Black-capped Chickadee with a deformed crossed beak
Black-capped Chickadee with a deformed crossed beakA Black-capped Chickadee with a beak that has grown long and crossed
Large numbers of Black-capped Chickadees with abnormal beaks were reported in south-central Alaska in the late 1990s. More recently, similar beak deformities have appeared in other species throughout the state. At least 30 Alaskan bird species are affected and the geographic extent of the problem appears to be growing. In addition to Alaskan observations, we have received increasing numbers of reports from other parts of North America and Europe.
Return to Ecosystems >> Terrestrial Ecosystems or Wildlife Disease and Environmental Health >> Beak Deformities
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The most commonly observed physical abnormalities among Alaskan birds are overgrown or crossed beaks. The severity of the deformities varies, ranging from a nearly indiscernible “overbite” to beaks that are more than double their normal length. The upper and lower parts of the beak are also frequently crossed or gapped. Affected birds often have difficulty foraging and preening and may not be able to keep themselves warm and well-fed during cold winter months. Although some birds with beak deformities breed successfully, they typically encounter more challenges than normal birds.
Typically, beak deformities are relatively rare among adult birds, with most published reports being of single anomalous individuals (Craves 1994). However, in Alaska, the prevalence of beak deformities in Black-capped Chickadees and American Crows is much higher than typical background levels for a normal, wild population. Based on reports from around the state, deformities in other Alaskan species also appear to be unusually common and warrant further investigation.
Below are other science projects associated with this project.
Beak Deformities in Landbirds
Over the past 26 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. If...
Links Related to Beak Deformity Research
Links, videos, and news articles related to beak deformity research.
Possible Causes of Beak Deformities
Beak deformities can be caused by a variety of factors, including contaminants, nutritional deficiencies, disease, parasites, blunt trauma, or genetic abnormalities. In 2016, we identified a novel picornavirus (Poecivirus) in Black-capped Chickadees with avian keratin disorder (AKD). Our results suggest that Poecivirus is the most likely factor responsible for beak deformities in Alaskan birds...
Literature Cited for Beak Deformities
Literature Cited in the Beak Deformity web pages
Physical Description of Beak Deformities
The most commonly observed physical abnormalities among Alaskan birds are overgrown or crossed beaks.
Prevalence, Distribution and Timing of Beak Deformities in Birds
The rates of beak deformities documented in Black-capped Chickadees and American Crows in Alaska are the highest ever recorded within a wild bird population anywhere.
Effects of Beak Deformities on Birds
Birds with beak deformities often have difficulty foraging and preening and may not be able to keep themselves warm and well-fed during cold winter months. Although some birds with beak deformities breed successfully, they typically encounter more challenges than normal birds.
Species Affected by Beak Deformities
At least 30 Alaskan bird species are affected by beak deformities and the geographic extent of the problem appears to be growing. In addition to Alaskan observations, we have received increasing numbers of reports from other parts of North America and Europe.
Below are multimedia items associated with this project.
Black-capped Chickadee with a deformed crossed beak
Black-capped Chickadee with a deformed crossed beak
Black-capped Chickadee with a deformed crossed beakA Black-capped Chickadee with a beak that has grown long and crossed
Red-breasted Nuthatch with an elongated deformed beak
Red-breasted Nuthatch with an elongated deformed beakA female Red-breasted Nuthatch with an elongated deformed beak. It was captured in Anchorage as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues.
Red-breasted Nuthatch with an elongated deformed beak
Red-breasted Nuthatch with an elongated deformed beakA female Red-breasted Nuthatch with an elongated deformed beak. It was captured in Anchorage as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues.
Boreal Chickadee with a mildly deformed beak
A Boreal Chickadee with a mildly deformed beak.
A Boreal Chickadee with a mildly deformed beak.
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight. Over the past 26 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight. Over the past 26 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight
Black-capped Chickadee captured at an Anchorage banding station
Black-capped Chickadee captured at an Anchorage banding stationA Black-capped Chickadee with a normal beak captured at an Anchorage banding station.
Black-capped Chickadee captured at an Anchorage banding station
Black-capped Chickadee captured at an Anchorage banding stationA Black-capped Chickadee with a normal beak captured at an Anchorage banding station.
Black-capped Chickadee with a mildly deformed beak
Black-capped Chickadee with a mildly deformed beakA Black-capped Chickadee with an upper beak slightly longer than the lower beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a mildly deformed beak
Black-capped Chickadee with a mildly deformed beakA Black-capped Chickadee with an upper beak slightly longer than the lower beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a deformed beak that has grown long and curved down
Black-capped Chickadee with a deformed beak that has grown long and curved downA Black-capped Chickadee with a beak that has grown long and curved down. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a deformed beak that has grown long and curved down
Black-capped Chickadee with a deformed beak that has grown long and curved downA Black-capped Chickadee with a beak that has grown long and curved down. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a crossed beak on a branch
Black-capped Chickadee with a crossed beak on a branchBlack-capped Chickadee with a crossed beak on a branch.
Black-capped Chickadee with a crossed beak on a branch
Black-capped Chickadee with a crossed beak on a branchBlack-capped Chickadee with a crossed beak on a branch.
Normal Black-capped Chickadee
Normal Black-capped Chickadee
Normal Black-capped Chickadee
Northwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska
Northwestern Crow with deformed top beak in Auke Bay, Juneau, AlaskaNorthwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska. Avian keratin disorder (AKD) is a disease 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.
Northwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska
Northwestern Crow with deformed top beak in Auke Bay, Juneau, AlaskaNorthwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a long down-curved elongated top beak
Black-capped Chickadee with a long down-curved elongated top beakBlack-capped Chickadee with a long down-curved elongated top beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a long down-curved elongated top beak
Black-capped Chickadee with a long down-curved elongated top beakBlack-capped Chickadee with a long down-curved elongated top beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with an elongated and decurved maxilla
Black-capped Chickadee with an elongated and decurved maxillaBlack-capped Chickadee with an elongated and decurved maxilla.
Black-capped Chickadee with an elongated and decurved maxilla
Black-capped Chickadee with an elongated and decurved maxillaBlack-capped Chickadee with an elongated and decurved maxilla.
Northwestern Crow with an elongated lower beak
Northwestern Crow with an elongated lower beak. It was captured as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease 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.
Northwestern Crow with an elongated lower beak. It was captured as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with elongated upper beak
Black-capped Chickadee with elongated upper beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with elongated upper beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with upper long, curved down beak and crossed
Black-capped Chickadee with upper long, curved down beak and crossedBlack-capped Chickadee with upper long, curved down beak and crossed. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with upper long, curved down beak and crossed
Black-capped Chickadee with upper long, curved down beak and crossedBlack-capped Chickadee with upper long, curved down beak and crossed. Avian keratin disorder (AKD) is a disease 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.
Large numbers of Black-capped Chickadees with abnormal beaks were reported in south-central Alaska in the late 1990s. More recently, similar beak deformities have appeared in other species throughout the state. At least 30 Alaskan bird species are affected and the geographic extent of the problem appears to be growing. In addition to Alaskan observations, we have received increasing numbers of reports from other parts of North America and Europe.
Return to Ecosystems >> Terrestrial Ecosystems or Wildlife Disease and Environmental Health >> Beak Deformities
Media
Sources/Usage: Public Domain. View Media Details
The most commonly observed physical abnormalities among Alaskan birds are overgrown or crossed beaks. The severity of the deformities varies, ranging from a nearly indiscernible “overbite” to beaks that are more than double their normal length. The upper and lower parts of the beak are also frequently crossed or gapped. Affected birds often have difficulty foraging and preening and may not be able to keep themselves warm and well-fed during cold winter months. Although some birds with beak deformities breed successfully, they typically encounter more challenges than normal birds.
Typically, beak deformities are relatively rare among adult birds, with most published reports being of single anomalous individuals (Craves 1994). However, in Alaska, the prevalence of beak deformities in Black-capped Chickadees and American Crows is much higher than typical background levels for a normal, wild population. Based on reports from around the state, deformities in other Alaskan species also appear to be unusually common and warrant further investigation.
Below are other science projects associated with this project.
Beak Deformities in Landbirds
Over the past 26 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. If...
Links Related to Beak Deformity Research
Links, videos, and news articles related to beak deformity research.
Possible Causes of Beak Deformities
Beak deformities can be caused by a variety of factors, including contaminants, nutritional deficiencies, disease, parasites, blunt trauma, or genetic abnormalities. In 2016, we identified a novel picornavirus (Poecivirus) in Black-capped Chickadees with avian keratin disorder (AKD). Our results suggest that Poecivirus is the most likely factor responsible for beak deformities in Alaskan birds...
Literature Cited for Beak Deformities
Literature Cited in the Beak Deformity web pages
Physical Description of Beak Deformities
The most commonly observed physical abnormalities among Alaskan birds are overgrown or crossed beaks.
Prevalence, Distribution and Timing of Beak Deformities in Birds
The rates of beak deformities documented in Black-capped Chickadees and American Crows in Alaska are the highest ever recorded within a wild bird population anywhere.
Effects of Beak Deformities on Birds
Birds with beak deformities often have difficulty foraging and preening and may not be able to keep themselves warm and well-fed during cold winter months. Although some birds with beak deformities breed successfully, they typically encounter more challenges than normal birds.
Species Affected by Beak Deformities
At least 30 Alaskan bird species are affected by beak deformities and the geographic extent of the problem appears to be growing. In addition to Alaskan observations, we have received increasing numbers of reports from other parts of North America and Europe.
Below are multimedia items associated with this project.
Black-capped Chickadee with a deformed crossed beak
Black-capped Chickadee with a deformed crossed beakA Black-capped Chickadee with a beak that has grown long and crossed
Black-capped Chickadee with a deformed crossed beak
Black-capped Chickadee with a deformed crossed beakA Black-capped Chickadee with a beak that has grown long and crossed
Red-breasted Nuthatch with an elongated deformed beak
Red-breasted Nuthatch with an elongated deformed beakA female Red-breasted Nuthatch with an elongated deformed beak. It was captured in Anchorage as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues.
Red-breasted Nuthatch with an elongated deformed beak
Red-breasted Nuthatch with an elongated deformed beakA female Red-breasted Nuthatch with an elongated deformed beak. It was captured in Anchorage as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues.
Boreal Chickadee with a mildly deformed beak
A Boreal Chickadee with a mildly deformed beak.
A Boreal Chickadee with a mildly deformed beak.
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight. Over the past 26 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight. Over the past 26 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight
Black-capped Chickadee with lower elongated and upper curved beak
Black-capped Chickadee with lower elongated and upper curved beakA Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight
Black-capped Chickadee captured at an Anchorage banding station
Black-capped Chickadee captured at an Anchorage banding stationA Black-capped Chickadee with a normal beak captured at an Anchorage banding station.
Black-capped Chickadee captured at an Anchorage banding station
Black-capped Chickadee captured at an Anchorage banding stationA Black-capped Chickadee with a normal beak captured at an Anchorage banding station.
Black-capped Chickadee with a mildly deformed beak
Black-capped Chickadee with a mildly deformed beakA Black-capped Chickadee with an upper beak slightly longer than the lower beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a mildly deformed beak
Black-capped Chickadee with a mildly deformed beakA Black-capped Chickadee with an upper beak slightly longer than the lower beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a deformed beak that has grown long and curved down
Black-capped Chickadee with a deformed beak that has grown long and curved downA Black-capped Chickadee with a beak that has grown long and curved down. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a deformed beak that has grown long and curved down
Black-capped Chickadee with a deformed beak that has grown long and curved downA Black-capped Chickadee with a beak that has grown long and curved down. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a crossed beak on a branch
Black-capped Chickadee with a crossed beak on a branchBlack-capped Chickadee with a crossed beak on a branch.
Black-capped Chickadee with a crossed beak on a branch
Black-capped Chickadee with a crossed beak on a branchBlack-capped Chickadee with a crossed beak on a branch.
Normal Black-capped Chickadee
Normal Black-capped Chickadee
Normal Black-capped Chickadee
Northwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska
Northwestern Crow with deformed top beak in Auke Bay, Juneau, AlaskaNorthwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska. Avian keratin disorder (AKD) is a disease 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.
Northwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska
Northwestern Crow with deformed top beak in Auke Bay, Juneau, AlaskaNorthwestern Crow with deformed top beak in Auke Bay, Juneau, Alaska. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a long down-curved elongated top beak
Black-capped Chickadee with a long down-curved elongated top beakBlack-capped Chickadee with a long down-curved elongated top beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with a long down-curved elongated top beak
Black-capped Chickadee with a long down-curved elongated top beakBlack-capped Chickadee with a long down-curved elongated top beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with an elongated and decurved maxilla
Black-capped Chickadee with an elongated and decurved maxillaBlack-capped Chickadee with an elongated and decurved maxilla.
Black-capped Chickadee with an elongated and decurved maxilla
Black-capped Chickadee with an elongated and decurved maxillaBlack-capped Chickadee with an elongated and decurved maxilla.
Northwestern Crow with an elongated lower beak
Northwestern Crow with an elongated lower beak. It was captured as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease 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.
Northwestern Crow with an elongated lower beak. It was captured as part of the beak deformity research project. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with elongated upper beak
Black-capped Chickadee with elongated upper beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with elongated upper beak. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with upper long, curved down beak and crossed
Black-capped Chickadee with upper long, curved down beak and crossedBlack-capped Chickadee with upper long, curved down beak and crossed. Avian keratin disorder (AKD) is a disease 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.
Black-capped Chickadee with upper long, curved down beak and crossed
Black-capped Chickadee with upper long, curved down beak and crossedBlack-capped Chickadee with upper long, curved down beak and crossed. Avian keratin disorder (AKD) is a disease 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.