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More than 500 of the world’s smallest penguins have mysteriously washed up dead on beaches across New Zealand in recent months. Experts aren’t exactly sure what killed so many of the adorable seabirds, but they suspect climate change may have played a role.
Clumps of Deceased Little Penguins (Eudyptula minor), known locally as kororā, have been reported washing up on beaches in the country’s North Island since early May The guard (opens in new tab). The largest group was a group of 183 dead birds that washed up on Ninety Mile Beach near Kaitaia last week; Another 109 penguins were found on the same beach in early May. Another group of about 100 dead penguins also washed up on Cable Bay near Nelson last week, although the exact number is unclear. New Zealand’s Department of Conservation (DOC) has now revealed several other deaths have been reported on North Island beaches, ranging from a few to dozens of bodies, The Guardian reported.
It wasn’t immediately clear what was killing the penguins, but experts have determined that most of the dead seabirds were significantly underweight. Small penguins should weigh between 0.8 and 1 kilograms, but some of the bodies weighed less than half that.
“There was just no body fat on them; there was hardly any muscle to flex,” Graeme Taylor, a DOC seabird researcher, told The Guardian. “When they get to that stage of emaciation, they can’t dive anymore,” which eventually leads to them starving or dying of hypothermia because they lack a protective layer of blubber, he added.
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The malnutrition of the dead penguins shows they ate too little fish, their preferred food, which could be a sign of overfishing by humans. But Taylor suspects that rising sea surface temperatures are being caused by it climate change and an ongoing cyclical event called La Niña have forced the fish into deeper, cooler waters where the birds can no longer reach them.
“This little species [of penguin] can dive up to 20 or 30 meters deep [66 to 98 feet] routinely, but it’s not as good to dive much deeper,” Taylor said. (Ironically, the genus of little penguins, Eudyptulameans “good little diver” in Latin.)
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This hypothesis could explain why little penguins from New Zealand’s South Island have remained unaffected, because the waters there near the surface have remained much cooler than waters farther north.
The New Zealand government lists little penguins as “Vulnerable Declining”, which is below “Vulnerable” and “Extinct” on the country’s list of endangered species. According to this, there are fewer than 500,000 breeding adults in the wild Bird Life International (opens in new tab). Other threats to the species include dogs, cats, and other invasive animals that kill the birds or eat their eggs. In 2021, Tasmania’s entire small penguin population, which numbered 3,000 breeding pairs wiped out by Tasmanian devilsbrought to the island by conservationists.
This isn’t the first time little penguins have died in large numbers in New Zealand. Dozens or even hundreds of little penguins die, on average, about once a decade, either from food shortages or extreme storms. However, this is the third time there has been a death in the past 10 years, which is worrying, Taylor said.
“When you see it happening regularly like this, the birds really don’t have much of a chance to recover between events and rebuild the numbers,” Taylor said.
Unfortunately, New Zealanders can probably expect more dead penguins to wash up on their shores.
“This event is probably not over and will continue through the winter,” Ian Armitage, a councilor for Birds New Zealand, a non-profit bird society that helped document the penguins’ deaths, told The Guardian. This means people are likely to find many more dead penguins, he added.
Originally published on Live Science.
https://www.livescience.com/mass-little-penguin-die-off-new-zealand Hundreds of the world’s smallest penguins have mysteriously washed up dead. What killed them?