Auckland Teal vs Brent Goose
Anas aucklandica 比較対象 Branta bernicla
Side-by-Side Comparison
| 属性 | Auckland Teal | Brent Goose |
|---|---|---|
| 学名 | Anas aucklandica | Branta bernicla |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Near Threatened | Least Concern |
| 体長 | — | — |
| 翼開長 | 27.0 cm (10.6 in) | 63.9 cm (25.2 in) |
| 体重 | 522.25 g (18.42 oz) | 1335.0 g (47.09 oz) |
| 食性 | Dives for molluscs, crustaceans, and aquatic invertebrates; diet dominated by hard-shelled prey in coastal habitats. | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … |
| 一腹卵数 | 1-6 | 1-10 |
| Population Trend | — | — |
Habitat Comparison
Auckland Teal
Restricted to predator-free islands of the Auckland Islands subantarctic group (Adams, Disappointment, Ewing islands). Inhabits dense tussock grassland, scrub, and freshwater streams.
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
Auckland Teal
Female gives a short, nasal quack; male produces a barely audible high note. Nearly flightless; extremely quiet and seldom vocal; calls are reduced even compared with other flightless 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
Auckland Teal
Breeds in Arctic and sub-Arctic North America; winters on Pacific and Atlantic coasts south to California and the Carolinas.
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
保全状況
Auckland Teal
Brent Goose
How to Tell Them Apart
Auckland Teal
Dark chocolate-brown plumage; males have iridescent dark green head and white eye-ring. Females dark brown with white eye-ring. Near-flightless. Iridescent speculum. Flightless wings. Auckland Islands endemic.
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
Auckland Teal
オークランドティールはニュージーランドのオークランド諸島に固有の飛べないカモです。マガモから進化した島嶼固有種で、翼が退化して飛行能力を失っています。島の森林内の池や小川に生息し、無脊椎動物、植物、種子などを採食します。外来捕食者の排除が保全の鍵です。
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。