Brent Goose vs Masked Duck
Branta bernicla 比較対象 Nomonyx dominicus
Side-by-Side Comparison
| 属性 | Brent Goose | Masked Duck |
|---|---|---|
| 学名 | Branta bernicla | Nomonyx dominicus |
| 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) | 27.6 cm (10.9 in) |
| 体重 | 1335.0 g (47.09 oz) | 361.0 g (12.73 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dives and dabbles for aquatic seeds, plant matter, and invertebrates in freshwater marshes and ponds … |
| 一腹卵数 | 1-10 | 4-6 |
| 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.
Masked Duck
Male emits a soft, dove-like cooing note; female gives a harsh, emphatic quack. The male's gentle, almost melodic cooing is surprising for a stiff-tail; heard in tropical American marshes.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Masked Duck
Resident from Mexico and the Caribbean south through Central America to northern South America. Found in lowland freshwater marshes and lagoons.
保全状況
Brent Goose
Masked 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.
Masked Duck
Male is rich rufous-chestnut with black mask from forehead to face, boldly spotted black on upperparts; blue bill. Female is streaked buff and brown with two dark facial stripes crossing …
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。
Masked Duck
マスクドダックは中南米に分布するカモです。雄は黒い顔の模様と青い嘴が特徴的で、尾を立てる習性があります。深い葦原に覆われた湿地に隠れるように生活し、観察が難しいです。水草の種子や無脊椎動物を採食します。