Using a substitute species to inform translocation of an endangered territorial mammal.

Abstract

Substitute species can inform management strategies without exposing endangered species unnecessarily. Further, experimental approaches may help to identify the causes of translocation failures, leading to improve the chances of success. We used a surrogate subspecies, Tamiasciurus fremonti fremonti to test different translocation techniques to inform potential management actions on the endangered Mt. Graham red squirrel (Tamiasciurus fremonti grahamensis). We fitted VHF radio collars to 54 animals, and we monitored their survival and movements until individuals settled on a new territory. We considered the effect of season, translocation technique (soft or hard release), and body mass on survival, distance moved after release, and time to settlement of translocated animals. Survival probability averaged 0.48 after 60 days from the translocation event and was not affected by season or translocation technique. 54% of the mortality was caused by predation. Distance moved and number of days to settlement varied with season, where winter was characterized by shorter distances (average of 364 m in winter versus 1752 m in fall) and a smaller number of days (6 in winter versus 23 in fall). These data emphasize the potential of substitute species to provide valuable information on possible outcomes of management strategies for closely related endangered species.