Iconic penguin colony sees

A remote island near Antarctica is no longer home to the world's largest penguin colony as climate-driven changes to ocean food chains likely devastated its once-thriving inhabitants and caused a "population collapse," researchers said Wednesday.

"That's a very rapid loss," Norman Ratcliffe, the lead author of the BAS study published in the journal Current Biology, told AFP.

The scientists, who released video of their research, suggest that the "alarming declines" should lead to chinstrap penguins being redesignated as "endangered" by the International Union for Conservation of Nature (IUCN).

Surveys in 2011 had concluded that chinstrap populations across the South Sandwich Islands were stable.

But their number on Zavodovski fell from around 1.09 million breeding individuals in January 2011 to 402,000 in 2025, or a 63% decline, according to the study.

Together, chinstraps and macaronis now total more than 835,000 on Zavodovski.

The researchers said the Adelie penguins of Cape Adare, on the other side of Antarctica, are now the world's largest penguin colony, numbering more than one million as of 2018.

But the researchers found that the ash cloud was blown northeast over an area not inhabited by the flightless birds.

"We don't think the volcano is implicated or it's not the main driver (of the population decline) because what we see is a linear decline in the chinstrap penguins," Ratcliffe told AFP.

Warming ocean temperatures have pushed the crustaceans south toward colder waters, which chinstraps do not tolerate.

The island's chinstrap population has been falling at a rate of 7% per year.

"The observed numerical shift from chinstraps to macaronis on Zavodovski represents the most striking change in penguin community composition that has been observed at a single location in Antarctica to date," the study said.