A 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 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Caroline R Van Hemert, Ph.D. (Former Employee)
Science and Products
Wildlife Disease and Environmental Health in Alaska
Links Related to Beak Deformity Research
Literature Cited for Beak Deformities
Possible Causes for Beak Deformities
Physical Description of Beak Deformities
Prevalence, Distribution and Timing of Beak Deformities in Birds
Beak Deformity's Effects on Birds
Background of Beak Deformity Research
Beak Deformities in Landbirds
Species Affected by Beak Deformities
Harmful Algal Bloom Toxins in Alaska Seabirds
Landbird Research in Alaska
Cryptosporidium and Giardia Occurrence Data in Wildlife from Arctic Alaska, 2012-2017
USGS National Wildlife Health Center necropsy results to determine cause of illness/death for seabirds collected in Alaska from January 1, 2017 through December 31, 2021
Serological Survey Data for Francisella tularensis and Brucella spp. Exposure in Wildlife on the Arctic Coastal Plain of Alaska
Tissue Concentrations and Congener Profiles of Harmful Algal Toxins in Seabirds, Forage Fish, and Other Organisms
Dataset: Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
Data Associated with Poecivirus Testing of Individual Birds with Beak Deformities
SUPERSEDED: Data Associated with Algal Toxin Testing of Seabirds from the Bering and Chukchi Seas, 2017
SUPERSEDED: Data Associated with Algal Toxin Testing of Common Murres (Uria aalge) and Forage Fish in Alaska, 2015–2017
Blood Parasite Infection Data from Northwestern Crows (Corvus caurinus), Alaska, 2007-2008
Serological data on influenza A from birds and mammals on the Arctic Coastal Plain of northern Alaska, 2011-2017
Genetic Data Associated with Avian Keratin Disorder and Poecivirus in Black-capped Chickadees, Alaska, 2001-2017

A 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 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Increased pathogen exposure of a marine apex predator over three decades
Giardia and Cryptosporidium in resident wildlife species in Arctic Alaska
Partnering in search of answers: Seabird die-offs in the Bering and Chukchi Seas
A serological survey of Francisella tularensis exposure in wildlife on the Arctic Coastal Plain of Alaska
Paralytic shellfish toxins associated with Arctic Tern mortalities in Alaska
Harmful algal blooms in the Alaskan Arctic: An emerging threat as oceans warm
Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
Alaska Landbird Conservation Plan
U.S. Geological Survey Arctic ecosystem assessments
Investigation of algal toxins in a multispecies seabird die-off in the Bering and Chukchi seas
Poecivirus is present in individuals with beak deformities in seven species of North American birds
Cryptic and extensive hybridization between ancient lineages of American crows
Science and Products
Wildlife Disease and Environmental Health in Alaska
Links Related to Beak Deformity Research
Literature Cited for Beak Deformities
Possible Causes for Beak Deformities
Physical Description of Beak Deformities
Prevalence, Distribution and Timing of Beak Deformities in Birds
Beak Deformity's Effects on Birds
Background of Beak Deformity Research
Beak Deformities in Landbirds
Species Affected by Beak Deformities
Harmful Algal Bloom Toxins in Alaska Seabirds
Landbird Research in Alaska
Cryptosporidium and Giardia Occurrence Data in Wildlife from Arctic Alaska, 2012-2017
USGS National Wildlife Health Center necropsy results to determine cause of illness/death for seabirds collected in Alaska from January 1, 2017 through December 31, 2021
Serological Survey Data for Francisella tularensis and Brucella spp. Exposure in Wildlife on the Arctic Coastal Plain of Alaska
Tissue Concentrations and Congener Profiles of Harmful Algal Toxins in Seabirds, Forage Fish, and Other Organisms
Dataset: Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
Data Associated with Poecivirus Testing of Individual Birds with Beak Deformities
SUPERSEDED: Data Associated with Algal Toxin Testing of Seabirds from the Bering and Chukchi Seas, 2017
SUPERSEDED: Data Associated with Algal Toxin Testing of Common Murres (Uria aalge) and Forage Fish in Alaska, 2015–2017
Blood Parasite Infection Data from Northwestern Crows (Corvus caurinus), Alaska, 2007-2008
Serological data on influenza A from birds and mammals on the Arctic Coastal Plain of northern Alaska, 2011-2017
Genetic Data Associated with Avian Keratin Disorder and Poecivirus in Black-capped Chickadees, Alaska, 2001-2017

A 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 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
A 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 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds.
Increased pathogen exposure of a marine apex predator over three decades
Giardia and Cryptosporidium in resident wildlife species in Arctic Alaska
Partnering in search of answers: Seabird die-offs in the Bering and Chukchi Seas
A serological survey of Francisella tularensis exposure in wildlife on the Arctic Coastal Plain of Alaska
Paralytic shellfish toxins associated with Arctic Tern mortalities in Alaska
Harmful algal blooms in the Alaskan Arctic: An emerging threat as oceans warm
Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
Alaska Landbird Conservation Plan
U.S. Geological Survey Arctic ecosystem assessments
Investigation of algal toxins in a multispecies seabird die-off in the Bering and Chukchi seas
Poecivirus is present in individuals with beak deformities in seven species of North American birds
Cryptic and extensive hybridization between ancient lineages of American crows
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government