Comprehensive guide to all 23 species of tern found in Europe and North America. Terns are birds of sea and marshland; they are also long-distance migrants. With considerable variation among species and their subspecies, identification is often highly problematic. Much attention is devoted to immature and winter plumages, which have been previously poorly covered. Also covered are the problems of moult, species and subspecies, as well as in-hand identification. There are introductory chapters, a main colour plate section, with brief notes and distribution map for each species on the facing page, plus a 48-page photographic section. The full species descriptions cover identification, description, geographical variation, voice, habitats and habits, breeding, status and distribution, movements, moult, measurements and references.