House sparrows are our typical city sparrows just as tree sparrows are our traditional country sparrows. In winter the two species quite often move in common flocks. In that case there will be birds of three different featherings: male and female tree sparrows look similar.
 

The tree sparrow has a red-brown crown, and white cheeks with a black patch. They are smaller than their relatives, with clearer plumage colours. A careful observer will not confuse them, although their behaviour and their chirping calls are quite similar.