Black-headed Duck vs Magellanic Steamerduck
Heteronetta atricapilla compared with Tachyeres pteneres
Side-by-Side Comparison
| Attribute | Black-headed Duck | Magellanic Steamerduck |
|---|---|---|
| Scientific Name | Heteronetta atricapilla | Tachyeres pteneres |
| Order | Anseriformes | Anseriformes |
| Family | Anatidae | Anatidae |
| Conservation Status | Least Concern | Least Concern |
| Length | — | — |
| Wingspan | 34.7 cm (13.7 in) | 52.2 cm (20.6 in) |
| Weight | 528.5 g (18.64 oz) | 4881.25 g (172.18 oz) |
| Diet | Parasitic; adults may feed on aquatic plants, seeds, and invertebrates in South American marshes. Diet … | Feeds on seeds, aquatic invertebrates, and plant matter; dabbles in wetlands; diet heavily invertebrate during … |
| Clutch Size | 2 | 4-8 |
| Population Trend | — | — |
Habitat Comparison
Shared Habitats
None
Black-headed Duck only
Magellanic Steamerduck only
Magellanic Steamerduck
Rocky coastal shores, kelp-fringed channels, and sheltered bays of Patagonian Chile and Argentina. Flightless; confined to coastline. Nests on rocky shorelines. Uses wings to propel across water surface.
Song & Call Comparison
Black-headed Duck
Male gives a soft, raspy peeping note; female produces a muted quack. An obligate brood parasite with reduced vocalizations; subdued calls suit its secretive lifestyle among Argentine reeds.
Magellanic Steamerduck
A loud, rattling, staccato 'kik-kik-kik' that sounds like a steam engine — hence 'steamerduck'. The wings also produce a loud churring sound as they beat the water surface.
Geographic Range & Migration
Black-headed Duck
Resident in southern South America from southern Brazil and Bolivia south to Argentina and Chile. Found on lakes and marshes in open lowlands.
Magellanic Steamerduck
Breeds in the Arctic and sub-Arctic; winters on the open Pacific Ocean from British Columbia to Baja California.
Conservation Status
Black-headed Duck
Magellanic Steamerduck
How to Tell Them Apart
Black-headed Duck
Male has distinctive jet-black head and neck, warm chestnut-brown back, and pale buff underparts; blue-grey bill with red base. Female is streaked brown above with pale supercilium and whitish underparts.
Magellanic Steamerduck
Heavy, flightless. Males gray with white eye-stripe and orange-yellow bill. Breast and flanks mottled rufous-brown. Females more brown with white eye-ring and olive-yellow bill. Wings used for steaming.
About These Birds
Black-headed Duck
A small diving duck (~530 g) of South America, family Anatidae, and the sole member of genus Heteronetta. Inhabits freshwater marshes and lakes in Argentina, Bolivia, Brazil, Chile, and Uruguay. Unique among waterfowl as an obligate brood parasite, laying eggs in nests of coots and other waterbirds. Feeds on seeds and aquatic invertebrates. Least Concern.
Magellanic Steamerduck
A large flightless steamerduck with grey-blue plumage, a rust-orange head (male), and massive orange-red bill. Named for its habit of steaming across water using wings and feet. Found on rocky Patagonian coasts and sheltered channels. Among the world's heaviest ducks at up to 6 kg.