The Black-crowned night heron (Nycticorax nycticorax) is a medium-sized heron found throughout a large part of the world. These birds have a stocky appearance as if hunched over, the head tucked down into the shoulders, and they are usually seen with this posture. They are most active at dusk or at night when their ghostly forms fly from their daytime roosts to the wetlands where they forage.
Adult birds have a black crown and back with the remainder of the body white or grey, red eyes, and short yellow legs. They have pale gray wings and white under parts. Two or three long white plumes, erected in greeting and courtship displays, extend from the back of the head. The sexes are similar in appearance although the males are slightly larger. Black-crowned night herons do not fit the typical body form of the heron family. They are relatively stocky with shorter bills, legs, and necks than their more familiar cousins, the egrets and "day" herons. Their resting posture is normally somewhat hunched but when hunting they extend their necks and look more like other wading birds. Immature birds have dull grey-brown plumage on their heads, wings, and backs, with numerous pale spots. Their underparts are paler and streaked with brown. The young birds have orange eyes and duller yellowish-green legs.
Black-crowned night herons breed on every continent apart from Antarctica and Australasia. In the Americas, it is from Washington to Quebec, through coastal Mexico, and in Central America and the Caribbean. In winter they can be found as far north as the New England states and Oregon. The Old World subspecies occur from Japan to Europe, Africa, and India. This heron lives in a wide range of habitats, from swamps, rivers, and lakes to salt marshes, lagoons, and mudflats. Aquatic and marginal vegetation like mangroves, reed beds, bamboo, and other trees are necessary for nesting and roosting.
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