Effectiveness of Translocation for Nuisance American Black Bears Varies By Sex and Age and Is Dependent on Distance and Habitat

Managing human-wildlife conflict is increasingly important for wildlife management and conservation. Translocation is a widely used non-lethal tool to mitigate human-wildlife conflicts, particularly for carnivores such as American black bears (Ursus americanus). Yet translocation efforts are often costly, while their effectiveness in mitigating human-wildlife conflicts is variable. We report on the characteristics of 1,571 translocations from 1,386 nuisance black bears in Wisconsin from 1979–2016 and evaluate the effects of different variables on whether translocated bears returned to their original home range. Translocation distances ranged from 2–235 km (mean = 58 km) and 88.3% of bears were not recaptured (i.e., did not repeat nuisance behavior) following translocation. Bears returned to their original home range in 127 of 201 (63%) translocations where bears were subsequently recaptured. The probability of nuisance bears returning decreased with increasing translocation distance, and yearling bears were less likely to return than adults. The proportion of agriculture within 100 km of the release site had the strongest effect on return probability out of our four land cover covariates and the probability of returning increased with increasing agricultural land cover. Our models suggest that mangers should use minimum translocation distances of 89–97 km for cubs, 60–70 km for yearlings in high-agriculture/low-forest landscapes and 90–99 km for cubs, 49–59 km for yearlings in low-agriculture/high-forest landscapes to have a predicted probability of returning of ≤10%. Estimated probability of returning for translocated adults was ≥25% across all translocation distances (≤167 km) and almost all landscape contexts. Because the vast majority of translocated bears did not repeat nuisance behavior, our results suggest that translocation was generally successful at reducing nuisance behavior. Our results also provide guidelines for further minimizing a translocated bear’s probability of returning given its age, sex, and landscape context.