,
Andhra Pradesh, India in the
Yolo Bypass Wildlife Area, California Egrets hold a separate group with bitterns and herons within the 74 species found in the bird family Ardeidae. Many egrets are members of the
genera Egretta or
Ardea, which also contain other species named as herons rather than egrets. The distinction between a heron and an egret is rather vague, and depends more on appearance than biology. The word "egret" comes from the French word
aigrette that means both "silver heron" and "brush", referring to the long, filamentous feathers that seem to cascade down an egret's back during the breeding season (also called "egrets"). 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 just white. The
little blue heron has all-white juvenile plumage. ==Species in taxonomic order==