Migration strategy varies with novel environment response in common noctule bats

Global ecosystems are changing dramatically due to land transformation and climate change. Global change is a particular challenge for migratory animals that rely on multiple stepping stones on their journeys. Migratory animals have a range of strategies to accomplish this, but not all of these strategies may be appropriate for the challenges ahead. Understanding the variation in migratory strategies and their behavioural correlates is therefore critical to understand how vulnerable species will be in the future, especially in endangered and elusive taxa such as bats. Here, we combined isotopic geolocation with an in-situ behavioural assay to investigate whether behavioural responses to a roost-like novel environment correlated with variation in migration strategies (local or distant origin based on isotopic geographic assignments), in the partially migratory bat, Nyctalus noctula. We quantified emergence behaviour, spatial activity, and echolocation call activity. Local bats were more likely to emerge into the novel environment than bats from more distant origins. However, local and distant bats did not differ in spatial activity and acoustic exploration (relative call activity per space unit). Our findings indicate that local bats may more pro-actively cope with novelty, but that acoustic exploration is equally important for local and migratory bats during explorations.