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 another underlying factor that 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 here, hardly helps.