Brent Goose vs Gadwall
Branta bernicla 比較対象 Mareca strepera
Side-by-Side Comparison
| 属性 | Brent Goose | Gadwall |
|---|---|---|
| 学名 | Branta bernicla | Mareca strepera |
| 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) | 50.3 cm (19.8 in) |
| 体重 | 1335.0 g (47.09 oz) | 857.5 g (30.25 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dabbles for seeds and aquatic invertebrates; diet shifts toward invertebrates in spring; forages in shallow … |
| 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.
Gadwall
Freshwater lakes, reservoirs, marshes, and rivers with emergent vegetation across Eurasia and North America. Winters on large open wetlands and coastal estuaries. Range and population increasing in Europe.
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.
Gadwall
Male utters a soft, nasal nheck note; female produces a series of descending, quacking notes. Both sexes are relatively quiet; female's quacking is softer and less strident than a Mallard.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Gadwall
Found year-round in Australia and New Zealand; nomadic in arid Australia, following temporary rainfall-fed wetlands.
保全状況
Brent Goose
Gadwall
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.
Gadwall
Males have finely vermiculated gray-brown plumage with black rump and undertail. White speculum patch diagnostic in flight. Females mottled brown like Mallard but smaller and with orange-sided bill. Subtle but …
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。
Gadwall
カドワール。ユーラシア大陸と北アメリカに広く分布するカモ。雄は灰褐色の体と黒い尾部が特徴的。体長46〜56cm。湖や池、湿地に生息。植物性の食物を好む雑食性。北半球で繁殖し南へ渡る。低危険種。