A few days ago I wrote about a Black-capped Chickadee with a severly deformed bill. The bird had been seen and photographed at a feeder in Maple Grove. At that time I knew of no other such sightings here. Caroline Van Hemert, biologist in Alaska with the U.S. Geological Survey, in answer to a question, wrote to say that there have been several other reports from Minnesota. They include three more chickadees, a Red-breasted Nuthatch, and a Hairy Woodpecker. Thousands of birds with deformed bills have been seen in Alaska and the Pacific Northwest. Ms. Van Hemert wrote of a few reports from the northeastern U.S. and Canada, mostly of nuthatches and woodpeckers, and a smalller number of chickadees. There is no known cause. Ongoing studies hope to identity the problem.
Information on this condition can be found at http://alaska.usgs.gov/science/biology/landbirds/beak_deformity/index.html
Here again in the photo of the Maple Grove bird.