Uniform Swiftlet

The uniform swiftlet, also known as the Vanikoro swiftlet or lowland swiftlet, is a gregarious, medium-sized swiftlet with a shallowly forked tail. The colouring is dark grey-brown, darker on the upperparts with somewhat paler underparts, especially on chin and throat. This species is widespread from the Philippines through Wallacea, New Guinea and Melanesia. It forages for flying insects primarily in lowland forests and open areas. It nests in caves where it uses its sense of echolocation, rare in birds, to navigate.

Source: Wikipedia