Density and Feeding Habits of Elk and Deer in Relation to Livestock Disturbance

Kenneth Clegg, Utah State University

This work made publicly available electronically on April 25, 2011.


Elk (Cervus elaphus) and mule deer (Odocoileus hemionus) density and foraging behavior were monitored in conjunction with disturbance by livestock (cattle and sheep) from 1991 to 1993 at Deseret Land and Livestock property near Woodruff, Utah. Elk and deer densities declined by as much as 92% in response to introduction of livestock, while associated areas where livestock were absent did not show this response. Biting rates and bite sizes were estimated and used to determine instantaneous intake rate. These measures were similar between pastures with cattle present or absent in 1992 but differed in 1993 for bite rate and marginally so for instantaneous intake rate. Bite rate and bite size but not instantaneous intake rate showed significant differences among years when the data for both treatments were combined. My results indicated that livestock locally displaced wild ungulates but displacement occurred only while the livestock were present. Differences in elk foraging behavior were greater between years than between treatments, and instantaneous intake rate alone was viewed as an inaccurate indicator of potential reductions in fitness.