swiftlets

Swiftlets are small aerial birds in the family Apodidae, belonging to genera such as Aerodramus and Collocalia. They are insectivores that spend most of their lives in flight, feeding on flying insects. Swiftlets breed in dark environments such as caves and, in many parts of Southeast Asia, in purpose-built human structures known as swiftlet houses.

Physically, swiftlets are compact and typically measure around 9 to 12 centimeters in length. They have streamlined bodies, short necks, and dark plumage that helps camouflage them while foraging at high speeds. Many species have glossy blue-gray or brownish plumage and are adapted to rapid, agile flight.

Diet and navigation: Swiftlets feed mainly on flying insects, catching them in midair. In caves and dark nesting sites, some species produce faint clicking sounds that aid navigation, a form of echolocation that helps them maneuver in cluttered spaces.

Nesting and nests: A distinctive characteristic of swiftlets is their nests, which are built almost entirely from the birds’ saliva. The nests, especially those of the edible-nest swiftlet, are harvested for use in bird’s nest soup. Nests are attached to cave ceilings or to man-made structures designed for nesting, and harvesting occurs under regulated or commercial farming practices in various countries.

Distribution and habitat: Swiftlets are distributed across tropical and subtropical regions of Asia, Oceania, and the Pacific. They commonly inhabit caves, cliff faces, and the interiors of buildings where nesting sites are available.

Conservation and economy: The nest trade is economically significant in several countries but can threaten wild populations if unsustainable. Conservation measures include habitat protection, regulated harvesting, and the development of controlled swiftlet farming to reduce pressure on wild colonies.