Ross's Goose vs Brent Goose
Anser rossii 比較対象 Branta bernicla
Side-by-Side Comparison
| 属性 | Ross's Goose | Brent Goose |
|---|---|---|
| 学名 | Anser rossii | Branta bernicla |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Least Concern |
| 体長 | — | — |
| 翼開長 | 69.2 cm (27.2 in) | 63.9 cm (25.2 in) |
| 体重 | 1513.5 g (53.39 oz) | 1335.0 g (47.09 oz) |
| 食性 | Eats aquatic plants, seeds, and grasses near wetlands; omnivorous in breeding; takes invertebrates in shallow … | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … |
| 一腹卵数 | 2-8 | 1-10 |
| Population Trend | — | — |
Habitat Comparison
Ross's Goose
Breeds on tundra near Hudson Bay and the central Canadian Arctic. Winters in agricultural fields, rice paddies, and wetlands in the central and southern United States, particularly California's Central Valley.
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
Ross's Goose
A high, nasal yelping 'whoik' or 'hoik' — higher-pitched than Snow Goose. Flocks mix with Snow Geese; calls differ noticeably by pitch. Fast, repeated notes in flight.
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
Ross's Goose
Breeds in high Arctic tundra; winters at sea in the North Atlantic from Iceland to the British Isles and northeastern United States.
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
保全状況
Ross's Goose
Brent Goose
How to Tell Them Apart
Ross's Goose
Smallest white North American goose; pure white plumage with black wingtips. Short triangular pink bill with warty pinkish-gray base. Pink-red legs. Occasional blue morph. Sexes similar.
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
Ross's Goose
ロスガンは北米北極地方に繁殖し、カリフォルニアや南部の農地で越冬する小型のガンです。白い羽毛と短い嘴が特徴的です。ハクガンと混群することが多いです。農地、湿地、草地に生息し、農作物の葉や根を採食します。
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。