The Macaroni
Penguin (Eudyptes chrysolophus) is a species of penguin found from the Subantarctic to the Antarctic Peninsula.
One of six species of crested penguin, it is very closely related to the Royal Penguin, and some authorities consider the two to be a single species. It bears a distinctive yellow crest, and the face and upperparts are black and sharply delineated from the white underpants. Adults weigh on average 5.5 kg (12 lb) and are 70 cm (28 in) in length. The male and female are similar in appearance although the male is slightly larger with a relatively larger bill. Like all penguins, it is flightless, with a streamlined body and wings stiffened and flattened into flippers for a marine lifestyle.
The diet consists of a variety of crustaceans, mainly krill, as well as small fish and cephalopods; the species consumes more marine life annually than any other species of seabird. These birds moult once a year, spending about three to four weeks ashore, before returning to the sea. Numbering up to 100,000 individuals, the breeding colonies of the Macaroni Penguin are among the largest and densest of all penguin species. After spending the summer months breeding, penguins disperse into the oceans for six months; a 2009 study found that Macaroni Penguins from Kerguelen travelled over 10,000 km (6,200 mi) in the central Indian Ocean. With about 18 million individuals, the Macaroni Penguin is the most numerous penguin species. However, widespread decline in populations have been recorded since the mid 1970s. These factors result in their conservation status being reclassified as vulnerable.
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) post-moult to 6.4 kg (14 lb) pre-moult, while females average 3.2 kg (7 lb) post-moult to 5.7 kg (13 lb) pre-moult. The head, chin, throat and upperparts are black and sharply demarcated against the white underparts. 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 there is a patch of pinkish bare skin from the base of the bill to the eye. The legs and feet are pink. The male and female are similar in appearance, although 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.
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 3–4 years, a year or two before breeding age.
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.
Like other penguin species, the Macaroni Penguin is a social animal in its nesting and its foraging behaviour; its breeding colonies are among the largest and most densely populated of all penguin species. Outside the breeding season, the penguin is pelagic; birds disperse to sea from April or May until October. A 2009 study by a French team led by scientist Charles Andre Bost found that Macaroni Penguins nesting at Kerguelen dispersed eastwards over an area exceeding 3×106 km2. Fitted with geolocation sensors, the 12 penguins studied travelled over 10,000 km (6,200 mi) in this period and spent their time largely within a zone 47–49° S and 70–110° E in the central Indian Ocean, not coming ashore once. This area, known as the Polar Frontal Zone, was notable for the absence of krill.
Living in
colonies results in a high level of social interaction between birds, which has led to a large repertoire of visual as well as vocal displays. These behaviours peak early in the breeding period, and colonies particularly quieten when the male Macaroni Penguins are at sea. Agonistic displays are those which are intended to confront or drive off, or alternately, appease and avoid conflict with other individuals. Macaroni Penguins, particularly those on adjacent nests, may engage in bill-jousting; birds lock bills and wrestle, each trying to unseat the other, as well as batter with flippers and peck or strike their opponent's nape. Submissive displays include the slender walk, where birds move through the colony with feathers flattened, flippers moved to the front of the body, and head and neck hunched, and general hunching of head and neck when incubating or standing at the nest