Yellow-billed Duck vs Brent Goose
Anas undulata 比較対象 Branta bernicla
Side-by-Side Comparison
| 属性 | Yellow-billed Duck | Brent Goose |
|---|---|---|
| 学名 | Anas undulata | Branta bernicla |
| 目 | Anseriformes | Anseriformes |
| 科 | Anatidae | Anatidae |
| 保全状況 | Least Concern | Least Concern |
| 体長 | — | — |
| 翼開長 | 48.1 cm (18.9 in) | 63.9 cm (25.2 in) |
| 体重 | 907.6666666666666 g (32.02 oz) | 1335.0 g (47.09 oz) |
| 食性 | Dives for fish, frogs, and aquatic invertebrates; uses serrated bill to grip prey; diet shifts … | Primarily herbivorous; grazes aquatic plants, grasses, and sedges; swans upend in shallow water for submerged … |
| 一腹卵数 | 4-12 | 1-10 |
| Population Trend | — | — |
Habitat Comparison
Yellow-billed Duck
Freshwater lakes, rivers, marshes, and dams across eastern and southern Africa from Ethiopia and Uganda south to the Cape. Tolerates agricultural impoundments and urban wetlands. Largely sedentary.
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
Yellow-billed Duck
Female gives a loud, descending quacking series; male utters a soft, raspy rehb note. The female's strong quacking call is the dominant sound at sub-Saharan African wetlands.
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
Yellow-billed Duck
Found across sub-Saharan Africa from Senegal to Ethiopia and south to South Africa. Sedentary in freshwater wetlands.
Brent Goose
Breeds across boreal and subarctic Canada and Alaska; winters in the southern United States, Mexico, and Central America.
保全状況
Yellow-billed Duck
Brent Goose
How to Tell Them Apart
Yellow-billed Duck
Brown body with scaly pale-edged feathers; head brown with paler face and throat. Diagnostic bright yellow bill with black central stripe. Iridescent green-and-black speculum with white borders. Sexes similar.
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
Yellow-billed Duck
イエローカモはアフリカ東南部に生息するカモで、黄色い嘴が最大の特徴です。内陸の湖、沼地、川、ダムに生息し、水草、種子、無脊椎動物などを採食します。通常は小さな群れを作りますが、乾燥期には数百羽の大群になることもあります。
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。