A sudden decline in critically endangered bats is troubling experts, who recorded about 5,000 fewer southern bent-wing bats than usual at Naracoorte’s “bat cave” this summer. These tiny russet-toned microbats roost in caves and forage for insects over long distances across south-west Victoria and south-east South Australia. View image in fullscreen Southern bent-wing bats’ decline in numbers is a ‘huge concern’ to researchers. Severe declines since then have seen southern bent-wing bats listed as one of Australia’s eight critically endangered mammals. Southern bent-wing bats depend heavily on adult survival, she said.