS :
Common gray foxes are omnivorous, opportunistic feeders; they prey mainly on
small mammals, but fruit and invertebrates form a substantial portion of
the diet. In the central United States cottontails (Sylvilagus spp.)
formed the major portion of the common gray fox winter diet. Other mammals
taken in noticeable numbers include voles (Microtus spp.), mice
(Peromyscus spp.), woodrats (Neotoma spp.), and cotton rats (Sigmodon
spp.). Invertebrates increase in importance in the spring. With
seasonally advancing vegetative growth and development, plant material,
particularly fruit, increases in common gray fox diets, sometimes comprising up
to 70 percent by volume . Grasshoppers (Orthoptera), beetles
(Coleoptera), and butterflies and moths (Lepidoptera) are the preferred
invertebrates; plant materials include fruits, nuts, grains, and
grasses. Carrion is eaten opportunistically . In some areas birds
(nestlings and eggs), particularly ground-nesters, are taken by common gray
foxes; in Texas wild turkey (Meleagris gallopavo) nests were broken up
by common gray foxes .
In a riparian area in the Central Valley of California, a common gray fox ate
mostly ring-necked pheasant (Phasianus colchicus), California ground
squirrels (Spermophilus beecheyi), California voles (Microtus
californicus), and berries . In Oregon primary prey items include
mice, pocket gophers (Thomomys and Geomys spp.), kangaroo rats
(Dipodomys spp.), woodrats, ground squirrels (Spermophilus spp.),
chipmunks (Tamias spp.), brush rabbit (Sylvilagus bachmanii), and birds
including domestic poultry. Other food items include grasshoppers,
beetles, manzanita (Arctostaphylos spp.) berries, juniper cones, and
cascara (Rhamnus purshiana) berries . In the Sonoran Desert the
fruit of the California palm (Washingtonia filifera) forms a substantial
portion of the common gray fox winter diet . In eastern Tennessee plant
foods included persimmon (Diospyros virginiana), black cherry (Prunus
serotina), blackberry (Rubus spp.) , and cancerroot (Conophilus
americana). The most common vertebrate prey determined in scat analysis
(by volume) was eastern cottontail (Sylvilagus floridana), followed by
white-tailed deer (Odocoileus virginiana), presumably as carrion, and
Adult common gray foxes have few predators, but are occasionally taken by
golden eagle (Aquila chrysaetos), coyote (Canis latrans), and bobcat
(Lynx rufus) ; pups are taken by bobcat, great horned owl (Bubo
virginianus), and possibly large hawks .
MANAGEMENT CONSIDERATIONS :
Common gray fox pelts are of some value but are not as valued as those of red
fox . Trapping increases and decreases with pelt values; in a 1987
report it was mentioned that sales in the United States had increased
dramatically in the last decade. The common gray fox has "furbearer"
management status in many states [13,38].
Population Status: The common gray fox is characterized by widespread, healthy
populations in most areas. Habitat availability may limit its
distribution, but lack of habitat does not appear to pose an immediate
threat . Common gray foxes are uncommon to common in New England .
Reported population densities range from 1 to 27 per square mile .
Common gray foxes are considered pests by many farmers who raise domestic
poultry; biologists claim that this damage is usually overstated and
that common gray foxes benefit agriculture by controlling rodent and rabbit
populations . In northern bobwhite (Colinus virginianus) management
areas only a small number of common gray foxes (0.7%) were found to have
northern bobwhite remains in their stomachs .
Common gray foxes commonly carry rabies, most frequently in the Appalachian
states (KY, TN, VA, WV) . They also carry tularemia  and canine
distemper which is not as virulent in common gray foxes as it is in domestic
dogs (Canis familiaris) .
FIRE EFFECTS AND USE
WILDLIFE SPECIES: Urocyon cinereoargenteus
DIRECT FIRE EFFECTS ON ANIMALS :
Death of common gray foxes due to fire has not been documented in the
literature. They are highly mobile animals and are probably only
rarely caught by fast-moving or intense wildfire.
HABITAT RELATED FIRE EFFECTS :
Common gray foxes use brush and brushy woods in most areas. Fire that reduces
brush cover will decrease common gray fox habitat. Fire usually increases the
productivity of early successional prey species and improves predator
efficiency by reducing hiding cover for prey . In the Southeast
fire produces immediate short-term habitat reduction for prey animals;
prey is concentrated in unburned habitat islands . The most
important common gray fox prey in the Southeast are cottontails and cotton
rats. Cottontails and cotton rats are not usually killed by fire but
prefer habitats with more cover than is found in immediate postfire
environments. Both species return to postfire habitats when there is
sufficient vegetation for food and cover. Fire often reduces fruit
production in the short term, but edges of older burns are usually good
regeneration sites for fruiting shrub species such as blackberries and
blueberries (Vaccinium spp.); gallberry (Ilex glabra) produces the most
fruit a few years after fire pruning .
FIRE USE :
Hon  and Landers  suggest that in the Southeast, burning fields
and slash pine forests on 3-year rotations would create desirable
furbearer habitat; areas supporting fire-sensitive fruit-bearing plants
should be protected from fire.
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 for species: Urocyon cinereoargenteus
1. 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. 
2. Bullock, Stephen H. 1980. Dispersal of a desert palm by opportunistic frugivores. Principes. 24(1): 29-32. 
3. Butts, Gregory L. 1977. Aerial pursuit of red-tailed hawks (Accipitridae) by turkey (Meleagrididae) hens. The Southwestern Naturalist. 22(3): 404-405. 
4. Carey, Andrew B. 1982. The ecology of red foxes,
gray foxes, and rabies in the eastern United States. Wildlife Society Bulletin. 10(1): 18-26. 
5. Clark, Mary K.; Lee, David S.; Funderburg, John B., Jr. 1985. The mammal fauna of Carolina bays, pocosins, and associated communities in North Carolina: an overview. Brimleyana. 11: 1-38. 
6. Davis, Russell; Sidner, Ronnie. 1992. Mammals of woodland and forest habitats in the Rincon Mountains of Saguaro National Monument, Arizona. Technical Report NPS/WRUA/NRTR-92/06. Tucson, AZ: The University of Arizona, School of Renewable Natural Resources, Cooperative National Park Resources Study Unit. 62 p. 
7. DeGraaf, Richard M.; Yamasaki, Mariko. 1986. New England wildlife: habitat, natural history, and distribution. Gen. Tech. Rep. NE-108. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 491 p. 
8. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
9. Fritzell, Erik K.; Haroldson, Kurt J. 1982. Urocyon conereoargenteus. Mammalian Species. 189: 1-8. 
10. Fritzell, E. K. 1987. Gray fox and island fox. In: Novak, M.; Baker, J. A.; Obbard, M. E.; Malloch, B., eds. Wild furbearer management and conservation in North America. North Bay, ON: Ontario Trappers Association: 408-420. 
11. Fuller, Todd K. 1978. Variable home-range sizes of female
gray foxes. Journal of Mammalogy. 59(2): 446-449. 
12. 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. 
13. Ginsberg, J. R.; Macdonald, D. W. 1990. Foxes, wolves, jackals, and dogs: An action plan for the conservation of canids. [Place of publication unknown]: The World Conservation Union, Gland, Switzerland. 116 p. 
14. Greenberg, Cathryn H.; Pelton, Michael R. 1991. Food habits of
gray foxes (Urocyon cinereoargenteus) and red foxes (Vulpes vulpes) in east Tennessee. Journal of the Tennessee Academy of Science. 66(2): 79-84. 
15. Grinnell, Joseph; Dixon, Joseph S.; Linsdale, Jean M. 1937. Fur-bearing mammals of California: Their natural history, systematic status, and relations to man. Berkeley, CA: University of California Press. 2 vol. 777 p. 
16. Hall, E. Raymond. 1981. The mammals of North America. 2nd ed. Vol. 2. New York: John Wiley and Sons. 1271 p. 
17. Hallberg, Donald L.; Trapp, Gene R. 1984. Gray fox temporal and spatial activity in a riparian/agricultural zone in California's Central Valley. In: Warner, Richard E.; Hendrix, Kathleen M., eds. California riparian systems: Ecology, conservation, and productive management. Berkeley, CA: University of California Press: 920-928. 
18. Haroldson, Kurt J.; Fritzell, Erik K. 1984. Home ranges, activity, and habitat use by
gray foxes in an oak-hickory forest. Journal of Wildlife Management. 48(1): 222-227. 
19. Hon, Tip. 1981. Effects of prescribed fire on furbearers in the South. In: Wood, Gene W., ed. Prescribed fire and wildlife in southern forests: Proceedings of a symposium; 1981 April 6-8; Myrtle Beach, SC. Georgetown, SC: Clemson University, Belle W. Baruch Forest Science Institute: 121-128. 
20. 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. 
21. 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. 
22. Lord, Rexford D., Jr. 1961. A population study of the
gray fox. The American Midland Naturalist. 66(1): 87-109. 
23. Maser, Chris; Mate, Bruce R.; Franklin, Jerry F.; Dyrness, C. T. 1981. Natural history of Oregon Coast mammals. Gen. Tech. Rep. PNW-133. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 496 p. 
24. McKeever, Sturgis. 1959. Relative abundance of twelve southeastern mammals in six vegetative types. The American Midland Naturalist. 62: 222-226. 
25. Mullin, Keith; Williams, Kenneth L. 1987. Mammals of longleaf-slash pine stands in central Louisiana. In: Pearson, Henry A.; Smeins, Fred E.; Thill, Ronald E., compilers. Proceedings of the southern evaluation project workshop; 1987 May 26-27; Long Beach, MS. Gen. Tech. Rep. SO-68. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station: 121-124. 
26. Murray, Robert W.; Frye, O. E., Jr. 1964. The bobwhite quail and its management in Florida. 2d ed. Game Publ. No. 2. [Place of publication unknown]: Florida Game and Fresh Water Fish Commission. 55 p. 
27. Nicholson, W. S.; Hill, Edward P. 1984. Mortality in
gray foxes from east-central Alabama. Journal of Wildlife Management. 48(4): 1429-1432. 
28. Petersen, LeRoy R.; Martin, Mark A.; Pils, Charles M. 1977. Status of
gray foxes in Wisconsin, 1975. Research Report 94. Madison, WI: Wisconsin Department of Natural Resources. 18 p. 
29. Quinn, Ronald D. 1990. Habitat preferences and distribution of mammals in California chaparral. Res. Pap. PSW-202. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 11 p. 
30. Raphael, Martin G. 1988. Long-term trends in abundance of amphibians, reptiles, and mammals in Douglas-fir forests of northwestern California. In: Szaro, Robert C.; Severson, Kieth E.; Patton, David R., technical coordinators. Management of amphibians, reptiles, and small mammals in North America: Proceedings of the symposium; 1988 July 19-21; Flagstaff, AZ. Gen. Tech. Rep. RM-166. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 23-31. 
31. Reynolds, Hudson G.; Johnson, R. Roy. 1964. Habitat relations of vertebrates of the Sierra Ancha Experimental Forest. Res. Pap. RM-4. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 16 p. 
32. Richards, Stephen H.; Hine, Ruth L. 1953. Wisconsin fox populations. Final Report: Pittman--Robertson Research Project 12-R. Technical Wildlife Bulletin No. 6. Madison, WI: Wisconsin Conservation Department, Game Management Division. 78 p. 
33. Root, David A.; Payne, Neil F. 1985. Age-specific reproduction of
gray foxes in Wisconsin. Journal of Wildlife Management. 49(4): 890-892. 
34. Trapp, Gene Robert. 1973. Comparative behavioral ecology of two southwest Utah carnivores: Bassariscus astutus and Urocyon cinereoargenteus. Madison, WI: University of Wisconsin. 251 p. Dissertation. 
35. Trapp, Gene R.; Hallberg, Donald L. 1975. Ecology of the
gray fox (Urocyon cinereoargenteus): a review. In: Fox, M. W., ed. The wild canids: Their systematics, behavioral ecology and evolution. Behavioral Science Series. New York: Van Nostrand Reinhold Company: 164-178. 
36. Sheldon, Jennifer W. 1992. Wild dogs: The natural history of the nondomestic Canidae. San Diego, CA: Academic Press, Inc. 248 p. 
37. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
38. Samuel, David E.; Nelson, Brad B. 1982. Foxes: Vulpes vulpes and allies. In: Chapman, Joseph A.; Feldhamer, George A., eds. Wild mammals of North America: Biology, management, and economics. Baltimore, MD: The Johns Hopkins University Press: 475-490. 
39. Committee on the Status of Endangered Wildlife in Canada. 1992. Canadian species at risk. Ottawa, ON. 10 p. 
40. U.S. Department of the Interior, Fish and Wildlife Service. 2016. Endangered Species Program, [Online]. Available: http://www.fws.gov/endangered/. 
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