Georgia Wildlife Web

Home Glossary Classification Conservation Status Regions of Georgia Fishes of Georgia Make a Donation

Species Description

Great Blue Heron

Ardea herodias


Species Image
Last      Next

Classification

Phylum: Chordata
Subphylum: Vertebrata
Class: Aves
Order: Ciconiiformes
Family: Ardeidae

Description

The Great Blue Heron is gray-blue overall. A dark stripe extends dorsally above the eye. The front of the throat is light gray with dark streaks. The bill is yellowish, and the legs are brown. The largest heron in the United States, measuring 117 cm (46 in) from tip of bill to tip of tail, and 183 cm (72 in) from wing tip to wing tip. The Great Blue Heron has a long neck and legs. During breeding, ornate plumes appear on the head, back, and neck.

Life Cycle

Breeding season lasts from March through August. Pairs perform elaborate courtship displays and nest in breeding colonies. Large stick nests are built in tall trees 10-30 m (30-70 ft) above ground on islands, in swamps, and sometimes along rivers and lakes. Eggs are laid every 2 to 3 days until 3-5 light blue eggs have been accumulated. Incubation lasts about 28 days. Both parents incubate the eggs and feed young fish to the chicks. When the chicks hatch, they are semi-altricial and remain in the nest for 9-10 weeks. By the seventh week, they are hopping to nearby branches and by the ninth week they can make short flights.

Natural History

The Great Blue Heron forages close to shore in slow-moving water in both marine and freshwater environments, including coastal habitats, estuaries, mangroves, rivers, and lakes. It commonly forages alone or well-distanced in loose flocks. The Great Blue Heron typically walks and forages more slowly than other herons. When a Great Blue Heron finds prey, it quickly thrusts its head and neck into the water and comes up with the prey in its bill. In addition to fish, its primary food source, this heron eats crustaceans and amphibians. Prey are swallowed whole.

Range

Great Blue Heron Region Map The Great Blue Heron occurs in suitable habitat throughout most of Georgia. It is uncommon in the northern parts of the state. In general, it is most abundant during winter months. Its range extends across much of the rest of the United States, but it breeds only sporadically across large parts of its range.

Conservation Status

This species does not yet enjoy any special conservation attention, but these herons are easily disturbed by humans. Building roads and even simply walking near colonies usually results in the herons leaving temporarily or permanently. Colonies contaminated with toxic chemicals result in eggs with thin shells that are more likely to break during incubation.

Similar Species

The Great Blue Heron is unlikely to be confused with other wading birds. The Great Egret is almost as large (99 cm, or 39 in), but it is completely white. The Tricolored Heron is smaller (66 cm, or 26 in) and is dark blue with a contrasting white neck and belly.