Functional and numerical responses of coyotes, Canis latrans, to fluctuating prey abundance in the Curlew Valley, Utah, 1963--1993

Predator-prey interactions were investigated in Curlew Valley, Utah by correlating prey abundances with prey consumption data sets. This extended data series allowed us to evaluate coyote diet trends that encompassed substantial fluctuations in abundance of various prey species. Previous studies reported a cyclic trend in jackrabbit density with a period of ten years and >150-fold amplitude, as well as short-term fluctuations among some rodent species that exceeded an 8-fold difference in amplitude over two-year periods. Our results suggest changes in coyote diets mainly reflect the fluctuations in jackrabbit abundance. Prey switching to rodents during periods of low jackrabbit abundance was also evident. Our main objective was to assess coyote functional feeding responses to these changing prey populations. We used the initial feeding pattern analysis to compare prey consumption data to prey abundance. Knowledge of coyote-prey interactions can aid in understanding coyote food preferences, population density, habitat selection, and depredation rates.