rybitwa rzeczna Sterna hirundo

Medium-sized tern found on open ocean, beaches, and large lakes. Adults have pale gray body and black cap. Bill color differs by subspecies: most have red bill with black tip, but some Asian birds have all-black bills. First-years show dark outer primaries, dark shoulder, and black restricted to back of neck. Similar to Forster's, Arctic, and Roseate Terns. Separated from breeding Forster's Tern by entirely gray upperwings; nonbreeding Forster's shows black ear patch. Somewhat longer-billed and shorter-tailed than Arctic Tern, with paler body. Shorter-tailed and overall darker than gleaming white Roseate Tern. Often found in large flocks, especially in late summer. Gives a harsh screeching call "KEEE-yurrrr."