Size They may have a wingspan of up to 2 metres (6.6 ft).
Adults are large .plumage bright white except for yellow-buff tinge on rear part of head with black wingtips. They have a recognisable shape with a relatively long neck and long pointed stout and bluish white beak, long pointed tail, and long pointed wings. 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. At sea they flap and then glide low over the water, often travelling in small groups.The feeding behaviour is to by fly high circling before plunging into the water.
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.
Habitat Pelagic but seldom far from land. Breeds mainly on isolated stacks or islands but there are mainland colonies (Bempton Cliffs) where the images below where taken