Terrestrial LiDAR-based automated counting of swiftlet nests in the caves of Gomantong, Sabah, Borneo.

High resolution terrestrial laser scanning (TLS) within the Simud Hitam cave, Gomantong, has proven successful at discriminating the nests of black-nest swiftlets from roosting bats in high, inaccessible locations. TLS data was imported into ArcGIS software, allowing for semi-automated counting of nests. Spatial analysis of nest locations has established a maximum packing density of 268 nests/m2 in optimum locations, which correspond to roof slopes of >20 degrees. Rhinolophid bats roost adjacent to, but not within nest locations, preferring roof surfaces close to horizontal.