Dispersal Movements by Subadult American Black Bears in Virginia

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Dispersal plays an important role in the population dynamics of large carnivores; however, dispersal by subadult American black bears (Ursus americanus) is poorly understood in Virginia, as well as in North America. Thus, during 1999-2002, we studied the movements of 31 (11M:20F) subadult black bears born on 2 study areas in western Virginia and 70 (44M:26F) subadult bears captured during the summer on the study areas. No radiomarked, natal-captured, subadult female bears exhibited dispersal behavior while 3 of 11 (27%) radiomarked, natal-captured, subadult males dispersed. Natal-captured and summer-captured male bears moved greater distances than females from yearling den location and summer-capture locations. The longest subadult male movement was 80 km (x̄ = 13.4 km, range = 0.6-80.0 km), and dispersal movements primarily occurred within the 1 and 2-year-old age classes. Direction of movement between initial and final locations for dispersing bears was not random; bears appeared to follow the orientation of the predominant ridgelines and avoided leaving the national forest. All known mortality of dispersing and non-dispersing bears was due to harvest. Lack of female dispersal may require managers to control local harvest of females to provide for continued reproduction and growth in some areas.