This medium-sized bird chooses one single partner for life. Both parents share the incubation of the eggs, and the search for food for the offspring.
The razorbill is black above and white below. It has a thick black beak, which is deep and blunt, unlike the thinner bill of the similar guillemot or murre (Uria aalgae). Birds only come to shore to breed, forming large colonies over coastal cliffs in late spring-early summer, and spend the winter out at sea, in the Northern Atlantic. They mainly feed of fish, and dive usually to depths of 25m to catch them, although they are able to dive up to over 100m of depth.