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Article Title

Denning Characteristics of Black Bears in the San Gabriel Mountains of Southern California

Volume

93

Issue

1

First Page

30

Last Page

37

Abstract

Denning habits of San Gabriel Mountain black bears were studied during the winters of 1987 through 1990. Mean denning period of five male bears was mid-November to mid-March. Denning periods for all bears ranged from late October to late March. Bears entered dens significantly later in 1988 than in 1987, 1989, and 1990 (P < .05). We speculate that fluctuations in food item availability might have affected the onset of denning. Exit dates (x 2 = 1.2, P = 0.758) and denning duration (x 2 = 4.79, P — 0.1 87) were not significantly different between years. Dens were located primarily in tree cavities {Pseudotsuga macro- carpa and Quercus chrysolepis) or under large boulders. All bears with more than one known den site reused a previous den. No incidents of winter activity were observed.