Coyote Movements, Habitat Use, and Food Habits in Southwestern Oklahoma

Eighteen radio-equipped coyotes (Canis latrans) were found to have home ranges averaging 68.7 km2 for adult females, 31.3 km2 for adult males, 39.9 km2 for yearling females, and 1.0 km2 for pups. Coyotes involved in pup rearing occupied smaller home ranges than did unmated coyotes. Home ranges of adult females overlapped, as did adjacent male-female home ranges. Coyotes were located more in savanna and less in prairie than expected (P < 0.05) by the availability of these habitats. Seventy-eight percent of the observations of coyotes were of lone animals, 17% were of pairs, and less than 6% were of more than 2 coyotes. Analysis of coyote scats indicated rodents, fruits and seeds, and fawn deer (Odocoileus virginianus) were important foods. J. WILDL. MANAGE. 44(1):62-68 This study was initiated to investigate patterns of coyote movements and food habits on the southern Great Plains. Specific objectives were to (1) determine coyote home ranges, (2) determine coyote group size, (3) describe habitat use, and (4) estimate food habits of coyotes. The study was conducted on the 23,917ha Wichita Mountains National Wildlife Refuge (WMNWR) in southwestern Oklahoma. The WMNWR supports bison (Bison bison), longhorn cattle, elk (Cervus canadensis), and white-tailed deer. The refuge contains 12,505 ha of woodland, 8,547 ha of grassland, and 405 ha of marsh and water. Detailed descriptions of the floral communities were provided by Buck (1964) and Crockett (1964). We thank J. A. Bissonette, F. L. Knopf, and P. A. Vohs, Jr. for comments during preparation of this manuscript. Assistance in the field by D. Martin, D. L. Peters, and S. Pratt is acknowledged. Special thanks are due L. Crabb, D. Snay, C. Harrison, and K. Podborney of the Division of Animal Damage Control, U.S. Fish and Wildlife Service, for their assistance in trapping coyotes. G. Stout, Fish a d Wildlife Biologist, Fort Sill, is also acknowl dged for his assistance throughout the study. METHODS AND MATERIALS Coyotes were captured with steel leghold traps that had offset, padded jaws, 2-pronged drags, and a tranquilizer tab (Basler 1965) containing 80 mg of Tranvet (Diamond Laboratories, Des Moines, Iowa). (Mention of a manufacturer does not indicate endorsement by the authors or cooperating agencies.) Traps were set where coyote scats and tracks were most evident. Captured coyotes were weighed, sexed, and aged (yearling or adult). Coyotes were then ear-tagged and fitted with radio-transmitter collars (Wildlife Materials, Inc., Carbondale, Ill.) and released at capture sites. Coyote pups were captured by hand and age was determined by weight and development (Gier 1968, Bekoff and Jamieson 1975). Those estimated to be 6 weeks of age or older were ear-tagged and fitted with radio-transmitters having expandable collars. Most relocations were obtained through 1 This study was supported by Pittman-Robertson Project W-122-R; the Oklahoma Cooperative Wildlife Research Unit, U.S. Fish and Wildlife Service, Oklahoma Department of Wildlife Conservation, Wildlife Management Institute and Oklahoma State University, cooperating. 2 Present address: U.S. Fish and Wildlife Service, 333 W. 4th St., Tulsa, OK 74103. 62 J. Wildl. Manage. 44(1):1980 This content downloaded from 157.55. 39.246 on Tue, 27 Sep 2016 05:18:40 UTC All use subject to http://about.jstor. org/terms COYOTES IN SOUTHWESTERN OKLAHOMA * Litvaitis and Shaw 63 triangulation using portable receivers (AVM Corp., Champaign, Ill.) and handheld 4-element Yagi antennas. At least 2 signal azimuths were taken from known locations and later plotted on aerial photographs (scale = 1:7,920). The accuracy of this technique was estimated to be +-50 through placement and subsequent relocation of transmitters in the field. Once a visual estimation was made of the coyote's location, an effort was made to take signal azimuths within 1 km of the coyote to minimize error. Most relocations were taken from May through August, 1976 and 1977, from 0600-2000 CST. Daily movements were evaluated by plotting straight-line distances between consecutive daily locations and monitoring at 2.5-hour intervals for 24hour periods. The capture site, all relocations, and the carcass or transmitter recovery site were plotted for each coyote, and home range boundaries were determined by the minimum area method (Mohr 1947). Habitat use was measured by comparing the number of relocations in each habitat to the proportion of that habitat found within coyote home ranges. Habitats included prairie, prairie creek, savanna, and woodland (closed-canopy forest). The percentage of each habitat within a home range was determined using a modified acreage grid (Mosby 1971) and aerial photographs (scale = 1:20,000). Habitat preference was expressed as a percentage of the expected value: [(Obs. Exp.)/Exp. ] x 100, with positive (+) and negative (-) values indicating departures of observed from expected values (Follmann 1973). Coyote group sizes were determined through direct observations from hilltops during morning and evening, and from chance observations during travel through the study area. Coyote food habits were determined through analysis of scats collected biweekly and dried in a desiccating oven prior to storage. Food items were identified through comparison with a reference collection and were reported by percentage occurrence. Relative availability of various prey groups was estimated by several methods. Small rodent abundance was sampled bimonthly using the North American Standard method (Calhoun 1948) consisting of 3 snap-traps placed within a 1.5-m radius at 15.4-m intervals along a 292-m transect. Traps were baited with a peanut butter, raisin, and oat mixture and rebaited for 3 consecutive evenings per trapping period. One transect passed through savanna and woodland and another was located exclusively in prairie. Lagomorph population indices were derived from roadside counts (Lord 1961) begun at approximately V2 hour before sunrise or 1 hour after sunset along a 32km route. The route was driven biweekly at 32 km/hour. Availability of whitetailed deer fawns was estimated from a concurrent study of fawn mortality (Bartush 1978). Data were evaluated using t-tests and significance was assigned at P < 0.05.