Brent Goose vs Spectacled Eider
Branta bernicla 比較対象 Somateria fischeri
Side-by-Side Comparison
| 属性 | Brent Goose | Spectacled Eider |
|---|---|---|
| 学名 | Branta bernicla | Somateria fischeri |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Near Threatened |
| 体長 | — | — |
| 翼開長 | 63.9 cm (25.2 in) | 49.2 cm (19.4 in) |
| 体重 | 1335.0 g (47.09 oz) | 1443.75 g (50.93 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dives for bivalves, crustaceans, and aquatic insects in shallow Arctic coastal and freshwater habitats. Insects … |
| 一腹卵数 | 1-10 | 1-9 |
| 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.
Spectacled Eider
Male gives a low, melodious aah-ooo cooing; female produces a guttural, grunting call. The male's ghostly, organ-like cooing call carries across Arctic tundra ponds in the breeding season.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Spectacled Eider
Breeds on coastal tundra of western and northern Alaska. Winters along the Bering Sea coast from Alaska to Kamchatka. Largely sedentary.
保全状況
Brent Goose
Spectacled Eider
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.
Spectacled Eider
Male has white back and black breast with pale sage-green head framed by large white goggle-like spectacles edged black. Female mottled tawny-brown with faint spectacle outline.
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。
Spectacled Eider
A medium-large sea duck of the family Anatidae, weighing ~1.4 kg with distinctive pale green goggles in males. Breeds on Arctic tundra of Alaska and Russia; winters in pack ice of the Bering Sea. Dives for benthic invertebrates and mollusks. Near Threatened due to population declines linked to lead poisoning and habitat change.