INHS Reports March-April 1998

Coyotes and Foxes in the Town and Country

Since the 1960s, coyote (Canis latrans) populations have increased and stabilized while red fox (Vulpes vulpes) populations apparently have decreased throughout Illinois. Previous studies suggest that coyotes are intolerant of foxes where their ranges overlap. Some farmers, trappers, and hunters who recall seeing higher numbers of foxes in the past now believe there are "too many" coyotes and blame coyote predation for decreasing fox numbers and low pheasant populations. Foxes may be more tolerant of human activity and thus persist in agricultural areas by exploiting habitat near human development.

We are trying to determine the nature of coyote intolerance towards foxes (direct aggression? competition for a limited resource? etc.). With funding from the Illinois Department of Natural Resources (IDNR) Furbearer Fund, researchers from the Illinois Natural History Survey and University of Illinois are using radiotelemetry to study dispersal, habitat use, and mortality of foxes and coyotes in urban and rural habitat that they share. Preliminary results suggest some emerging patterns of urban and rural fox pups. Nearly all the Co-author Tod Gosselink with young coyote.
fox pups in developed areas have died prior to dispersal due to sarcoptic mange, while over half of the rural fox pups have died after being hit by cars. To date, no fox mortalities have been attributed to coyote depredation. Coyote pups also have had high mortality rates (80%), but most of the mortality occurred during dispersal and the causes were due mostly to car collisions and hunters. The mortality causes for adults were similar. Nearly half of the coyotes were shot over the winter months, while the majority of the adult foxes were hit by cars. Den locations of coyotes and foxes in the rural areas were located in contrasting habitats. Coyote dens were typically in the middle of a mile section, along drainage ditches or fence rows, while rural fox dens were all located under abandoned or little-used farm buildings.

Radiotelemetry continues to reveal interesting behaviors. Both species tend to prefer cornfields over soybean fields during hot summer days. On several occasions, foxes were found in the middle of subdivisions or small towns prowling people's yards at night. Foxes also use industrial areas and large city parks in the Champaign area. One fox pup was consistently found in Memorial Stadium and scat was found several times on the bleachers (possibly a comment on the 1997 Illini football season). Fox pups in the country consistently used culverts under country roads once they had left the dens.

INHS researcher Rebecca Crawford examines captured red fox.

Monitoring the dispersal relied heavily on aerial tracking since dispersal movement often included concentrated bursts of movement to new areas. One female juvenile coyote dispersed 60 miles southwest of Champaign before establishing a new range. Other coyotes are continually on the move and apparently do not maintain a discrete home range. The foxes are also extraordinary dispensers. One fox has been recorded moving 35 miles in six days or less, while another juvenile fox dispersed 50 miles north of Champaign before being trapped.

The adult foxes in the rural areas typically seemed to forage along roadsides during the night, while the coyotes often avoided roads and used drainage ditches and fence rows instead. On several occasions we located coyotes and foxes on or near farmsteads. The home range analysis has shown coyote and fox home ranges overlapping, and active fox dens often lie within the coyote home ranges.

As of January 1998 we have seen no evidence of coyote aggression toward foxes. Both species continue to use similar habitat and probably hunt for similar prey. Their interactions are obviously complex, and we find that conservationists are eager to learn more about this. This research will help IDNR managers design programs that will benefit both of these charismatic species.

Todd E. Gosselink, Department of Natural Resources and Environmental Sciences, University of Illinois, and Tim Van Deelen, Center for Wildlife Ecology

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