also called Uropygium, is a leathering of the sacral portion of the back. The most posterior feathers arise in front of the oil gland. This area is bounded laterally, by the flanks and posteriorly by the uppertail coverts. The feathers usually extend far enough to overlap the bases of the tail feathers.
The lower back of the bird, above the tail; conspicuously colored in some birds.
The general area of a bird where the lower back and base of the tail join. The rump is sometimes marked with distinctive plumage. Hidden beneath the rump feathers is the uropygial gland.
The hind portion of the back and bones.
Area between the uppertail coverts and the back.
The part of the back from the front of the pelvis to the root of the tail. Croup