This large, dark-capped, white-rumped, shearwater is seen in offshore waters during the summer and early autumn.

Great Shearwaters breed on a handful of islands in the South Atlantic and leave their breeding sites from March or early April, undertaking a huge flight that will see them complete a clockwise loop around the Atlantic, before heading back to their breeding islands.

These birds typically arrive in British and Irish waters during August, as can be seen in the BirdTrack reporting rate graph. Many individuals head to the Bay of Biscay, where large numbers can congregate through to October. These are thought to be non-breeding birds because breeding has already commenced in the South Atlantic colonies by October.