Taxonomy
The razorbill is in the family Alcidae and its genus is Alca. It is closest living relative to the Great Auk (Pinguinis impennis) which is now extinct. The Alcini clade also includes the Common Murre (Uria aalge), the Thick-billed Murre (Uria lomvia) and the Dovekie (Alle alle).
There are two subspecies of Razorbill recognized by the American Ornithologists' Union. Alca torda torda, named by Linnaeus in 1758, occurs in eastern North America, Greenland, Bear Island (Norway) and the Baltic and White Seas. Alca torda islandica was named by C. L. Brehm in 1831 and occurs throughout the British Isles and northwestern France. The two subspecies differ slightly in bill measurements. A third suspecies, Alca torda pica, is no longer recognized because the distinguishing characteristic, an additional furrow in the upper mandible, is now known to be age-related.
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