Hopin' that some of the info provided at these web sites, may be beneficial to some ...
* NOTE *
Any references herein to any methodology mentioned, do not necessarily constitute or imply its endorsement or recommendation .. by *me*.
The Sialis site, explicitly states (and urges) ..
Quoting:
Before using any active management methods, you must be able to positively identify a House Sparrow. A good bird book like Sibley's is invaluable in this regard. Some other "brown birds", that are sometimes confused with the House Sparrow .. are listed below. Only wrens and rarely house finches will use a nestbox. When in doubt, let it out!
House Sparrow History (Compiled by E.A. Zimmerman) > http://www.sialis.org/hosphistory.htm
Discouraging HouseWrens Discouraging House Wrens > http://www.sialis.org/wrens.htm
The Magic Halo and Other Means to Deter House Sparrows from feeders > http://www.sialis.org/halo.htm
Passive management .. involves discouraging HOSP feeding and nesting. > http://www.sialis.org/hosp.htm#passive
Managing House Sparrows ..
* Warning!! * There are graphic images and descriptions!! > http://www.sialis.org/hosp.htm
- Magpye