Intrinsic and extrinsic factors influencing coyote predation of small mammals in Yellowstone National Park

We examined the intrinsic (age, sex, and social status) and extrinsic factors (snow depth and hardness, temperature, cloud cover, wind speed, and habitat) influencing coyote (Canis latrans) predation of small mammals in Yellowstone National Park, Wyoming. We observed 54 coyotes (49 residents from 5 packs, plus 5 transients) for 2507 h from January 1991 to June 1993. We observed 6433 prey detections by coyotes during which coyotes made 4439 attempts to capture prey, resulting in 1545 successful prey captures. The age of the coyote influenced prey-detection rates, predation attempts, and capture rates, plus the proportions of prey attacked after being detected and capture success. Pups had higher prey-detection rates and higher attempt rates than alphas and betas, but capture rates were similar. Snow depth and hardness and habitat type were factors influencing detection rates, predation attempt rates and capture rates. Coyotes hunted mainly in mesic meadows and shrub-meadows, where prey-detection rates, predation attempt rates, and capture rates were highest. Snow depth influenced coyote predation on small mammals, prey-detection rates, predation attempt rates, and capture rates being highest in low snow cover and lower in deeper snow. Our findings indicated that young, inexperienced coyotes detected and attacked small mammals at a higher rate than older coyotes. Yearlings and adults were more selective, and thus detected and attempted to capture prey at a lower rate than pups. Overall, however, pups and older coyotes captured similar numbers of prey per hour.