The tufted puffin (Fratercula cirrhata), also known as crested puffin, is a relatively abundant medium-sized pelagic seabird in the auk family (Alcidae) found throughout the North Pacific Ocean. It is one of three species of puffin that make up the genus Fratercula and is easily recognizable by its thick red bill and yellow tufts. Tufted puffins are around 35 cm (14 in) in length with a similar wingspan and weigh about three quarters of a kilogram (1.6 lbs), making them the largest of all the puffins. Birds from the western Pacific population are somewhat larger than those from the eastern Pacific, and male birds tend to be slightly larger than females. They are mostly black with a white facial patch, and, typical of other puffin species, feature a very thick bill which is mostly red with some yellow and occasionally green markings. Their most distinctive feature and namesake are the yellow tufts (Latin: cirri) that appear annually on birds of both sexes as the summer reproductive season approaches. Their feet become bright red and their face also becomes bright white in the summer. During the feeding season, the tufts moult off and the plumage, beak and legs lose much of their lustre. As among other alcids, the wings are relatively short, adapted for diving, underwater swimming and capturing prey rather than gliding, of which they are incapable. As a consequence, they have thick, dark myoglobin-rich breast muscles adapted for a fast and aerobically strenuous wing-beat cadence, which they can nonetheless maintain for long periods of time. Juvenile tufted puffins resemble winter adults, but with a grey-brown breast shading to white on the belly, and a shallow, yellowish-brown bill. Overall, they resemble a horn-less and unmarked rhinoceros auklet (Cerorhinca monocerata). Tufted puffins form dense breeding colonies during the summer reproductive season from British Columbia, throughout southeastern Alaska and the Aleutian Islands, Kamchatka, the Kuril Islands and throughout the Sea of Okhotsk. While they share some habitat with horned puffins (F. corniculata), the range of the tufted puffin is generally more eastern. They have been known to nest in small numbers as far south as the northern Channel Islands, off the coast of southern California. However, the last confirmed sighting at the Channel Islands occurred in 1997.