Museum Notebook: King Penguin: a Royal Line in Trouble

King penguin egg. Photo / supplied

New Zealand was once home to a gigantic species of penguin, as tall as an adult male human. Like many megafauna species of the planet, this species is now extinct and exists only as fossil remains held in museums.

Two other very large penguins, the Emperor penguin and the King penguin, live in huge colonies around the southern seas.

They were so numerous that it appeared there was no risk of them following New Zealand's fossil Giant penguin into extinction. This, however, may no longer be true of the King penguin. The once numerous bird may be already be an endangered species. The end of the current century, according to scientific research, might signal the end of this royal branch of penguins through the effects of climate change on ocean currents and sub-Antarctic habitats.

King penguins live and breed between latitudes of 45 and 55 degrees south, on sub-Antarctic islands and northern parts of Antarctica. The most numerous colony, with about half of the global population of King penguins, has historically been the Crozet Islands in the Southern Indian Ocean.

In 1982 the King penguin population of these islands was estimated, through aerial survey, to be around two million individuals. Recent analysis of satellite images taken over the last thirty-five years indicates that the population has plummeted by 90% to around 200,000 birds, with just 60,000 breeding pairs. While this is still a very large number, such a rapid decline is concerning. So what has changed?

Researchers suggest the causes may be overcrowding and the resultant competition for resources, disease such as avian cholera, or the possible arrival of invasive pest species. A non-migratory species, such as the King penguin, relies on the continued health of its sub-Antarctic habitat for survival. King penguins leave their young and swim south to forage for fish and squid along the polar front, where cold, deep water meets more temperate sea.

Taxidermied King penguin Photo / supplied

The research team suspects that climate change could be contributing to the decline, as it has with colonies of penguins in parts of Antarctica. In 1997, a strong El Niño weather event warmed the southern Indian Ocean and temporarily pushed fish and squid, normally eaten by King penguins, further south, beyond their foraging range.

The result was population decline for all King penguin colonies in that region. Although El Niño events are cyclical, they can be amplified by global warming. The researchers have concluded that based on current climate change predictions the Crozet Islands, once home to half the world's population of King penguins will become uninhabitable for these penguins by the mid-century.

With nowhere else to go, the Crozet Islands population of King penguins will be in serious trouble. It would be such a shame if one of the world's most iconic and loved penguins exists only as taxidermied specimens in natural history museums.

Margie Beautrais is the Educator at Whanganui Regional Museum.