Slender, long-winged gull slightly smaller than Herring Gull. Common in Europe; population in North America has increased dramatically in the last couple decades; now regular on the Atlantic coast, rarer inland and farther west. Adults show dark gray back and yellow legs; in winter note fairly heavy streaking on head and neck. Takes four or five years to reach adult plumage; immatures can be difficult to distinguish from other gulls, especially Herring. On first- or second-year birds, look for contrastingly whitish head with dark smudge around the eye, long wings, dark bill, whitish rump and tail base, and evenly dark wings in flight. Can be found around any body of water but prefers beaches. Often with flocks of other large gulls.