Identification
Endemic to the upper massif of Mount Kinabalu, Borneo (on current knowledge). This small, fast flier is extremely difficult to identify since it overlaps with the abundant, very similar Plume-toed Swiftlet (formerly a subspecies of Glossy Swiftlet). A typical “white-bellied swiftlet”, with a white belly, dusky throat, and glossy dark upperparts, and bat-like flight. Compared to Plume-toed, Bornean averages a paler, matte green mantle (not heavily glossed) and neater upper breast and less contrasting crown, but this is difficult to confirm in flight. Only readily identified on nests, in the rocky upper reaches of the mountain (above 1,850m); has long been misidentified at middle altitudes, where only Plume-toed occurs. Gives a high-pitched yipping chitter, especially when near the nest.