Climate change strips island’s title of largest penguin colony

Climate change has caused the remote volcanic island of Zavodovski, once home to the world's largest penguin colony, to lose more than two-thirds of its chinstrap penguin population between 2011 and 2025. The British Antarctic Survey's study found that the chinstrap numbers fell from around 1.09 million breeding individuals in 2011 to just 402,000 in 2025, a 63% decline.

Scientists blame the drop on a reduction in krill – the main food source for chinstrap penguins – as warming ocean temperatures push the crustaceans into colder waters beyond the island's reach. Chinstrap penguins now face being reclassified as endangered by the International Union for Conservation of Nature, a sharp downgrade from their previous "least concern" status.

While macaroni penguin numbers have risen, they are less vulnerable to the same food chain changes and may now outnumber chinstraps on Zavodovski. The volcanic eruption in 2016 did not significantly impact the penguin populations, as ash clouds were blown away from the island. Instead, the researchers attribute the decline to a broader climate-induced shift detrimental to chinstraps but favorable to macaronis.