The Razorbill (Alca torda) is the knife-billed auk — jet black above, white below, with a deep, laterally flattened bill crossed by a bold white vertical line. It is the sole living species in its genus, found along North Atlantic coasts from northeastern North America to Iceland, Britain, and France eastward to the White Sea. It is a medium-sized auk, 37–43 cm long, with a wingspan of about 63–68 cm and a weight of 590–730 grams. In summer plumage the head and entire upperparts are jet black and the underparts pure white; the surest mark is the deep, tall, laterally compressed bill crossed by that white vertical line, with a thin white line also running back from the bill toward the eye. In winter plumage the throat and cheek become white. It typically sits upright on cliffs and flies low and fast with whirring wingbeats, showing a fairly long, pointed tail in flight.
At the colony it is most vocal, giving deep, muttering, growling "urr-urr" sounds, though otherwise silent. Razorbills breed in Swedish archipelagos, with the largest colonies on Stora Karlsö and Gotska Sandön and in the outer Bohuslän archipelago; the Swedish population is estimated in the tens of thousands of pairs, and the species is a resident to short-distance migrant, wintering at sea in ice-free parts of the Baltic, Kattegat, and Skagerrak. It nests in dense colonies on sea cliffs and rocky skerries, often alongside Common Guillemots, but unlike that species — which incubates its egg on open ledges — the Razorbill places its single egg more protectively in a rock crevice, fissure, or under a boulder; both parents incubate for about a month, and the chick leaves the cliff before it can fly, heading to sea with the male, who continues to feed it. It feeds on small fish such as sprat, herring, and sandeel, along with crustaceans, diving and swimming underwater using its wings to reach depths of several tens of metres.
Read about this species in Swedish →