Common Swift

The common swift is a medium-sized bird, superficially similar to the barn swallow or house martin but somewhat larger and unrelated to them. It is 16 to 17cm long with a wingspan of 38 to 40cm and is entirely blackish-brown except for a small white or pale grey patch on the chin. It has a short forked tail and very long swept-back wings that resemble a crescent or boomerang (Wikipedia, general species account).

Some individuals go ten months without landing. The call is a loud, two-pitched scream, and in summer evenings 10 to 20 swifts gather in flight around their nesting area in screaming parties. Tree holes and cliffs may have been the historical nest sites, but removal of ancient forest has led it to adapt to man-made sites. The sources opened say nothing of how it occurs in Nepal.