Survival, reproduction, and movements of translocated nuisance black bears in Virginia

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Virginia Tech

Forty-three radio-collared black bears (Ursus americanus) captured in northwestern Virginia were released in the Mt. Rogers National Recreation Area (MRA) in southwestern Virginia, and monitored from June 1990-March 1992. Survival was 0.23 over the 22 month study; male (0.12) and female (0.37) survival rates were not different (P = 0.16). Vehicle collisions caused most of the mortality (53%), but legal harvest outside of the study area (16%) and illegal kills in the study area (11%) also were important.

Female bears failed to reproduce in the first winter following translocation, but during the second winter mean litter size was 2.75 (n = 4). A computer simulation of the female segment of the translocated population at the MRA predicted 45 females in the population in 1992, but only 29 females by 2002. The instantaneous rate of increase of the simulated population was -0.05 from 1993-2002.

Mean distance translocated from capture to release was 297.7 km. Eleven bears remained in their release areas (i.e., moved <10 km from release), while 32 left their release areas. The mean distance moved from release to recovery/last location was 3.6 km for the former and 48.8 km for the latter. There was no difference (P > 0.05) in the probability of remaining in or leaving the study area for either sex. Bears recovered dead were more frequently outside the study area than in the study area (P < 0.01).

For bears that left their release areas, the mean direction of travel from release to recovery/last location relative to the capture location (i.e., release to capture direction = 0°) was 31° and did not differ (P > 0.05) from the homeward direction. Despite some homeward orientation, no bears returned to their capture areas during this study.