Freak storms stopped tens of thousands of birds breeding in Antarctica

Extreme storms in Antarctica prevented tens of thousands of seabirds reproducing last year, and if climate change causes similar events in the future, it could accelerate a decline in numbers.

Sébastien Descamps at the Norwegian Polar Institute and his colleagues monitor three seabird species in Queen Maud Land, which makes up one-fifth of Antarctica.

The birds – the Antarctic petrel, the snow petrel and the south polar skua – breed once a year in the Antarctic summer, laying eggs at the end of November and the start of December. The petrels lay a single egg, but the skuas tend to lay two, with hatchlings ready to fly between February and March.

But particularly violent storms between December 2021 and January 2022 meant the three species basically didn’t breed in this part of Antarctica that summer. “Colonies more than 500 kilometres apart were impacted,” says Descamps. “The storms simply prevented any reproduction at all – with the exception of a few snow petrels that were likely breeding in cavities sheltered from the storms.”

Tens of thousands of nests are usually found in this corner of the continent, says Descamps, whose team estimates seabird populations by counting the number of nests in 200 small plots and extrapolating the results to the wider area.

The snowstorms probably put the birds off, because strong winds make it harder to keep the body warm and to incubate eggs, says Descamps.

“At some point, long-lived species like seabirds prefer to abandon their egg and increase their chance of survival by going back to sea, where they can feed and gain energy,” he says.

“These long-lived seabirds have many chances to breed successfully throughout their lifespan and it’s possible that the long-term impacts of this particular event, though startling to witness, may be muted,” says Heather Lynch at Stony Brook University in New York. “It will take many years, and further monitoring, to know for sure,” she says.

Descamps echoes this, but says the Antarctic petrel has been declining in Queen Maud Land for 20 years and if storms like this become more frequent or severe, it could accelerate the population’s reduction. “Unfortunately, this is what climate models predict,” he says.

Thankfully, the number of birds breeding in these colonies appears to have returned to normal during the current Antarctic summer, he says.

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