Learning and the development of habitat-specific bat echolocation

Bats use echolocation calls that are suited for foraging in particular habitats. Many generalist bats alter their call design patterns as they move between open and spatially complex areas. This plasticity probably allows them to respond to the perceptual challenges posed by different structural environments. I tested the hypothesis that bats learn to produce these habitat-specific calls. I recorded the echolocation calls and foraging success of 14 juvenile little brown bats, Myotis lucifugus, as they foraged repeatedly in a large flight arena in two habitat treatments: open space and cluttered space. Calls were plastic across habitats. Furthermore, as bats gained experience, their foraging performance improved significantly in both open and cluttered habitat treatments. These improvements were related to changes in echolocation behaviour within the open habitat, which is consistent with the hypothesis that bats learn to produce more efficient calls in the open. Although the bats changed some aspects of their calls in the cluttered treatment, their use of space in the arena was the best predictor of foraging success. Bats that foraged in the centre of the arena were more successful. When bats switched habitat treatments, performance in the open was not affected by previous experience in the cluttered treatment. Bats that had previously experienced the open treatment, however, tended to use a more 'open-area' call when foraging in cluttered space. This result is discussed in light of habitat selection in young M. lucifugus.