Chinstrap penguins have lost the designation of world's largest penguin colony from Zavodovski Island, with the title now belonging to Cape Adare in the Ross Sea. Occupied nests of chinstrap penguins saw a 63% reduction between 2011 and 2025.
Macaroni penguins, conversely, are reportedly thriving on Zavodovski Island. The decline in the chinstrap population has been a steady process since 2011.
Experts attribute the chinstrap decline to issues with food supply and rising ocean temperatures linked to climate change. Prof Norman Ratcliffe stated that warming waters have caused the krill, which chinstrap penguins consume, to move further south.
Furthermore, Prof Norman Ratcliffe noted that sea-ice cover to the south and a scarcity of suitable nesting islands prevent the chinstraps from following their food source. In contrast, Macaroni penguins appear more adaptable because they possess a broader and more flexible diet.
The Macaroni penguins were observed foraging in warmer waters located to the northeast of Zavodovski Island. Dr Ratcliffe stated, “Our data shows that the cold-adapted Antarctic chinstrap species are no longer thriving beside their sub-Antarctic neighbours.”
Zavodovski Island itself is situated within the South Sandwich Islands, a territory administered by the UK. Estimates from 2011 placed the population on Zavodovski Island at 600,000 chinstrap penguins and 90,000 macaroni penguins.
Mount Curry, an active volcano, stands near the nesting grounds of the chinstrap penguins. The last significant eruption from Mount Curry occurred in 2016.
