I arrived at 6760 Alex. Bell Drive about 9:30 and seeing 3 birders off the paved trail in back of the building, I headed up toward them.  They (Harvey Mudd, et al) were watching a mixed group of birds feeding on the dirt trail that heads off from the picnic tables and saw the Harris's in that group, but the birds spooked before I got to see it.  After the others left, I went on up the dirt trail and waited for the birds to return to feed on the seed and also watched the feeders across the ravine.  The Harris's didn't come back to feed on the trail, but a little after 10:00, it began to sing and I found it in the brush along the fence line.  It gave quite a few good looks, even though partially obscured by the brush.  In the same area there was a fox sparrow.  Thanks to all for the instructions and directions.

Tom Jones
Washington, D.C.