Adult: plumage is white except for yellow-buff tinge on rear part of head and contrasting black ends to wings. Bill stout and bluish white, with dark lines. Bare skin of face and gular stripe dark blue-grey, eye blue-grey. Legs and fully webbed feet grey-black; mid-ridge of toes greenish. Immature: Juvenile essentially black-brown inconspicuously speckled white. Takes four years to reach maturity and immature plumage variable between juvenile and adult with juvenile plumage increasingly invaded by white, starting on lower body, then head, neck and breast and last on secondaries and tail.

Pelagic but seldom far from land. Breeds mainly on isolated stacks or islands but there are mainland colonies (Bempton Cliffs).

All year round on the coast.

Nests on ledges of cliffs above the splash zone with life-long monogamy the rule, pair-bond renewed each season. Only on breeding sites during breeding season, otherwise at sea.

Abundant breeder at twenty-six colonies and can be seen around the coast at anytime of the year.

Rare vagrant, mostly in autumn (September/October but also in May & June).