Seabirds in north-west European waters were surveyed offshore througho
ut the year from 1979 to 1993. During the breeding season the distribu
tion of Manx Shearwaters centred around the main colonies of Rhum, Sko
mer and Skokholm. Densities were low in the North Sea, where birds wer
e mainly restricted to waters off the north-east coasts of England and
Scotland, in particular the Moray Firth, the Firth of Forth and Flamb
orough Head. Manx Shearwaters can forage at long distances from the co
lonies, but highest densities were observed in the Irish Sea, south-we
st Wales, south-west Ireland and the inshore waters of West Scotland d
uring the chick-rearing period when parent birds visit the colony more
frequently. The area of the Irish Sea front was important, particular
ly in the autumn, and feeding occurred here in preference to other are
as of the Irish Sea. From November to February Manx Shearwaters were v
irtually absent from north-west European waters.