Was about to post a shot of two Redpolls, taken back in February, when it struck me that the one on the lower right is paler and finer-streaked than Redpolls I generally see around here. Even the one upper left is a bit lighter than most, but the broader streaks make me confident that that one is a Common Redpoll. I do know that we occasionally get visits from Arctic (aka Hoary) Redpolls, sometimes in mixed flocks with Commons. Have I captured an Arctic without realizing it at the time? That would be a lifer for me, so I don't dare trust my own judgement on this.