World's largest penguin colony hit by 'alarming' decline in numbers — SkimNews
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- British Antarctic Survey aerial surveys found 63% fewer occupied chinstrap penguin nests on Zavodovski Island in 2025 than in 2011, using drones, aerial photography, and tracking devices fitted to 20 birds; the team sailed 15 days to reach the remote South Sandwich Islands.
- Zavodovski Island lost its title as the world's largest penguin colony to Cape Adare in the Ross Sea, more than 5,000 km away on the opposite side of Antarctica.
- Prof Norman Ratcliffe, who led the research published in Current Biology, attributed the decline to chinstraps' specialist krill diet and preference for cooler waters — warming has pushed krill southward, but sea-ice cover and a lack of suitable nesting islands prevent the penguins from following the food.
- Macaroni penguins on the same island are thriving, with tracking data showing they forage in warmer waters to the northeast and supplement their diet with fish and other crustaceans.
- Ratcliffe called the opposite trajectories of the two species "the biggest change in community composition ever observed at a single location in Antarctica," and said chinstraps may now qualify as officially endangered.
- Researchers ruled out two other suspects — Mount Curry's volcanic fumes (last major eruption 2016) and krill competition from migrating humpback whales — concluding that a climate-driven shift in ocean food supplies is the primary driver.
Why it matters: A 63% collapse of the world's former largest penguin colony in just 14 years is the starkest documented case of rapid Antarctic warming restructuring a single seabird community, and the chinstrap species may now qualify as officially endangered. The mechanism — cold-adapted specialist feeders trapped behind shifting prey — has implications beyond penguins, signaling how Antarctic ecosystems reorganize as the ocean warms.
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