Small, pale gull with white underparts and gray back. Thin, black bill. Often seen in flight. Note unique wing pattern: several outer primaries white with black tips. Red legs. Adults in breeding plumage show black head. Nonbreeding and immatures have white head with black spot behind eye. Immatures also show white primaries with blackish-brown markings on the upperwing. Often seen in large flocks in coastal areas, bays, coves, and lakes during migration and winter. Feeds on small fish, invertebrates, and insects, often picking them off the surface in flight. Breeds near water in the boreal forest; the only gull that makes a stick nest.