American Badgers in Illinois

American Badgers in Illinois
		by *Barbara Ver Steeg* Illinois Natural History Survey *Richard E. Warner* University of Illinois
The American badger (Taxidea taxus) is a medium-sized carnivore found in treeless areas across North America, such as the tall-grass prairie (Lindzey 1982). Badgers rely primarily on small burrowing mammals as a prey source; availability of badger prey may be affected by changes in land-use practices that alter prey habitat. In the midwestern United States most native prairie was plowed for agricultural use beginning in the mid-1800's (Burger 1978). In the past 100 years, Midwest agriculture has shifted from a diverse system of small farms with row crops, small grains, hay, and livestock pasture to larger agricultural operations employing a mechanized and chemical approach to cropping. The result is a more uniform agricultural landscape dominated by two primary row crops, corn and soybeans. The effects of such land-use alterations on badgers are unknown. In addition, other human activities such as hunting and trapping have no doubt had an impact on native vertebrates such as the badger. Our ongoing study was initiated to determine the distribution and status of badgers in Illinois.
Trends in carnivore abundance are difficult to evaluate because most species are secretive or visually cryptic. Trapping records, one of the earliest historical data sources for furbearers, are virtually nonexistent for badgers in the 1800's (Obbard et al. 1987). In Illinois, badgers have been protected from harvest since 1957. Furthermore, population estimates derived from furbearer harvest data are complicated by market price bias (Erickson 1982). Thus, data for estimating long-term population trends in Illinois badgers are few and flawed. Our approach is to document and evaluate current population parameters, behavior, and habitat use in the context of present and historical habitat quality and availability.
Most research on badgers has been limited to the western United States. Although results have varied somewhat among these studies, average densities (estimated subjectively from mark-recapture and home range data) have ranged from 0.38 to 5 badgers/km² (0.98-12.95 badgers/mi²). We use radio telemetry to collect intensive data at a field site in west-central Illinois. Preliminary results suggest that individual badger home range size in Illinois is an order of magnitude larger than that of western badgers, implying that badger density in Illinois is much lower. The home range size estimates of two badgers in Minnesota were also larger than those reported for western states (Sargeant and Warner 1972; Lampe and Sovada 1981).
More than 65% of the Illinois landscape is under intensive row-crop agriculture (Neely and Heister 1987). Although badger prey exist throughout Illinois, available prey in row crops is limited to small species such as the deer mouse (Peromyscus maniculatus), which occur in low uniform densities. Important prey species reported in the West, such as ground squirrels (Spermophilus spp.), have average densities similar to Illinois deer mice, but they are much larger animals and may be concentrated into easily hunted loose colonies (Messick and Hornocker 1981; Minta 1990).
In Illinois, badgers appear to use most frequently cover types that are relatively undisturbed by plowing, including hayfields, pastures, and linear habitats such as roadsides and fencelines. These habitats offer the greatest concentration of small mammalian prey and the lowest frequency of agricultural disturbance. If badgers are limited by available prey, it is possible that the current badger population density is lower than when native prairie and its accompanying prey species' populations dominated the landscape.
Although badgers are legally protected in Illinois, human-induced mortality such as vehicle collisions and agricultural accidents take a toll on populations. Large predators that might prey on adult badgers, such as the black bear (Ursus americanus), gray wolf (Canis lupus), and mountain lion (Felis concolor), have been extirpated since the 19th century (Hoffmeister 1989). However, our study shows that predation by coyotes (Canis latrans) and domestic dogs significantly affects juvenile badgers; fewer than 70% of juveniles survive to dispersal, reducing overall recruitment.

American badger (Taxidea taxus). Courtesy M. Georgi, Illinois Natural History Survey

The badger's range may be expanding eastward from its former boundaries within the Midwest; observations of range expansion in Missouri, southern Illinois, Indiana, and Ohio suggest that agricultural practices have converted previously forested acres to more suitable badger habitat (Moseley 1934; Leedy 1947; Mumford 1969; Hubert 1980; Mumford and Whitaker 1982; Long and Killingley 1983; Gremillion-Smith 1985; Whitaker and Gammon 1988).

Our study revealed that badgers are distributed and breeding throughout Illinois. The dynamics of badger range expansion are difficult to pinpoint, in part because of the cryptic nature of the species. In Illinois and probably the agricultural Midwest in general, individual badgers move over such large areas that live sightings or indications of badger presence are few and far between. Opportunistic observations to evaluate local badger distribution underestimate geographic range; thus, a focused regionwide attempt to evaluate badger range in the Midwest might demonstrate a wider distri-bution than expected.
Badgers in Illinois appear to be a species with intermediate status: though they are neither abundant nor of high economic value, they are widely distributed and have adapted to a greatly altered environment. Understanding what factors cause a species such as the badger to become more or less abundant is vitally important in conservation biology and wildlife management.
		For further information: Barbara Ver Steeg Illinois Natural History Survey 607 E. Peabody Dr. Champaign, IL 61820

References
Burger, G.V. 1978. Agriculture and wildlife. Pages 89-107 in H.P. Brokaw, ed. Wildlife and America. Council on Environmental Quality, Washington, DC. Erickson, D.W. 1982. Estimating and using furbearer harvest information. Pages 53-66 in G.C. Sanderson, ed. Midwest furbearer management. Central Mountains and Plains Section of The Wildlife Society, Wichita, KS. Gremillion-Smith, C. 1985. Range extension of the badger (Taxidea taxus) in southern Illinois. Transactions of the Illinois Academy of Science 78:111-114. Hoffmeister, D.F. 1989. Mammals of Illinois. University of Illinois Press, Urbana, IL. 348 pp. Hubert, G.F., Jr. 1980. Badger status evaluation. Illinois Department of Conservation, Job Completion Report, Federal Aid Project W-49-R-34, Study XII. 12 pp. Lampe, R.P., and M.A. Sovada. 1981. Seasonal variation in home range of a female badger (Taxidea taxus). Prairie Naturalist 15:55-58. Leedy, D.L. 1947. Spermophiles and badgers move eastward in Ohio. Journal of Mammalogy 28:290-292. Lindzey, F.G. 1982. The North American badger. Pages 653-663 in J.A. Chapman and G.A. Feldhammer, eds. Wild mammals of North America. Johns Hopkins University Press, Baltimore, MD. Long, C.A., and C.A. Killingley. 1983. The badgers of the world. Charles C. Thomas Publishers, Springfield, IL. 404 pp.	Messick, J.P., and M.G. Hornocker. 1981. Ecology of the badger in southwestern Idaho. Wildlife Monograph 76. 53 pp. Minta, S.C. 1990. The badger, Taxidea taxus, (Carnivora: Mustelidae): spatial-temporal analysis, dimorphic territorial polygyny, population characteristics, and human influences on ecology. Ph.D. thesis, University of California, Davis. 317 pp. Moseley, E.L. 1934. Increase of badgers in northwestern Ohio. Journal of Mammalogy 15:156-158. Mumford, R.E. 1969. Distribution of the mammals of Indiana. Indiana Academy of Science Monograph 1. 114 pp. Mumford, R.E., and J.O. Whitaker, Jr. 1982. Mammals of Indiana. Indiana University Press, Bloomington, IN. 537 pp. Neely, R.D., and C.G. Heister, compilers. 1987. The natural resources of Illinois: introduction and guide. Illinois Natural History Survey Special Publ. 6. 224 pp. Obbard, M.E., J.G. Jones, R. Newman, A. Booth, A.J. Satterthwaite, and G. Linscombe. 1987. Furbearer harvests in North America. Pages 1007-1038 in M. Novak, J.A. Baker, M.E. Obbard, and B. Malloch, eds. Wild furbearer management and conservation in North America. The Ontario Trappers Association and the Ministry of Natural Resources, Toronto, Ontario. Sargeant, A.B., and D.W. Warner. 1972. Movements and denning habits of a badger. Journal of Mammalogy 53:207-210. Whitaker, J.O., Jr., and J.R. Gammon. 1988. Endangered and threatened vertebrate animals of Indiana; their distribution and abundance. Indiana Academy of Science Monograph 5. 122 pp.

References

Burger, G.V. 1978. Agriculture and wildlife. Pages 89-107 in H.P. Brokaw, ed. Wildlife and America. Council on Environmental Quality, Washington, DC.

Erickson, D.W. 1982. Estimating and using furbearer harvest information. Pages 53-66 in G.C. Sanderson, ed. Midwest furbearer management. Central Mountains and Plains Section of The Wildlife Society, Wichita, KS.

Gremillion-Smith, C. 1985. Range extension of the badger (Taxidea taxus) in southern Illinois. Transactions of the Illinois Academy of Science 78:111-114.

Hoffmeister, D.F. 1989. Mammals of Illinois. University of Illinois Press, Urbana, IL. 348 pp.

Hubert, G.F., Jr. 1980. Badger status evaluation. Illinois Department of Conservation, Job Completion Report, Federal Aid Project W-49-R-34, Study XII. 12 pp.

Lampe, R.P., and M.A. Sovada. 1981. Seasonal variation in home range of a female badger (Taxidea taxus). Prairie Naturalist 15:55-58.

Leedy, D.L. 1947. Spermophiles and badgers move eastward in Ohio. Journal of Mammalogy 28:290-292.

Lindzey, F.G. 1982. The North American badger. Pages 653-663 in J.A. Chapman and G.A. Feldhammer, eds. Wild mammals of North America. Johns Hopkins University Press, Baltimore, MD.

Long, C.A., and C.A. Killingley. 1983. The badgers of the world. Charles C. Thomas Publishers, Springfield, IL. 404 pp.

Messick, J.P., and M.G. Hornocker. 1981. Ecology of the badger in southwestern Idaho. Wildlife Monograph 76. 53 pp.

Minta, S.C. 1990. The badger, Taxidea taxus, (Carnivora: Mustelidae): spatial-temporal analysis, dimorphic territorial polygyny, population characteristics, and human influences on ecology. Ph.D. thesis, University of California, Davis. 317 pp.

Moseley, E.L. 1934. Increase of badgers in northwestern Ohio. Journal of Mammalogy 15:156-158.

Mumford, R.E. 1969. Distribution of the mammals of Indiana. Indiana Academy of Science Monograph 1. 114 pp.

Mumford, R.E., and J.O. Whitaker, Jr. 1982. Mammals of Indiana. Indiana University Press, Bloomington, IN. 537 pp.

Neely, R.D., and C.G. Heister, compilers. 1987. The natural resources of Illinois: introduction and guide. Illinois Natural History Survey Special Publ. 6. 224 pp.

Obbard, M.E., J.G. Jones, R. Newman, A. Booth, A.J. Satterthwaite, and G. Linscombe. 1987. Furbearer harvests in North America. Pages 1007-1038 in M. Novak, J.A. Baker, M.E. Obbard, and B. Malloch, eds. Wild furbearer management and conservation in North America. The Ontario Trappers Association and the Ministry of Natural Resources, Toronto, Ontario.

Sargeant, A.B., and D.W. Warner. 1972. Movements and denning habits of a badger. Journal of Mammalogy 53:207-210.

Whitaker, J.O., Jr., and J.R. Gammon. 1988. Endangered and threatened vertebrate animals of Indiana; their distribution and abundance. Indiana Academy of Science Monograph 5. 122 pp.