What causes beak deformities in birds?

Since the late 1990s, Alaskans have reported large numbers of beak deformities in Black-capped Chickadees and other species of resident birds. This disease, called avian keratin disorder (AKD), is characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues. Affected birds have difficulty feeding and preening, and can suffer high rates of mortality.

The USGS has identified a new picornavirus (Poecivirus) as the most likely factor responsible for AKD. Current research is focused on confirming the role of this virus in the development of AKD and learning more about how it might be transmitted among wild birds.

Other types of beak deformities can be caused by a variety of factors, including:

•      Contaminants
•      Nutritional deficiencies
•      Disease
•      Parasites
•      Blunt trauma
•      Genetic abnormalities

Learn more:

•  Beak deformity research at the USGS Alaska Science Center
•  Report a bird with a beak deformity:  USGS beak deformity form