Scottish Crossbill (Loxia scotica)
House Sparrow (Passer domesticus)
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
Image search Flickr NB! May give other species
CCCollage 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.
Male told from Tree Sparrow by grey crown, grey cheeks with no cheek-patch, larger black bib and grey rump. Female rather featureless, and thus not likely to be confused with Tree Sparrow. Confusion with female Scarlet Rosefinch possible, but underparts unstreaked. Profile of House Sparrow differs from Tree Sparrow by larger, less rounded head and less heavy bill.
Sound:Most calls very similar to Tree Sparrow, but lacks said species' distinct high pitched call (chew-itt), and alarm call is less dry and raucous. Song a primitive, monosyllabic, or slightly disyllabic "chilp", hard to distinguish from Tree Sparrow.
Song:
Distribution:
Wikipedia: map (se also Xeno-canto below)
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CC