A small seabird can spend its year traveling between the Arctic and the far south.
Researchers fitted Arctic terns from Greenland and Iceland with tiny light-recording geolocators to follow their annual movements. In the 2007–08 tracking study, some birds covered more than 80,000 kilometers over the year. The routes were not straight lines: birds took different paths south, then broadly similar looping routes on their return.
The tracking also revealed a North Atlantic stopover area used by birds from both breeding populations. In the Southern Ocean, the tracked terns spent the austral summer in waters rich in marine life. The sample was small, and the devices could not locate birds precisely every day, but the tags uncovered an extraordinary journey hidden across a vast ocean.