This Black-capped Chickadee, captured in Anchorage, Alaska, demonstrates an overgrown beak characteristic of avian keratin disorder. Beak deformities in this species were first observed in the late 1990s and biologists have since documented more than 2,100 affected individuals in Alaska. Image credit: U.S. Geological Survey
ANCHORAGE, Alaska – The highest rate of beak abnormalities ever recorded in wild bird populations is being seen in a number of species in the Northwest and Alaska, and scientists to this point have not been able to isolate the cause.
Black-capped Chickadees, Northwestern Crows, and other birds are being impacted by the problem, which affects their ability to feed and clean themselves and could signal a growing environmental health problem.
In birds affected by what scientists have termed “avian keratin disorder,” the keratin layer of the beak becomes overgrown, resulting in noticeably elongated and often crossed beaks, sometimes accompanied by abnormal skin, legs, feet, claws and feathers. Biologists with the U.S. Geological Survey’s Alaska Science Center published their findings in this month’s issue of The Auk, a Quarterly Journal of Ornithology.
“The prevalence of these strange deformities is more than ten times what is normally expected in a wild bird population,” said research biologist Colleen Handel with the USGS, “We have seen effects not only on the birds’ survival rates, but also on their ability to reproduce and raise young. We are particularly concerned because we have not yet been able to determine the cause, despite testing for the most likely culprits.” (more…)