American Black Duck vs Steller's Eider
Anas rubripes 比較対象 Polysticta stelleri
Side-by-Side Comparison
| 属性 | American Black Duck | Steller's Eider |
|---|---|---|
| 学名 | Anas rubripes | Polysticta stelleri |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Vulnerable |
| 体長 | — | — |
| 翼開長 | 53.4 cm (21.0 in) | 40.7 cm (16.0 in) |
| 体重 | 1211.25 g (42.73 oz) | 815.75 g (28.77 oz) |
| 食性 | Eats fish and aquatic invertebrates; dives in coastal and freshwater habitats; diet shifts toward molluscs … | Eats molluscs, crustaceans, and aquatic invertebrates; dives in shallow coastal and estuarine habitats; diet invertebrate-dominated. |
| 一腹卵数 | 1-17 | 3-10 |
| Population Trend | — | — |
Habitat Comparison
American Black Duck
Freshwater and brackish wetlands in eastern North America from Atlantic Canada south along the coast to Georgia. Breeds in northern bogs and wetlands. Winters on coastal marshes, estuaries, and freshwater lakes.
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
American Black Duck
Female produces a loud, deep quacking series; male gives a low, raspy grunt. Voice is deeper and huskier than a Mallard; pairs call powerfully across northeastern North American wetlands.
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
American Black Duck
Breeds in the steppe zone of Central Asia; winters in South Asia, East Africa, and coastal Southeast Asia.
Steller's Eider
Breeds in boreal Canada and Alaska; winters along Pacific and Atlantic coasts and on large interior lakes of the US.
保全状況
American Black Duck
Steller's Eider
How to Tell Them Apart
American Black Duck
Sooty dark brown body; head and neck paler buff with dark streaking. Iridescent purple speculum without white border. Males have yellow-green bill; females olive with orange blotches. Silvery underwings in …
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
American Black Duck
北米東部の湿地、沼、河川に生息するカモ（体長53〜61cm）。全体的に暗褐色でマガモの雌に似るが、嘴の色や翼鏡の色が異なる。Anas rubripes（アメリカクロガモ）は海岸の塩性湿地から内陸の淡水域まで幅広く利用し、マガモとの雑種が多く観察される。Anatidae科。
Steller's Eider
A small sea duck. Males have a white head with green facial markings, black throat patch, chestnut underparts, and white back; females are dark brown. The smallest eider. Breeds in Arctic tundra; winters in Baltic Sea and Alaskan coastal waters. Vulnerable to contaminants and oil spills.