Ardea herodias

The Great Blue Heron, Ardea herodias, is found in small isolated patches of suitable habitat including rivers, lakeshores, beaches, sand flats, farmlands and urban areas of calm freshwater. Of all the herons, A. herodias is the most commonly seen due to the places it likes to inhabit.

A. herodias can reach op to 4.5 ft tall and has a wingspan of up to 6 ft. The plumage of a non-breeding adult is gray. The neck is long and straight and the bill has a darker yellow upper bill than lower. The legs are long and dark with thighs of a chestnut brown color. The breeding plumage differs in the more intense colors, the thin, pointed plumes of the crown and throat and the presence of a light brown stripe on the leading edge of the underwing. The take off of A. herodias appears clumsy at initiation, though in air the long, slow and steady wingbeat allow long distance travel. In flight their necks are held in a shallow ‘S’ curve with legs and feet extended out behind the body. The shape of the neck in flight can help to distinguish from cranes, as the crane holds the neck out straight. There are other features to distinguish A. herodias from cranes, such as the faster movement and presence of fluffy feathers over the tail observed in cranes.

The feeding behavior of A. herodias consists of standing in one place waiting for the prey to come along or slowly stalking prey in shallow water or grassy areas. Prey include fish, amphibians, reptiles, invetebrates, small mammals and birds. The method of attack used on prey once it is stalking is by impaling with their bill. Occasionally, a scavenger lifestyle is taken, feeding on the carcasses of fish remains or domestic animals, especially in the winter.

The nests of A. herodias are typically located in tree snags, tall bushes or marsh vegetation. Sticks and twigs are collected and constructed into a 4 ft diameter bottom that is then lined with softer material like pine needles, moss, reeds and dry grass. With successive broods, the nests are repaired for reuse. A breeding pair will incubate 3 to 5 light blue eggs for 27 to 29 days. As typical of many bird species, the hatchlings are fed by regurgitation from the parents.

In Oregon, A. herodias is common year round west of the Cascade mountain range and also breeds there year round. East of the Cascades, A. herodias is less common but has been known to breed there in the summer months or visit in the winter.

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Ardea_herodias (6)

References

Burrows, R. and J. Gilligan (2003) Birds of Oregon. Lone Pine Publishing. Washington, Alberta.

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