Scientific name: Aptenodytes patagonicus
When king penguins were first discovered by European explorers in the early 18th century they were thought to be the largest penguin species alive. It was only in 1844 that George Robert Gray from the British Museum separated them from the even larger emperor penguin that had been seen for the first time during Captain Cook’s second voyage. Close relatives, kings and emperors belong to the genus Aptenodytes derived from the Greek meaning ‘featherless diver’.
Physical description and related species
King penguins are the second largest penguin. Males tend to be slightly larger than females but there is a lot of overlap in the sizes between the sexes. Their body mass changes throughout the breeding season. When the birds return to their colonies and start courting they weigh 10–15 kg. By the end of the breeding season, they may weigh only 8–11 kg. Most noticeable are their brightly coloured orange ear patches that extend via a thin strip to the upper chest.
Two subspecies are now recognised: A. patagonicus patagonicus at South Georgia, the Falkland Islands and in southern Chile, and A. patagonicus halli at the Kerguelen Islands, Crozet Island, Prince Edward Islands, Heard Island and McDonald Islands, and Macquarie Island.
King penguins are the closest relatives of emperor penguins. Kings are thinner and the colouration of their ear patches differs from that of emperors. Their flippers in proportion to their body size are also larger in comparison to the flippers of emperors.
Distribution and abundance
King penguins breed on many of the sub-Antarctic islands between 45° and 55°S. Occasionally king penguins are seen on the South Sandwich Island off the Antarctic Peninsula and a couple of new colonies appear to be establishing themselves in Patagonia. Individual colonies vary in size and some large colonies appear to have decreased. However, in recent decades the global population of king penguins appears to have stabilised at approximately 1.6 million breeding pairs.
King penguins tend to form very large and dense colonies. The largest populations are found at South Georgia and Crozet islands that are occupied by several hundred thousand breeding pairs. The colonies occupy beaches, and valleys and moraines free of snow and ice, preferring level ground near the sea.
Immature and non-breeding birds disperse and travel far from breeding localities. However, chicks remain in colonies throughout the year and breeding adults return to feed chicks on an irregular basis throughout the winter. Thus, the chicks fast for long periods (sometimes several months) between meals while the adults are away feeding at sea.
Conservation status: least concern
During the 19th through to the early 20th centuries, following the decimation of the fur seal population, the sealing industry on sub-Antarctic islands turned to the exploitation of king penguins as a source of oil. Many populations were nearly exterminated through these activities. However, in the decades since the end of sealing, populations have been increasing at most breeding localities.
The breeding cycle, including the pre-moult period, of king penguins is much longer (13–16 months) than that of any other penguin and egg laying is highly asynchronous. Eggs are laid from November to April. Like their cousins, the emperors, kings do not build a nest but incubate the eggs on their feet. But unlike the emperors, king penguins are very territorial. Incubation lasts about 54 days. The males take on the first incubation shift. Should the female not return on time to relieve her mate, the egg will be abandoned if the male had insufficient body reserves to sustain himself. After all, he may not have eaten for five weeks. Abandoned and lot eggs are usually not replaced.
Breeding birds tend to lay eggs every year but the breeders that were late will be even later the following year. The chicks of late breeders usually do not survive because they are too small to survive the long winter. Thus, king penguins are at best successful every two years.
Early moulting adults that finish their moult in October can have eggs by November. This increases the chances of their chicks to survive because the young ones can grow and put on enough body mass to last the winter.
King penguins are highly gregarious, although the breeding adults remain separated from non-breeding birds. Fighting among birds in these colonies is rare.
Diet and feeding
King penguins are quite specialised in the prey they catch. Their diet comprises mainly lantern fish (myctophids), espeically during the the breeding season. Over winter, the percentage of squid increases in their diet. At sea, predators of king penguins include leopard seals and killer whales. In the colonies, skuas, sheathbills and giant petrels take eggs and young birds. At the Falkland Islands (Malvinas), turkey vultures and caracaras also feed on eggs and chicks.