Foraging Behavior by Mule Deer: The Influence of Cattle Grazing

Abstract

We studied the effects of different cattle stocking rates on activity patterns of female mule deer (Odocoileus hemionus) on a summer range in the Sierra Nevada of California. Using an automated telemetry system, we determined that deer averaged 32±2.2 (SE)% of the time feeding, 8±1.1% traveling, and 60±2.4% resting per 24-hour period. Deer spent more time feeding and less time resting with increased cattle stocking rates. During 1984, a year of average precipitation, deer spent more time feeding per day in late summer than in early summer in range units grazed by cattle but did not do so in ungrazed range units. In 1985, a drier year, deer spent less time feeding per day in late summer in grazed range units