The slate-colored fox sparrow [grey head/neck/back] was spotted in a mixed species foraging flock feeding on/near the ground ~ 11:45 AM, as we were finishing up our morning run. We were in the area of the park that is a transition/edge zone in-between the woods adjacent to the river, and on the slightly lower elevation fringe just below the grassy park-like portion of the park.
The fox sparrow, ID'ed by its large size, rufous-colored wings/tail, plain head & heavily marked throat & upper chest, was amongst a feeding group that initially included DE juncos, RC kinglet, House wren, Bewick's wren & later Swamp sparrow. I saw the bird moving leaf litter around with its feet at a distance of ~ 15 '. I had a long enough look for John G to get over to me & be able key in on the bird, even if it was briefly.
We saw the Purple Finch with a mixed flock of juncos and sparrows along the riverside woods adjacent to picnic area of Perch St. Pk. Time was approximately 12:00 noon or a bit later. Good light conditions. Observation was approximately 30 seconds and good photos were obtained. We did not hear any vocalization.
Field marks observed: massive white supercillium and strong face pattern, bold but blurry streaking on breast and flanks tapering to a white lower belly and vent. Bill shape was conical, pointed and with very slightly curved culmen. Back was brown and streaked. These marks helped us rule out similar Cassin's Finch.
ID was made following morning after reviewing photos. It appears to be the eastern race of Purple Finch. Photos have been submitted to eBird reviewer and confirmed.