Collocalia

Collocalia 

(swiftlets), a genus of birds of the suborder Apodes of the order Apodiformes. The birds are 10–14 cm long and have long, narrow wings. The plumage is dark brown or blackish. There are about 20 species, distributed in Southeast Asia, northern Australia, and the islands of the Indian and Pacific oceans (from the Mascarene Islands to Samoa). Most are sedentary birds; only two species, found in China, are migratory.

Swiftlets nest on cliffs, in large tree hollows, and, less frequently, in buildings. Some nest in dark caves, orienting themselves by echolocation. The birds live in colonies and feed on insects. Their nests (edible birds’ nests) are made from saliva or from plant material and feathers glued together with saliva. Swiftlets build their nests over a period of 30 to 50 days. A clutch contains one or two white eggs, which are incubated for about 28 days. The young remain in the nest for as long as two months.