Black-headed Duck vs Steller's Eider
Heteronetta atricapilla 对比 Polysticta stelleri
Side-by-Side Comparison
| 属性 | Black-headed Duck | Steller's Eider |
|---|---|---|
| 学名 | Heteronetta atricapilla | Polysticta stelleri |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保护状况 | Least Concern | Vulnerable |
| 体长 | — | — |
| 翼展 | 34.7 cm (13.7 in) | 40.7 cm (16.0 in) |
| 体重 | 528.5 g (18.64 oz) | 815.75 g (28.77 oz) |
| 食性 | Parasitic; adults may feed on aquatic plants, seeds, and invertebrates in South American marshes. Diet … | Eats molluscs, crustaceans, and aquatic invertebrates; dives in shallow coastal and estuarine habitats; diet invertebrate-dominated. |
| 产卵数 | 2 | 3-10 |
| Population Trend | — | — |
Habitat Comparison
Steller's Eider
Breeds on low-lying coastal tundra in Arctic Russia and occasionally Alaska. Winters on shallow rocky sea coasts, kelp beds, and sheltered bays in the Baltic Sea and Pacific coast of Alaska. Listed as Vulnerable.
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.
Steller's Eider
Male produces a low, soft cooing note; female gives a guttural, grunting purr. Quieter than other eiders; the male's gentle cooing is unlike the louder calls of the Common Eider.
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.
Steller's Eider
Breeds in boreal Canada and Alaska; winters along Pacific and Atlantic coasts and on large interior lakes of the US.
保护状况
Black-headed Duck
Steller's 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.
Steller's Eider
Males have white head with green nape spot, black eye patch and chin; orange-buff underparts; black back with white wing patches. Females mottled dark brown with blue speculum bordered white. …
About These Birds
Black-headed Duck
黑头鸭是南美洲的寄生性鸭子，不自己筑巢，而将卵产于其他水鸟（包括其他鸭类、䴙䴘、红鹭等）的巢中，由寄主孵化并抚育。分布于阿根廷、乌拉圭、智利和巴西南部。雄鸟头部黑色，体羽深褐色；雌鸟头部褐色。是唯一真正的全职巢寄生鸭类。
Steller's Eider
小绒鸭是北极海鸭，以俄罗斯博物学家斯泰勒命名。雄鸟色彩极为艳丽：头部白色有绿斑，嘴基有细黑圈，胸部橙黄色，体侧黑白相间；雌鸟褐色，翼具双白色翼镜。繁殖于阿拉斯加和西伯利亚北极海岸，越冬于阿留申群岛和西伯利亚沿岸，以无脊椎动物为食，被列为易危物种。