Birds’ beaks are made of keratin, similar to human fingernails and hair. Normally, beaks wear down with use, continuing to grow at the same time. There’s a balance. But something is causing this super-fast growth — and it doesn’t get turned off. There seems to be a concentration in the Pacific Northwest and Alaska but the cause is unknown still.
Read more about this mystery at the Alaska Science Center or the Falcon Research Group or the University of Michigan Dearborn.