Great Egret

Casmerodius albus

(c) Glen Tepke
  • ARDEIDAE
  • Herons, Bitterns, Egrets
  • Ciconiiformes
  • Garza blanca, Garza grande, Garza real
  • Grande aigrette
Introduction
The elegant Great Egret is a tall, white wading bird found on every continent except Antarctica. The Great Egret is the symbol of the National Audubon Society, one of the nation's oldest conservation organizations, which was first established to protect birds from feather hunters.
(c) Jim Fenton
Appearance Description

Tall and slender, the Great Egret is pure white in color, with a yellow, spear-like bill, a long neck, and long black legs. Measuring three feet in height and 1.9 pounds, with a four-foot wingspan, it is one of the largest members of the heron family, second in size only to the Great Blue Heron. During breeding season, the birds grow spectacular plumes, which are raised like fans during courtship displays. There is no pronounced difference between the sexes. 

Range Map
Courtesy Kenn Kaufman
Range Distribution
A cosmopolitan species, the Great Egret is broadly distributed throughout tropical and temperate wetlands around the globe. In the Americas, it breeds from Canada to Argentina and Chile. Wintering populations can be found as far north as waters remain ice-free in North America. Generally this ranges from Oregon south along the West Coast, and along Mexico down to Panama, as well as throughout much of the southern United States, and up the Eastern Seaboard, sometimes into New York and Massachusetts during warmer years.
 
A legend for the range map to the right can be found here.
Habitat

Great Egrets inhabit all kinds of wetlands, both inland and along the coast, including marshes, river margins, lakeshores, coastal swamps, lagoons, mudflats, and manmade impoundments and drainage ditches. They can also be found in more terrestrial habitats, such as agricultural fields. Nesting takes place mostly in waterside trees or shrubs, often on islands.

Feeding
Strictly carnivorous, Great Egrets stalk their prey by either standing still or walking slowly in shallow water and marshland. Their diet consists mainly of fish, but also includes aquatic invertebrates (particularly crustaceans), insects, amphibians, reptiles, other birds, and small mammals. Great Egrets feed individually or in loose flocks, sometimes with other herons, cormorants, and ibises. They sometimes forage in open fields.
Reproduction

At the beginning of the breeding season, Great Egrets develop long showy plumes, called aigrettes, which trail from their backs, and are prominently displayed during courtship. Their bills become orange-yellow and the skin around their eyes changes from yellow to lime-green. Seasonally monogamous, the birds typically nest in large colonies, often with other species such as Great Blue Herons or Snowy Egrets. A Great Egret pair produces a single brood each year, starting when the birds are two or three years of age. In temperate zones they breed in spring or summer, depending on when food is most abundant; in the tropics, they can breed at any time of the year. Their platform nests, made of twigs, are constructed in treetops or woody vegetation. Females lay one to six pale blue-green eggs, which both sexes incubate for about three weeks. Both parents care for the chicks, which can fly at six to seven weeks of age.

Migration

In North America, Great Egrets are migratory in their northern and interior breeding areas, but they are apparently influenced by temperature fluctuations. In milder winters, the birds may stay on their breeding grounds if the waters where they feed remain open. Spring migration occurs between late February and May, with birds occupying their summering grounds until late August through November, and sometimes even into December. They migrate individually or in small, V-shaped or wavy-lined flocks of less than 25, often following routes along coastlines and major rivers.

  • 1,225,000
  • 270,000
  • no current conservation concerns
Population Status Trends
Great Egrets were common and widely distributed in the United States until plume hunters decimated more than 95 percent of the population in the early 1900s. After passage of the Migratory Bird Treaty Act in 1918, the birds mounted a remarkable recovery. They can now be seen not only in their historic ranges, but further north than ever before.
Conservation Issues

Great Egret populations in the United States were nearly wiped out a century ago by commercial hunting to supply the millinery trade with the birds' beautiful breeding plumes. Efforts by concerned citizens to end the slaughter led to protective legislation and the birth of the modern conservation movement, and saved the species from extinction. While Great Egrets are no longer jeopardized by indiscriminate shooting, they are vulnerable to the loss of wetlands, and disturbance of their nesting colonies. In Florida, they are classified as a "species of concern" due to habitat destruction and the alteration of natural watercourses. In addition, Great Egrets are susceptible to contamination from high mercury levels within the Florida Everglades.

What You Can Do
Avoid disturbing Great Egret nesting colonies.
Remain vigilant to local, regional, and national legislation affecting wetlands, and support wise land management practices that protect the birds' habitats.
 
Support governmental efforts to reduce mercury emissions and releases. Read about mercury issues at the Mercury Project Policy website
 
For actions you can take, including Audubon activities, please visit our resources page.
More Information
Visit our resources page for more information about this species.
Natural History References
McCrimmon, D. A., Jr., J. C. Ogden, and G. T. Bancroft. 2001. Great Egret (Ardea alba). In The Birds of North America, No. 570 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
 
Kaufman, Kenn. Lives of North American Birds, Houghton Mifflin Company, New York, 1996.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, New York, 2000.
Conservation Status References
McCrimmon, D. A., Jr., J. C. Ogden, and G. T. Bancroft. 2001. Great Egret (Ardea alba). In The Birds of North America, No. 570 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
 
Kaufman, Kenn. Lives of North American Birds, Houghton Mifflin Company, New York, 1996.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, New York, 2000.