Great Skua (Stercorarius skua)
Treecreeper (Certhia familiaris)
Large and heavy skua with broad wings and short tail. The white patches at base of primaries are more striking than in the other skuas, and are visible both on upper and underside of wings. Size comparable to Herring Gull, but build more compact. Seemingly black at a distance, but white wing-patches usually visible. Confusion with juvenile Pomarine Skua possible, but body is heavier (not just the chest), wings rounder, bill longer, neck thicker and tail shorter.
Sound:Heard mostly at breeding ground. Short, and dry "kek", when agitated. Also a nasal, slightly mewing "kew".
Alarm 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, except in areas where it coexists with Short-toed Treecreeper. Differs from said species in pure white flanks (sub-species macrodactyla has faintly buff flanks but not as marked as in Short-toed), shorter and only moderately curved bill, hind-claw as long as hind-toe and "notched" wing-bar (uneven "steps"). Tips of primaries with buffish/white tips/fringes extending along inner web. Mostly distinguished from Short-toed by call, and identification exclusively by plumage characters difficult in areas where both species occur.
Sound:Contact call a drawn, high-pitched "tzreeee". Similar to Goldcrest in timbre, but of longer duration with a vibrating and slightly rolling tone. Generally repeated in evenly paced, slow series (unlike Goldcrest). Song a short, continuous three-part phrase. Each phrase starts with a few contact call-like notes followed by a Willow Warbler-like descending part, which then jumps to a few descending high notes to form a marked conclusion. Note that "mixed singers" 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
CC