Echolocation and distribution of Saccolaimus saccolaimus in north-western Australia

WA Museum Records and Supplements | Updated 6 years ago

ABSTRACT – Specimens of the vulnerable bat Saccolaimus saccolaimus have recently been recognised among museum collections from north-western Australia. They include one whose search mode echolocation pulses were being recorded when it was collected. In terms of spectral characters, this pulse sequence was indistinguishable from reference sequences by S. saccolaimus from the Northern Territory.
We compare these reference sequences with free-flying sequences: (1) from the two other species at the same detection sites that have a similar acoustic niche (Saccolaimus flaviventris and Chaerephon jobensis), and (2) recorded from sites elsewhere in north-western Australia. Equivalent sequences were detected at 40 of 173 recording sites scattered throughout north-western Australia, and in all five of its bioregions, implying that S. saccolaimus is widespread at the western end of its geographical range in Australia. At an overall average frequency of 20.3 kHz, these sequences, like their Northern Territory counterparts, are significantly different from S. flaviventris and C. jobensis in all spectral parameters measured, and consistent with (albeit 2.8 kHz lower than) S. saccolaimus sequences from Queensland.