Yellow Purple Finch

Or, the way the AOU does things, a Yellow Purple-Finch. No, not a newly split species of South American emberizid. It's a xanthochromic Purple Finch visiting my sister's feeder in San Anselmo, California. She sent me these pictures when she wasn't able to identify the bird herself (click for larger view):





She was relieved to learn that this bird really isn't in the field guides, it wasn't just that she couldn't find it! I've never seen a bird like this in person, and only found a very few references to this color variation in this species when I googled. One I did find was the Born Again Birdwatcher, which uses a shot of a very similar bird (from Oregon) as its header.

P.S. If you are wondering why this isn't just a yellow House Finch, note the typical Purple Finch face pattern with less sharply contrasting eyebrow line, the extensive suffusion of the yellow color over the head and onto the wings, and the absence of prominent brown streaking anywhere on the bird's underparts (marks all easier to see on the larger view). Also note the size and stockiness compared to the female House Finch. Turn the yellow on this bird into wine-red and you'd have a typical male Purple Finch.