At least 452 of the world’s smallest penguins have been found dead on the beaches of New Zealand’s North Island over the past six weeks—and more than half of those over the past 10 days.
Kororā, otherwise known as little blue penguins, are native to New Zealand but “at risk” and “declining” in numbers, according to the country’s Department of Conservation (DoC). Their biggest threats are typically dogs, wild predators, and road vehicles, which have been known to strike the birds down as they come ashore between May and June—waddling up to 1.5 kilometres from the sea—to build their nests.
These specimens were different, though. Hundreds of kororā discovered over the past month-and-a-half showed little to no signs of being attacked, and in multiple cases appeared to be at similar stages of decomposition, as though having suffered from some kind of mass death event.
Locals at Ninety Mile Beach last week collected a total of 183, while others at nearby Cable Bay days later discovered more than 100 that appeared to be dumped and decaying on the shore.
Experts believe the birds are starving to death as a result of global heating, as rising temperatures force the fish on which they feed down into cooler waters that are too deep for the penguins to reach.
2021 was New Zealand’s warmest year on record, according to an annual climate summary from the National Institute of Water and Atmospheric Research, with New Zealand Climate Change Research Institute adjunct senior research fellow Nathanael Melia telling Radio New Zealand in January that the waters surrounding the country “have been pulsing up to 3 [degrees celsius] recently, inexorably driving up our surface air temperatures.”
In other cases, experts believe kororā may be dying from hypothermia as the lack of food drives them to shed the requisite blubber needed to keep their bodies warm.
“All of the bodies were found to be super underweight. These birds should be around 800 to 1,000 grams, but they were way down around half that weight,” Graeme Taylor, a principal science adviser at New Zealand’s Department of Conservation (DoC), was quoted as saying in The Guardian this week.
“There was just no body fat on them, there was hardly any muscle to show. When they get to that stage of emaciation, they can’t dive.”
Taylor also believes the number of kororā washing up dead could be far higher than those that have been publicly recorded, as some are likely to have been found and buried by passers by. He wagers that the death count since the start of May could be north of 500, and approaching as many as 1,000.
Researchers estimate that there are less than 500,000 breeding adults of the species. But if the temperatures continue to rise, Taylor says, then more mass death events could be on their way—decimating whole populations of the penguins in warmer regions of the North Island.
“In the past, you might have had a lot of good years followed by one bad year where a lot of birds die, but then they rebound in those good years. But if we start to see the balance tipping towards more bad years versus good years, then they're just not going to be able to recover,” Taylor told Radio New Zealand.
“This isn't just actually involving chicks, there are now adults dying as well, which is even worse because if adults die, you know then they're not back to breed the following season to replenish the population.”
It’s not just the kororā that are at risk, either. Populations of other seabirds in the warmer areas around the top of the North Island have also been in rapid decline over the past 10 years. In some cases, entire colonies appear to have vanished.
“We've lost whole colonies of the tītī or muttonbird or sooty shearwater,” Taylor said. “They were going down a little bit, but then they really plunged from about 2010 downwards. Since then, we've been starting to see the entire colonies disappearing.”
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