Integrating information on species-specific sensory perception with spatial activity provides a high-resolution understanding of how animals explore environments, yet frequently used exploration assays commonly ignore sensory acquisition as a measure for exploration. Echolocation is an active sensing system used by hundreds of mammal species, primarily bats. As echolocation call activity can be reliably quantified, bats present an excellent model system to investigate intraspecific variation in environmental cue sampling. Here, we developed an in situ roost-like novel environment assay for tree-roosting bats. We repeatedly tested 52 individuals of the migratory bat species, Pipistrellus nathusii, across 24 h, to examine the role of echolocation when crawling through a maze-type arena and test for consistent intraspecific variation in sensory-based exploration. We reveal a strong correlation between echolocation call activity and spatial activity. Moreover, we show that during the exploration of the maze, individuals consistently differed in spatial activity as well as echolocation call activity, given their spatial activity, a behavioral response we term ’acoustic exploration’. Acoustic exploration was correlated with other exploratory behaviors, but not with emergence latency. We here present a relevant new measure for exploration behavior and provide evidence for consistent (short-term) intra-specific variation in the level at which wild bats collect information from a novel environment.

Integrating information on species-specific sensory perception together with spatial activity provides a high-resolution understanding of how animals explore environments, yet frequently used exploration assays commonly ignore sensory acquisition as a measure for exploration. Echolocation is an active sensing system used by hundreds of mammal species, primarily bats. As echolocation call activity can be reliably quantified, bats present an excellent animal model to investigate intra-specific variation in environmental cue sampling. Here, we developed an in situ roost-like novel environment assay for tree-cave roosting bats. We repeatedly tested 52 individuals of the migratory bat species, Pipistrellus nathusii, across 24 hours, to examine the role of echolocation when crawling through a maze-type arena and test for consistent intra-specific variation in sensory-based exploration. We reveal a strong correlation between echolocation call activity and spatial activity. Moreover, we show that during the exploration of the maze, individuals consistently differed in spatial activity as well as echolocation call activity given their spatial activity, a behavioral response we term ‘acoustic exploration’. Acoustic exploration was correlated with other exploratory behaviors, but not with emergence latency. We here present a relevant new measure for exploration behavior and provide evidence for consistent (short-term) intra-specific variation in the level at which wild bats collect information from a novel environment.

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.