Great egret

Name and taxonomy

Carl Linnaeus described the bird in 1758 and gave it the name Ardea alba. Ardea is the Latin word for a heron, and alba means white. Linnaeus set the type locality as Europe. English speakers also call it the common egret, the large egret and the great white egret. The word egret comes from the French aigrette, a name for both a white heron and a brush.

Four subspecies are recognised, and they differ only a little. The differences lie in size and in the colour of the bare parts during the breeding season. The Asian and Australasian form, A. a. modesta, is the smallest of the four. Some taxonomists raise it to a full species, the eastern great egret, but most keep it as a subspecies. The other three forms breed in Europe and the Palearctic, in the Americas and in Africa.

Evolution and relatives

The great egret belongs to Ardeidae, the heron family. It sits in the genus Ardea beside the grey heron and the great blue heron. The typical small egrets belong to a different genus, Egretta, so the name egret does not track the family tree. Earlier authors placed the species in Egretta, or alone in a genus called Casmerodius.

Herons were once grouped with the storks in the order Ciconiiformes. They now sit in the Pelecaniformes, which makes pelicans their closer relatives. A pale form of the great blue heron looks similar, and people in North America often confuse the two. Like other herons, the great egret probably kept its stalking habits with very little change over a long span.

Appearance

The plumage is white all over at every age and in every season. An adult measures 80 to 104 cm in length and stands up to 1 m tall. The wingspan runs from 131 to 170 cm. Body mass ranges from 0.7 to 1.5 kg, and about 1 kg is normal. That makes the bird only a little smaller than the grey heron.

The bill is yellow and the legs and feet are black. In the breeding season the bill can darken and the lower legs can pale. Breeding adults also grow long lacy plumes along the back, and these are the aigrettes of the hat trade. The gape runs back well past the eye, which separates the bird from the intermediate egret. The snowy egret is smaller, with a black bill and yellow feet, so the colours are reversed.

The neck is long and folds into a tight S shape. Herons manage this with modified neck bones, of which they have 20 or 21. The bird keeps the neck folded in flight and beats its wings slowly. Storks, cranes and ibises fly with the neck stretched out, so the shape names the family at a distance. On the ground the egret walks with the neck extended and the wings held in.

Habitat and range

Great egrets live in warm temperate and tropical wetlands around the world. Streams, lakes, ponds, mud flats and marshes all suit the bird. Wooded swamps appear to be the favourite, because they hold both feeding water and nest trees. The species uses fresh water and salt water without any obvious preference. It also feeds in dry fields when grasshoppers and rodents are easy to find.

In North America the bird is common right across the southern states and up the Atlantic coast. Its breeding range now reaches the Great Lakes and southern Canada. Birds leave the northern edge in winter and stay only where water keeps flowing. Many wander north after the young fledge, which is why late summer records run far beyond the nesting range.

Europe has watched a fast expansion northwards over the last two decades. The first Swedish nest was found in 2012 and the first Danish nest in 2014. A pair raised four young in a grey heron colony at Porvoo in Finland in 2018. Britain gained its first nest at Shapwick Heath in Somerset in 2012. Seven Somerset nests fledged 17 young in 2017, and Scotland gained its first chicks in 2024.

Diet and feeding

Fish are the mainstay of the diet. The bird also takes frogs and other amphibians, crayfish, snakes, mice and large insects. Grasshoppers and aquatic insects turn up often in studies of what it eats. The great egret seems to be an opportunist, and it will try most small animals it can swallow.

Hunting appears simple and is not. The bird wades through shallow water at a slow pace, or holds still and lets prey come to it. The strike is a single fast thrust of the bill, driven by the folded neck. Work on foraging found that a motionless bird takes more mid-sized prey than a bird on the move. That result suggests the egret works for good prey rather than for the largest possible number.

Great egrets also rob other birds. A high share of their food is taken from smaller herons that have already caught it. Chicks in the same nest fight each other over food that a parent brings. Other large waders eat the same prey and compete with the egret at the same pools.

Behaviour and social life

The great egret feeds by day and gathers at dusk into shared roosts. Birds come in to these roosts from wide areas of wetland around them. Nesting is colonial, so the species is social at the roost and at the colony. A single feeding bird still guards its patch of water.

The bird is strongly territorial over courtship, nest sites and feeding places. Studies found high aggression even when food was plentiful, so hunger is not the only trigger. An intruder may be met with a harsh squawk, a leap or a jab of the bill. Adults and grown young travel long distances together after the breeding season ends. This post-breeding dispersal is common and moves birds well outside the nesting range.

Communication and senses

The great egret is a quiet bird for most of the year. A disturbed bird gives a low hoarse croak as it lifts off. At the colony the voice is louder, with repeated croaks and higher squawks. Animal Diversity Web writes the usual call as a harsh low note.

Much of the signalling is visual rather than vocal. Courtship uses a long set of displays at the nest site, and the plumes are raised during them. Territorial display probably carries the same message to a rival that a call would. Like other herons, the bird relies mainly on sight to find prey under the surface. The eyes sit high on the head, which seems to suit a hunter that looks down into water.

Reproduction and life cycle

Great egrets form a new pair each season and stay with that partner for the season. Whether the same two birds pair again the next year is not known. Most birds first breed at two or three years old. In North America the season opens in the middle of April. The male picks the site, starts a nest and then displays to draw a female in.

Colonies sit in trees near large lakes with reed beds or other wide wetlands. Nests are usually placed between 3 and 12.2 metres above the ground or water. The nest itself is a loose platform of sticks and stems, lined with softer plant matter. Other heron species often nest in the same trees.

A clutch holds three or four pale blue-green eggs, and up to six are possible. A pair will lay again if the first eggs are broken. Both parents incubate, and the eggs hatch after 23 to 26 days. Chicks hatch helpless under a coat of long white down. Parents first feed them by bringing food back up, then hold prey for the chick to grab.

The young start to fly at about six weeks and are flying well by seven. One brood a year is the rule. A wild great egret lives about 15 years. The oldest ringed bird reached 22.8 years, and a captive bird reached 22.

Predators and threats

An adult great egret has no natural predator apart from people. Eggs and chicks are a different matter and many animals take them. Crows and vultures raid the nests from the air. Raccoons climb to the colony and do the most damage of any nest predator.

Habitat loss is the main modern threat in parts of the southern United States. Drainage, grazing, clearing, burning and groundwater extraction all shrink the wetlands the bird needs. Rising salinity and invading plants damage the remaining marshes. Water pollution appears to add a second problem that is harder to see. Hydrocarbons thin the eggshells, so more eggs crack before the chicks hatch. Mercury builds up in the feathers and can change behaviour, body chemistry and breeding.

Parasites are typical of a fish-eating bird. A field study in central Europe that ran from 1962 to 2013 found 17 helminth species in great egrets. Young birds carried fewer kinds of worm than adults but heavier infections.

Population and conservation

The IUCN lists the great egret as Least Concern. The range is large, and it has expanded in both Europe and North America. Birders have logged 419272 observations of the species on iNaturalist. GBIF holds records from 227 countries and territories, which include zoos and stray birds.

The global picture appears to hide sharp regional differences. The French IUCN committee lists the bird as Vulnerable in Guadeloupe. Indiana treats it as a species of special concern, and NatureServe ranks its breeding population there as critically imperilled. In New Zealand the eastern form nests at a single site, Waitangiroto Nature Reserve near Whataroa. Predator control lifted that colony to 56 pairs in 2023.

The recovery in North America is one of the best known in conservation. The Migratory Bird Treaty Act brought the species under protection in 1918. Numbers climbed steadily through the middle of the twentieth century. The bird now nests as far north as southern Canada.

Relationship with humans

The great egret adapts well to places where people live. It feeds in ditches, farm ponds and park lakes in towns and suburbs. A wading bird that stands in the open probably makes the easiest subject a marsh photographer can find. Animal Diversity Web records no harmful effect of the species on people.

The history appears darker than the present. Hat makers in Europe and America wanted the breeding plumes for women's hats and clothes. Hunters shot the adults at the colony, in the season when the plumes are grown. That timing likely killed the chicks as well as the parents. Large numbers died in North America at the end of the nineteenth century. Wardens who guarded colonies stopped the trade, and the population came back quickly.

In culture and myth

The National Audubon Society took the great egret as its symbol. The choice probably records the fight against the plume trade that founded the society. The bird appears on the back of the 5 real note of Brazil. New Zealand puts it on the two dollar coin, and Hungary puts it on the 5 forint coin. Belarus has struck a commemorative coin with the same bird on it.

In Maori tradition the bird is the kotuku, and it stands for a rare and honoured visitor. The comparison was paid to Queen Elizabeth II when she toured New Zealand in 1953. Its rarity probably gives the image force, because only one colony nests in the country. Werner Krutein photographed a breeding bird for the cover of Angel Dust, a 1992 album by Faith No More. The white shape in a green marsh has likely drawn artists for as long as people have painted birds.