Great Blue Heron (GTM Research Reserve Bird Guide)

Great Blue Heron

Ardea herodias

Summary ⁷

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 America and Central America as well as the Caribbean and the Galápagos Islands. It is a rare vagrant to Europe, with records from Spain, the Azores, England and the Netherlands. An all-white population found only in the Caribbean and southern Florida was once treated as a...

Description ⁸

At over a metre and half in height, the great blue heron is the largest heron in North America and one of the continent's most recognisable wading birds (2) (3). There are two main colour morphs of this statuesque species: a dark form that is mostly blue-grey, with chestnut thighs, and a white cap over a black eye stripe that merges into long, black plumes; and a light form which is all white. The neck, legs and wings are characteristically long, the tail is short, and the yellowish bill is thick, elongate and tapered. In flight, it coils its neck back into a distinctive s-shape, extends its legs back along its body axis, and beats its wings with steady, powerful strokes (2) (3) (4). Although the sexes are similar in appearance, the female is normally around ten percent smaller than the male, while juveniles are duller and lack the long plumes of the adults (4) (5). Considerable uncertainty surrounds the separation of subspecies of the great blue heron, with between two and seven recognised for North America alone (4). However, five main subspecies, that differ in size and plumage and occupy different parts of the species overall range, are commonly referred to: Ardea herodiasherodias, A. h. fannini, A. h. wardii, A. h. occidentalis (the white form), and A. h. cognata (2) (4).