Scientists have expressed concerns about the future of emperor penguins after virtually no chicks hatched at the species's second largest breeding ground.
Around 15,000 to 24,000 emperor penguins usually use Halley Bay as a breeding site, which was considered safe enough to breed despite global warming.
Yet almost none have been born there in the past three years, according to a study in Antarctic Science.
Another nearby breeding ground has increased significantly in that time, but not near enough for the amount missing in Halley Bay.
“We’ve never seen a breeding failure on a scale like this in 60 years,” said study author Phil Trathan, head of conservation biology at the British Antarctic Survey.
“It’s unusual to have a complete breeding failure in such a big colony.”
Around eight per cent of the world's emperor penguin population breeds at Halley Bay, Mr Trathan said.
In 2016 and 2017, there was no breeding in Halley Bay and last year there was just a bit, the study found.
The animals, the largest of the penguin species, can weigh up to 40kg and live around 20 years.
He said it is not possible to say yet if human-caused warming — from fossil fuel burning that creates heat-trapping gases globally — is a factor.
A 2014 study by Jenouvrier projected that because of climate change the global population of emperor penguins will likely fall by at least 19% by the year 2100.