urner, in 1544, referred to 'a Larus' and called it 'stern', apparently the Black Tern Chlidonias niger. Willughby, in 1678, referred to the terns as 'the least sort of gull, having a forked tail'. Gesner (1516-1565) referred to three terns in the genus Larus as well as gulls, and in 1662 Sir Thomas Browne wrote of 'Lari, seamews and cobs' in Norfolk, including Larus cinereus, apparently the Common Tern Sterna hirundo, commonly called Sterne, but also of the "Hirundo marirui or sca-swallowe, a bird much larger than a Swallow Hirundo rustica, neat, white and fork-tailed. The confusion with gulls continued for many years; indeed, it still does. In the General Synopsis, 1781, Latham knew the Common Tern well enough to publish an accurate plumage description, but he did not recognise Arctic S. paradisaea, Roseate S. dougallii and Sandwich Terns S. sandvicensis. Briinnich, however, had described the Arctic Tern as a separate species in 1764, despite Henry Seebohm's later assertion that the distinction was not made until 1819. Montagu did not mention Arctic Tern in his 1802 Dictionary of British Birds, although he was good enough to distinguish difficult pairs such as Hen Circus cyaneus and Montagu's Harriers C. pygargus. Iinnaeus, in 1758, made no mention of the Arctic Tern either, although it is likely that the bird he described under the name Sterna hirundo hirundo was actually a specimen of an Arctic, not a Common Tern. The identification of Common, Arctic and Roseate Terns in the field still presents a