Back
Ad. in summer. -Back and wings slaty black; wing-feathers tipped GULLS. with white; rest of plumage white; tail sometimes mottled with dusky. Ad. in winter.-Similar to the above, but with the head and neck streaked with grayish. Im. Head and nape whitish, streaked with grayish; back and wings, except primaries, brownish, the feathers margined and irregularly marked with pale buffy; primaries dark brownish black, the inner ones with small white tips; tail mottled with black and white; under parts whitish, more or less streaked or barred with grayish. L., 29.00; W., 18.50; T., 8.00; B., 2.50.