Салангана сундайська Aerodramus fuciphagus

One of a number of essentially identical-looking small swifts. Famous for its unique, gelatinous, pale nest, which is harvested throughout much of its range; reliably identified only while on the nest. Like many other swiftlets, nests in caves and crevices, often in massive colonies with other species. Frequently gathers in huge flocks, particularly over water. Chitters buzzily in flight.