Gray-rumped Treeswift

The grey-rumped treeswift is a species of bird in the Hemiprocnidae family. Currently, four extant species are placed in the family. Like the other members of the Hemiprocnidae, this species is closely related to true swifts, but unlike true swifts, the treeswifts are arboreal, often seen perched on trees, high-tension power transmission lines, and pylons. When perched, the wing tips cross over the tail. This species is commonly found in peninsular Malaysia, but has an extremely large range; there is limited information about population trends.

Source: Wikipedia