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In June 2021 we used ultrasonic recorders to inventory zoophagic bats at mangrove patches in three bioregions on the Northern Territory coast: Darwin Coastal, Arnhem Coast and Gulf Coastal. All species could be separated in terms of their search-mode echolocation sequences using tropical Western Australian and Northern Territory reference libraries based on pulse peak frequency (F peak), fineness-of-tuning (Q − 6dB), repetition-rate and shape. Twenty-five of the 27 species that comprise the 'Top End' zoophagic bat fauna are now known to occur in its mangroves, an average of 21.3 ± 0.3 (s.e.) species per bioregion. Northern Territory and Western Australian populations of all but three species show few discernable differences in the four echolocation metrics assessed. Unlike the tropical bioregions in Western Australia, no bat species is confined to mangroves in the Northern Territory. Even so, analysis of data from these and adjacent bioregions shows that bat community structures throughout tropical north-western Australia are adapted to their environmental setting. In this paper we discuss how to recognise 'Top End' bats from their echolocation sequences, data needed for rapid inexpensive survey and monitoring programmes that inform conservation planning. We present the results of the first systematic survey of the bats occupying Northern Territory mangrove forests. More broadly, we identify environmental controls influencing the species composition and structure of tropical bat communities across north-western Australia. [ABSTRACT FROM AUTHOR]

We update the list of indigenous mammals known from each of Western Australia's mainland bioregions since European settlement, assess their regional status in terms of extent of occurrence, then compare these regional status lists and derived faunal attrition values with those published in 2006. Seven bioregions show substantially more faunal attrition since 2006, including the Avon Wheatbelt, Victoria Bonaparte and Northern Kimberley. The status of 27 species has worsened in at least one bioregion, an average of 1.7 species per bioregion across the 26 bioregions. We also examine potential explanatory factors associated with faunal attrition across the bioregions using beta regression and AIC-based model selection. Faunal attrition was strongly associated with low average annual rainfall, a low proportion of species that shelter in rockpile habitat, high environmental change, a high proportion of species in the 'Critical Weight Range' and, to a lesser degree, a high proportion of omnivorous species. Only conservation management outside of havens can reverse this downward trend. [ABSTRACT FROM AUTHOR]

Little is known about the extent of the foraging habitat and characteristics of the threatened Ghost Bat (Macroderma gigas) in the arid regions of Western Australia. We used GPS satellite tracking technology to accurately measure the Pilbara Ghost Bat's foraging characteristics. We provide detailed foraging and commuting data for ten bats, eight males and two females tracked over multiple nights. From the time and location data collected, results for five foraging characteristics were calculated. These were the minimum time spent outside the diurnal roost, the time spent for short periods in a specific foraging area, the typical area used for during a foraging period, the maximum radial distance flown from the diurnal roost, and the minimum 'cave-to-cave' distance covered. The time spent outside the roost varied widely with bouts lasting from under half the night to the full period of darkness. The average time spent at a particular foraging area was 116 minutes during which the bats used multiple perches for typically 20 minutes each. Little pattern was evident in the areas used for foraging. The bats made use of the majority of an area available once they had begun to forage there. During foraging bouts, the average radial distance from the roost from all available data was 8.5 km and the maximum distances recorded was 17.7 km. The average return flight distance from all data was 19.4 km with a maximum length of 41 km. One bat totaled over 90 km in four nights. A one-way commute of 27.4 km was also recorded. The Pilbara Ghost Bat is confirmed to be foraging across a varied habitat and over distances not previously recognised. Generally, thinly wooded areas of Mulga, other Acacia or Eucalypt spp. or linear woodland features are preferred in areas with a moderate percentage of open ground (typically 30--70%) to facilitate the perch and sally 'surface' foraging strategy used for terrestrial prey. No pattern was evident in substrate type. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Claramunt et al. (2019), published a list of vertebrate prey items taken by Ghost Bats in the Pilbara Region of Western Australia but did not identify the bat wing bones that were contained in their samples. We identified those bones to extend (from four to nine species) knowledge of other bats consumed by Ghost Bats in the Pilbara showing that bats are an important component of their diets. [ABSTRACT FROM AUTHOR]