The little blue heron 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.
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.