The Great Egret (Ardea alba), also known as the Great White Egret or Common Egret or (now not in use) Great White Heron, and called k?tuku in New Zealand, is a large egret. Distributed across most of the tropical and warmer temperate regions of the world, in southern Europe and Asia it is rather localized. It is sometimes confused with the Great White Heron in Florida, which is a white morph of the closely related Great Blue Heron (A. herodias). Note however that the name Great White Heron has occasionally been used to refer to the Great Egret.
The Great Egret is a large bird with all-white plumage that can reach one meter in height and weigh up to 950 g. It is thus only slightly smaller than the Great Blue or Grey Heron (A. cinerea). Apart from size, the Great Egret can be distinguished from other white egrets by its yellow bill and black legs and feet, though the bill may become darker and the lower legs lighter in the breeding season. In breeding plumage, delicate ornamental feathers are borne on the back. Males and females are identical in appearance; juveniles look like non-breeding adults.
It has a slow flight, with its neck retracted. This is characteristic of herons and bitterns, and distinguishes them from storks, cranes, ibises and spoonbills, which extend their necks in flight.
The Great Egret is not normally a vocal bird; at breeding colonies, however, it often gives a loud croaking cuk cuk cuk.
Systematics and taxonomy
Like all egrets, it is a member of the heron family, Ardeidae. Traditionally classified with the storks in the Ciconiiformes, the Ardeidae might in fact be closer relatives of pelicans and belong in the Pelecaniformes instead. The Great Egret "? unlike the typical egrets "? does not belong to the genus Egretta but together with the great herons is today placed in Ardea. In the past, however, it was sometimes placed in Egretta or separated in a monotypic genus Casmerodius.
There are four subspecies in various parts of the world, which differ but little. Differences are bare part coloration in the breeding season and size; the largest subspecies is A. a. modesta.
- Ardea alba alba from Europe
- Ardea alba egretta from Americas
- Ardea alba melanorhynchos from Africa
- Ardea alba modesta from Asia and Australasia
Ecology and status
The Great Egret is partially migratory, with northern hemisphere birds moving south from areas with cold winters. It breeds in colonies in trees close to large lakes with reed beds or other extensive wetlands. It builds a bulky stick nest.
Although generally a very successful species with a large and expanding range, the Great Egret is highly endangered in New Zealand, with only one breeding site at Okarito Lagoon. In North America, large numbers of Great Egrets were killed around the end of the 19th century so that their plumes could be used to decorate hats. Numbers have since recovered as a result of conservation measures. Its range has expanded as far north as southern Canada. However, in some parts of the southern United States, its numbers have declined due to habitat loss. Nevertheless, it adapts well to human habitation and can be readily seen near wetlands and bodies of water in urban and suburban areas. In 1953 the Great Egret in flight was chosen as the symbol of the National Audubon Society, which was formed in part to prevent the killing of birds for their feathers.
They are Protected in Australia under the National Parks and Wildlife Act, 1974.
The Great Egret is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
Spearing a fish
The Great Egret feeds in shallow water or drier habitats, spearing fish, frogs or insects with its long, sharp bill. It will often wait motionless for prey, or slowly stalk its victim. It is a common species, usually easily seen.
Though it might appear that they feed on the parasites off buffalos, they actually feed on leaf hoppers, grass hoppers and other insects which are stirred open as buffalos move about in water.
In human culture
The Great Egret is depicted on the reverse side of a 5-Brazilian Reais banknote and on the reverse side of a New Zealand $2 coin.