Redhead vs Brent Goose
Aythya americana 比較対象 Branta bernicla
Side-by-Side Comparison
| 属性 | Redhead | Brent Goose |
|---|---|---|
| 学名 | Aythya americana | Branta bernicla |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Least Concern |
| 体長 | — | — |
| 翼開長 | 43.7 cm (17.2 in) | 63.9 cm (25.2 in) |
| 体重 | 1055.0 g (37.21 oz) | 1335.0 g (47.09 oz) |
| 食性 | Dives for molluscs, crustaceans, and aquatic invertebrates in shallow coastal water; hard-shelled benthic prey dominates … | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … |
| 一腹卵数 | 7-14 | 1-10 |
| Population Trend | — | — |
Habitat Comparison
Redhead
Breeds on prairie marshes and potholes in western North America. Winters on large bays, coastal waters, lakes, and reservoirs across the southern United States and Mexico. Large concentrations on Laguna Madre, Texas.
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
Redhead
Male gives a low, mewing may-heah call; female produces a purring, rolled quacking. The mewing, nasal call is unlike any other North American duck; flocks create a cat-like chorus.
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
Redhead
Breeds in boreal and temperate North America; winters from southern Canada to northern South America along both coasts.
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
保全状況
Redhead
Brent Goose
How to Tell Them Apart
Redhead
Males have rounded rufous-red head; black breast and undertail; pale gray body. Blue-gray bill with white ring and black tip. Red eye. Females brown with paler face. Rounder head than …
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
Redhead
中型の潜水ガモ。雄は丸い赤褐色の頭部・黒い胸と後部・灰色の体；雌は褐色。高度な托卵性で他のカモの巣に頻繁に卵を産む。北米全域に分布。大きな湾や沿岸の水域で越冬する。
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。