Other Names: none
Distribution: Migrates throughout the North Pacific; 99.7% of the population breeds on the Hawaiian Islands.
Size: 81-83 cm in length with a 195-203 cm wingspan. Males weigh 2.4-4.1 kg and females weigh 1.9-3.6 kg.
Plumage: Adults have black wings, back, upper rump, and tail; their head, lower rump, and undersides are white. It has a black spot over the eye that fades into the white head coloring, and its underwing pattern is variable white on black, with the white feathers in the middle and black feathers around the edges. The bill is pink at the base with a dark tip. Juveniles have a gray bill and a solid black rump.