Description 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. Habitat 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, 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. Breeding Female Macaroni Penguins can begin breeding at around five years of age, while the males do not normally breed until at least six years old. Females breed at a younger age because the male population is larger. Adult Macaroni Penguins typically begin to breed late in October, and lay their eggs in early November. The nest itself is a shallow scrape in the ground which may be lined with some pebbles, stones, or grass, or nestled in a clump of tussock grass (on South Georgia Island). Nests are densely packed, ranging from around 66 cm apart in the middle of a colony to 86 cm at the edges. A fertile Macaroni Penguin will lay two eggs each breeding season. The first egg to be laid weighs 90–94 grams (3.2–3.3 oz), 61–64% the size of the 145–155-gram (5.1–5.5 oz) second, and is extremely unlikely to survive. The two eggs together weigh 4.8% of the mother's body weight; the composition of an egg is 20% yolk, 66% albumen, and 14% shell. The task of incubating the egg is divided into three roughly equal sessions of around 12 days each over a five week period. The first session is shared by both parents, followed by the male returning to sea, leaving the female alone to tend the egg. Upon the male's return, the female goes off to sea and does not return until the chick has hatched. Both sexes fast for a considerable period during breeding; the male fasts for 37 days after arrival until he returns to sea for around ten days before fasting while incubating eggs and young for another 36 days, and the female fasts for 42 days from her arrival after the male until late in the incubation period. Both adults lose 36–40% of their body weight during this period. The second egg hatches around 34 days after it is laid. Macaroni Penguins typically leave their breeding colony by April or May to disperse into the ocean. From the moment the egg is hatched, the male Macaroni Penguin cares for the newly hatched chick. For about 23 to 25 days the male protects its offspring and helps to keep it warm, since only a few of its feathers have grown in by this time. The female brings food to the chick every one to two days. When they are not being protected by the adult male penguins, the chicks form crèches to keep warm and stay protected. Once their adult feathers have grown in at about 60–70 days, they are ready to go out to sea on their own. Diet The diet of the Macaroni Penguin consists of a variety of crustaceans, squid and fish, although the proportions that each makes up vary with locality and season. Krill, particularly Antarctic krill (Euphausia superba), account for over 90% of food during breeding season. Cephalopods and small fish such as the Marbled rockcod, Painted notie, the lanternfish species become more important during chick-rearing. Threats The Macaroni Penguin's predators consist of birds and aquatic mammals. The Leopard Seal, Antarctic Fur Seal and Subantarctic Fur Seal sometimes hunt adult Macaroni Penguins in the water. Colonies suffer low rates of predation if undisturbed; predators generally only take eggs and young that have been left unattended or deserted. Skua species, the Snowy Sheathbill, and prey on eggs, and skuas and Giant Petrels also sometimes take chicks.