Arctic Tern (Sterna paradisaea)
Short-toed Treecreeper (Certhia brachydactyla)
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
Image search Flickr NB! May give other species
CCVery similar to Treecreeper C. familiaris, and id by sound generally easier than by appearance in areas where both species occur. Primaries with small, almost pure white tips restricted to outer web. Hind-claw shorter than hind-toe. Wing-bar usually with even "steps", but often difficult to determine. Underparts less white and more brownish than in continental C. familiaris (which again is browner than the pure white northern subspecies). Bill longer and with a stronger curved tip.
Sound:Contact call very similar to C. familiaris. A thin "sreee" often repeated in an even rhythm, perhaps with slighly shorter pauses. Flight call a short and sharp "wit" used freely when moving about. Song diagnostic, and introductory notes often used singly when interacting. Full song starts with one or two staccato introductory notes, the first higher pitched than the second, followed by a rapid, ascending crescendo ending in a drawn-out, less pure "sree". The tone is loud and much more penetrating and clear than C. familiaris. Timbre recalls wet rubber-boots on vinyl flooring. Note that "mixed singers" of C. familiaris are not uncommon in areas where both species of treecreepers occur.
Song:
Distribution:
Xeno-canto: map
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CCCC-photo:Agustín Povedano, Licence,Link.