辨識
The most common small gull through most of North America, especially inland. Breeding adults have a black head, thin white eye arcs, bright red legs, light gray upperparts, and black wingtips. Note distinctive wing pattern on adults in flight: white wedge on the leading edge of the wing, with small black tips on the outer wing feathers. Nonbreeding adults and immatures have pinkish legs and a mostly white head with black ear spot. Immatures are more heavily marked with brown and black on the wings. Breeds near water in boreal forest; the only gull that makes a stick nest in a tree. Often seen in large flocks along beaches, bays, coves, and lakes during migration and winter. Feeds on small fish and invertebrates, often gracefully fluttering around and picking them off the water surface.