Well, We have a local bird expert that seems to think it's a juvi that didn't molt this year. In the spring they preen mud into thier feathers for camoflage, then molt before thier flight south. When you look at the picture closely you can see where he has no feathers on the neck indicating disease. So my guess is that he is simply a sick or malnurished bird that din't molt.
Here are some from the Bosque today:
Northern Flicker---Sorry, I wasn't up for cleaning up all of the small branches
