American Black Duck vs Brent Goose
Anas rubripes 比較対象 Branta bernicla
Side-by-Side Comparison
| 属性 | American Black Duck | Brent Goose |
|---|---|---|
| 学名 | Anas rubripes | Branta bernicla |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Least Concern |
| 体長 | — | — |
| 翼開長 | 53.4 cm (21.0 in) | 63.9 cm (25.2 in) |
| 体重 | 1211.25 g (42.73 oz) | 1335.0 g (47.09 oz) |
| 食性 | Eats fish and aquatic invertebrates; dives in coastal and freshwater habitats; diet shifts toward molluscs … | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … |
| 一腹卵数 | 1-17 | 1-10 |
| 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.
Brent Goose
Breeds on high-Arctic tundra; winters on estuaries, coastal mudflats, saltmarshes, and sea-grass beds along Atlantic and Pacific coastlines. One of the most strictly coastal wintering geese.
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.
Brent Goose
A low, guttural 'rronk' or 'ronk-ronk' from flocks. Soft nasal calls in feeding groups. A subtle, understated call for a goose — less loud than most Anser geese.
Geographic Range & Migration
American Black Duck
Breeds in the steppe zone of Central Asia; winters in South Asia, East Africa, and coastal Southeast Asia.
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
保全状況
American Black Duck
Brent Goose
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 …
Brent Goose
Small; mostly black head, neck, and breast. Small white neck-patch on adults. Back dark brownish-gray; belly pale gray to white depending on subspecies. White undertail coverts. Sexes similar.
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。
Brent Goose
北極圏で繁殖し、北半球の海岸で越冬する小型のガン（体長55〜66cm）。黒い頭・首・胸に短い白い首輪が特徴。Branta bernicla（コクガン）は主にアマモなどの海草を食べ、干潟や浅い入り江を好む。日本でも北海道・東北の海岸で越冬する姿が見られ、個体数は比較的少ない。Anatidae科。