Other Names: none
Distribution: arctic coasts worldwide in summer; north Atlantic and Pacific waters in winter.
Size: 60-70 cm in length with a 95-105 cm wingspan.
Plumage: Males have black underparts, a white back, head and breast, a dark crown, and a greenish tinge on back of head. Females are generally mottled brown, with flanks barred with white. The eyes are black and the bill is gray with a yellowish-gray tip.