Avian Beak Deformities
Sometimes, birds in North America have beaks that are deformed—they are somehow not normal. Most are beaks that are unusually long, or beaks in which the top and the bottom parts cross over.
Since the early 1990s, the number of beak deformities has increased sharply in several bird species in Alaska and B.C. The most commonly affected species are Black-capped Chickadees and Northwestern Crows. Researchers do not know what causes these deformities.