The Bird That Lives in Two Summers

A bird about the weight of a bar of soap commutes between the two ends of the world every year.

The Arctic tern nests in the far north during the northern summer. Then it flies to the waters around Antarctica for the southern summer, and back again. It gets two summers each year and hardly any real winter.

The numbers

Small tracking devices have changed what we know. A well-known 2010 study of terns nesting in Greenland recorded an average round trip of about 70,000 kilometers. The birds do not fly straight. They follow winds in long curves over the Atlantic, stopping to feed in rich ocean areas along the way.

Terns can live for around 30 years, so a long life can add up to more than 2 million kilometers. That is a few trips to the Moon and back, on feathers.

A life in the light

With continuous daylight in both of its summer homes, the Arctic tern is thought to see more daylight per year than any other animal.

It is our favorite resident of this two-ended world, and the reason our Two Summers tumbler exists.