Coscoroba Swan

The coscoroba swan is among the largest waterfowl in South America, but smaller than the true swans, making it the smallest "swan" species. It is somewhat goose-like in appearance with a duck-like bill. It is shorter-necked than other swans. Unlike other swans, its feathers go straight to the base of the bill. The adults are completely white, except for black tips to the outer six primary feathers. They have bright pink legs and feet. Their posture and longer legs allow the coscoroba swan to walk easily on land, this also lets them take off into flight quickly from land or water, much faster than the true swans. The sexes are similar, but the male is larger. Males can weigh up to 5.4 kg (12 lb). The wing length of males is 44–49.8 cm (17.3–19.6 in) and in females 41.5–47.7 cm (16.3–18.8 in). Those in southern Brazil have differing measurements, the wings of males being 37.5–39 cm (14.8–15.4 in) and females 35–35.8 cm (13.8–14.1 in).

The coscoroba swan is a year-round resident of central Argentina and along the Uruguay-southern Brazil coast. It also breeds, but does not winter from southern Chile and Argentina south to Tierra del Fuego and occasionally to the Falkland Islands. In winter, its range extends north to central Chile, northern Argentina, Paraguay, Uruguay, and southern Brazil. It has been recorded as a vagrant in Bolivia and at several locations in Brazil north of its usual limit. The coscoroba swan inhabits well-vegetated lagoons, freshwater swamps, and sometimes human-made reservoirs. It is mainly a bird of the lowlands, though there are scattered records as high as 1,300 m (4,300 ft) and at least one at 2,000 m (6,600 ft).

The coscoroba swan's diet has not been studied in detail, but it apparently feeds on aquatic and some terrestrial plants, small aquatic invertebrates, and small fish. It forages mainly while swimming or wading in shallow water and in contrast to other swans rarely upends. It also grazes on land. It often feeds with black-necked swans (Cygnus melanocoryphus).