Detection and distribution of eastern small-footed bats (Myotis leibii) in the Delaware Water Gap National Recreation Area

Abstract Eastern small-footed bats have traditionally been considered rare throughout their range in eastern and central North America. However, recent research suggests that this apparent rarity may be due to specialized habitat preferences combined with survey techniques that are ineffective for this species. We surveyed six talus slope sites within the Delaware Water Gap National Recreation Area for eastern small-footed bats in the summer and fall of 2018. We also compared four different survey techniques using detection probabilities calculated from repeated site visits. Eastern small-footed bats were documented at all six sites within the park, suggesting that this species is widespread in suitable habitats. Active acoustic monitoring had the highest detection probability (0.40 ± 0.20 SE), followed by passive acoustic monitoring (0.30 ± 0.075 SE), whereas visual roost searches and mist-netting were both unsuccessful (0.00) at detecting this species. We found some evidence for seasonal movement of eastern small-footed bats between different talus areas.