[cobirds] Purple vs. Cassin's Finches

Birders,

I believe that Chris Petrizzo's finch is a Purple Finch.

I had the good fortune to photograph both Purple and Cassin's Finches on my feeder in Las Animas, Bent County, CO on 2/28/15. For a long time, I kept seeing one extralimital finch that I confidently identified as a Purple Finch, only to doubt myself when I saw one that looked more like a Cassin's. Finally, both cooperated and appeared at my feeder at the same time. I got to reclaim my sanity card.

The Purple Finch is on the left and the Cassin's finch is on the right. Note that the Purple Finch has a shorter bill with a decurved culmen, while the Cassin's Finch has a pointed, longer, conical beak. The ear coverts on the Purple Finch are uniformly dark, and outlined much more boldly by a pale border. I also think the Purple finch has a rounder head, looks stockier, and appears to have a shorter tail. The breast streaks are bolder and more defined in the Purple Finch. Out of sight in this picture are the undertail coverts, immaculately white in a Purple Finch, and finely streaked in a Cassin's Finch.

I hope this is useful to Colorado birders.

Duane Nelson

Las Animas, Bent County, CO