The researchers, led by Norman Ratcliffe, analysed drone and satellite footage and reported a 63‑percent drop in the island’s chinstrap penguins, from 1.09 million in 2011 to 402,000 in 2025.
Ratcliffe said the decline began before Mount Curry’s 2016 eruption and continued unabated, suggesting volcanic ash was not the culprit – a finding that surprises many observers.
Instead, the team links the loss to a 7‑percent‑annual shrinkage in krill, the penguins’ primary food source, as warming seas push crustaceans southward into colder habitats that chinstraps cannot tolerate.
Meanwhile, macaroni penguins have surged, rising from 338,000 in 2011 to 433,000 in 2025, now outnumbering chinstraps on the island. Their broader diet may explain their resilience.
The study recommends that the International Union for Conservation of Nature downgrade chinstrap penguins from "least concern" to "endangered," a move that would trigger global conservation efforts and potentially trigger new funding streams.
According to a spokesperson for the IUCN, the proposal is under review and a decision is expected by the end of the year, after which international policy makers will need to integrate the new status into national protection plans.