Petrels and shearwaters
They are strictly marine, many coming ashore to breed in burrows, then only under the cover of darkness, although one of the most widespread, the fulmar, nests on open ledges. None are properly able to walk on land. Petrels in the UK are small, oceanic birds, which fly low over the sea, except for the larger fulmar. Shearwaters are larger, long-winged, flying over vast areas of sea by using winds and air currents over the waves.