Other Names: none
Distribution: discontinuously throughout northern North America in summer; coastal areas of the United States and Mexico in winter.
Size: 50-56 cm in length with a 125-130 cm wingspan, weighing 400-500 g.
Plumage: The head, neck and undersides are white, the back and wings are silver-gray, and the legs are yellow. The tail is black with white spots on the sides. Juveniles are white with dark brown scale patterns on the uppersides, and develop adult plumage over three years.
The eyes are yellow with red eyerings and the beak is yellow with a black ring around the tip.