Brent Goose vs Scaly-sided Merganser
Branta bernicla 比較対象 Mergus squamatus
Side-by-Side Comparison
| 属性 | Brent Goose | Scaly-sided Merganser |
|---|---|---|
| 学名 | Branta bernicla | Mergus squamatus |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Endangered |
| 体長 | — | — |
| 翼開長 | 63.9 cm (25.2 in) | 51.2 cm (20.2 in) |
| 体重 | 1335.0 g (47.09 oz) | 1145.8 g (40.42 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dives for fish in fast-flowing East Asian rivers. Endangered; highly piscivorous with serrated bill adapted … |
| 一腹卵数 | 1-10 | 4-14 |
| 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.
Scaly-sided Merganser
Male gives a quiet, low grunting call; female produces a guttural, croaking series. Endangered; calls are poorly known; similar to Red-breasted Merganser but quieter in Manchurian forest rivers.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Scaly-sided Merganser
Breeds in southern Russia, northern China, and the Russian Far East. Winters in southern China and Korea. Found on fast-flowing forested rivers.
保全状況
Brent Goose
Scaly-sided 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.
Scaly-sided Merganser
Male has iridescent dark green head with long flat crest, white body with distinctive black scaly pattern on flanks, and black back with white patches. Female has brownish-red crested head …
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。
Scaly-sided Merganser
カワアイサはロシア極東と中国東北部の急流河川に繁殖し、東アジアで越冬する潜水性カモです。鱗状の羽毛パターンが名前の由来で、雄は緑光沢の黒い頭部と赤い嘴を持ちます。清澄な河川で魚を潜って採食します。絶滅危惧種です。