Echolocation and foraging ecology of the bristle-faced free-tailed bat, Setirostris eleryi, in central Australia

Abstract

We document the spectral characteristics of echolocation sequences of Setirostris eleryi recorded from riparian zones in the Central Ranges in Western Australia, near Warakurna. These are the first records of this species in Western Australia. The sequences are comparable to reference S. eleryi sequences from near Alice Springs, as well as to sequences from a nearby vouchered specimen locality (Hull River in the Northern Territory), yet distinct from Scotorepens greyii sequences from Western Australia, including locations in the Central Ranges. The central Australian S. eleryi sequences average 3kHz higher in frequency than reference S. eleryi recordings from eastern Australia. We deduce the species’ foraging strategy, microhabitat, wing beat frequency and flight speed from the echolocation sequences, then show that these deductions are consistent with calculations based on an airframe analysis of museum specimens, and with available field observations. The echolocation recordings provided a quick, passive, cost-effective characterisation of foraging niche, useful for conservation planning.