Checked a few fields in Hadley on this frigid afternoon without too much success (just a few small flocks of Horned Larks) before deciding to make a late afternoon dash for the campus pond at UMass. The pond was packed tight with Canada Geese, at least 700 birds in all, the largest concentration that I've seen here this fall. Also one Cackling Goose, almost certainly the same bird from last weekend, giving excellent views towards the Fine Arts Center end of the pond. Having watched this bird a little more I'm rather less comfortable in calling it a Richardson's. The whole bird looks darker that most hutchinsii that I've seen, and the breast is especially dark for that form.
Update Nov 24th: Despite a few of my own doubts about this bird, Steve Mlodinow has kindly offered to comment and allowed me to post those comments here; "The first pic looks like a typical Richy, just a bit dark. I've seen some photos of flocks of Richys, and dark ones are uncommon but not hideously rare. The bill and head shape seem very good. The bird is an immature, which is why its wing coverts are relatively heavily patterned and why it is kind of mottled beneath."