Flock of Siskins

 On the one nice morning of this week, I had to tend to "preping" my snowblower of the inevitable. Thus, I find myself forced to return to old shots for my birding experience. On the 20th of this month, I snapped this flock of siskins flying in Blackhead.

As I look over the flock shot, I found this odd-one-out. I don't think it is a siskin. The tail is right, but the apparent white rump and hint of an eye ring suggests it is something different. At this time of the year, it pays to look over every bird in a seemingly humdrum flock. Now what is this bird?