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