Appearance:

Olive green upperparts, yellowish chest with gradual transition to off-white belly. Very similar to Willow Warbler, and most field characters are subtle and often hard to see. Distinguished by (usually) black, or dark-brown legs, only faint dark framing to ear-coverts, less marked supercilium. Shorter primary projection (1/2 to 2/3'rds the lenght of tertials), with regularly spaced tips (visible when wing folded). Wings more fan-shaped and less pointed than in Willow Warbler. Juveniles much less yellow below than in W.Warbler. Generally leaves a duller and greyer impression than W. Warbler, but plumage very variable. Frequently flicks tail, even sideways. Generally also more active when moving among the foliage.

Sound:

Contact/alarm call a soft, plaintive ascending "hooeet". Similar to W.Warbler, but shorter with a monosyllabic feel. Song a very distinct: "chiff-chaff-chiff-chiff-chaff-chiff", in a regular clock-like rhythm. Each syllable at seemingly random pitch, but no large intervals tonally. Sometimes "get stuck" at one note.

Contact call, 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:

White forehead with white wedge above eye in all plumages. Legs, and most of bill yellow in adult breeding plumage. Very small and longwinged tern. Only 2/3 of size of Common Tern. Head and bill proportionally longer than Chlidonias species and congeners, while tail is shorter. Back paler grey and belly whiter. First primaries form a dark front edge to wing. In winter the bill darkens, legs turn a dirty yellow and the white forehead expands. Juvenile resembles adult winter, but has yellowish bill base and scale patterned back. Flight fluttering with rapid wing-beats, which together with size, is usually sufficient to determine the species.

Sound:

Fairly distinct voice. Contact call a sharp "kitt", often combined to form undulating, rolling series. Not as sharp and penetrating as Common- and Arctic Tern.

Contact call:

Distribution:

Xeno-canto: map

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-photo:Lars Buckx, Licence,Link.