Black-headed Duck vs Knob-billed Duck
Heteronetta atricapilla comparé à Sarkidiornis melanotos
Side-by-Side Comparison
| Attribut | Black-headed Duck | Knob-billed Duck |
|---|---|---|
| Nom scientifique | Heteronetta atricapilla | Sarkidiornis melanotos |
| Ordre | Anseriformes | Anseriformes |
| Famille | Anatidae | Anatidae |
| Statut de conservation | Least Concern | Least Concern |
| Longueur | — | — |
| Envergure | 34,7 cm (13.7 in) | 64,2 cm (25.3 in) |
| Poids | 528,5 g (18.64 oz) | 1817,5 g (64.11 oz) |
| Régime alimentaire | Parasitic; adults may feed on aquatic plants, seeds, and invertebrates in South American marshes. Diet … | Dabbles for seeds and aquatic invertebrates; diet shifts toward invertebrate prey in spring breeding season; … |
| Taille de la couvée | 2 | 6-20 |
| Population Trend | — | — |
Habitat Comparison
Habitats partagés
Black-headed Duck only
Aucun(e)
Knob-billed Duck only
Aucun(e)
Knob-billed Duck
Freshwater lakes, marshes, floodplains, and forested wetlands across sub-Saharan Africa and South and Southeast Asia from India to southern China. Nests in large 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.
Knob-billed Duck
A low, grunting 'wuk' or soft, nasal 'krank'. Similar to Comb Duck in call quality. Generally quiet; calls are not loud or distinctive compared to other large African waterfowl.
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.
Knob-billed Duck
Breeds on sub-Arctic tundra; winters on the Atlantic coast of North America from Labrador to Florida and the Gulf Coast.
Statut de conservation
Black-headed Duck
Knob-billed Duck
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.
Knob-billed Duck
Males have white head with black spots; iridescent dark blue-black back and wings; white underparts with gray flanks. Large black fleshy knob atop bill. Females smaller, brown, and lack the …
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.
Knob-billed Duck
Old World equivalent of the Comb Duck, with iridescent black-and-white body and the male's distinctive bill knob. Found across sub-Saharan Africa and South Asia. Uses tree cavities for nesting. Gregarious outside breeding season; forms large flocks at seasonal wetlands.