Installation and monitoring of bat windows in a grated roost cave in the Pilliga Forest, northern inland New South Wales, Australia

Bat departure activity was monitored at a grated cave site where bat windows had been added to the existing grate to improve accessibility for echolocating bats. Eastern Horseshoe-bats Rhinolophus megaphyllus were able to exit and re-enter the grated cave through bat windows measuring 150 mm high × 1270–1330 mm wide. Most of the bats, however, continued to use a 200 mm high × 600 mm wide gap between the top of the grate and the irregularly-shaped cave roof, despite this requiring a more circuitous flight path. The study concluded that the addition of bat windows was a useful but not essential improvement at the site, increasing the number of horizontal fly-through areas available for bats at the cave entry whilst maintaining necessary security.