Largest tern in the world; widespread but typically uncommon. Thick, bright-red bill is distinctive; most have small dark marking near the tip. Note solid black cap in summer which turns to black streaks in winter. Juveniles have V-shaped markings on the upperparts. Feeds by cruising over lakes, rivers, estuaries, and reservoirs looking for fish, then plunging to catch them. Smooth wingbeats, more gull-like than choppy flight of small-bodied terns. Very vocal, giving loud raucous screams. Compare especially with Royal Tern, which is slightly smaller and more slender, and has a thinner, more orangey bill.