The Manx shearwater is entirely marine, typically flying within of the sea surface. It nests in burrows on small islands, which it visits only at night. Its nesting colonies are in the north Atlantic Ocean in the United Kingdom, Ireland, Iceland, the Faroe Islands, France, the Isle of Man, the Channel Islands, the Azores, Canary Islands, and Madeira. The most important colonies, with a total of more than 300,000 pairs, are on islands off Wales, Scotland, and Northern Ireland. Three-quarters of the British and Irish birds breed on just three islands; Skomer, Skokholm, and Rùm. Around 7000–9000 pairs breed in Iceland, with at least 15,000 pairs on the Faeroes. Other populations are of at most a few hundred pairs. The northeast of North America has recently been colonised from Newfoundland and Labrador to Massachusetts; although breeding was first recorded in 1973, populations remain small. Records in the northeast Pacific are increasing, and breeding has been suspected in British Columbia and Alaska.