The Eurasian tree sparrow, Mazurek, wróbel mazurek, wróbel polny (Passer montanus) 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 are similarly plumaged. In Europe it is a bird of lightly wooded open countryside, but now it is appearing more and more often in cities, breeding in the more urban areas.
[The second sparrow species in Poland next to the house sparrow (Passer domesticus)]