Canard bleu

Identification

The blue duck is 53 cm (21 in) long and varies in weight by sex. Females are smaller than males, weighing 680–870 g (24–31 oz), whereas the males weigh 820–970 grams (29–34 oz). The plumage is a dark slate-grey with a greenish sheen on the head, a chestnut-flecked breast. The outer secondaries are tipped with white and the inner ones have black margins. The plumage of the two sexes are mostly the same, although the female has slightly less chestnut in the chest. The pinkish-white bill has fleshy flaps of skin hanging from the sides of its tip. The beak is green at hatching and develops its final colour eight hours later .<p>The male's call is a high-pitched whistle. The female's call is a rattling growl or low-pitched grating notes.

Taxonomie

Captain James Cook saw the blue duck in Dusky Sound, South Island, New Zealand, on his second voyage to the south Pacific. In 1777 both Cook and the naturalist Georg Forster mentioned the blue duck in their separate accounts of the voyage. A specimen was described in 1785 by the English ornithologist John Latham in his A General Synopsis of Birds. Latham used the English name, the "soft-billed duck". When in 1789 the German naturalist Johann Friedrich Gmelin revised and expanded Carl Linnaeus's Systema Naturae he included the blue duck and placed it with all the other ducks in the genus Anas. He coined the binomial name Anas malacorhynchos and cited the earlier works. The blue duck is now the only species placed in the genus Hymenolaimus that was introduced specifically for the species by George Robert Gray in 1843. The genus name combines the Ancient Greek humēn, humenos meaning "skin" or "membrane" with laimos meaning "throat". The specific epithet malacorhynchos is also from Ancient Greek and combines malakos meaning "soft" with rhunkhos meaning "bill".<p>The species has no close relatives. Its taxonomic relationships with other waterfowl species remains uncertain; DNA analysis has placed it as a sister to the South American dabbling ducks (Anatini), but with no close relative. As of 2013, it was commonly listed as incertae sedis but likely within the Anatinae and allied to the Anatini. It was formerly thought to be related to the shelduck tribe.<p>It is commonly known in New Zealand English by its Māori name Whio, pronounced /ˈfiɔː/ FEE-oh, which is an onomatopoeic rendition of the males' call. Other names may be known by are Mountain Duck or Blue Mountain Duck.<p>Two subspecies are recognised:<p>Prior to 2022, the North Island and South Island whio were considered distinct but were not distinguished as subspecies; they were, however, treated as separate management units. However, the populations were defined as distinct subspecies by the International Ornithological Congress in 2022, based on strong genetic divergence and some plumage differences.

Nom scientifique

Hymenolaimus malacorhynchos

Autorité

(Gmelin, JF, 1789)

Ordre

Ansériformes

Famille

Inconnu

Genre

Hymenolaimus

Répartition et habitat

Migration

Espèce sédentaire

Comportement

Mode de migration: Espèce sédentaire.

Conservation

Tendance de la population: en déclin.

Tendance de la population

en déclin