Rook (Corvus frugilegus)
Black Tern (Chlidonias niger)
An all shiny black crow with diagnostic bare, pale grey base of bill, and "baggy trousers". Juveniles lacks bare bill base and are difficult to separate from Carrion Crow. Young Rooks however, has a steeper forehead and more conical bill with less curved culmen. Tail is more rounded and base of wings more narrow. Flight action includes less gliding than Carrion Crow, and individuals are more spread when a flock flies.
Sound:Makes similar caws as Carrion Crow, but is harsher, softer, flatter with less rolling r's. Also gives a varied song of soft gurgling and rattling sounds, interwoven with calls at breeding ground.
Contact call:
Distribution:
Wikipedia: map (se also Xeno-canto below)
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CCUnmistakable in breeding plumage, but otherwise easily confused with other marsh terns. Breeding plumage with black head and belly, but pale underwing and grey rump. When in immature and winter plumage it differs from Common and Arctic tern by smaller size and short, moderately forked tail, and from other marsh terns by slimmer body and wings (compared to White-winged tern), and relatively long, thin bill. Both immature and adult winter show dark front edge of wing, and characteristic dark shoulder patch at wing base. Back is dark in immature birds. Grey rump in all plumages. Flight usually different from Sterna-terns, with erratic dives for no apparent reason, and "aimless" change of direction. Note that when foraging over saltwater, flight becomes more Sterna-like.
Sound:Moderately vocal. Flight call a more or less clear "kleck, or a disyllabic "klee-ake" with accented first syllable. Sometimes slightly rolling "klirr-eke", but never as much as in White-winged Tern. Also a slightly harsher "kreek", but not as raspy as in Whiskered Tern.
Flight call:
Distribution:
Wikipedia: map (se also Xeno-canto below)
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CC