The Eurasian tree sparrow (Passer montanus) is a passerine bird known for its chestnut crown and white cheeks with black patches. Both sexes are similarly plumaged, and young birds are duller in color. This species breeds across temperate Eurasia and Southeast Asia and has been introduced to areas like the United States, where it’s called the German sparrow to distinguish it from the American tree sparrow.
Nests are often built in natural cavities or abandoned nests of other birds, typically containing five to six eggs that hatch in under two weeks. Their diet mainly consists of seeds, with some invertebrates, especially during breeding. The average lifespan is around two years, with threats from parasites and predation.
While common in eastern Asian urban areas, in Europe, they prefer lightly wooded open countryside. Although globally not endangered, western European populations have declined due to changes in farming practices.
