It was for some time considered the same species as its eastern relative, the gray-rumped treeswift (Hemiprocne longipennis), but they do not interbreed where their ranges overlap.

[2] Young birds have a dark grey head and wings but the feathers are edged in white and the rest of the soft plumage is much streakier than that of the adults.

They are found in small groups that fly in wide circles in open forest, occasionally perching atop a tall and leafless tree.

He collected specimens during his travels in the Borabhum and Dholbhum area while serving as a lieutenant in the 31st regiment of native infantry.

[6] The genus Hemiprocne was erected by Christian Ludwig Nitzsch in 1829 but the species has variously been incorrectly treated in the past in Dendrochelidon and Macropteryx.

It is found in India, Sri Lanka, Bhutan, Bangladesh, Nepal, Myanmar, Thailand, Vietnam, Cambodia, Laos and China.

Most birds live in the lowlands below 1000 m.[3] The crested treeswift builds a tiny and thin-walled and shallow nest made up of pieces of bark and feathers which is glued with saliva to the side of an exposed tree branch.

[3] The breeding season is during the hottest part of summer from March to July and nests may be positioned on the eastern side of a branch so that the adult would have the sun on its back during the afternoon.