The little blue heron (Egretta caerulea) is a small heron. It breeds in the Gulf states of the US, through Central America and the Caribbean south to Peru and Uruguay. It is a resident breeder in most of its range, but some northern breeders migrate to the southeastern US or beyond in winter. There is post-breeding dispersal to well north of the nesting range, as far as the Canada–US border.
This species is about 60 cm (24 in) long, with a 102 cm (40 in) wingspan, and weighs 325 g (11.5 oz). It is a medium-large, long-legged heron with a long pointed blue or greyish bill with a black tip. Breeding adult birds have blue-grey plumage except for the head and neck, which are purplish and have long blue filamentous plumes. The legs and feet are dark blue. The sexes are similar. Non-breeding adults have dark blue head and neck plumage and paler legs. Young birds are all white except for dark wing tips and have dull greenish legs. They gradually acquire blue plumage as they mature.
This species is distributed from Massachusetts to Florida in the United States and from the Gulf of Mexico to Uruguay through the West Indies, Central America, Colombia, Peru, Ecuador, Bolivia, Venezuela, Chile and Brazil. In Colombia it is found up to 2,600 meters above sea level on the Atlantic coast, also in Santander, Cauca, Antioquia, Valle del Cauca, Vaupés, Amazonas, Boyacá and La Sabana de Bogotá.
It lives mainly in aquatic environments such as: lakes, ponds, floodplains, rice fields, marshes, estuaries and mangroves.
This heron generally breeds between April and May in North America and between February and July in the eastern Caribbean. Reproductive events have also been reported between July and October in the Venezuelan plains.
During the reproductive season it forms colonies and nests in trees between 0.5 and 12 m high near or on a body of water. It lays 2 to 5 blue eggs that incubate between 22 and 24 days and the young leave the nest around day 30.
It nests in colonies, often with other herons, usually on platforms of sticks in trees or shrubs. Three to seven light blue eggs are laid.
The little blue heron stalks its prey methodically in shallow water, often running as it does so. It eats fish, frogs, crustaceans, small rodents and insects.
White little blue herons often mingle with snowy egrets. The snowy egret tolerates their presence more than little blue herons in adult plumage. These young birds actually catch more fish when in the presence of the snowy egret and also gain a measure of protection from predators when they mix into flocks of white herons. It is plausible that because of these advantages, they remain white for their first year.