White-nest Swiftlet Aerodramus fuciphagus

A small acrobatic swiftlet, often in large swirling flocks above fields, forests, and settlements. Dark brown above, washed-out gray-brown below; all but identical for the most part to many other swiftlets in range. Rump is marginally paler than Himalayan, Black-nest, and Mossy-nest swiftlets, but not white, as in House Swift. Most reliably identified while on the nest, a pale gelatinous bowl in a cave or crevice. Often nests in large colonies with other swiftlet species. Gives buzzy trills in flight.