Abstract
During 1964, 1410 hours of observation yielded 6746 sightings of black-tailed deer (Odocoileus hemionus columbianus) within the Cedar Creek study enclosure on the Tillamook Burn, Oregon. Deer activity was influenced by age, sex, reproductive phase, extremes or sharp changes in temperature, minimum relative humidity, and precipitation. Deer sought cover by midmorning from mid-May to November when weekly extreme temperatures exceeded 60°F. Their activity was sharply reduced by heavy summer rainfall, but was not influenced by winter rains. Monthly and annual home ranges were related to age and sex, and varied with changes in the reproductive cycle and forage availability. Annual home ranges varied from one-eighth to one-half square mile.