But Peters accepted Mathews’ notion that A. p. patagonicus was characterised by a ring of blue feathers around the tarsus and occurred at the Falkland Islands and South Georgia. In contrast, the tarsi of A. p. halli were supposed to be white at the front and coloured at the back. A. p. halli was thought to breed at the Kerguelen, Crozet, Prince Edward, Heard, and Macquarie islands. However, examination of images of King penguins from different locations quickly shows that the vast majority of King penguins at any location has the two-coloured feathering on their tarsi. In 1936, Robert C Murphy also dismissed Mathew’s second argument for the division into subspecies, namely that the variations of the colouration in the penguins’ flippers were also ‘proof’ for the existence of subspecies (Murphy 1936). Murphy examined many specimens and found that the variations described by Mathew’s commonly occurred in all King penguin populations. In 1960, Bernard Stonehouse also concluded that there were no grounds to postulate sub-species among King penguins (Stonehouse 1960).
In one of the first genetic studies on King penguins French researchers compared DNA of King penguins from the Crozet and the Kerguelen islands. According to Mathews, these two populations should be very similar. However, the genetic distance between them was relatively high (Viot et al. 1993). This is further evidence that the division into subspecies as suggested in 1911 cannot be upheld.
King penguins are the second largest penguins alive today in terms of size and body weight. The largest penguins are the King penguins’ cousins, the emperor penguins. The colouration of male and female King penguins looks alike but males tend to be slightly larger. However, there is much overlap between the genders and a large female can be difficult to distinguish from a small male. Measured from the tip of their beaks to the tip of their tails they are approximately 90 cm long but when they are upright they stand about 65 cm tall. Their necks comprising 13 vertebrae are flexible and highly extendable. When an adult pulls in its head, the cervical vertebrae form a strong S-bend and shorten the appearance of the penguin.
The bodies of King penguins are cigar shaped and streamlined. The flippers are about 32 to 34 cm long and are highly specialised for fast underwater movement. Head, chin, throat and neck are black and contrast strongly with the deep yellow paisley-shaped auricular (ear) patches. The upper part of the chest is also deep yellow but most of the chest and underside of the flippers are a soft white which is demarcated from the dark grey-blue back by a black stripe. The beak is narrow and long with a curved tip. The mandibles are black and the mandibular plates on the lower mandible range in colour from yellow or orange. The feet and legs are black and the iris is dark brown.
The body mass is highy variable throughout the year. When arriving at the colony at the start of the breeding season (October), the penguins weigh around 13 to 15 kg. Unlike their Antarctic cousins, King penguins can go to sea regularly during the chick rearing period since they are not restricted by seaice. Nevertheless, when feeding chicks the parents have to work hard and it is not uncommon to find adults that weigh only about 9 kg during the chick rearing period.
It takes about 2 to 3 years for a King penguin to acquire its full mature plumage. Juveniles have faint yellow feathers on the chest and the ear patches. Their throats and chins are a soft grey and their beaks are entirely black in their first year and then develop a pinkish colour. As they mature they gradually acquire the full intensity of adults. First breeders are on average 5 years old.
Chicks are covered in soft brown down; the early sealers thought they were a separate penguin species, the woolly penguin.
The International Union for the Conservation of Nature classifies King penguins as “Least Concern”. The range of these penguins is vast and their populations have recovered from the slaughter during the sealing days. Some populations appear still to be increasing. Note, however, that it is very challenging to obtain good population estimates of these penguins. There is no time of the year where one could count, for example, all the incubating males (like in Adélie penguins) because of the long and highly asynchronous breeding cycle of King penguins. The composition of the colony in terms of breeders still feeding the chick from the previous, prospecting birds, moulters, new breeders changes throughout the breeding season making it difficult to determine the number of breeders present at any one time. If the number of breeders cannot be ascertained, it is also problematic to estimate breeding success. When King penguin colonies are censused, counts tend to made at the same time of year to provide at least a relative comparision between years (e.g. DeLord et al 2004).
The islands and island groups that are home to King penguins are usually occupied by several colonies. King penguins were cruelly slaughtered for their blubber oil in their tens of thousands (possibly hundreds of thousands) in the 19th and early 20th century. Some colonies were nearly driven into extinction. For example, in November 1951, only five King penguins were sighted at Spit Bay, one of them a chick, but in December 1954, no King penguins were seen at Spit Bay (Budd and Downes 1965). Today one of the largest colonies is located at Macquarie Island at Lusitania Bay. Here, only just over 3000 King penguins were left in 1930. The sealers did not keep good records on how many bird they killed and it is impossible to estimate how large the exploited colonies once were. But there were certainly many more in 1810 when the island was discovered than there were in 1930. The killing at Macquarie Island had stopped in 1918; the King penguin numbers started to recover and by 1980 there were an estimated 218 000 birds at Lusitania Bay (Rounsevell and Copson 1982). The largest King penguin population is currently at the Crozet Islands where more than half a million pairs breed. In recent years, King penguins have been seen at a small beach at Terra de Fuego in Argentina. Whether or not they will try to establish a colony there is as yet unknown but the birds are carefully watched by the locals. The size of the global population is difficult to estimate but ranges between 2 and 3 million.
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