Other Names: none
Distribution: tropical, temperate, and subarctic Atlantic waters, excluding waters off equatorial Africa.
Size: 43-51 cm in length with a 105-122 cm wingspan.
Plumage: The throat, breast, and underparts are white except for a brown belly patch, and the back is medium brown to gray with a white stripe pattern. The shoulder feathers show a strong black and white striping in flight. It has a black cap, black bill, and a black tail with a white horseshoe at the base.