PARENT SESSION
Poster Session # 20: Predator - Prey / Mutualism - Parasitism Ecology.

Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Functional feeding responses of coyotes to fluctuating prey abundances in the Curlew Valley, Utah, 1977-1993.

Bartel, Rebecca^*,1, Knowlton, Frederick^{1, 2}, ¹ Utah State University, Logan, UT, USA² USDA/WS/National Wildlife Research Center, Logan, UT, USA

ABSTRACT- 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. Our results show coyotes respond to jackrabbit abundance with a Type II curve. Knowledge of coyote-prey interactions can aid in understanding coyote food preferences, population density, habitat selection, and depredation rates. This information is useful in predicting future predator-prey interactions and evaluating management options.

Key words: functional feeding response, predator-prey interactions, numerical response, community ecology