The planet's largest colony of king penguins has dropped nearly 90 percent in three decades, researchers said Monday.
The last time scientists enter the remote Ile aux Cochons of France, about half way between the tip of Africa and the Antarctic The island was covered by two million of the flightless birds, which are about three feet high. But new satellite images and photos of helicopters show that the population has collapsed and only 200,000 remain, according to a study published in Antarctic Science.
King Penguins are Homö bodies. While adults go in search of food for days, the species does not migrate. Why the colony was so decimated on Ile aux Cochon remains a mystery
"It is totally unexpected and particularly significant, as it represents almost a third of the king penguins in the world," said lead author Henri Weimerskirch Ecologist at the Center for Biological Studies in Chize, France, which first examined the colony in 1
Climate change could play a role. A particularly strong El Niño weather event heated the southern Indian Ocean in 1997 and temporarily drove the fish and cuttlefish on which king penguins live in the south out of reach.
"This led to population decline and poor breeding successes" for all the king penguin colonies in the region, said Weimerskirch.
El Ninos are cyclical events that occur every two to seven years. But they can be amplified by global warming, which itself produces many of the same results, albeit on a longer timescale.
In fact, Weimerskirch and colleagues in a previous study showed that climate change on its current route is likely to be intolerable for Iles aux Cochon, the archipelago with the Ile aux Cochon, mid-century for king penguins. Migration is not an option as there are no other suitable islands in range.
Other factors may contribute to the decline of colony Ile aux Cochon, including overpopulation.
"The bigger the population, the sharper the competition between individuals," said a statement from the National Center for Scientific Research in France, which funded the study.
"The effects of food shortages are exacerbated by this and can trigger an unprecedented rapid and dramatic decline in numbers."
But the so-called "density-dependent effect" can be exacerbated by climate change, the study finds.
Another possible culprit is bird cholera, which has plagued seabirds on nearby Marion and Amsterdam islands, including some king penguins. But until Weimerskirch and other researchers return to Ile aux Cochons in early 2019, he hopes that he will not be sure. It is also possible that invasive species such as rats, mice or cats have found their way to the island.
King penguins are the second largest penguin species after the emperor. They do not make a nest, but lay one egg after another and carry it around on their feet, covered with a belly flap called a breeding patch. The parents alternately change the egg and change every two weeks over a period of two months.
There are two subspecies of kings. Aptenodytes patagonica patagonicus inhabits the Falklands and South Georgia Island, while Aptenodytes patagonica halli is native to the southernmost regions of the Indian Ocean and the South Pacific.
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