FORAGING ECOLOGY OF COYOTES (CANIS LATRANS) - THE INFLUENCE OF EXTRINSIC FACTORS AND A DOMINANCE HIERARCHY

We examined the influence of intrinsic (age, sex, and social status) a nd extrinsic (snow depth, snowpack hardness, temperature, available un gulate carcass biomass) factors in relation to time-activity budgets o f coyotes (Canis latrans) in Yellowstone National Park, Wyoming. We ob served 54 coyotes (49 residents from 5 packs, plus 5 transients) for 2 507 h from January 1991 to June 1993. Snow depth, ungulate carcass bio mass, and habitat type influenced the amount of time coyotes rested, t ravelled, hunted small mammals, and fed on carcasses. Coyotes decrease d travelling and hunting and increased resting and feeding on carcasse s as snow depth and available carcass biomass increased. Age and socia l status of the coyote influenced activity budgets. During times of de ep snow and high carcass biomass, pups fed less on carcasses and hunte d small mammals more than alpha and beta coyotes. Pups apparently were restricted by older pack members from feeding on a carcass. Thus, pup s adopted a different foraging strategy by spending more time hunting small mammals. Coyotes spent most of their time hunting small mammals in mesic meadows and shrub-meadows, where prey densities were highest. Prey-detection rates and prey-capture rates explained 78 and 84%, res pectively, of the variation in the amount of time coyotes spent huntin g small mammals in each habitat in each winter. Our findings strongly suggested that resource partitioning, as mediated by defense by older coyotes, occurred among coyote pack members in Yellowstone National Pa rk.