An aggressive display with which some male birds (e.g. green heron, Butorides virescens) challenge another bird that seeks to invade its territory by landing on the tree where it intends to build its nest. The displaying bird holds its body horizontally, with its feathers fully erect, its eyes bulging, its mouth open, and its tail moving rapidly up and down. The bird then lunges at the intruder, waving its wings and uttering a harsh cry.
Subjects: Zoology and Animal Sciences.