The great egret ( Ardea alba), also known as the common egret, large egret, great white egret,[ is a large, widely distributed egret. The four subspecies are found in Asia, Africa, the Americas, and southern Europe. Recently, it has also been spreading to more northern areas of Europe. Distributed across most of the Tropics and warmer temperate regions of the world, it builds tree nests in colonies close to water.
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Taxonomy
The great egret was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the binomial name Ardea alba. He specified the type locality as Europe.
Like all egrets, it is a member of the heron family, Ardeidae. Traditionally classified with the in the Ciconiiformes, the Ardeidae are closer relatives of 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.
The Old World population is often referred to as the "great white egret". This species is sometimes confused with the great white heron of the Caribbean, which is a white morph of the closely related great blue heron.
Subspecies
Four subspecies are found in various parts of the world, which differ but little.[
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A. a. alba Carl Linnaeus, 1758 – nominate, found in Europe and across the Palearctic.
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A. a. egretta Gmelin, JF, 1789 – found in the Americas
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A. a. melanorhynchos Wagler, 1827 – found in Africa
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A. a. modesta Gray, JE, 1831 – eastern great egret, found in India, Southeast Asia, East Asia and Oceania
Description
The great egret is a large heron with all-white plumage. Standing up to tall, this species can measure in length with a wingspan of .[ Body mass can range from , with an average around .][ 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 beak 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 nonbreeding adults. Differentiated from the intermediate egret ( Ardea intermedia) by the gape, which extends well beyond the back of the eye in case of the great egret, but ends just behind the eye in case of the intermediate egret.
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Its flight is slow with its neck retracted. This is characteristic of herons and , and distinguishes them from , cranes, , and , which extend their necks in flight. The great egret walks with its neck extended and wings held close. The great egret is not normally a vocal bird; it gives a low, hoarse croak when disturbed, and at breeding colonies, it often gives a loud croaking cuk cuk cuk and higher-pitched squawks.[
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Owing to its wide distribution across so much of the Americas, as well as Africa, Europe and Asia, the great egret shares its habitat with many other similar species. For example, the little egret ( Egretta garzetta), intermediate egret ( Ardea intermedia), Chinese egret ( Egretta eulophotes), and the western reef heron ( Egretta gularis). In the Americas, the snowy egret ( Egretta thula)—a medium-sized heron that shares the same habitat as the great egret—is one such species. The snowy egret is readily distinguished from the great egret because it is noticeably smaller, and it has a more slender bill which is black in color and yellow feet, whereas the great egret has a yellow bill and black feet. Another species that—in North America—is easily confused with the great egret is the white morph of the great blue heron ( Ardea herodias). The great blue heron is a bit larger, and has a thicker bill than that of the great egret.
Distribution and habitat
The great egret is generally a very successful species with a large and expanding range, occurring worldwide in temperate and tropical habitats. It is ubiquitous across the Sun Belt of the United States and in the Neotropics.[
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In the Nordic countries, it was historically a rare visitor. The first breeding was observed in Sweden in 2012 and in Denmark in 2014.
Presence in Great Britain
On 22 May 2012, a pair of great egrets was observed nesting in the UK for the first time at the Shapwick Heath nature reserve in Somerset.[ The species was a rare visitor to the UK and Ben Aviss of the BBC stated that the news could mean the UK's first great egret colony had become established.][ The following week, Kevin Anderson of Natural England confirmed a great egret chick had hatched, making it a new breeding bird record for the UK.][ In 2017, seven nests in Somerset fledged 17 young,]
Behaviour and ecology
The great egret breeds in Bird colony in trees close to large lakes with or other extensive , preferably at height of .
Diet
The great egret forages in shallow water or in drier habitats, feeding mainly on fish, frogs, other amphibians,
Parasites
A long-running field study (1962–2013) suggested that the great egrets of central Europe host 17 different Parasitic worm species. Juvenile great egrets were shown to host fewer species, but the intensity of infection was higher in the juveniles than in the adults. Of the found in central European great egrets, numerous species likely infected their definitive hosts outside of central Europe itself.
Threats
In North America, large numbers of great egrets were killed around the end of the 19th century so that their plumes, known as "", could be used to decorate hats.[
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In culture
The great egret is depicted on the reverse side of a 5-Brazilian real banknote.
The great egret is the symbol of the National Audubon Society.[
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An airbrushed photograph of a great egret in breeding plumage by Werner Krutein is featured in the cover art of the 1992 Faith No More album Angel Dust.
In Belarus, a commemorative coin has the image of a great egret.
See also
External links
