Brent Goose vs Red-breasted Merganser
Branta bernicla 比較対象 Mergus serrator
Side-by-Side Comparison
| 属性 | Brent Goose | Red-breasted Merganser |
|---|---|---|
| 学名 | Branta bernicla | Mergus serrator |
| 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) | 46.7 cm (18.4 in) |
| 体重 | 1335.0 g (47.09 oz) | 1058.3333333333333 g (37.33 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dives for small fish, crustaceans, and aquatic invertebrates in coastal and freshwater habitats. Pursues fish … |
| 一腹卵数 | 1-10 | 6-14 |
| 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.
Red-breasted Merganser
Male produces a harsh, rasping series of notes; female gives a rough, guttural grunting. The harsh, rattling call is louder than Goosander; pairs and flocks create a rasping coastal cacophony.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Red-breasted Merganser
Circumpolar breeder in boreal and Arctic zones. Winters on coasts and large water bodies south to the Mediterranean and southern Asia.
保全状況
Brent Goose
Red-breasted Merganser
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.
Red-breasted Merganser
Male has dark green shaggy double crest, speckled chestnut breast band, white collar, and grey flanks; red bill. Female has rufous-brown head with ragged crest blending gradually into grey neck …
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。
Red-breasted Merganser
ウミアイサはユーラシアと北米に繁殖する潜水性カモです。雄は緑色の頭部と二重の冠羽、赤い鋸状の嘴が特徴的です。日本では冬鳥として海岸や湾に飛来します。魚を主食とし、沿岸の海や河川で潜って採食します。