Pygmy swiftlet

The pygmy swiftlet (Collocalia troglodytes) is a species of swift in the family Apodidae. It is endemic to the Philippines.

Its natural habitat is subtropical or tropical moist lowland forests. At under 9 cm, it is the world's smallest swift. It weighs only 5 grams.

Swiftlets that nest in complete darkness in caves can use echolocation, the ability to position an object by reflected sound, used by other animals such as dolphins and bats.