Deformed beaks in Alaska birds puzzle scientists
By Yereth Rosen, Reuters (December 2, 2010 9:01pm)
ANCHORAGE, Alaska - Crows, chickadees and other birds living year-round in Alaska are suffering an epidemic of beak deformities that is confounding scientists.
The grossly overgrown, overly-curved and sometimes crossed beaks started showing up in large numbers about a decade ago, and are now being widely reported across southern and interior Alaska, as well as neighboring parts of the Pacific northwest, said Caroline Van Hemert, a wildlife biologist.
“It’s really rare to have so many birds in a geographic area that are affected at one time,” said Van Hemert, who co-authored a pair of studies published in the current edition of The Auk, the quarterly journal of the American Ornithologists’ Union.
The most dramatic problems seem to be in Northwestern crows, she said.
Van Hemert and fellow U.S. Geological Survey scientist Colleen Handel found the rate of beak deformities among adult crows to be 16.9 percent, the highest rate of gross deformities ever recorded in a wild bird population.
On some parts of the Kenai Peninsula, south of Anchorage, the beak deformity rate hit 36 percent, according to the biologists’ research.
Hardest hit were black-capped chickadees, according to the studies.
Since 1999, scientists have documented beak deformities in 2,160 chickadees, mostly in and around Anchorage. About 6.5 percent of the chickadees in the region have the deformed beaks, according to the newly reported studies.
Other affected birds include Steller’s jays, woodpeckers and magpies. Many of the birds also have abnormalities in their skin, legs, claws or feathers.
Potential causes include environmental pollution, nutritional deficiencies or disease, according to the scientists.
Van Hemert said she and other scientists have few clues to the cause.
“At this point, we really don’t know,” she said Thursday.
The deformed beaks make if difficult for the birds to feed and preen.
“A lot of birds with the really severe deformities can’t open up a sunflower seed,” Van hemert said.
