Population characteristics of black bears in west central Idaho

Publication Type:

Journal Article

Authors:

Beecham, John J.

Source:

Journal of Wildlife Management, The Wildlife Society, Volume 47, Issue 2, p.405-412 (1983)

Call Number:

A83BEE01IDUS

Keywords:

black bear, Ursus americanus

Abstract:

Population characteristics of black bears (Ursus americanus) were studied in west central Idaho from 1973 through 1977. A total of 175 bears was captured 509 times. Estimated density of bears on the 130-km² study area was approximately 1 bear/1.3 km². Capture-recapture records revealed that 2.5-year-old males were captured in higher numbers (P < 0.01) than were 2.5-year-old females, but were recaptured less frequently (P < 0.05). No differences were observed in recapture rates among other sex and age-classes. The oldest bears captured were in excess of 20 years of age. The only age-class in which the sex ratio differed (P < 0.05) from unity was among 2.5-year-old bears. Both extrinsic and intrinsic factors are apparently involved in the regulation of black bear numbers. Annual variation in reproductive success is the main factor influencing short-term population fluctuations. Climate, with its resultant influence on habitat, appears to be the primary extrinsic factor controlling long-term population size.