The great blue heron (Ardea herodias) is a large wading bird in the heron family Ardeidae, common near the shores of open water and in wetlands over most of North and Central America, as well as far northwestern South America, the Caribbean and the Galápagos Islands.

Debate exists about whether these white birds are a color morph of the great blue heron, a subspecies of it, or an entirely separate species.

[2][3] The great blue heron was one of the many species originally described by Carl Linnaeus in his 18th-century work, Systema Naturae.

It exhibits a minor degree of sexual dimorphism; males are slightly larger than females, but otherwise the sexes are not easily outwardly distinguishable.

The cocoi is distinguished by a striking white neck and solid black crown, but the duller juveniles are more easily confused.

More superficially similar is the slightly smaller grey heron, which may sometimes appear as vagrants on the northern coasts of North America.

It may be found in numbers in fresh and saltwater marshes, mangrove swamps, flooded meadows, lake edges, or shorelines.

Great blue herons rarely venture far from bodies of water, but are occasionally seen flying over upland areas.

They usually nest in trees or bushes near water's edge, often on islands (which minimizes the potential for predation) or partially isolated spots.

[24] California herons were found to live mostly on sculpin, bass, perch, flounder, and top smelt.

Amphibians such as leopard frogs, American bullfrogs, toads and salamanders are readily taken, as well as reptiles such as small turtles, snakes and lizards.

Remains of muskrats (Ondatra zibethicus) and long-tailed weasels (Mustela frenata) was also found in pellets during the study.

[32] There are reports that great blue heron prey on both young and adults of eastern cottontails (Sylvilagus floridanus).

[33][34] Though not often, birds such as black rails (Laterallus jamaicensis), phalaropes, American dippers (Cinclus mexicanus), pied-billed grebes (Podilymbus podiceps) and chicks of marsh terns (Chlidonias) are also taken.

[20] Occasionally, loose flocks gather to feed, and may be beneficial since they are able to locate schools of fish more easily.

Adults generally return to the colony site after winter from December (in warmer climes such as California and Florida) to March (in cooler areas such as Canada).

When not, herons may nest on the ground, sagebrush, cacti, channel markers, artificial platforms, beaver mounds, and duck blinds.

Canada's Stanley Park has had a healthy colony for some years right near its main entrance and tennis courts adjacent to English Bay and not far from Lost Lagoon.

Parent birds have been shown to consume up to four times as much food when they are feeding young chicks (about 4300 kJ/day) than when laying or incubating eggs (about 1200 kJ/day).

Red-tailed hawks (Buteo jamaicensis), American black bears (Ursus americanus), and raccoons (Procyon lotor) are known to take larger nestlings or fledglings, and in the latter predator, many eggs.

[11][49][50][51] In exceptional case, a young Harris's hawk (Parabuteo unicinctus) killed a subadult great blue heron.

[22][53][54] And less frequently, golden eagles (Aquila chrysaetos) and great horned owls (Bubo virginianus) are known to take adults.

[55][56] There is a single report that a large bobcat (Lynx rufus) managed to subdue and kill an adult great blue heron.

[24][59] John James Audubon illustrates the great blue heron in Birds of America, Second Edition (published, London 1827–1838) as Plate 161.

[61] Great white herons feature prominently in the logo for the Major League Soccer club Inter Miami CF.