tree sparrow

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A North American sparrow (Spizella arborea) having a reddish-brown crown and a dark spot on the breast.
• noun A Eurasian sparrow (Passer montanus) that is similar to but smaller than the house sparrow.

from The Century Dictionary.

• noun In Great Britain, Passer montanus, a near relative of the house-sparrow. It has been naturalized to some extent in the United States. See Passerand sparrow.
• noun In the United States, Spizella monticola.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun Eurasian sparrow smaller than the house sparrow
• noun finch common in winter in the northern U.S.