WINTER RECREATION AND HIBERNATING BLACK BEARS URSUS-AMERICANUS

The increase of recreational activities in winter wildlife habitats is of concern because wildlife populations are under considerable stress during winter. To assess the effects of winter activities on black bears Ursus americanus, denning ecology was studied for three winters in the Sierra Nevada and Sweetwater Mountains in Nevada and California. Fourteen bears in the Sierra entered 31 dens earlier and were more selective in their choice of den sites than five Sweetwater bears using 10 dens. Bears at both sites abandoned dens and cubs in response to investigator disturbance, and all but one bear remained active after abandonment. High overlap between bear denning sites and potential winter recreation areas indicated a high potential for den abandonment due to human disturbance. Bear denning areas should be protected from human disturbance during winter.