How do birds navigate over long distances? This complex question has been the subject of debate and controversy among scientists for decades, with Earth’s magnetic field and the bird’s own sense of smell among the factors said to play a part. Now, researchers from the universities of Oxford, Barcelona and Pisa have shown in a new experiment that olfaction — or sense of smell — is almost certainly a key factor in long-distance oceanic navigation, eliminating previous misgivings about this hypothesis.