Estimating the Population Size of Wrinkle-Lipped Free-Tailed Bats, Tadarida Plicata in Borneo Using Image Counting Techniques

Bats are ecologically important around the world, partially because they eat insects. They are globally threatened by human activities. The extent of bat populations in South Asia has not been as well-monitored or researched as other parts of the world. Determining the size of a large colonial bat population is difficult, and can be aided through video footage or photographs. This study aimed to determine the population size of Tadarida plicata that inhabit the Gomantong Cave system in Borneo. Images of an evening emergence were used to determine the speed of flight, and then the number of bats to emerge from the cave through particle analysis in ImageJ. The counts, subsequent extrapolation, and comparison to previous estimates of flight speed indicated a population size approximately half the size of previous estimates, emphasizing the importance of continued monitoring. Using ImageJ particle analysis was deemed to be an effective way of estimating the number of bats in large populations