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:

Differs from Barn Swallow in all plumages by pale throat and black under tail coverts, which are visible at greater distance than the red rump. Rufous cheeks and collar. Underparts finely streaked, giving the bird a slightly "dirty" look from a distance, with less contrast to the upperparts than in Barn Swallow. Immature birds with short streamers and buff cheeks and rump. Build more compact than Barn Swallow, with shorter bill, rounded wings and slightly shorter streamers. Flight slower and with more frequent gliding.

Sound:

Less vocal than Barn Swallow. Song slower, and less energetic. Each phrase starts with a few staccato notes, leading to a short, twittering sequence of a few seconds length, with some drawn notes. Timbre is metallic and "broken", and quite diagnostic.

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

CC-sound:Jordi Calvet, Licence,Link.