Amsterdam Duck vs Brent Goose
Anas marecula 比較対象 Branta bernicla
Side-by-Side Comparison
| 属性 | Amsterdam Duck | Brent Goose |
|---|---|---|
| 学名 | Anas marecula | Branta bernicla |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Extinct | Least Concern |
| 体長 | — | — |
| 翼開長 | — | 63.9 cm (25.2 in) |
| 体重 | 289.5 g (10.21 oz) | 1335.0 g (47.09 oz) |
| 食性 | Extinct Auckland Islands Merganser; fed on freshwater fish and aquatic invertebrates in streams; inferred from … | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … |
| 一腹卵数 | -- | 1-10 |
| Population Trend | — | — |
Habitat Comparison
Amsterdam Duck
Historically restricted to Amsterdam Island in the southern Indian Ocean. Now extinct. Presumably inhabited the island's freshwater sources and coastal areas.
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
Amsterdam Duck
Extinct (EX). No recordings exist. As an Anas relative, likely gave a typical duck-like quacking call; male may have had a soft whistled note similar to other island teals.
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.
Geographic Range & Migration
Amsterdam Duck
Breeds on sub-Antarctic islands of the South Indian Ocean; disperses across the Southern Ocean when not nesting.
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
保全状況
Amsterdam Duck
Brent Goose
How to Tell Them Apart
Amsterdam Duck
Extinct Amsterdam Island duck known only from bones and a single historical description. Presumably brown plumage typical of Anas dabbling ducks. Flightless or near-flightless; extirpated by introduced predators.
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.
About These Birds
Amsterdam Duck
An extinct diving duck known from subfossil remains discovered on Amsterdam Island in the southern Indian Ocean. Flightless or nearly flightless; probably resembled the Laysan Duck in size. Went extinct around 1800 following human colonization of the island.
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。