Black-crowned night heron

Breeding black-crowned night-herons occur throughout the United States and southern Canada, as well as Central and South America. They winter from southern New England along the Atlantic Coast, along the Gulf and Pacific Coasts, in the West Indies, and in Central and South America. The Atlantic Coast breeding population winters largely in the Bahamas and the Greater Antilles, including Cuba, Jamaica, and the Dominican Republic.

In New Jersey, black-crowned night-herons nest primarily along the Atlantic Coast. They also occasionally nest along the coast of the Delaware Bay and River and will rarely nest inland. Nonbreeding individuals may reside in the state during the summer months.

Black-crowned night-herons feed in marshes and along the edges of ponds and creeks. Forests, scrub/shrub, marshes, and ponds serve as nesting and roosting habitats for black-crowned night-herons. They avoid nesting at exposed sites that offer little cover. When nesting in mixed-species colonies with low vegetation height, they tend to nest closer to the ground than other species. When in mixed-species colonies, black-crowned night-herons tend to nest nearby other black-crowned night-herons due to their similar habitat preferences.

Black-crowned night-herons are generalist predators whose diet ranges from insects to other birds. Fish and crustaceans, including shrimp, crabs, and crayfish, comprise much of the birds’ diets while feeding in coastal marshes. They also pursue aquatic and terrestrial insects, earthworms, leeches, mollusks, frogs, toads, tadpoles, salamanders, snakes, lizards, eggs, and young of other birds, small mammals, and carrion. Algae and fruit, such as beach plums, are rarely consumed.

Night-herons are largely nocturnal but may also hunt during the day, especially when prey is abundant or when their hungry chicks demand food. Feeding activity is strongly influenced by tidal cycles, as prey availability varies with the tides. Black-crowned night-herons often sit and wait for prey or slowly stalk prey before striking at it with their dagger-like bills.

Black-crowned night-herons arrive at their colonies in March and April. They are one of the first species to appear at wading bird colonies each Spring. They nest in single- or mixed-species colonies that typically include other herons, egrets, and the glossy ibis. Nesting pairs often occupy the same rookery each year. Previous nest failures, predation, or disturbance may cause birds to abandon and relocate.

Nests are located within dense cover in trees, shrubs, or thickets and may be placed on the ground. The nest is built by both the male and female and is constructed of sticks, twigs, and reeds and lined with thinner twigs, roots, grasses, and pine needles. The female lays three to four greenish blue eggs during early May. Both adults incubate the eggs for 24 to 26 days. The eggs then hatch and the chicks are cared for by both adults by early to mid-June. The young branch out from the nest, climbing and hopping about in the surrounding vegetation, by two or three weeks of age. Chicks that fall to the ground during this time are vulnerable to ground predators such as dogs, cats, raccoons, and foxes. Young night-herons return to the nest to receive food from their parents until they are about four weeks old. The young, now feathered, are fed away from the nest at four weeks of age. They are quite capable of flight at about six weeks old (usually by late July).

Some young may disperse far from the colony where they were born following fledging. They are able to breed at two to three years of age. Some individuals may breed when only one year old. Black-crowned night-herons exhibit strong fidelity to the site where they were born, often.jpg’eturning to these areas as adults.

Fall migration of black-crowned night-herons peaks from mid- or late September to mid-October and may extend through mid-November. Small numbers overwinter in New Jersey but are forced south during harsh winters.