Grey-rumped Treeswift

The grey-rumped treeswift is a bird of the treeswift family, which has four living species. When perched, the wing tips cross over the tail. Adult males have a distinct dark grey throat and chest contrasting with a white belly and dull orange-red or chestnut ear coverts, which females lack (Wikipedia, general species account).

Like other treeswifts it is closely related to true swifts, but unlike them it is arboreal, often perched on trees, high-tension power lines and pylons. The half-saucer nest is made of hardened saliva mixed with feathers, moss or flakes of bark and is built on a tree branch. The single egg is reportedly attached to the nest with saliva, so the bird does not sit directly on the nest; both sexes help incubate, one perching near the incubating adult and sliding carefully over the nest at changeover (Wikipedia, general species account).