Penguins shift breeding season earlier as Antarctica warms

A decade-long study found Gentoo, Chinstrap and Adelie penguins have begun breeding earlier by roughly 10–13 days on average, a change the authors say is highly correlated with rising Antarctic temperatures and reduced sea ice.

Scientists reported that three penguin species in Antarctica are beginning their breeding seasons earlier than historical records. The observations come from a 2012–2022 study that used dozens of time-lapse cameras at colonies across the continent. Researchers linked the shift to rising temperatures and reduced sea ice, which affect food access and nesting space. The findings were published in the Journal of Animal Ecology. Key findings: - Gentoo, Chinstrap and Adelie penguins advanced their breeding timing; Gentoos moved about 13 days earlier on average and up to 24 days in some colonies, while Adelie and Chinstrap averaged about 10 days earlier. - Observations were made between 2012 and 2022 using time-lapse cameras placed at nesting zones across Antarctica. - The study reported a strong correlation between earlier breeding and rising Antarctic temperatures and reduced sea ice, altering hunting grounds and snow-free nesting availability. - Researchers noted differing species responses: Gentoo numbers are expanding in milder areas, while Chinstrap and Adelie penguins were reported as declining; scientists are now studying chick-raising success to understand longer-term effects. Summary: The study reports an unusually rapid advance in penguin breeding timing, described as the fastest change recorded in any bird and possibly any vertebrate. Species are responding differently, with Gentoos appearing to benefit from milder conditions and Adelie and Chinstrap showing declines. Researchers said it is too early to know whether the changes will be beneficial overall and are now studying chick survival and breeding success to assess longer-term impacts.