I saw Sherry's post and remember that I had forgotten to post about the above Sparrows this weekend.  I went to the end of Old Spring Road and saw them everywhere.  I believe many were the same birds being seen 2 or 3 times, but I did have one group of close to 15 fly off and everyone I looked at were the Bell's/Sagebrush.  They weren't in a tight flock but when one flew, another flew from a few feet away and then another and so on.  I'm guessing 20 is a nice conservative number.