Effect of family support on the success of translocated black-tailed prairie dogs.

Translocation has become a widely used conservation tool but remains only marginally successful. High mortality is often attributed to predation, but for highly social species, founder group composition may also play a critical role in postrelease survival. I compared the fitness of black-tailed prairie dogs translocated with or without their family groups. Animals in the family translocated groups were individually marked and observed until coterie membership was determined. Nonfamily translocated animals were trapped without regard to family membership. I measured fitness by retrapping all marked animals remaining at release sites in the summer following release. Family translocated animals were five times more likely to survive and had significantly higher reproductive success than those translocated without families. Predation was an important impediment of translocation success, but family translocation significantly reduced the success of predators on newly established prairie dog colonies. Postrelease survival was also affected by the timing of release, but appeared to be more important for juveniles than adults. These results demonstrate the importance of considering familiarity when translocations are required. More broadly, these results illustrate the value of applying animal behavior to conservation efforts and suggest that other species dependent on social interactions for survival and reproduction may benefit substantially from the maintenance of social groups during translocations.