Chinstrap penguin population declines on Zavodovski Island

A major colony of chinstrap penguins on Zavodovski Island, a volcanic islet near Antarctica, has seen a 63% decline in occupied nests between 2011 and 2025. Research conducted by the British Antarctic Survey (BAS) indicates that the population has dropped significantly from an estimated 600,000 chinstrap penguins in 2011.

The primary driver for this decline is attributed to climate change affecting marine food supplies. As ocean temperatures rise, krill—the specialized diet of the chinstrap penguin—has shifted southward. The combination of southward ice cover and a lack of suitable nesting islands prevents the penguins from following their food source.

In contrast, macaroni penguins on the same island have experienced a population increase due to their more varied diet, which includes fish and other crustaceans. Researchers ruled out volcanic activity or competition with humpback whales as the cause for the chinstrap penguin's decline.