Environmental Contaminants and Beak Deformities in Alaskan Chickadees Completed
Black-Capped Chickadee with Beak Deformity
A recent study by the U.S. Geological Survey (USGS) provides some of the first environmental contaminants data for a species of passerine bird (perching birds) in Alaska but leaves unanswered questions as to the cause of beak abnormalities found in this species.Beginning in the late 1990s, biologists and members of the public reported an unusual number of beak abnormalities among black-capped chickadees (Poecile atricapillus) in south-central Alaska. The frequency and distribution of observations increased during the ensuing decade, and subsequent studies have since revealed the highest rates of gross abnormalities reported in a wild bird population. To determine if environmental contaminants might be associated with beak deformities in Alaska, the USGS tested for a broad suite of inorganic and organic compounds in the tissues of affected and unaffected adult chickadees, their nestlings, and their eggs.
Results from toxicological analyses did not point to any individual compoundas a cause for the beak abnormalities in chickadees; however, affected birds had elevated levels of chromosomal damage, a biomarker that has been associated with exposure to environmental contaminants in other species. In addition, strong correlations between levels of chromosomal damage, and lipid concentrations of select organochlorine pesticides (such as dichlorodiphenyldichloroethylene [DDE]) suggest a possible relation between beak abnormalities and exposure to lipophilic contaminants. Further analyses of additional compounds, including polycyclic aromatic hydrocarbons, polychlorinated dibenzo-dioxins and polychlorinated dibenzofurans, and brominated flame retardants, are necessary to answer outstanding questions about the role of environmental contaminants in the development of beak deformities in black-capped chickadees. Although generally detected at low concentrations, organochlorine compounds were detected in chickadees at all life stages.
Chickadees are nonmigratory and have small home ranges, which indicates that the contaminants detected in the tissues of these birds are present in the local environment. This study provides contaminant data for a terrestrial passerine in North America and offers important baseline information for birds in Alaska.
This research was funded by the USGS Ecosystems Mission Area’s Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology), the USGS Wildlife: Terrestrial and Endangered Resources and Contaminant Biology Programs and the U.S. Fish and Wildlife Service Environmental Contaminants Program.
Below are other science projects associated with this project.
Ecologically-Driven Exposure Pathways Science Team
Beak Deformities in Landbirds
- Overview
A recent study by the U.S. Geological Survey (USGS) provides some of the first environmental contaminants data for a species of passerine bird (perching birds) in Alaska but leaves unanswered questions as to the cause of beak abnormalities found in this species.Beginning in the late 1990s, biologists and members of the public reported an unusual number of beak abnormalities among black-capped chickadees (Poecile atricapillus) in south-central Alaska. The frequency and distribution of observations increased during the ensuing decade, and subsequent studies have since revealed the highest rates of gross abnormalities reported in a wild bird population. To determine if environmental contaminants might be associated with beak deformities in Alaska, the USGS tested for a broad suite of inorganic and organic compounds in the tissues of affected and unaffected adult chickadees, their nestlings, and their eggs.
Sources/Usage: Public Domain. View Media DetailsTypical beak deformity in a black-capped chickadee (Poecile atricapillus) affected by avian keratin disorder in Anchorage, Alaska. Photo credit: Colleen Handel, USGS. Results from toxicological analyses did not point to any individual compoundas a cause for the beak abnormalities in chickadees; however, affected birds had elevated levels of chromosomal damage, a biomarker that has been associated with exposure to environmental contaminants in other species. In addition, strong correlations between levels of chromosomal damage, and lipid concentrations of select organochlorine pesticides (such as dichlorodiphenyldichloroethylene [DDE]) suggest a possible relation between beak abnormalities and exposure to lipophilic contaminants. Further analyses of additional compounds, including polycyclic aromatic hydrocarbons, polychlorinated dibenzo-dioxins and polychlorinated dibenzofurans, and brominated flame retardants, are necessary to answer outstanding questions about the role of environmental contaminants in the development of beak deformities in black-capped chickadees. Although generally detected at low concentrations, organochlorine compounds were detected in chickadees at all life stages.
Chickadees are nonmigratory and have small home ranges, which indicates that the contaminants detected in the tissues of these birds are present in the local environment. This study provides contaminant data for a terrestrial passerine in North America and offers important baseline information for birds in Alaska.
This research was funded by the USGS Ecosystems Mission Area’s Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology), the USGS Wildlife: Terrestrial and Endangered Resources and Contaminant Biology Programs and the U.S. Fish and Wildlife Service Environmental Contaminants Program.
- Science
Below are other science projects associated with this project.
Ecologically-Driven Exposure Pathways Science Team
The Ecologically-Driven Exposure Pathways Integrated Science Team identifies how ecological pathways and physiological processes within a single organism can alter exposure and toxicity of contaminants and pathogens and seek to understand outcomes at different scales from individuals to populations and ecosystems.Beak Deformities in Landbirds
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. - Publications