Brent Goose vs Ruddy Duck
Branta bernicla 比較対象 Oxyura jamaicensis
Side-by-Side Comparison
| 属性 | Brent Goose | Ruddy Duck |
|---|---|---|
| 学名 | Branta bernicla | Oxyura jamaicensis |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Least Concern |
| 体長 | — | — |
| 翼開長 | 63.9 cm (25.2 in) | 27.9 cm (11.0 in) |
| 体重 | 1335.0 g (47.09 oz) | 586.6666666666666 g (20.69 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dives for aquatic plant seeds, roots, and invertebrates in freshwater marshes. Uses stiff tail as … |
| 一腹卵数 | 1-10 | 5-15 |
| Population Trend | — | — |
Habitat Comparison
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
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.
Ruddy Duck
Male produces a mechanical, drumming bok-bok-bok staccato beat; female gives a harsh, nasal quack. The male's rapid drum-roll call on the bill during display is startlingly loud and distinctive.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Ruddy Duck
Breeds across interior North America from western Canada south to Mexico. Winters on coasts and inland waters south to northern South America.
保全状況
Brent Goose
Ruddy Duck
How to Tell Them Apart
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.
Ruddy Duck
Breeding male has vivid rufous-chestnut body, black crown, white cheeks, and bright sky-blue bill; stiff tail often cocked upright. Female is dull brown with pale cheek crossed by single dark …
About These Birds
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。
Ruddy Duck
北米で繁殖し、中米・南米北部で越冬する小型の潜水ガモ（体長35〜43cm）。雄の繁殖羽は栗色の体に白い頬、青い嘴が特徴的。Oxyura jamaicensis（ルディダック）は特徴的な扇状の尾羽を立てる姿勢で知られる。北米原産だがヨーロッパに移入・定着し、近縁のフェルギネオウ・ホワイトヘッドダックとの交雑が問題となっている。Anatidae科。