Ardea (genus)


Ardea is a genus of herons. The genus name comes from Latin ardea "heron". Linnaeus named this genus as the great herons, referring to the generally large size of these birds, typically 80–100 cm or more in length.
resembles the other Ardea in habitus, and the little egret only in color.
These large herons are associated with wetlands where they prey on fish, frogs, and other aquatic species.
Most members of this almost worldwide group breed colonially in trees, building large stick nests. Northern species such as great blue, grey, and purple herons may migrate south in winter, although the first two do so only from areas where the waters freeze.
These are powerful birds with large spear-like bills, long necks and long legs, which hunt by waiting motionless or stalking their prey in shallow water before seizing it with a sudden lunge. They have a slow steady flight, with the neck retracted as is characteristic of herons and bitterns; this distinguishes them from storks, cranes, flamingos, and spoonbills, which extend their necks.

Taxonomy

Some members of Ardea are clearly very closely related, such as the grey, great blue, and cocoi herons, which form a superspecies. However, the great egret, in particular, has been placed in other genera by various authors as Egretta alba and Casmerodius albus. Nevertheless, this species closely resembles the large Ardea herons in everything but color, whereas it shows fewer similarities to the smaller white egrets.

Species

A number of Ardea species are only known from subfossil or fossil bones. Their placement in Ardea versus Egretta may be provisional:
The remains described as Ardea perplexa are nowadays usually believed to be from an ibis of the genus Geronticus or closely related genera. "Ardea formosa" is now Proardeola, "Ardea" brunhuberi and "A." similis refer to a misidentified cormorant and partridge, respectively. "Ardea" lignitum - a fossil of quite recent age as it seems - is some large owl, perhaps even a Eurasian eagle-owl.