BATVIEW · A bat's-ear view of natural soundscapes during flight

The knowledge of sensory systems is of central importance for our understanding of life. The brain commands the behaviour, but it banks on sensory input to do so. Biosonar is a particularly enticing sensory system to study. A seemingly exotic sense, it is in fact the main sensory modality of one in five mammalian species and it bears the big advantage that we can tap directly into the sensory stream. The echolocator only receives information when it emits sound, exerting full control over the information flow while allowing us to eavesdrop. From lab studies with bats, we thus have profuse knowledge of their striking biosonar capabilities, but paradoxically very little knowledge about how bats use these capabilities to play ecologically and economically critical roles in a large suite of ecosystems in the wild, under conditions for which they evolved. BATVIEW will utilize a unique, world-first solution to the problem of how to study echolocation of individual bats catching prey on the wing in the wild. BATVIEWs host lab has very recently developed a 2.6g ultrasound-recording and inertial-sensing tag for free-flying bats. Along with logging detailed information on flight and capture behaviour, the tag records not only the bat?s outgoing calls but also the weak returning echoes for an entire night of foraging. With such high-quality quantitative data in the form of echograms and synchronised accelerometer readings, I will answer fundamental questions of sensory and foraging ecology in an August-Krogh species, the fringe-lipped bat. In accomplishing BATVIEW?s objectives, I will (A) gain a clear and reliable assessment of the percept that biosonar provides, in order to determine (B) how the percept changes dependent on (C) different ambient conditions and (D) different behavioural contexts. BATVIEW will offer an unprecedented understanding of how sensory information flow governs behavioural transitions in the wild and pave the way into a new era of sensory ecology.