Differentiating Western Australian Nyctophilus (Chiroptera: Vespertilionidae) echolocation calls.

Abstract

The ultrasound calls of the six species of Nyctophilus bat in Western Australia can be differentiated using power spectral analysis. Their search-mode call sequences show distinctive trends of variation in peak-frequency (Fpeak) values call-to-call. These differences are too subtle to be separated in amplitude-time domain with the processing tools currently available. The call-to-call variations in Fpeak through time can be characterised from the call sequence recordings using Fourier analysis if care is taken to select genuine search-mode sequences. These variations can then be used to correctly identify the species emitting the call.