Blue Duck vs Mallard
Hymenolaimus malacorhynchos compared with Anas platyrhynchos
Side-by-Side Comparison
| Attribute | Blue Duck | Mallard |
|---|---|---|
| Scientific Name | Hymenolaimus malacorhynchos | Anas platyrhynchos |
| Order | Anseriformes | Anseriformes |
| Family | Anatidae | Anatidae |
| Conservation Status | Endangered | Least Concern |
| Length | — | 58.0 cm (22.8 in) |
| Wingspan | 45.6 cm (18.0 in) | 90.0 cm (35.4 in) |
| Weight | 861.75 g (30.40 oz) | 1100.0 g (38.80 oz) |
| Diet | Eats aquatic invertebrates, seeds, and plant material; dabbles in shallow fresh water; invertebrate diet peaks … | Omnivorous — aquatic plants, seeds, insects, crustaceans, and mollusks. Feeds by dabbling, upending, and grazing … |
| Clutch Size | 5-6 | 4-18 |
| Population Trend | — | — |
Size Comparison
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.
Mallard
Nearly any wetland habitat including lakes, rivers, ponds, marshes, estuaries, and urban park ponds.
Song & Call Comparison
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.
Mallard
Female gives the classic 'quack-quack-quack', descending in pitch. Male utters soft nasal 'raeb-raeb'. Both give a high 'gag-gag-gag' when alarmed or taking flight.
Geographic Range & Migration
Blue Duck
Breeds on open prairie wetlands of the Great Plains; winters in shallow estuaries and marshes along the Gulf of Mexico.
Mallard
Native across the Northern Hemisphere in North America, Europe, and Asia. Introduced to Australia and New Zealand.
Conservation Status
Blue Duck
Mallard
How to Tell Them Apart
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.
Mallard
Breeding males have an iridescent green head, white neck ring, chestnut breast, and grey body. Females are mottled brown. Both sexes show a blue speculum bordered by white.
Broad, flat bill — yellow-green in males, orange-brown in females
About These Birds
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.
Mallard
The mallard is the ancestor of most domestic duck breeds and the most abundant and widespread dabbling duck in the world. Males perform elaborate courtship displays including head-bobbing and whistle-grunt calls. Mallards are highly adaptable, thriving in both wilderness and urban environments.