Common Swift

The common swift is 16–17 cm long with a wingspan of 38–40 cm and is entirely blackish brown apart from a small white or pale grey patch on the chin that is not visible from a distance. It has a short forked tail and very long swept-back, sickle-shaped wings, longer than its body, so that its silhouette in the air resembles an anchor. Its nearest relatives are the New World hummingbirds and the treeswifts of Southeast Asia. Some individuals go ten months without landing (Wikipedia, general species account).

It is migratory and breeds in Eurasia; the cached account describes the species in general and gives nothing specific to its occurrence as a winter visitor in Southeast Asia (Wikipedia, general species account).