The greater ani is about 48 cm (19 in) long and weighs 170 g (6.0 oz). The adult is mainly blue-glossed black, with a long tail, massive ridged black bill, and a white iris. Immature birds have a dark iris.
This ani is a breeding species from Panama and Trinidad through tropical South America to northern Argentina. It is found in mangrove swamps, semi-open woodland near water, and the edges of forests. It is a seasonal migrant in at least some parts of its range.
This is a very gregarious species, always found in noisy groups.
The greater ani feeds on large insects and even lizards and frogs.
The nest, built and lived in communally by two to five pairs, is a deep cup lined with leaves and placed usually 2–5 m (6.6–16.4 ft) high in a tree. A number of females lay their chalky deep blue eggs in the nest and then share incubation and feeding. These breeding groups may also include non-breeding helpers. Nests have been found containing 3–10 eggs, with an incubation time of 11–12 days, with nestlings free to leave the nest after five days. They will be fed for several weeks if they choose not to leave.
In a recent longterm study, it was found that around 15% of females lay their eggs in the nest of another nesting group. This conspecific brood parasitism happens primarily when a female has lost her own clutch to predation. In regards to the nesting group, the first couple eggs will be rejected by other nest members when the mother of those specific egg leaves to forage. Egg rejection happens more often with larger groups, and one theory claims there is a balance within having more ani's to defend the nest from predation, and less ani's to minimize intraspecific competition. This leads to an average of two to three breeding pairs in one nest, with any greater amount being rare.
