Chinstrap penguin nests on Zavodovski Island fall 63% since 2011

Almost two-thirds of the chinstrap penguins on Zavodovski Island have disappeared, according to aerial surveys reported by BBC News on 7 October. Research led by the British Antarctic Survey (BAS) found 63 per cent fewer occupied chinstrap nests in 2025 than at the same time in 2011. Euronews reported researchers said the island now has the highest rate of chinstrap population decline in the world. Zavodovski is part of the South Sandwich Islands, a UK overseas territory north of Antarctica, and Euronews reported it lies about 2,000 kilometres from the nearest permanent human settlement.

In 2011, BAS estimated 600,000 chinstrap penguins and 90,000 macaroni penguins nested on the island, which the BBC reported was then described as the world's largest penguin colony. Euronews reported the island has now lost that title to Cape Adare in the Ross Sea, and that the loss represents more than half a million chinstrap penguins, more than a quarter of the island's penguins. The BBC reported the research team said the penguins may now be officially endangered.

Prof Norman Ratcliffe, who led the research, said the chinstraps' specialist diet and preference for cooler waters appear to have left them vulnerable. He said that as waters warm, the krill — small shrimp-like sea creatures the penguins eat — have moved southwards into the Weddell Sea, and that sea-ice cover to the south and a lack of suitable nesting islands stop the penguins from following the food. Euronews reported Ratcliffe said the change is the biggest shift in community composition — the mix of species in one place — ever observed at a single location in Antarctica.

Macaroni penguins on the island increased by 28 per cent from 2011 to 2016 and have remained stable since, according to Euronews. Researchers said macaroni penguins have a broader diet and can switch to fish and crustaceans when krill become less abundant. Tracking data showed them foraging mainly in warmer waters northeast of the island, where researchers said they were likely supplementing their diets.

The team examined other possible causes. The BBC reported Mount Curry's last major eruption was in 2016, but the declines analysed in the study have been steady and ongoing since 2011, suggesting something else was happening; Euronews reported the March 2016 eruption deposited smoke and ash over the volcano's lower slopes. The BBC reported the team also considered competition for krill from migrating humpback whales, but noted the whales also fertilise marine plants the krill eat, boosting krill production. Euronews reported the researchers ruled out other explanations for the change.

BAS said Zavodovski is one of the most extreme places in the world to undertake fieldwork. The BBC reported a BAS team sailed for 15 days to reach the island and used drones, aerial photography and tracking devices fitted to 20 birds. Ratcliffe told BBC News that with penguin guano — seabird droppings — added to the volcano's fumes, the island is one of the smelliest places in the world. Euronews reported the scientists said even the most remote parts of the planet are not immune to climate change.