This latest mass-mortality event is another sign of the Arctic’s rapidly changing climate.
Ed Yong reports for The Atlantic
Lauren Divine first heard that the birds were dying on October 13, 2016, when one of her colleagues stumbled across the corpse of a tufted puffin while walking along a beach on Alaska’s St. Paul Island. The next day: another carcass. Soon, several of the island’s 450 residents started calling in with details of more stranded puffins. Some were already dead. Others were well on their way—emaciated, sick, and unable to fly.
Nestled in the middle of the Bering Sea between Alaska and Russia, St. Paul is the largest of the four Pribilof Islands, which together support more than 2 million seabirds. Dead individuals aren’t uncommon. Divine’s team, which works on environmental issues that affect St. Paul’s Aleut community, would usually expect to find one or two on its monthly beach surveys. But that October, “you couldn’t walk more than a few steps before having to pick up another bird,” she says. “It was pretty apparent that something was really wrong in the environment.”
The team stepped up its surveys, braving biting winds and crashing waves to comb the beaches on all-terrain vehicles. Over the next few months, it located more than 350 bodies, a rate that was about 70 times higher than normal. Stranger still, most of these birds were tufted puffins—a species that very rarely washes up dead. In the previous decade, the team had only ever found six puffin carcasses, and never in the winter months. It seemed that the puffins had become the latest species to experience a mass-mortality event—a large-scale die-off, of a kind that’s becoming more and more common.
To work out how many puffins had actually died, Timothy Jones of the University of Washington used the locations of the known bodies and data on local wind patterns to simulate where the dead birds were coming from. He estimated that between 3,150 and 8,800 tufted puffins perished in the final months of 2016.
What killed these birds? Most of them were intact, with no signs of either predator attacks or disease. Some of them had saxitoxin—a potent poison made by algae—in their stomach, but at levels almost 100 times lower than what would be considered safe for humans to eat. Instead, the most likely cause of death was starvation. The birds were extremely thin, with weak flight muscles and very little body fat. “They literally didn’t have enough to eat and became weak to the point of death,” says Julia Parrish of the University of Washington, who led the study.
Tufted puffins look like fancier versions of the more widely known Atlantic puffins, with elaborate yellow eyebrows that sweep backwards down their neck. On land, they have a clownish, goofy disposition. But in the sea, they become grace personified, using their streamlined body and sickle-shaped wings to fly underwater in pursuit of small fish.
But what if there are no fish to pursue?
