Black-headed Duck vs Radjah Shelduck
Heteronetta atricapilla compared with Radjah radjah
Side-by-Side Comparison
| Attribute | Black-headed Duck | Radjah Shelduck |
|---|---|---|
| Scientific Name | Heteronetta atricapilla | Radjah radjah |
| Order | Anseriformes | Anseriformes |
| Family | Anatidae | Anatidae |
| Conservation Status | Least Concern | Least Concern |
| Length | — | — |
| Wingspan | 34.7 cm (13.7 in) | 54.0 cm (21.3 in) |
| Weight | 528.5 g (18.64 oz) | 883.5 g (31.16 oz) |
| Diet | Parasitic; adults may feed on aquatic plants, seeds, and invertebrates in South American marshes. Diet … | Dabbles for seeds and aquatic invertebrates; also grazes on grasses; diet shifts between land and … |
| Clutch Size | 2 | 6-15 |
| Population Trend | — | — |
Habitat Comparison
Radjah Shelduck
Mangroves, tidal mudflats, tropical coastal wetlands, and freshwater lagoons in New Guinea and the tropical north of Australia (Queensland, Northern Territory, Western Australia). Nests in tree hollows near water.
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.
Radjah Shelduck
A loud, rattling 'radjah-radjah' or repeated cackling 'rak-rak-rak'. Calls from tropical Australian and New Guinea wetlands. Name is partly onomatopoeic.
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.
Radjah Shelduck
Breeds in the eastern Arctic of Russia; winters across southern Asia, from the Indian subcontinent to Southeast Asia.
Conservation Status
Black-headed Duck
Radjah Shelduck
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.
Radjah Shelduck
White head and body with chestnut breastband and white-spotted chestnut scapulars. Pink bill and legs. Iridescent green speculum with white bar visible in flight. Sexes similar. Australasian mangrove specialist.
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.
Radjah Shelduck
A medium-sized elegant shelduck with white body plumage, chestnut breast band, dark green back, and pinkish-red bill and legs. Found in coastal mangroves, mudflats, and tropical wetlands of New Guinea and northern Australia. Calls with a loud raspy rattling sound.