Atlantic puffin pair billing, Shetland Islands, Scotland

© Vince Burton/Minden Picture

Billing time. Kissing Day

This affectionate pair of Atlantic puffins know a thing or two about the restorative pleasures of kissing, which we are celebrating today on International Kissing Day. Started in the United Kingdom, the holiday went global about 20 years ago as a yearly reminder that kissing isn't reserved just for greetings or social formalities. Puffins engage in an endearing form of courtship behavior seen here called billing, in which they playfully tap each other's beaks by swinging their heads from side to side.

Atlantic puffins, also called common puffins, are the only one of three species of puffin native to the Atlantic. They inhabit the far north, in Newfoundland, Labrador, Greenland, Norway, and especially Iceland. They spend fall and winter on the open ocean fishing. They're expert flyers, swimmers, and divers and can spend years at sea without returning to land. They can fly as fast as 50 mph, and dive as deep as 200 feet for their food. Come spring and summer, adult puffins return to shore to breed and raise their young in cliffside colonies. A female lays a single egg, but both parents take turns incubating it, and later feeding their chick. Puffin couples often reunite each year at the same nesting site. How they find the exact same spot is a mystery.

These two puffins are enjoying the warm season in the far north of the Shetland Islands in Scotland. In winter, their beaks turn a drab gray, but come spring their colors return, just in time for mating season. That's probably not a coincidence, scientists have concluded. With beaks flush with bright colors, the billing begins. The behavior is generally limited to mated pairs, but sometimes puffins bill with neighbors as well. Whether you call it billing or kissing, it sure seems to be the way puffins show they care.