Black-headed Duck vs Spectacled Eider
Heteronetta atricapilla в сравнении с Somateria fischeri
Side-by-Side Comparison
| Характеристика | Black-headed Duck | Spectacled Eider |
|---|---|---|
| Научное название | Heteronetta atricapilla | Somateria fischeri |
| Отряд | Anseriformes | Anseriformes |
| Семейство | Anatidae | Anatidae |
| Охранный статус | Least Concern | Near Threatened |
| Длина | — | — |
| Размах крыльев | 34,7 cm (13.7 in) | 49,2 cm (19.4 in) |
| Масса | 528,5 g (18.64 oz) | 1443,75 g (50.93 oz) |
| Питание | Parasitic; adults may feed on aquatic plants, seeds, and invertebrates in South American marshes. Diet … | Dives for bivalves, crustaceans, and aquatic insects in shallow Arctic coastal and freshwater habitats. Insects … |
| Размер кладки | 2 | 1-9 |
| Population Trend | — | — |
Habitat Comparison
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.
Spectacled Eider
Male gives a low, melodious aah-ooo cooing; female produces a guttural, grunting call. The male's ghostly, organ-like cooing call carries across Arctic tundra ponds in the breeding season.
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.
Spectacled Eider
Breeds on coastal tundra of western and northern Alaska. Winters along the Bering Sea coast from Alaska to Kamchatka. Largely sedentary.
Охранный статус
Black-headed Duck
Spectacled Eider
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.
Spectacled Eider
Male has white back and black breast with pale sage-green head framed by large white goggle-like spectacles edged black. Female mottled tawny-brown with faint spectacle outline.
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.
Spectacled Eider
A medium-large sea duck of the family Anatidae, weighing ~1.4 kg with distinctive pale green goggles in males. Breeds on Arctic tundra of Alaska and Russia; winters in pack ice of the Bering Sea. Dives for benthic invertebrates and mollusks. Near Threatened due to population declines linked to lead poisoning and habitat change.