Hundreds of thousands of birds just haven’t bred after a stormy summer in Antarctica


December and January represent seabird breeding season in Antarctica, a time when it should be thousands of active nests. BBut heavy snowstorms during the 2021-2022 season made it difficult for birds to access their usual grounds and resulted in a complete inability to breed for several species.

A recent study published in the log Current biology find This, from December 2021 to January 2022, almost no birds nested or laid eggs. Breeding failures have occurred in the past, but near complete breeding failure is rare and of concern, the scientists written in the study.

The team examined breeding in colonies of Antarctic petrels, snow petrels and skua birds in Droning Maud Land. It is an area that is about one-sixth of Antarctica and is claimed by Norway. It is home to two of the largest colonies of Antarctic petrel colonies, as well as nesting of snow petrels and south polar skuas. Antarctic petrels lay their eggs on the ground, and snow petrels breed in crevices and cavitiesbut above average snow accumulation made difficult to access these areas. The researchers found that, in January 2022, over 50% of the Antarctic petrel breeding area around Svarthamaren Mountain in Droning Maud Land was covered in snow.

The problem does not only affect some of the birds. Observations from 1985 to 2020 revealed that there were between 20,000 and 200,000 petrel nests around Svarthamaren. There were also 2,000 snow petrel nests and about 100 skua nests in any given year. But during the 2021 to early 2022 season, there were only three breeding Antarctic petrels, a “handful” of snow petrel nests, and no skua nests. The researchers also noticed this breeding season had poorer feeding conditions. Skuas feed on the eggs and chicks of Antarctic petrels, and as these birds did not breed successfully in the 2021-2022 season, skua colonies had fewer food options.

“We know that in a seabird colony, when there is a storm, you will lose chicks and eggs, and breeding success will be lower,” Sébastien Descamps, first author of the study and researcher at the Norwegian Polar Institute, said in a Press release. “But here we are talking about tens, if not hundreds of thousands of birds, and none of them have been breeding throughout these storms. Having zero breeding success is really unexpected.

Previous research has shown that snowstorms have been intensified by climate change. Rising emissions mean a warming planet, and climate change is often associated with deadly heat waves And less snow. But it also changes the weather by taking what is normal and making it more intense, like louder snow storms at the South Pole. So much so that even animals meant to be in these environments will struggle.

Harald Steen, co-author of the study, said that because there were empty nests and no dead chicks, the researchers believe the birds saw how harsh the conditions were at the start of the breeding season and simply left their usual breeding grounds. According to the study, researchers observed fewer Antarctic seabirds flying around research stations compared to previous years. It was another allusion to the severity of snowstorms at the start of the breeding season. Steen said that means many birds have returned to sea instead of staying.

“They’re very fit,” Steen told Earther. “They can cope, but if the frequency of these breeding failures increases, we would expect colonies to decline in the long term.”

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