by Mike Bingham
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Organisation for the Conservation of Penguins
King Penguin - Aptenodytes patagonicusBreeding Range: Marion, Prince Edward, Crozet, Kerguelen, Heard, Macquarie, South Georgia and Falkland Islands
World Population: 1,500,000 breeding pairs
Despite the scientific specific name patagonicus, King Penguins no longer breed in Patagonia, or any other part of South America, expect for a tiny colony of less than 50 pairs near to Porvenir in Tierra del Fuego. King penguins used to breed on Islas de los Estados (Staten Island) until the colony was wiped out by sealers in the 19th Century, and moulting adults still come ashore there on occasions. There is a breeding population of about 500 pairs on the Falkland Islands, but this is very small indeed in comparison to the estimated world population of one and a half million breeding pairs. The major breeding sites are found on the islands of South Georgia, Crozet, Prince Edward, Kerguelen, Macquarie and Heard, which all lie close to the Antarctic Convergence.
KING PENGUIN: Drawing by Mike Bingham
The King Penguin has distinctive orange patches on each side of the head, which extend down and meet beneath the chin, where they become yellow and fade into the silvery-white breast plumage. The mandibular plates on either side of the bill are also orange in colour. The female is slightly smaller than the male, but has similar plumage.
King Penguins make no nest, and instead lay a single egg of around 310g, which they hold on their feet for the entire incubation period of about 55 days. This allows breeding in much colder terrain than would be the case for species that lay their eggs on the ground, and negates the need for nesting material. The eggs are brooded by both parents in turn, with shift changes of 6 - 18 days; the non-brooding parent going to sea on extended foraging trips.
The newly hatched chicks are also held on the parents feet for the first 30 - 40 days, by which time they have developed their mesoptile plumage, and are able to regulate their own body temperature. During chick-rearing, parents continue to take turns at brooding, but change over periods vary from 3 - 14 days, so chicks may have fairly prolonged waits between feeds. The King Penguin is known to travel far from the Falkland Islands in search of food during chick-rearing.
Chicks are eventually left in creches, to allow both adults to go to sea on prolonged foraging trips, with chicks being fed even less frequently. During the austral winter chicks may go for periods of up to 3 months between feeds, and healthy chicks have been shown to be able to survive for up to 5 months without a feed. Chicks can loose up to 50% of their body weight during the winter.
Despite this lack of food, King Penguin chicks are still able to survive prolonged periods of extremely cold weather. This is achieved by increasing metabolic activity through the burning of body fat in muscle tissue, despite remaining inactive. Stored body fat reserves are usually adequate to maintain the chicks for at least 3 months, but as body fat reserves become depleted, chicks must begin to break down body protein to provide energy. Weight loss then becomes more rapid, and starvation would eventually result unless the chick was fed. Nevertheless, starvation does not usually result until a chick, which perhaps weighed around 10kg at the start of winter, has gone down to just 3kg. Very few animals are able to survive a 70% loss of body weight, and still be capable of recovery.
Preferred breeding sites are flat coastal plains within easy reach of the ocean via a sandy beach. The breeding cycle is different to that of other Falklands penguins, with chicks taking the better part of a year to fledge. This requires them to over-winter at the breeding colony, and during this period the chicks remain in creches, and are well insulated from the cold by their long brown downy coats. They eventually fledge the following summer, and will not return to breed until they are at least 3 years of age.
King Penguins can live to over 30 years of age in captivity, and in the wild they normally return to the same site to breed throughout their life. Breeding is preceded by the annual moult, which lasts 4 to 5 weeks. Their return to the breeding colony is poorly synchronised, and hence birds often change partners each breeding cycle.
A complete breeding cycle lasts over a year. This tends to result in individual birds having their following breeding cycle out of phase with other birds, thus large chicks and eggs may both occur in a colony at the same time. Because the Falklands population is so small, at several sites there are insufficient breeding birds to form a colony. When adult numbers drop below about 15 individuals, they tend to merge with Gentoo Penguin colonies. This presumably offers some of the benefits of colony life, such as greater protection from predators, but because Gentoo chicks fledge by February, King Penguin chicks are left to over-winter alone.
King Penguins are remarkably curious of humans, and the chicks in particular will approach to investigate people who are sitting quietly, using their bills to probe boot laces, hair, or anything else that takes their fancy. By contrast the adults can be quite aggressive towards each other in the colony, pecking and beating each other with their flippers. Adults announce themselves by extending the neck to look skywards and giving out a trumpet like call. The chicks by comparison usher a squeaky piping call.
King Penguins generally forage at depths of 150 - 300m, with dives of 500m being recorded for this species. These are the deepest dives of any penguin, except for the Emperor Penguin which is not found outside the frozen waters of Antarctica. King Penguins mainly feed on small bioluminous Lanternfish, and some squid, (including Gonatus antarcticus, Onychoteuthis sp. and Moroteuthis sp.). Deep dives are only made during the daytime, but King Penguins can also feed at night by making shallow dives. Presumably they can still hunt by sight at night because of the bioluminous light emitted from their prey. Since light penetration does not appear to be the only factor determining foraging depth, it could be that foraging depth is largely determined by diurnal migration of prey species in response to day and night. In the Falkland Islands the foraging range extends to the edge of the Antarctic Peninsula, to the Atlantic coast of South America as far north as Buenos Aires, and across to South Georgia and perhaps beyond.
King Penguins at Volunteer Point are sometimes preyed upon by Orcas (Killer Whales), which patrol close to shore in search of Gentoo, Magellanic and King Penguins. Sea Lions and Leopard Seals also take penguins around Falkland waters. There are no terrestrial predators which pose a threat to adult King Penguins, but birds such as skuas and gulls will take eggs and small chicks if they get the opportunity. This is particularly the case when just one or two pairs of King Penguin breed in a Gentoo colony, since the King Penguin chicks lack the protection of a creche when the Gentoo chicks leave in February.
Human impact is currently very low, despite King Penguins being a great tourist attraction. They are very tolerant of human presence, and are not alarmed by the presence of tourists provided that they remain at the outskirts of the colony. There is no direct exploitation of King Penguins in the Falkland Islands, and they are seldom caught as a result of commercial fishing, other than through the occasional discarded net. There is very little overlap between the prey of King Penguin, and the commercially harvested species of squid and fish. The Falklands fishing industry is therefore unlikely to greatly influence King Penguin population trends. By contrast, the fact that virtually the entire Falklands' population exists at Volunteer Point makes it very susceptible to an incident such as an oil spill in that vicinity.
The tiny colony in Tierra del Fuego has been in existence since 2004, gradually growing from about 5 individuals to about 40 pairs by 2020. It has quite a large number of visitors each year, and care is needed to ensure that such a small fragile colony is not adversely affected by tourism.