The black-headed duck is a South American duck in subfamily Oxyurinae of family Anatidae. It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay.
Region
Southern Cone of South America
Typical Environment
Occurs across lowland wetlands of Argentina, Chile, Uruguay, Paraguay, southern Brazil, and Bolivia. It frequents shallow freshwater marshes, reedy lagoons, floodplains, and vegetated lake margins. During the non-breeding season it disperses widely to suitable wetlands, often following changing water levels. It avoids fast-flowing rivers and very open deep waters, preferring areas with dense emergent plants for cover.
Altitude Range
0–1500 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
The black-headed duck is the only duck known to be an obligate brood parasite, laying its eggs in the nests of coots and other waterbirds. Adults provide no parental care; ducklings leave the host nest and fend for themselves within a day of hatching. They favor marshes with dense emergent vegetation and can dive or dabble for food. Their movements track seasonal water availability across southern South America.
Temperament
wary and secretive
Flight Pattern
short rapid wingbeats
Social Behavior
Often seen singly or in small groups, becoming more gregarious where wetlands concentrate birds. It is an obligate brood parasite, placing eggs in the nests of coots and occasionally other waterfowl. Adults do not build nests or incubate; ducklings depart the host nest shortly after hatching to feed independently.
Migratory Pattern
Partial migrant
Song Description
Generally quiet; males give soft, wheezy whistles and grunts, mostly during courtship. Females produce low quacks and chatters at close range. Vocalizations are typically heard from cover within marsh vegetation.
Plumage
Male shows a glossy black head and neck contrasting with a gray-brown, finely barred body; underparts are paler. Female is overall mottled brown with a duskier crown and paler throat, lacking the male’s black head. Both sexes have a short tail and compact, rounded body typical of stiff-tailed ducks.
Diet
Feeds on seeds, stems, and leaves of aquatic plants, supplemented by aquatic invertebrates such as snails and insect larvae. It will dabble at the surface, tip-up, and occasionally dive to reach submerged vegetation. Opportunistic foraging includes gleaning seeds from floating mats and shallow bottoms. Diet composition varies with seasonal availability in wetlands.
Preferred Environment
Forages in shallow marshes, reedy shorelines, and flooded grasslands with abundant emergent vegetation. Prefers calm waters where it can feed under cover and avoid disturbance. Often feeds near coots and other waterbirds without direct competition.
