Thjodhatid is a four-day, outdoor concert and cultural festival in the town of Heimaey in Vestmannaeyjar (the Westman Islands), a small, volcanic archipelago off the southern coast of Iceland. Thjodhatid, which has been celebrated since 1874, has become one of Iceland's largest and most popular festivals, attracting thousands of people to the tiny island widely known for its fishing industry and for its puffins, which has become a cultural emblem for the island's 4,000 inhabitants. Currently some 830,000 nesting pairs of puffins come to the Westman Islands each year to breed on the steep, grassy cliffs. But those numbers are down from over a million, as the Westman Islands are on their 11th consecutive year of complete reproductive failure and biologists are currently investigating whether warming ocean surface temperatures are driving the puffins' food supply, such as sand eels and other small fish, to colder waters in the north and impacting the seabirds ability to breed in the Westman Islands. This population collapse has led to a number of behavior adjustments, including the reduction of consuming smoked puffin, a traditional Icelandic dish, and abbreviating the puffin hunting season in the Westman Islands to only three days this year.