Something is warping the beaks of thousands of birds in Alaska and the Northwest. A recent US Geological Survey found a shocking number of birds with “avian keratin disorder,” which causes the either the upper beak, lower beak, or both to grow abnormally long and curved, often crossing the other beak. “The prevalence of these strange deformities is more than 10 times what is normally expected in a wild bird population,” one researcher told the AP.
The disorder, which can also cause elongated claws, can be caused by environmental contaminants, nutritional deficiencies, and various infections. Affected birds have difficulty feeding, though some appear to cope by eating from human-provided bird-feeders. The study focused on northwestern crows, but the deformities are also common in black-capped chickadees and have been seen in several other species as well, including nuthatches and woodpeckers. Biologists have documented more than 2,100 affected individuals.