also been observed to feed on carrion and Callinectes blue crabs. In Colombia, chicks have also been observed being fed predominantly fish and less frequently with amphibians and crustaceans. The cocoi heron catches prey by striking its head into the water and thrusting its bill to stab downwards. It may also tilt its head downward above the water so that only its bill is immersed. During feeding, the head and neck move rapidly while the body remains immobile. Feeding is usually diurnal and solitary, especially in Argentina, although in Chile, it is considered to be a largely nocturnal feeder, with diurnal roosting taking place in trees overlooking the water. In Venezuela, it has also been seen foraging in large groups. Where feeding is diurnal, there appears to be a peak in feeding activity at noon and a reduction at dusk. The cocoi heron appears able to use alternative food sources by exploring foraging sites distant from its breeding colonies, since terrestrial rodents and reptiles and marine organisms have been found in the diet of individuals from freshwater colonies. Some colonies also reside near to estuarine coastland and individuals from these colonies are more reliant on marine prey. Foraging individuals often stay near to colonies and colony site choice has been found to be strongly linked to proximity to high-quality foraging habitats. The heron may also sometimes exploit dead whitemouth croaker discarded by recreational fisheries. Breeding Generation length in years has been estimated as 10.5 years, with a maximum longevity of 24.4 years. This heron is primarily non-migratory, but may move toward the equator during winter to seek warmer temperatures. The onset of the nesting season varies geographically. In Suriname, it begins in July; whereas it begins in August to November in Brazil and Argentina, October in Uruguay and November in the Buenos Aires region. The cocoi heron nests colonially in trees. The large, deep nest is constructed from branches and sticks with grass, usually situated in trees. Near Buenos Aires, nests consisted of branches of Solanum glauca and dry thistles. They were roughly circular, 65 cm in diameter and very deep. In Chile, cocoi herons have been observed to construct their nests on weeping willow trees in standing water with rushes. The eggs are pale blue with paler speckles and some whitish traces. Egg dimensions from various clutches in South America lie in the range 62-69 x 45–48 mm. Eggs