A tiny, common swiftlet found over lowland forest. Gray below with a paler belly, a darker throat, and dark patches on the underside of the base of the forewing. Black above with a distinctive white band on the rump. Tail square, and dark under the base. Nests in caves, where it uses echolocation. Similar to Gray-rumped Swiftlet, but Pygmy is slightly smaller, with a cleaner white rump band. Gives grating calls in flight.