Great Bustard Otis tarda

Huge, unmistakable, regal bird of treeless open plains and natural steppes, occupying some low-intensity agricultural areas. Walks in a stately manner, but may run rather than fly if disturbed. Flight is heavy and gooselike. Highly gregarious, especially in winter. Males are much larger than the females and the sexes do not mix much outside of the breeding season. Spectacular "foaming bath" display at leks (display sites) as males bristle their body and wing feathers forward, turning them white, while burying their head in the plumage.