Appearance:

Only in the UK. Similar to Red and Parrot Crossbill in plumage. Bill size possibly the only visual identification clue, but even this overlaps with the other two species. Bill is usually deeper and heavier than Red Crossbill. Certain separation from Parrot Crossbill in the field by visual characters alone, probably not possible. Species status mainly upheld by isolated breeding population and differences in excitement calls from other crossbills. Calls probably play an important role in maintaining the reproduction barrier between Crossbill populations with different bill-size. See Birdlife link below for more info.

Sound:

Calls very similar to Parrot Crossbill, and sonogram analysis may be needed for certain identification. Flight and excitement calls show most unique quality. Sonogram image above by Ron Summers (used with permission). A detailed article about crossbill calls can be found here.

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

CC

Collage photo By Richard Crossley (The Crossley ID Guide Britain and Ireland) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons.

Appearance:

Most distinct species of the genus. Most similar to Willow Warbler, but with much more contrasting plumage. Upperparts pure green. Throat and upper chest yellow, contrasting with pure white underparts. Distinct and strong yellow supercilium and black eye-stripe. Long primary projection, with primaries reaching middle of relatively short tail. Tertials with pale green fringes. Legs pale yellowish brown. Posture often horizontal with drooping wings.

Sound:

Song distinct. An accelerating series of sharp, metallic "swee-swee-swee-swee". Typically with a staccato beginning. Pitch drops as the speed increases and the syllables fuses into a continuous trill. Often described as the sound of a spinning coin coming to rest on a glass table. Some phrases may be given in an almost even tempo, and may recall Bonelli's Warbler. Alternative (piping) song a series of 4-6 piping, plaintive and descending "pew - pew" calls. Resembles Willow Tit's song, but is softer with each note more evenly pitched. Contact call similar to individual syllables of piping song, but with heavier accent on the ending.

Song (two variants):

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