Eurasian tree sparrow

The tree sparrow (Passer montanus Latin pronunciation: [pas.ser mon.ta.nus]) is a passerine bird in the sparrow family with a rich chestnut crown and nape and a black patch on each pure white cheek. The sexes have similar plumage, and young birds are duller versions of the adult. This sparrow breeds across much of temperate Eurasia and Southeast Asia and has been introduced elsewhere, including the United States, where it is known as the Eurasian tree sparrow or German sparrow to differentiate it from the native American tree sparrow. Although several subspecies are recognised, the appearance of this bird varies little across its extensive range.

The untidy nest of the tree sparrow is built in a natural cavity, a hole in a building, or the disused nest of a European magpie or white stork. The typical clutch is five or six eggs, which hatch in under two weeks. This sparrow mainly feeds on seeds, but also consumes invertebrates, particularly during the breeding season. As with other small birds, infection by parasites and diseases, as well as predation by birds of prey, take their toll, and the typical lifespan is about two years.

The tree sparrow is widespread in the towns and cities of eastern Asia, but in Europe, it inhabits lightly wooded open countryside, while the house sparrow breeds in more urban areas. The tree sparrow's extensive range and large population mean it is not globally endangered, although there have been significant population declines in Western Europe, partly due to changes in farming practices involving increased use of herbicides and the loss of winter stubble fields.