The black-necked swan is a large waterfowl native to South America, particularly found in countries like Argentina, Chile, and Uruguay. It is easily recognizable by its striking black neck and white body. These swans typically inhabit freshwater lakes, ponds, and marshes, where they feed on aquatic plants. Black-necked swans are social birds, often seen in pairs or small groups. They are known for their graceful swimming and can be quite vocal, producing a range of honking sounds. Their diet mainly consists of submerged vegetation, and they are also known to graze on land during the breeding season.