Appearance:

Olive green upperparts, yellowish chest with gradual transition to off-white belly. Very similar to Chiff-chaff, and most field characters are subtle and often hard to see. Distinguished by (usually) pale, yellow-brown legs, dark framing to ear-coverts, stronger supercilium. Long primary projection (often 3/4ths the length of tertials) with irregularly spaced tips (visible when wing folded). Wings slightly more pointed than in Chiff-chaff, and not so fan-shaped. Juveniles often with whole underparts yellow. Frequently flicks tail, but not sideways (unlike Chiff-chaff). Generally also more calm when moving among the foliage.

Sound:

By far most easily identified by it's call or song. Contact/alarm call a soft, plaintive ascending "hoo-eet". Similar to Chiff-chaff, but first part more drawn, giving it a disyllabic feel. Song: A 3-5 second, falling phrase of soft, rippling "svi-svi" sounds, starting high with some attack, and then falling in a mellow manner. The phrase lacks any conclusion, and diminishes both in strength and tempo.

Song:

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:

At a distance quite similar to Guillemot. Bill deep, rectangular and with white markings. Flanks unstreaked and armpits white. Tail longer than in Guillemot, with legs not protruding behind tail in flight. Tail often held clear of the surface when swimming. Cheeks white in winter, with broad, short and black eye stripe. Neck collar short and wide. Upperparts blacker, and underparts whiter than Guillemot. Heavy neck, head and bill, in combination with the long tail, gives it a front heavy, and different profile from Guillemot, whether perched, swimming or flying. Top of head in line with tip of uptilted bill when swimming.

Sound:

Very coarse and deep voice. Grunting or snore-like, with little phrasing. Mostly heard at breeding ground, but also sometimes at sea.

Contact 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

Sounds:Recorded by Simon Elliott,http://www.xeno-canto.org ,CC license