Appearance:

Very large, mostly unmistakable bird. Grey upperparts, white underparts and yellow/yellowish bill. Keeps neck retracted when flying (as opposed to crane). May be mistaken for Purple Heron, but back of neck grey, not brown. Bill heavy and dagger-shaped. Neck thicker and less angular than in Purple Heron. Unmarked cheeks.

Sound:

Quite vocal. Most common call a short, far reaching and extremely harsh, rasping sound. At breeding ground a varied repertoire of harsh and clattering sounds.

Flight call:

Distribution:

Wikipedia: map (se also Xeno-canto below)

Ecology:

Birdlife ecology

Links:

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

CC

Appearance:

Differs from Common Tern in shorter head, and blood-red bill. Legs shorter, but tail streamers longer (extends well past wings in sitting birds). Underparts of primaries with sharply bordered dark trailing edge (diffusely bordered in Common Tern). Both primaries and secondaries transparent to sunlight. Crest less apparent than in Common Tern and underside greyer. Cheeks white just below the black cap, often in contrast to grey lower cheeks. Juveniles lacks buff coloured back.

Sound:

Similar to Common Tern but higher pitched. Typical call a series of high pitched "tip-tip-tip", and longer, ringing, high-pitched "kriiiiii" calls. The drawn out "kree-aaahh" call falls less distinctly in pitch than Common Tern.

Calls:

Distribution:

Wikipedia: map (se also Xeno-canto below)

Ecology:

Birdlife ecology

Links:

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

CC

CC-sound:Stein Ø. Nilsen, Licence,Link.