What can echolocation recordings reveal about the foraging ecology of Saccolaimus saccolaimus (Emballonuridae) in north-western Australia?

Abstract

Echolocation sequences reveal aspects of the foraging ecology of Saccolaimus saccolaimus (Emballonuridae). In combination, pulse peak-frequency and fineness-of-tuning values derived from free-flying search-mode echolocation sequences emitted by S. saccolaimus in north-western Australia imply that it generally forages in uncluttered airspaces using an air superiority foraging strategy. Wing-beat frequency values, derived from pulse repetition rates in these sequences, reveal that it has a maximum aerobic level-flight speed of 8.1 m s–1 (used for foraging). These predictions are consistent with deductions based on airframe design parameters taken from museum specimens, and with available field observations. The echolocation recordings provided a quick, passive, cost-effective characterisation of foraging niche, useful for conservation planning.