Climate Change Drives 63% Population Drop at Former World-Largest Penguin Colony

In 2011, the British Antarctic Survey identified Zavodovski Island, a UK overseas territory in the South Sandwich Islands, as the site of the world's largest penguin colony. The island hosted an estimated 600,000 chinstrap penguins and 90,000 macaroni penguins. This population status persisted until recent surveys showed a steady decline. Warming waters pushed krill populations southward. Cape Adare in the Ross Sea, located over 5,000 kilometers away, now holds the title for the largest colony.

Researchers published findings in the journal Current Biology. They attribute the chinstrap decline to climate change, which forced krill populations to move south. Chinstrap penguins struggle because of their specialized diet. Macaroni penguin populations on the island increased due to their more flexible diet. Mount Curry, an active volcano on the island, erupted in 2016. The steady population drop observed since 2011 indicates that volcanic activity is not the primary cause of the decline.

1. Researchers published their findings in the journal Current Biology. They provided a peer-reviewed analysis of the population shift. The study tracked the number of occupied chinstrap penguin nests on Zavodovski Island from 2011 through 2025. These records establish a timeline for the decline. Scientists use the data to distinguish between long-term environmental trends and isolated events like volcanic eruptions.

2. Chinstrap penguin populations on the island declined. Macaroni penguin populations increased during the same period. Researchers attribute this resilience to the macaroni penguin's broader, more flexible diet. Different species within the same ecosystem respond uniquely to shifting food availability.

3. Researchers determined that the active volcano Mount Curry is not the primary driver of the population decline. The population began to drop steadily in 2011. The last major eruption occurred in 2016. Volcanic activity does not account for the long-term trend. Conservation efforts now focus on climate-related factors rather than geological ones.

4. Macaroni penguin populations on Zavodovski Island increased, while chinstrap penguin numbers declined. Researchers attribute the macaroni penguin growth to a broader, more flexible diet.

1. The chinstrap penguin colony on Zavodovski Island saw a 63% decline in occupied nests from 2011 through 2025. The population previously exceeded 1 million individuals. Researchers identified this decline as a sign of disruption to the local ecosystem.

2. Rising ocean temperatures have pushed krill populations southward. This movement reduces the food supply for chinstrap penguins. Climate change forces these specialized species to seek new prey. Chinstrap penguins struggle to adapt to these shifts. This lack of flexibility increases their vulnerability to future environmental changes.

3. Zavodovski Island no longer hosts the world's largest penguin colony. The title now belongs to Cape Adare in the Ross Sea. This location sits more than 5,000 kilometers from the South Atlantic site. Penguin populations have shifted between these regions. The South Atlantic site experienced a notable population decline.

4. Science reported that the island hosted more than 1 million chinstrap penguins. The number of occupied nests fell by 63% between 2011 and 2025. Scientists attribute this decline to warming waters. These rising temperatures caused the krill population to migrate south.