Scientists Track Rapid Spread Of Crows' Beak Deformities Throughout SW B.C. - Van. Sun

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Formerly rare beak deformities are spreading rapidly among crows in southwestern B.C. and Puget Sound, according to researchers from the U.S. Geological Survey. The biologists observed an unusual concentration of crows with badly overgrown beaks in Alaska beginning a little over 10 years ago. According to the scientists, a capture program in 2007 and 2008 revealed that more than 16 per cent of the Alaskan crow population was afflicted, "the highest rate of gross deformities ever recorded in a wild bird population."

"That's about 10 to 20 times the normal rate," said Colleen Handel, co-author of a recent article on the phenomenon published in The Auk, a scientific journal of ornithology. "Some of us who had been working in the field for a long time had never seen anything more than a scattered incidence of this kind of deformity."

Handel and her co-author Caroline Van Hemert began to receive reports of similar deformities down the Alaska Panhandle, from the Vancouver area and communities surrounding Puget Sound in Washington state. There are also indications the ailment, known as Avian Keratin Disorder, has affected other bird species. Birds afflicted by overgrown beaks have difficulty feeding and are forced to take bigger risks to obtain enough food, making them more susceptible to predators.

The birds may also be unable to preen, leaving them vulnerable to the cold. Birds use their beaks to harvest oil from a gland near their tail that they spread on their feathers as a natural waterproofing that protects the downy insulating feathers underneath.

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