Penguins in Antarctica have dramatically shifted their breeding season, apparently in response to climate change, according to a decade-long study led by Penguin Watch at the University of Oxford and Oxford Brookes University. Some colonies have advanced their breeding by more than three weeks.
The changes threaten penguins’ access to food and raise concerns for their survival. “We are very concerned because these penguins are now breeding earlier than at any time on record,” said Dr. Ignacio Juarez Martínez, lead author of the report. “If chicks hatch before prey is available, it could be fatal. Even if penguins match prey timing, they cannot sustain this pace for long.”
The study examined breeding timing between 2012 and 2022, focusing on colony settlement—the first day penguins continuously occupy a nesting area. Three species were studied: Adélie (Pygoscelis adeliae), chinstrap (P. antarcticus), and gentoo (P. papua), with colony sizes ranging from a dozen nests to hundreds of thousands. Researchers used 77 time-lapse cameras across 37 Antarctic and sub-Antarctic colonies, recording both penguin activity and air temperature.
Published in the Journal of Animal Ecology, the results show unprecedented advances in breeding: gentoo penguins led with an average 13-day advance over the decade, reaching 24 days in some colonies—the fastest phenological shift recorded in any bird, possibly any vertebrate. Adélie and chinstrap penguins advanced by about 10 days.
These shifts may intensify competition among species. “Gentoos, a temperate species, benefit from milder conditions, expanding colonies and increasing numbers, while Adélies and chinstraps are declining along the Antarctic Peninsula,” said Juarez. Gentoos’ flexible diet allows them to switch between krill and fish, while Adélies and chinstraps rely heavily on krill.
Shifts in breeding periods may also create conflicts over nesting sites. Traditionally, Adélies and chinstraps breed first, with gentoos slightly later, reducing competition. “We’ve already seen gentoos occupy nests previously held by Adélies or chinstraps,” Juarez noted. Differences in hunting depths and sea-ice use have historically allowed species to coexist, but accelerated shifts may threaten this balance.
The exact drivers of the earlier breeding remain uncertain. Possible factors include warmer temperatures, earlier ice break-up, snow melt, and phytoplankton blooms.
Penguins are critical to Antarctic ecosystems, transporting nutrients from deep waters to the surface to support algae and broader food webs. “Chinstrap and Adélie populations are clearly declining, and emperor penguins also face significant threats,” Juarez said. “Losing multiple penguin species before the century ends could destabilize the Antarctic ecosystem, which relies on very few key links.”
Source: The Guardian
Bd-pratidin English/ Jisan
