Fairly small gull, common and widespread across Eurasia. All plumages have big white blaze on leading edge of wing. Breeding adult has dark brown (not black) hood, red bill and legs; nonbreeding and immature have dark ear spot on white head, dark tip to red bill. Juvenile has mottled brownish back, which molts to pale gray by winter. Can be found in essentially any wet habitat, from duck ponds and farm fields to wild wetlands and seacoasts. Locally occurs in flocks of hundreds, sometimes thousands. Rare but regular vagrant to North America, especially in the northeast, where usually seen singly among flocks of Bonaparte’s or Ring-billed Gulls. Compared to nonbreeding Bonaparte’s, note Black-headed’s red bill, dark red legs, and more extensive black in underwings.