Coscoroba Swan

Identification

The coscoroba swan is a medium-large waterfowl, smaller than true swans, measuring 90 to 115 cm in length with a wingspan of about 155 cm. Males weigh 3.8 to 5.4 kg and females 3.1 to 4.5 kg. Their appearance is distinctive and somewhat unusual, intermediate between geese and true swans. Adults are completely white except for black tips on the outer six primary feathers, which are often barely visible on the closed wing unless the bird is in flight. Unlike true swans, coscoroba swans have completely feathered faces and feet positioned directly under their bodies, enabling them to walk more efficiently than most other waterfowl. Both sexes have identical plumage. Their bills and feet are darker and redder than those of similar-sized ducks. Young chicks are born with blue-grey bills and feet and black striping along their bodies for camouflage, fading by about eight months of age.

Range & Habitat

The coscoroba swan is found throughout South America, with a year-round resident population in central Argentina and along the Uruguay-southern Brazil coast. The species breeds in southern Chile and Argentina south to Tierra del Fuego and occasionally the Falkland Islands, then migrates north in winter to central Chile, northern Argentina, Paraguay, Uruguay, and southern Brazil. It has been recorded as a vagrant in Bolivia and at various locations in Brazil beyond its usual range. These swans inhabit well-vegetated lagoons, freshwater swamps, and human-made reservoirs, primarily in lowland areas, though scattered records exist at elevations up to 1,300 m, with at least one record at 2,000 m.

Behaviour & Diet

Coscoroba swans feed on aquatic and terrestrial plants, small aquatic invertebrates, and small fish. They forage while swimming or wading in shallow water and, unusually among swans, rarely upend to feed. They also graze on land and often feed alongside black-necked swans. The species forms long-term pair bonds and breeds during the local spring—May to October in northern Argentina, July to December in Chile, and July to August in southern Brazil. Both partners construct a nest of vegetation lined with soft grass on small islets or in reedbeds close to water. Clutches typically contain four to nine eggs with an incubation period of about 35 days. Both parents care for young through fledging at 14 weeks and often beyond, sometimes until the chicks are a year old. Their vocalizations include an onomatopoeic "cos-cor-oo" call as a threat, a monosyllabic hooting note as contact between mates, and immature birds produce loud chirps and trills.

Best Time & Places to See It

Coscoroba swans are fairly common in Argentina, making it the most reliable location for sightings. They are uncommon in Paraguay and Uruguay, rare in Chile, and uncertain in Brazil. The species is a year-round resident in central Argentina and along the Uruguay-southern Brazil coast, so these areas offer consistent viewing opportunities. Winter months (June to August in the Southern Hemisphere) may concentrate birds in northern parts of their range as populations migrate from southern breeding grounds. Well-vegetated lagoons, freshwater swamps, and reservoirs are the best habitats to search.

Photography Tips

The coscoroba swan's pure white plumage makes it visually striking but challenging for exposure metering—be prepared to compensate to avoid underexposure of the white feathers. The black wingtips are subtle and often invisible on perched birds, so capture the birds in flight to showcase this identifying feature. Their upright posture and efficient walking gait offer good opportunities for full-body shots on land. Look for family groups during breeding season, as both parents actively tend young, providing dynamic compositional possibilities. The distinctive feathered face and darker red bill and feet are diagnostic features worth highlighting in close-up shots. Early morning light at lagoons and swamps will enhance the contrast between their white plumage and surrounding vegetation.