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 the largest North American heron and, among all extant herons, it is surpassed only by the goliath heron (Ardea goliath) and the white-bellied heron (Ardea insignis). Great blue herons are roughly twice as heavy as great egrets (Ardea alba), although only slightly taller than them, but only weigh about half as much as a large goliath heron. Notable features of great blue herons include slaty (gray with a slight azure blue) flight feathers, red-brown thighs, and a paired red-brown and black stripe up the flanks; the neck is rusty-gray, with black and white streaking down the front; the head is paler, with a nearly white face, and a pair of black or slate plumes runs from just above the eye to the back of the head. The feathers on the lower neck are long and plume-like; it also has plumes on the lower back at the start of the breeding season. The bill is dull yellowish, becoming orange briefly at the start of the breeding season, and the lower legs are gray, also becoming orangey at the start of the breeding season. Immature birds are duller in color, with a dull blackish-gray crown, and the flank pattern is only weakly defined; they have no plumes, and the bill is dull grey-yellow.
