Birds of the large, bright Greenland race, "leucorhoa", makes one of the longest transoceanic crossings of any passerine. In spring most migrate along a route (commonly used by waders and waterfowl) from Africa via continental Europe, the British Isles, and Iceland to Greenland. However, autumn sightings from ships suggest that some birds cross the North Atlantic directly from Canada and Greenland to southwest Europe, a distance of up to . Birds breeding in eastern Canada are thought to fly from Baffin Island and Newfoundland via Greenland, Ireland, and Portugal to the Azores, crossing of the North Atlantic) before flying onwards to Africa. Other populations from western Canada and Alaska migrate by flying over much of Eurasia to Africa.