The Yellow-crowned night heron is a gorgeous graceful bird. More solitary than the Black-crowned night heron and often more secretive, this species is quite common in some parts of the southeast, especially in coastal regions. It often feeds during the day as well as at night. Its stout bill is probably an adaptation for eating hard-shelled crustaceans. In some areas it is called "crab-eater". These birds were introduced into Bermuda in an attempt to control land crabs, which was successful.
The Yellow-crowned night-heron inhabits the central United States and coastal areas in the east of the U.S, as well as Central America and in the north of South America, and around the Galapagos and Caribbean Islands. It breeds along some Atlantic coasts, from New York to Kansas and Indiana, and south to South America, southern Brazil and the Pacific Coast of Peru. It winters on Atlantic and Gulf coasts, as far as South Carolina. In warmer locations, the birds are resident. They inhabit areas such as mangroves, rocky coasts, barrier beaches, and tidal mudflats. They are sometimes found in inland wetlands like swamps, rivers, lakes, lagoons and marshes.
Yellow-crowned night herons are mainly nocturnal, but sometimes will seek food at any time of the day. Apart from reproduction, this bird’s behavior can be divided into two categories: foraging and general. When not foraging, adults slowly walk through shallow waters of wetlands, coastal thickets and swamps, rarely entering deep waters. Preening is common and is an important behavior for these birds. Adults preen both themselves and each other, especially after foraging. The birds’ foraging behavior is based around a slow, stalking movement as they search in the shallow water for prey. When they find a prey item, they strike quickly, crushing it in their wide, stout beak. These birds typically forage alone, despite living in colonies. Large groups of herons may indicate the abundance of food. Juveniles and adults spend similar amounts in general and foraging behaviors. Adults are more efficient than juveniles at foraging, the younger birds learning by observation.
The Yellow-crowned night heron is carnivore and mainly eats crustaceans, but will also feed on fish, amphibians, snails, aquatic insects, and sometimes small snakes or young birds that have fallen from the nest.
This species is monogamous and nests either on its own or in a colony with four to five nests nearby. If in a colony, a pair will construct its nest on a different tree or perhaps on the ground. Pairs form either during migration or on the breeding range early on in the breeding season. Courtship displays include a circle flight used for territorial defense. Yellow-crowned night herons breed from early spring until mid-summer. 2 to 4 eggs are laid, of a pale blue green color. Usually one brood per season, is produced, sometimes two. Incubation is for around 21 to 25 days, and the parents take turns, and both feed the chicks with regurgitated food during the first few days. The young remain with the nest for about 25 days until they can fly, but will leave it to follow their parents along the shore. If threatened, chicks may climb onto branches to hide.
Like many wetland birds, Yellow-crowned night-herons are threatened by habitat degradation and loss. Some cultures consider them a delicacy and they are hunted in particular parts of their range. In urban areas, many deaths are caused by birds crashing into telephone wires and television towers.
According to IUCN, the Yellow-crowned night heron is common and widespread throughout its large range but no overall population estimate is available. Currently this species is classified as Least Concern (LC) and their numbers today remain stable.
The major role of the Yellow-crowned night-heron within its ecosystem is as a predator. Their prey items cover a wide variety, however, they mostly eat crustacean prey and their biggest impact is on crayfish and crab communities. Aside from human predation, these birds are not typically the prey of other species. Their freshwater and brackish habitats are specialized enough that they tend not to face competition from other species, such as scarlet ibis.