Temporal Habitat Partitioning and Spatial Use of Coyotes and Red Foxes in East-Central Illinois

Abstract

Coyote (Canis latrans) populations have increased across eastern North America over the past few decades. In Illinois, red fox (Vulpes vulpes) populations have synchronously declined, suggesting that coyotes may be displacing red foxes. We examined winter (Jan-Feb) and summer (Jul-Aug) habitat use of sympatric coyotes and red foxes in east-central Illinois, including a distinct urban fox population relatively free of interactions with coyotes. We radiomarked 28 coyotes, 16 rural foxes, and 19 urban foxes and systematically collected over 10,500 locations to infer habitat use. Compositional analysis at 3 levels (home range, location, resting) corresponded to 2 spatial scales of habitat use (study area and within home-range use). We used covariate analysis of regression models to examine interspecific differences in habitat use. Using Akaike's Information Criterion (AIC), optimal models included season, sex, and species of the covariate as sources of variation. Habitat partitioning was apparent at all levels of analysis during both seasons, diverging greatly during winter. Coyotes selected and rural foxes avoided cover-rich habitats (grassland, waterways, no-till corn). Rural foxes selected human-associated habitats (active and abandoned farmsteads and rural residential areas), which coyotes generally avoided. Habitat use and home-range selection by urban foxes were more seasonally stable than by rural foxes, but urban foxes selected residential areas more during winter than during summer. Home ranges of both coyotes and rural foxes increased substantially during winter. Rural fox home ranges were nearly 4 times larger than those of urban foxes during winter. Our study demonstrates that coyotes and sympatric red foxes partition habitat seasonally in response to a highly disturbed agricultural landscape. Farmland red foxes may avoid habitats used by sympatric coyotes, relying on human-associated habitats (farmsteads and urban areas) as refugia.