Brent Goose vs Blue-billed Duck
Branta bernicla 比較対象 Oxyura australis
Side-by-Side Comparison
| 属性 | Brent Goose | Blue-billed Duck |
|---|---|---|
| 学名 | Branta bernicla | Oxyura australis |
| 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) | 30.8 cm (12.1 in) |
| 体重 | 1335.0 g (47.09 oz) | 837.75 g (29.55 oz) |
| 食性 | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … | Dives for aquatic invertebrates, seeds, and plant material in Australian freshwater lakes and swamps. Highly … |
| 一腹卵数 | 1-10 | 5-6 |
| 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.
Blue-billed Duck
Male produces a mechanical, splashing display call with loud bill-drumming; female gives a harsh quack. The male's bizarre bubbling-cum-drumming display is spectacular on Australian lakes.
Geographic Range & Migration
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
Blue-billed Duck
Resident in southwestern and southeastern Australia. Found on freshwater swamps and lakes, avoiding arid and tropical regions.
保全状況
Brent Goose
Blue-billed 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.
Blue-billed Duck
Breeding male is deep rich chestnut with black head and broad bright blue bill; tail often held erect. Female is dark brown with finely barred buff pattern on body and …
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。
Blue-billed Duck
オーストラリアンブルービルはオーストラリア南部に固有の潜水性カモです。雄は鮮やかな青い嘴と栗色の体が特徴的です。深い葦原に覆われた湿地や湖に生息し、水草の塊茎、種子、水生無脊椎動物を潜って採食します。尾を立てて泳ぐ独特の姿勢で知られています。