Beak Deformities in Landbirds Active
Over the past 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds. This disease, called avian keratin disorder (AKD), is characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues. Affected birds have difficulty feeding and preening, and may suffer high rates of mortality.
Return to Ecosystems >> Terrestrial Ecosystems or Wildlife Disease and Environmental Health
We began research in 1999, and have since identified more than 3,000 affected Black-capped Chickadees in Alaska—the highest concentration of gross deformities ever recorded in a wild bird population! Increasing numbers of other species, including Northwestern Crows, Downy Woodpeckers, Steller’s Jays, and Black-billed Magpies have also been observed with beak deformities throughout the state. Growing numbers of reports from North America and Europe suggest that AKD may be spreading to a larger geographic area.
In 2016, we identified a novel picornavirus (Poecivirus) in Alaskan Black-capped Chickadees with AKD. We’ve subsequently confirmed a strong association between Poecivirus and beak deformities in chickadees and detected a closely related virus in other species with similar beak deformities. Together, this evidence suggests that Poecivirus is a likely candidate cause of AKD. Our current investigations are focusing on understanding more about this virus, including how it may be contributing to beak deformities, whether it occurs in multiple species, and how it is transmitted. Previously, we examined potential factors, such as environmental contaminants, nutritional deficiencies, and parasites, found no clear evidence linking these to AKD in Alaskan birds.
Reports from the public help us to determine where and how many birds are affected. If you see a bird with a beak deformity, please contact us.
- Beak Deformity and Banded Bird Observation Report
- Background
- Species Affected
- Physical Description
- Prevalence, Distribution and Timing
- Effects on Birds
- Possible Causes
- Photo Gallery - see the Multimedia tab
- Publications - see the Publications tab
- Links
- Literature Cited
- Landbirds
Below are other science projects associated with this project.
Landbird Research in Alaska
Below are data associated with this project.
Below are multimedia items associated with this project.
Below are publications associated with this project.
A natural experiment on the condition-dependence of achromatic plumage reflectance in black-capped chickadees
Beak deformities in Northwestern Crows: Evidence of a multispecies epizootic
Epizootic of beak deformities among wild birds in Alaska: An emerging disease in North America?
Alaskan birds at risk: Widespread beak deformities in resident species
Use of buccal swabs for sampling DNA from nestling and adult birds
- Overview
Over the past 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds. This disease, called avian keratin disorder (AKD), is characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues. Affected birds have difficulty feeding and preening, and may suffer high rates of mortality.
Return to Ecosystems >> Terrestrial Ecosystems or Wildlife Disease and Environmental Health
We began research in 1999, and have since identified more than 3,000 affected Black-capped Chickadees in Alaska—the highest concentration of gross deformities ever recorded in a wild bird population! Increasing numbers of other species, including Northwestern Crows, Downy Woodpeckers, Steller’s Jays, and Black-billed Magpies have also been observed with beak deformities throughout the state. Growing numbers of reports from North America and Europe suggest that AKD may be spreading to a larger geographic area.
In 2016, we identified a novel picornavirus (Poecivirus) in Alaskan Black-capped Chickadees with AKD. We’ve subsequently confirmed a strong association between Poecivirus and beak deformities in chickadees and detected a closely related virus in other species with similar beak deformities. Together, this evidence suggests that Poecivirus is a likely candidate cause of AKD. Our current investigations are focusing on understanding more about this virus, including how it may be contributing to beak deformities, whether it occurs in multiple species, and how it is transmitted. Previously, we examined potential factors, such as environmental contaminants, nutritional deficiencies, and parasites, found no clear evidence linking these to AKD in Alaskan birds.
Reports from the public help us to determine where and how many birds are affected. If you see a bird with a beak deformity, please contact us.
- Beak Deformity and Banded Bird Observation Report
- Background
- Species Affected
- Physical Description
- Prevalence, Distribution and Timing
- Effects on Birds
- Possible Causes
- Photo Gallery - see the Multimedia tab
- Publications - see the Publications tab
- Links
- Literature Cited
- Landbirds
- Science
Below are other science projects associated with this project.
Landbird Research in Alaska
On this page, learn about USGS work on Beak Deformities and Boreal Partners in Flight. - Data
Below are data associated with this project.
- Multimedia
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 17A natural experiment on the condition-dependence of achromatic plumage reflectance in black-capped chickadees
Honest advertisement models posit that only individuals in good health can produce and/or maintain ornamental traits. Even though disease has profound effects on condition, few studies have experimentally tested its effects on trait expression and even fewer have identified a mechanistic basis for these effects. Recent evidence suggests that black and white, but not grey, plumage colors of black-cAuthorsL. D'Alba, Caroline R. Van Hemert, Colleen M. Handel, M.D. ShawkeyBeak deformities in Northwestern Crows: Evidence of a multispecies epizootic
Beak abnormalities are rare among adult birds and, typically, are not widespread in a given population, within a region, or across multiple species. A high concentration of beak deformities was recently documented in Black-capped Chickadees (Poecile atricapillus) and other resident avian species in Alaska. We describe a parallel condition in Northwestern Crows (Corvus caurinus) that signals the emAuthorsCaroline R. Van Hemert, Colleen M. HandelEpizootic of beak deformities among wild birds in Alaska: An emerging disease in North America?
The sudden appearance of a large cluster of animals with gross abnormalities may signal a significant change in an ecosystem. We describe an unusual concentration of beak deformities that appear to have arisen rapidly within Alaska and now extend southward along the Pacific Coast. In Alaska we have documented 2,160 Black-capped Chickadees (Poecile atricapillus) and 435 individuals of 29 other specAuthorsColleen M. Handel, Lisa M. Pajot, Steven M. Matsuoka, Caroline R. Van Hemert, John Terenzi, Sandra L. Talbot, Daniel M. Mulcahy, Carol U. Meteyer, Kimberly A. TrustAlaskan birds at risk: Widespread beak deformities in resident species
The team creeps silently across a well-tended lawn, eyes drawn to a small wooden box perched several meters up a lone birch tree. The first biologist is armed with a broom in one hand and a bug net in the other. Her partner wields a lunchbox-sized plastic case and a tree-climbing ladder that looks like an oversized radio antenna. A neighbor peers out her window from across the street to watch theAuthorsCaroline R. Van HemertUse of buccal swabs for sampling DNA from nestling and adult birds
We evaluated the feasibility and efficiency of using swabs to collect buccal epithelial cells fromsmall (2‐ to 13‐g) birds as a source of DNA for genetic studies. We used commercially available buccal swab kits to collect samples from 42 adult and 39 nestling (4‐ to 8‐day‐old) black‐capped chickadees (Poecile atricapillus) and from6 4‐day‐old nestling boreal chickadees (P. hudsonica). We comparedAuthorsColleen M. Handel, Lisa M. Pajot, Sandra L. Talbot, George K. Sage