Widespread in small numbers. The only large inland tern. Breeds on large lakes and in marshes (usually on islands). Often migrates over land. Winters in s. coastal areas. Less sociable than most terns and usually hunts alone. Patrols over water, often covering large areas before doubling back to cover same ground. Mean appearance matches screaming call: ‘aargh.’ ID: Largest tern in the world with a thick, killer-looking blood-red bill. A real bruiser: heavy set, short-tailed, thick-necked, with broad head. Wings broad and less angular (more gull-like) than in other terns. Darker in outer primaries than ROTE. Ad br: solid black cap. Nonbr: unlike other terns, cap remains mostly dark. Nonbr/1st-s: as breeding with more crown flecking, but overall impression of a dark cap. Juv: striking black subterminal ‘V’s on upperparts become less distinct through fall. Legs yellow turning to black. Dark cap extends onto lores and cheeks. 1st-s: as adult nonbr but heavily worn.