Eurasian Tree Sparrow

The Eurasian tree sparrow is a compact sparrow about 12.5–14 cm long. Both sexes share a chestnut crown, white cheeks marked by a neat black spot, a small black bib and a brown streaked back. This identical male and female plumage contrasts with the house sparrow, whose male has a grey crown and larger bib while the female is much plainer. A complete white neck collar further sharpens the tree sparrow's pattern. (Wikipedia, Eurasian tree sparrow account)

Tree sparrows inhabit farmland, villages, woodland edge, scrub and gardens across Eurasia. They feed mainly on grass and crop seeds outside the breeding season, adding insects when provisioning nestlings. Pairs nest in holes in trees, cliffs or buildings and readily use nest boxes; loose colonies can form where cavities are plentiful. Many populations are resident, though some move seasonally. The opened account did not provide a Mongolia-specific habitat study, named site or national breeding dates, so those details are not inferred. (Wikipedia, Eurasian tree sparrow account)