Black-necked Swan

The Black-necked Swan is the smallest of the world's swan species and one of the most visually striking, with a clean white body contrasting sharply against an entirely black head and neck. A prominent red-orange fleshy knob sits at the base of the grey bill, particularly noticeable in adult males, and the legs are pink.

It is South America's only swan species and a familiar sight on wetlands throughout the southern part of the continent, often swimming with cygnets carried on an adult's back, a behavior it shares with only a few waterfowl species.

Key field marks

• Pure white body plumage
• Solid black head and neck, sharply demarcated from the white body
• Red-orange knob at the base of the bill
• Pink legs and feet

Similar species

No other swan combines a white body with an entirely black head and neck, making this species unmistakable within its South American range. It is smaller and more compact than the mostly black Black Swan of Australia, which lacks any white body plumage.

Range and habitat

The Black-necked Swan is found across southern South America, including Chile, Argentina, Paraguay, Uruguay, and southern Brazil, inhabiting freshwater lakes, marshes, slow rivers, and sheltered coastal lagoons.

Migration

Southern breeding populations, particularly in Tierra del Fuego and southern Patagonia, migrate northward to escape harsh winters, while more northerly populations tend to be largely resident.

Behavior

Black-necked Swans are strong swimmers that often gather in flocks outside the breeding season and, notably, frequently carry cygnets on their backs while swimming, a behavior that offers protection from predators and cold water.

Voice

Calls include soft whistling and low grunting notes, generally quieter than the calls of Northern Hemisphere swans.

Feeding

They feed primarily on aquatic vegetation and algae obtained by upending in shallow water, using their long necks to reach submerged plants.

Nesting and breeding

Nests are built as large mounds of reeds and vegetation near water, often on small islands; pairs are monogamous, and the habit of carrying cygnets on the back is a notable and well-documented parental behavior in this species.