Breeding birds: 130,000 pairs
Razorbills in breeding plumage have black upperparts and white underparts. Their upperwings are black with white-tipped secondary flight feathers. Their underwings are white with blackish flight feathers.
Razorbills have black heads, chins, and throats. They have a white line from the top of their bills to their eyes. Their large bills are black, eyes are brown, and legs and webbed feet are dark grey.
Our of breeding plumage razorbills have white throats, cheeks, and ear coverts and there is no white line on the face.
Females are slightly smaller than males and juveniles are similar to adults in winter plumage with dark streaks on the throat, cheeks, ear coverts, and sides of their breasts.
Razorbills breed in loose colonies often with other species of seabirds. They nest in rock crevices and caves.
Razorbills lay one egg directly on the rock. Both male and female incubate the egg in turns of 12-24 hours for 35-37 days. Chicks are semi-precocial and both parents feed and care for it until it fledges. The male accompanies the chick to the sea at 17-23 days.
Razorbills eat mainly fish, eels and crustaceans.
Razorbills can be found around the coast of the UK all year round. They are found on breeding cliffs from March to July, particularly in northern Scotland.
A pair of razorbills will mate up to 80 times a day over a 30-day period to ensure fertilisation. females will sometimes mate with other males to guarantee success.