A medium-sized (17-19 inches) auk, the Thick-billed Murre in summer is most easily identified by its black back and head, white breast, and black spear-shaped bill with a thick white stripe along both sides. During the winter, this species becomes paler gray on the neck and face. This species may be separated from the related Common Murre (Uria aalge) by that species’ thinner all-black bill and from the Razorbill (Alca torda) by that species’ much thicker bill. Male and female Razorbills are similar to one another in all seasons. The Thick-billed Murre breeds along the coasts of Alaska, northern Canada, northern Europe, and Siberia. This species spends the winter at sea, extending south from its breeding range as far as the Mid-Atlantic region, the Pacific Northwest, Britain, and northern Japan. Individuals may appear further south or inland from this species’ typical winter range after large storms. Thick-billed Murres breed in large seabird colonies on cliffs on islands or along rocky northern coasts. During the winter, this species is usually seen far out to sea on the open ocean, although vagrants blown inland may appear on other large bodies of water, such as bays, estuaries, or reservoirs. Thick-billed Murres primarily eat small fish. During the breeding season, birdwatchers have found that Thick-billed Murres are most easily observed from boats at the base of large seabird colonies. During the winter, this species may be observed from ships far out to sea or, if from shore, only during large storms with the use of high-power optics. Thick-billed Murres are mainly active during the day.