||The projects seeks to develop a means of accurately determining the population of Southern Bent-winged Bats Miniopterus bassanii in Bat Cave at Naracoorte Caves National Park.
The bat population in Bat Cave was estimated to be 100-200,000 by Dwyer and Hamilton-Smith in 1965. Various estimates between then and the next realistic count in 2000 placed (erroneously) the population at between 200,000 and 400,000 with one park brochure even suggesting three quarters of a million bats present. The population has been determined by a number of methods in the past including mark-recapture, estimating pup density and adult densities on cave walls and video recording the exit fly out. Survey started in 2000 and is ongoing.
The project will build on work by Terry Reardon and Chris Grant, who undertook video counts from 2001 to 2006. A similar methodology will be used. A second component will be working with Adelaide-based company Lastek, to develop an automated bat counting system. This involves placing a thin beam of light across the cave entrance and recording each bat's exit by means of light sensitive diodes linked to a computer. The objective is to develop a permanent system that will count the bats in and out of the cave every day of the year. Preliminary trials have shown the system has no disturbance to the bats.