Where and when Although the familiar and once abundant House Sparrow Passer domesticus has declined enormously in recent years, it is still locally common and can be found almost anywhere, usually around habitation. Tree Sparrow P. montanus is now very scarce, having declined by an astonishing 93% between 1970 and 2008, a result of changes in agricultural practices. Although still widespread, it is now most likely to be found in arable areas in the Midlands and E. and SE England, with small pockets elsewhere. It is generally absent from n. Scotland and pastoral areas of SW England, Wales and W. Ireland.
Identification Female House Sparrow is rather plain grey-brown (tinged olive) and streaked black above, with an unobtrusive pale supercilium. Juveniles are similar but generally paler and fluffier, with brighter yellow at the bill base and, when young, a yellow gape line. Male House Sparrow and both sexes of Tree Sparrow are more similar, but their separation is straightforward: note Tree’s brown crown, black ear-covert spot, white collar and buffer plumage tones. Whereas male House Sparrow has a large black bib that extends to the upper breast, Tree Sparrows of both sexes have a small bib confined to the chin and throat. Note, however, that in early winter, male House Sparrow is duller and also has a small bib (see ‘Moult’). Juvenile Tree Sparrows resemble adults but, like juvenile House Sparrows, are rather fluffy with yellow at the bill base and a prominent yellow gape line when young; their head markings are also slightly subdued compared to the adults. Both species fly fast and direct, and give muffled chirps in flight.
Calls The harder, more abrupt flight notes of Tree Sparrow are distinctive once learnt, as are its hard, dry ‘tecking’ and chattering noises at rest.
Moult Adults and juveniles of both species have one complete moult a year, in late summer and autumn. As a consequence, freshly moulted male House Sparrows have subdued colouring; most obvious is that the black bib is obscured by grey feather fringes, and is largely confined to the chin and throat. As winter progresses, the grey fringes gradually wear to reveal the full extent of the black bib on the chin, throat and upper breast. Moulting males in autumn (particularly juveniles) may show an odd combination of female-like characters (particularly a pale supercilium) and male characters (grey on the crown and black on the lores and throat).
Hybrids Rare. That illustrated opposite is based on one that showed characters obviously intermediate between the two.
A very rare vagrant (nine records to 2012, many if not all of which have probably been ship- assisted). Resembles House Sparrow but males have a chestnut-brown crown, very white face and extensively black underparts with thick streaking extending onto the flanks. The mantle is also more heavily striped black, buff and white. In fresh plumage (autumn and early winter) much of the plumage is obscured by buff feather fringes that gradually wear off (although its basic pattern is still obvious). Its ‘song’ is high-pitched and rather musical compared to House Sparrow: twoo-oo-lit… twoo-oo-lit…. Females are very similar to female House Sparrows but have a slightly larger bill and they are plainer-headed with diffuse black streaking on the breast and flanks (obvious on some, faint on others).