Several of the egrets have been reclassified from one genus to another in recent years; the great egret, for example, has been classified as a member of either Casmerodius, Egretta, or Ardea.
In the 19th and early part of the 20th centuries, some of the world's egret species were endangered by relentless plume hunting, since hat makers in Europe and the United States
demanded large numbers of egret plumes, leading to breeding birds being killed in many places around the world.
Several Egretta species, including the eastern reef egret, the reddish egret, and the western reef egret, have two distinct colours, one of which is entirely white.
The little blue heron has all-white juvenile plumage.