This large swift has long, pointed wings and catches insects in flight. It is recorded in Hong Kong as a passage migrant.
It has long, pointed wings, a short tail, and a silvery-grey area on the back. In flight it is conspicuous as it glides quickly with its wings spread.
It catches insects while flying. In Hong Kong it is recorded over forested hills and fish ponds, passing through during migration.
Although it often passes through Hong Kong quickly, a flock of up to 76 remained at Shek Kong catchwater during 16–23 March 2017.
The sexes look alike, with a dark forehead, an ill-defined dusky throat and a white horseshoe across the rear flanks and undertail coverts.
An extinction-risk assessment has not been added yet.