Habitat
Lakes, rivers, streams, lagoons, and coastal regions (AOU 1983). Wide slow-flowing rivers, lowland lakes, marshes, estuaries, brackish coastal lagoons, mangroves, and sometimes open beaches; also sometimes ricefields, reservoirs, canals, water gardens in cities, and Chilean fiords (Fry and Fry 1992). In Colombia and Bolivia, frequents primarily open habitat along the edges of lakes and streams (Remson 1990). BREEDING: Nests in a horizontal burrow dug in a steep earth or sand bank usually along a river but occasionally in erosion gullies and road cuts well away from water.
Reproduction
Known egg laying months: about March in Texas, about January in Tamaulipas, April-May in Belize, about March-May in Panama, February and June in Suriname, April in Trinidad, August in Guyana, and about November in southern Chile (Fry and Fry 1992). Clutch size 3-6 (commonly 4-5). Incubation 22 days or more, by both sexes in turn. Young tended by both parents, leave nest at 33-38 days when able to fly strongly. Generally nests solitarily, but "colonies" of several to 150 pairs have been reported from the Orinoco River, Venezuela (Fry and Fry 1992).