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Black-capped Chickadee with a deformed beak - photo by USGS
Black-capped Chickadee, USGS photo

Over the past decade, Alaskans have witnessed a startling increase of beak deformities among local birds.  Large numbers of Black-capped Chickadees and smaller numbers of many other species of birds have appeared with grossly overgrown and crossed beaks.

We began research in 1999, and have since identified more than 2,000 deformed Black-capped Chickadees in south-central Alaska—the highest concentration of such abnormalities ever recorded in a wild bird population anywhere!  More recently, rapidly increasing numbers of other species, including Northwestern Crows, Downy Woodpeckers,Steller’s Jays, and Black-billed Magpies have also been reported with beak deformities by biologists and local residents throughout the state.

Although we do not yet know the cause of this widespread problem, we continue to investigate potential agents, including environmental contaminants, nutritional deficiencies, and disease.  Nearly all of the species affected are year-round residents, and we suspect that factors responsible for this cluster of deformities may be unique to Alaska and the Pacific Northwest.  We are currently pursuing additional studies to determine where these deformities are occurring and why.  Reports from the public help us to determine where and how many birds are affected.  If you see a bird with a deformed beak, please contact us.


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