This is distinguished from Herodias by shorter bill and feet, by the nude portion of the tibia being shorter than the inner toe without claw, and by the changes in the breeding-season being quite different. The culmen is much shorter than the middle toe and claw, and these are shorter than the tarsus. In non-breeding plumage birds of this genus are pure white, but in the breeding-season buff hair-like plumes appear on the head, neck, and back. The habits of the present genus differ greatly from those of Herodias.
Only two species are known ; they inhabit the warmer parts of Europe and Asia, and the whole of Africa. One species is Indian.