Gorfou doré

Identification

The macaroni penguin is a large, crested penguin, similar in appearance to other members of the genus Eudyptes. An adult bird has an average length of around 70 cm (28 in); the weight varies markedly depending on time of year and sex. Males average from 3.3 kg (7 lb) after incubating, or 3.7 kg (8 lb) after moult to 6.4 kg (14 lb) before moult, while females average 3.2 kg (7 lb) after to 5.7 kg (13 lb) before moult. Among standard measurements, the thick bill (from the gape) measures 7 to 8 cm (2.8 to 3.1 in), the culmen being around a centimetre less. The wing, from the shoulder to the tip, is around 20.4 cm (8.0 in) and the tail is 9–10 cm (3.5–3.9 in) long. The head, chin, throat, and upper parts are black and sharply demarcated against the white under parts. The black plumage has a bluish sheen when new and brownish when old. The most striking feature is the yellow crest that arises from a patch on the centre of the forehead, and extends horizontally backwards to the nape. The flippers are blue-black on the upper surface with a white trailing edge, and mainly white underneath with a black tip and leading edge. The large, bulbous bill is orange-brown. The iris is red and a patch of pinkish bare skin is found from the base of the bill to the eye. The legs and feet are pink. The male and female are similar in appearance; males tend to be slightly larger. Males also bear relatively larger bills, which average around 6.1 cm (2.4 in) compared to 5.4 cm (2.1 in) in females; this feature has been used to tell the sexes apart.<p>Immature birds are distinguished by their smaller size, smaller, duller-brown bill, dark grey chin and throat, and absent or underdeveloped head plumes, often just a scattering of yellow feathers. The crest is fully developed in birds aged three to four years, a year or two before breeding age.<p>Macaroni penguins moult once a year, a process in which they replace all of their old feathers. They spend around two weeks accumulating fat before moulting because they do not feed during the moult, as they cannot enter the water to forage for food without feathers. The process typically takes three to four weeks, which they spend sitting ashore. Once finished, they go back to sea and return to their colonies to mate in the spring. Overall survival rates are poorly known; the successful return of breeding adults at South Georgia Island varied between 49% and 78% over three years, and around 10% of those that did return did not breed the following year.

Taxonomie

The macaroni penguin was described from the Falkland Islands in 1837 by German naturalist Johann Friedrich von Brandt. It is one of six or so species in the genus Eudyptes, collectively known as crested penguins. The genus name is derived from the Ancient Greek words eu "good", and dyptes "diver". The specific name chrysolophus is derived from the Greek words chryse "golden", and lophos "crest".<p>The common name was recorded from the early 19th century in the Falkland Islands. English sailors apparently named the species for its conspicuous yellow crest. It is similar to the then fashionable Macaroni.<p>Molecular clock evidence using DNA suggests the macaroni penguin diverged from its closest relative, the royal penguin (Eudyptes schlegeli), around 1.5 million years ago. The two have generally been considered different species, but the close similarities of their DNA sequences has led some, such as Australian ornithologists Les Christidis and Walter Boles, to treat the royal penguin as a subspecies of the macaroni penguin. The two species are very similar in appearance; the royal penguin has a white face instead of the usually black face of the macaroni penguin. Interbreeding with the Indo-Pacific subspecies of the southern rockhopper penguin (E. chrysocome filholi) has been reported at Heard and Marion Islands, with three hybrid subspecies recorded there by a 1987–88 Australian National Antarctic Research Expedition.

Nom scientifique

Eudyptes chrysolophus

Autorité

(Brandt, JF, 1837)

Ordre

Sphénisciformes

Famille

Spheniscidés

Genre

Eudyptes

Répartition et habitat

A 1993 review estimated that the macaroni was the most abundant species of penguin, with a minimum of 11,841,600 pairs worldwide. Macaroni penguins range from the Subantarctic to the Antarctic Peninsula; at least 216 breeding colonies at 50 sites have been recorded. In South America, macaroni penguins are found in southern Chile, the Falkland Islands, South Georgia and the South Sandwich Islands, and South Orkney Islands. They also occupy much of Antarctica and the Antarctic Peninsula, including the northern South Shetland Islands, Bouvet Island, the Prince Edward and Marion islands, the Crozet Islands, the Kerguelen Islands, and the Heard and McDonald Islands. While foraging for food, groups will range north to the islands off Australia, New Zealand, southern Brazil, Tristan da Cunha, and South Africa.

Migration

Migrateurs complets

Comportement

Mode de migration: Migrateurs complets.

Conservation

Tendance de la population: en déclin.

Tendance de la population

en déclin