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Great Blue Heron

Ardea herodias

Poised to strike, the Great Blue Heron stalks along American waterways in search of fish and other small animals. These widespread waterbirds are among the tallest of North America’s birds.

Great Blue Heron

Great Blue Heron

Great Blue Heron

Close up of a Great Blue Heron

Great Blue Heron

Great Blue Heron pair during courtship

Great Blue Heron

Great Blue Heron in flight

Quick Facts

Classification

Scientific name:

Ardea herodias

Other names:

Blue Heron

Family:

Herons, storks and ibises

Measurements

Length:

97cm to 137cm

Wingspan:

170cm to 200cm

Weight:

2kg to 2.5kg

Appearance & Identification

Great Blue Herons are large, distinctive American waterbirds. Continue reading to learn their most important identifying features.

What do Great Blue Herons look like?

Great Blue Herons vary in appearance across their range. All are tall, upright birds with long legs and a long, S-shaped neck and head. They have large, dagger-like bills and a long, thin crest at the back of their head.

Most Great Blue Herons are blue-gray overall, with a white crown, prominent black stripes across the top of the head, a white face, and a yellow bill and eye. However, several subspecies are recognized, and interestingly, the birds from Florida, the Caribbean, and southeast Mexico have all-white plumage.

Male and female Great Blue Herons look alike, although males develop longer plumes in the breeding season. Look for these attractive, elongated feathers on the chest/lower neck and back. Juvenile and immature birds resemble adults but have shorter, duller plumage and dark gray rather than white crowns.

Great Blue Heron flying low of a Florida bay

Great Blue Heron flying low of a Florida bay

The Great Blue Heron is one of America’s tallest birds and one of the largest species in its family. Males are typically larger than females.

Length

Great Blue Herons stand about 4 feet (1.2 m) tall. They have a total body length of 38 to 54 inches (97 - 137 cm). The biggest individuals occur in the Southeast of their range.

Weight

Great Blue Herons weigh 4 ½ to 5 ½ pounds (2 - 2.5 kg). The males are significantly heavier than the females.

Wingspan

These birds have a wingspan of 5 ½ to 6 ½ feet (1.7 - 2 m).

Great Blue Heron fishing in the sea

Great Blue Heron fishing in the sea

Calls & Sounds

Birds from the Heron family are not known for their singing abilities, and the Great Blue Heron is no exception. Keep reading to learn more about their vocalizations.

What sound does a Great Blue Heron make?

Great Blue Herons produce a variety of raucous calls, ranging from a series of brief squawks to more prolonged low-pitched grunts. These birds tend to vocalize most frequently in the breeding season when greeting their partner or when disturbed.

Diet

Great Blue Herons are carnivores that are capable of swallowing surprisingly large animals. These fierce birds use stealth, speed, and an impressive spear-shaped bill to catch their prey.

What do Great Blue Herons eat?

The Great Blue heron is, first and foremost, a fishing bird. They prefer to wade in shallow waters, poised to strike at fish up to about two feet long. However, these birds will not pass up the opportunity to hunt other prey like rodents, frogs, invertebrates, and smaller birds.

What do baby Great Blue Herons eat?

Baby Great Blue herons eat the same food as their parents - primarily fish. They are fed by regurgitation when the parent bird inserts its bill into the chick's open mouth, but they will also pick up food items deposited on the floor of the nest. Both parents feed the chicks.

Great Blue Heron catching a large fish

Great Blue Heron catching a large fish

Habitat & Distribution

Great Blue Herons are one of the most widespread waterbirds in North America. Read on to learn more about where they live.

What is the habitat of a Great Blue Heron?

Great Blue Herons are aquatic birds that occur wherever shallow water and fish are available. They hunt along streams, rivers, marshes, swamps, ponds, lakes, mangroves, and coastal areas.

It's not unusual to find them hunting away from water in pastures, grassy areas, and prairie.

What is the range of a Great Blue Heron?

Great Blue Herons occur from Central America and the north coast of South America to the south Coast of Alaska. Birdwatchers in the US can spot these birds in each of the Lower 48 states, although they are absent in the winter in some parts of the Midwest and Northeast.

They visit the South of Canada to nest, but resident populations occur along the west coast of British Columbia.

Great Blue Heron wading through the water, in its natural habitat

Great Blue Heron wading through the water, in its natural habitat

Where do Great Blue Herons live?

Great Blue Herons spend their time standing motionless or stalking along the shore of water bodies. They usually fly up to the safety of tall trees to sleep at night. In the nesting season, both sexes spend most of their time at the nest when not out hunting.

How rare are Great Blue Herons?

Great Blue Herons are not a rare species. Birdwatchers have a good chance of spotting these impressive birds in just about any aquatic habitat in North America.

Blue Heron flying low over a swamp, with prey in beak

Blue Heron flying low over a swamp, with prey in beak

Lifespan & Predation

Despite their large size, Great Blue Herons do not have a particularly long life expectancy and are not immune to predation.

How long do Great Blue Herons live?

Great Blue herons can live for over twenty years. The oldest known individual lived to be 24 years and six months old. However, most will not live to see their first birthday, and those that reach maturity probably survive about five years on average.

What are the predators of Great Blue Herons?

Despite their large size and weapons, Great Blue Herons are vulnerable to some predators, including Bald Eagles. Their eggs and nestlings are eaten by a greater variety of birds and mammals, including Crows, Ravens, Turkey Vultures, Bears, and Raccoons.

Are Great Blue Herons protected?

Great Blue Herons are protected in the United States by the Migratory Bird Treaty Act of 1918. As such, it is a crime to harm, trap, or kill these magnificent waterbirds.

Are Great Blue Herons endangered?

Great Blue Herons are not endangered. This common and widespread species is considered to be increasing and the IUCN (International Union for Conservation of Nature) lists them as a ‘Least Concern’ species.

Great Blue Heron hunting for fish

Great Blue Heron hunting for fish

Nesting & Breeding

Great Blue Herons nest in the spring and summer, sometimes starting in the late winter. Both parents work together, usually producing a single clutch of two to six eggs, although second clutches have been recorded.

Where do Great Blue Herons nest?

Great Blue Herons nest across most of the Lower 48 states, southern Canada, and up to the south coast of Alaska. Pairs usually build their nests in trees, although they will nest on the ground on islands where they are safe from predators.

They typically nest in large colonies of up to 1000 pairs, although they will also nest alone.

What do Great Blue Heron eggs look like?

Great Blue Herons lay two to six pale blue eggs. Most eggs measure 61 to 65 mm (about 2 ½ inches) long and 45 to 46 mm (about 1¾ inches) wide.

Do Great Blue Herons mate for life?

Great Blue Herons do not mate for life, although they are monogamous during the nesting season. Pairs work together to raise their young but pair up with new partners in successive years.

Nesting neighbors - Great Blue Herons nesting next to each other high up a tree

Nesting neighbors - Great Blue Herons nesting next to each other high up a tree

Behavior

Great Blue Herons are fascinating birds to observe, especially when hunting and during the nesting season. These birds may have an intimidating appearance, but bird watchers have little to fear from them.

Are Great Blue Herons aggressive?

Great Blue Herons are not aggressive toward humans, although they may strike out in self-defense if captured or cornered. They are generally peaceful towards their own species, although fights have been recorded on rare occasions.

Great Blue Herons may claim small territories in prime hunting areas, although they defend these areas with displays and chases, rarely engaging in physical combat.

Great Blue Heron wading through marshland swamp

Great Blue Heron wading through marshland swamp

Migration

Birds are mobile creatures that can move long distances in response to changing seasons. Great Blue Herons have varying strategies for dealing with the winter cold.

Do Great Blue Herons migrate?

Great Blue Herons are partial migrants. In areas where waterways remain ice-free, these birds can make a living throughout the year since their food source remains relatively abundant.

For example, individuals that nest in Canada must head south for warmer climates. However, those that live along the Pacific coast as far as Alaska can persist since the coastal waters provide year-long hunting opportunities.

Birds that migrate south may overwinter in the Lower 48 or travel as far south as the Caribbean and the north coast of South America.

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Other birds in the Herons, storks and ibises family

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