Colorful puffin falling victim to pollution, overfishing

GRIMSEY ISLAND, Iceland — Puffins are in trouble.

The birds have been in precipitous decline, especially since the 2000s, both in Iceland and across many of their Atlantic habitats.

The potential culprits are many: fickle prey, overfishing, pollution. Scientists say that climate change is diminishing food supplies and is likely to become more important over time.

And the fact that puffins are tasty, and thus hunted as game, hardly helps.

Though some puffin colonies are prospering, in Iceland, where the largest population of Atlantic puffins is found, their numbers have dropped from 7 million to about 5.4 million. Since 2015, the birds have been listed as “vulnerable” by the International Union Puffins gather in Borgarfjardarhofn, on the northeast coast of Iceland. Scientists are studying why puffin populations have been in precipitous decline, both in Iceland and across many of their Atlantic habitats. Overfishing, pollution, climate change and hunting all play a part. for Conservation of Nature, meaning they face a high risk of extinction in the wild.

Hunters with long nets can be seen tooling around Grimsey Island in the summer, leaving behind piles of bird carcasses, the breast

meat stripped away. Iceland has restricted the annual harvest, but hunting “is accelerating the decline,” said Erpur Snaer Hansen, acting director of the South Iceland Nature Research Center.

Around Iceland, the

puffins have suffered because of the decline of their favorite food, silvery sand eels, which dangle from the parents’ beaks as they bring them to their young.

That decline correlates to a rise in sea-surface temperatures that Hansen has been monitoring for years.

Without as many sand eels in the water, the birds have to fly farther to find food for themselves and their chicks. Hansen’s twice-yearly census of 700 puffin burrows in 12 colonies around Iceland show that 40 percent of the population of Icelandic puffin chicks is losing body mass over time, another bad sign.

When the adults can’t catch enough to feed themselves and the chicks, they make an instinctive choice for self-preservation: The chicks starve.

There are still millions of Atlantic puffins, but their plentiful colonies are deceiving, Hansen said.

“These birds are longlived, so you don’t just see them plummeting down,” he said.

But in the long run, he warns, “It’s not sustainable.”