Black-headed Duck vs Blue Duck
Heteronetta atricapilla so với Hymenolaimus malacorhynchos
Side-by-Side Comparison
| Thuộc Tính | Black-headed Duck | Blue Duck |
|---|---|---|
| Tên Khoa Học | Heteronetta atricapilla | Hymenolaimus malacorhynchos |
| Bộ | Anseriformes | Anseriformes |
| Họ | Anatidae | Anatidae |
| Tình Trạng Bảo Tồn | Least Concern | Endangered |
| Chiều Dài | — | — |
| Chiều Dài Sải Cánh | 34,7 cm (13.7 in) | 45,6 cm (18.0 in) |
| Khối Lượng | 528,5 g (18.64 oz) | 861,75 g (30.40 oz) |
| Chế Độ Ăn | Parasitic; adults may feed on aquatic plants, seeds, and invertebrates in South American marshes. Diet … | Eats aquatic invertebrates, seeds, and plant material; dabbles in shallow fresh water; invertebrate diet peaks … |
| Số Trứng | 2 | 5-6 |
| Population Trend | — | — |
Habitat Comparison
Blue Duck
Fast-flowing clear turbulent mountain rivers and streams in pristine native forest at 300–1,500 m in both main islands of New Zealand. Requires undisturbed riparian habitat with abundant aquatic invertebrates.
Song & Call Comparison
Black-headed Duck
Male gives a soft, raspy peeping note; female produces a muted quack. An obligate brood parasite with reduced vocalizations; subdued calls suit its secretive lifestyle among Argentine reeds.
Blue Duck
A soft, musical whistle from fast-flowing South Island rivers. Call is a clear 'whio' — giving the bird its Maori name. Also gives a soft, reedy 'squeak'. Endangered; rarely heard.
Geographic Range & Migration
Black-headed Duck
Resident in southern South America from southern Brazil and Bolivia south to Argentina and Chile. Found on lakes and marshes in open lowlands.
Blue Duck
Breeds on open prairie wetlands of the Great Plains; winters in shallow estuaries and marshes along the Gulf of Mexico.
Tình Trạng Bảo Tồn
Black-headed Duck
Blue Duck
How to Tell Them Apart
Black-headed Duck
Male has distinctive jet-black head and neck, warm chestnut-brown back, and pale buff underparts; blue-grey bill with red base. Female is streaked brown above with pale supercilium and whitish underparts.
Blue Duck
Distinctive slate-blue-gray plumage; breast spotted with chestnut-brown in both sexes. Pale bill with flexible pink lobes at tip. Chestnut eye. Sexes similar; adapted to fast-flowing mountain streams in New Zealand.
About These Birds
Black-headed Duck
A small diving duck (~530 g) of South America, family Anatidae, and the sole member of genus Heteronetta. Inhabits freshwater marshes and lakes in Argentina, Bolivia, Brazil, Chile, and Uruguay. Unique among waterfowl as an obligate brood parasite, laying eggs in nests of coots and other waterbirds. Feeds on seeds and aquatic invertebrates. Least Concern.
Blue Duck
A medium-sized blue-grey torrent duck with a pale pink bill tipped with a distinctive flap of skin, and chestnut-spotted breast. Endemic to New Zealand's fast-flowing mountain rivers. One of New Zealand's most endangered endemics. Monogamous with strong site fidelity to individual river territories.