Brent Goose vs Crested Shelduck
Branta bernicla 比較対象 Tadorna cristata
Side-by-Side Comparison
| 属性 | Brent Goose | Crested Shelduck |
|---|---|---|
| 学名 | Branta bernicla | Tadorna cristata |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Critically Endangered |
| 体長 | — | — |
| 翼開長 | 63.9 cm (25.2 in) | 59.8 cm (23.5 in) |
| 体重 | 1335.0 g (47.09 oz) | 1235.0 g (43.56 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Possibly extinct; Crested Shelduck fed on seeds, aquatic plants, and invertebrates near East Asian wetlands; … |
| 一腹卵数 | 1-10 | 10 |
| 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.
Crested Shelduck
Historically known from coastal Korea, Siberia, and possibly Japan. Habitat preferences poorly known; specimens were collected near coasts and rivers. Possibly extinct.
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.
Crested Shelduck
Critically endangered; last confirmed sightings in 1971. No vocalizations reliably recorded. Presumed similar to related shelducks based on phylogeny but effectively unknown.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Crested Shelduck
Breeds across the Palearctic; winters from West Africa to South Africa. Uses the western and central Palearctic–African flyways.
保全状況
Brent Goose
Crested Shelduck
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.
Crested Shelduck
Critically rare; known from few specimens. Males dark green head with bushy crest; black and white body with chestnut flanks. Females have white facial markings and brown-barred body. Possibly extinct; …
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。
Crested Shelduck
カンムリツクシガモは韓国と中国の一部に生息したとされる幻の鳥で、現在は絶滅したと考えられています。雄は緑色の羽毛と特徴的な冠羽を持っていました。20世紀初頭以降の確認記録がなく、生態はほとんど不明です。