For decades, the arctic tern’s yearly migration was presumed to be the longest in the world. Now, with the advent of tiny geolocators, an international team in Greenland has finally confirmed the tern’s migratory supremacy. The devices, which weigh just 0.05 ounces, record ambient light intensity, providing data on local sunrise and sunset times. The findings: Each year, the tern travels an average of 44,000 miles. “Impressive for a bird that weighs less than 3.5 ounces,” says Iain Stenhouse, a researcher who worked on the project.