Recent satellite images and a new study show that only 200,000 of the two million king penguins who lived on the French island of Île aux Cochons in 1982 still remain. The drastic disappearance of these penguins is a puzzling occurrence that scientists are still trying to piece together, but they are looking at climate change as the likely culprit.
The remote Île aux Cochons lies halfway between the tip of Africa and Antarctica and is home to the largest colony of king penguins in the world. Henri Weimerskirch, ecologist at the Centre for Biological Studies in Chize, France, first witnessed this colony in the early 1980s and plans to return to the island in early 2019 after three decades of satellite images revealed the population collapse. “It is completely unexpected, and particularly significant since this colony represented nearly one third of the king penguins in the world,” Weimerskirch said.
The IUCN Red List of Threatened Species is still listing the conservation effort for these creatures under the “least concern” status despite the recent decline in numbers. As for what happened to hundreds of thousands of mated pairs of king penguins, there are several possibilities that Weimerskirch and his colleagues are juggling.
The most likely causes are climate change and resulting El Niño weather events, competition for food and avian cholera. Scientists have not been able to examine the penguins for indications leading to a singular cause, but chances are that the factors are intermingled and aggravated by each other.
Competition, which can be worsened by climate change, leads to a lack of food, resulting in struggles that are “amplified and can trigger an unprecedented rapid and drastic drop in numbers,” according to Weimerskirch. Another possible factor in the penguins’ decline could be an incident similar to the El Niño event that decimated the Emperor penguin population in Terre Adélie by 50 percent in the late 1970s. Meanwhile, avian cholera has impacted birds on nearby islands, and could be the problem on Île aux Cochons.
The news is particularly daunting for the king penguins, because they only lay one egg at a time when nesting. The penguins carry the egg around on their feet, and the mates take turns every few weeks protecting and incubating the chick until it is hatched. This process takes over two months. Because the penguins do not nest year-round, and with food becoming scarcer and scarcer, a rapid rebound in population does not seem likely.
Image via Liam Quinn