Bald Eagle
The bald eagle is truly and all-American bird – it is the only eagle unique to North America. It ranges over most of the continent, from the northern reaches of Alaska and Canada down to northern Mexico.
While our national symbol was in danger of extinction throughout most of its range 25 years ago, the bald eagle has made a tremendous comeback, its populations greatly improving in numbers, productivity, and security in recent years.
Male bald eagles generally measure 3 feet from head to tail, weigh 8 to 12 pounds, and have a wingspan of about 6 ½ feet. Females are larger, some reaching 14 pounds and having a wingspan of up to 8 feet. This striking raptor has large, pale eyes; a powerful yellow beak; and great, black talons. The distinctive white head and tail feathers appear only after the bird is 4 to 5 years old.
Life History Bald eagles sometimes live 30 years or longer in the wild, and even longer in captivity. They mate for life and build huge nests in the tops of large trees near rivers, lakes, estuaries, or other open water. Nests are often re-used year after year. With additions to the nests made annually, some may reach 10 feet across and weigh as much as 2,000 pounds. Although bald eagles may range over great distances, they usually return to nest within 100 miles of where they were raised.
Bald eagles normally lay two to three eggs once a year and the eggs hatch after about 35 days. The young eagles are flying within 3 months and are on their own about a month later. However, disease, lack of food, bad weather, or human interference can result in the deaths of many eaglets. Typically fewer than half will survive their first year.
Diet The staple of most bald eagle diets is fish, but they will feed on almost anything they can catch or find, including water birds, rodents, turtles, and carrion. In winter, northern birds migrate southward and gather in large numbers near open water areas where fish or other prey are plentiful.
Threats and Concerns Wildlife experts believe there may have been 12,500 to as many as 37,500 nesting bald eagle pairs in the lower 48 states when the bird was adopted as our national symbol in 1782. Since that time, the eagle population has suffered from a number of factors including intentional persecution and degradation of its habitat. In 1940, noting that the national bird was “threatened with extinction,” Congress passed the Bald Eagle Protection Act, which made it illegal to kill, harass, possess (without a permit), or sell bald eagles. By the early 1960s there were fewer than 450 nesting pairs in the lower 48 states. In 1967, bald eagles were officially declared an endangered species under the Endangered Species Preservation Act, a law that preceded the Endangered Species Act (ESA) of 1973. This designation applied to all bald eagles in areas of the United States south of the 40th parallel (see map below).
From the 1940s to the 1960s, the greatest threat to the bald eagle’s existence arose from the widespread use of DDT and other pesticides. DDT was sprayed on croplands throughout the country and its residues washed into lakes and streams. Once in the water, the toxic chemical was absorbed by small animals that were eaten by fish. The contaminated fish, in turn, were consumed by bald eagles, which gradually built up dangerous levels of the pesticide.
DDT interfered with the bald eagle’s ability to develop strong shells for its eggs. As a result, bald eagles and many other bird species began laying eggs with shells so thin they often broke during incubation or otherwise failed to hatch. Their reproduction disrupted, bald eagle populations plummeted. As the dangers of DDT became known, in large part due to Rachel Carson’s famous book Silent Spring, this chemical was banned for most uses in the U.S. in 1972. Federal and state government agencies, along with private organizations, successfully sought to alert the public about the bald eagle’s plight and to protect its habitat from further damage.
Bald eagles have few natural enemies, though males are sometimes mortally injured during territorial disputes. In general, they simply need tall, mature trees in which to construct their large nests and clean waters where they can find food. Though eagles seem to prefer an environment of quiet isolation, in recent years many eagles have demonstrated remarkable tolerance of human activities and are thriving in the face of the development that has impacted so much of their habitat.
Recovery Efforts in Georgia In an effort to restore a healthy bald eagle population to this state, Georgia Department of Natural Resources, Wildlife Resources Division biologists used a method called hacking, a procedure adapted from the sport of falconry. At 8 weeks of age, nestling eaglets, obtained from captive breeding facilities or from wild nests in areas where surplus birds were available, were placed on manmade towers located in remote areas of suitable habitat. The eaglets were kept in an enclosure and fed by the biologists who stayed out of sight. When the birds were capable of flight, at about 12 weeks old, the enclosure around the artificial nest was opened and the birds were free to leave. Food was still provided at the release site until the birds learned to fend for themselves in the wild.
With hacking and other recovery methods, as well as habitat improvement and the banning of DDT, bald eagle populations have steadily increased. There are now nearly 4,500 adult bald eagle nesting pairs and an unknown number of young and subadults in the conterminous United States. In Georgia, there were no known nesting pairs through most of the 1970s, but since then the population has steadily increased to 83 known nesting pairs in 2004.
In 1995 the USFWS downlisted the bald eagle from endangered to threatened to reflect the species’ improved status. In 1999 the USFWS proposed to remove the bald eagle from protection under the ESA. The bald eagle has not yet been de-listed, but that will probably happen soon.
While habitat loss still remains a threat to the bald eagle’s full recovery, most experts agree that its status to date is encouraging. Soon the sight of our national symbol soaring the skies may be available for most Americans to once again behold.
The bald eagle is truly and all-American bird – it is the only eagle unique to North America. It ranges over most of the continent, from the northern reaches of Alaska and Canada down to northern Mexico.
While our national symbol was in danger of extinction throughout most of its range 25 years ago, the bald eagle has made a tremendous comeback, its populations greatly improving in numbers, productivity, and security in recent years.
Male bald eagles generally measure 3 feet from head to tail, weigh 8 to 12 pounds, and have a wingspan of about 6 ½ feet. Females are larger, some reaching 14 pounds and having a wingspan of up to 8 feet. This striking raptor has large, pale eyes; a powerful yellow beak; and great, black talons. The distinctive white head and tail feathers appear only after the bird is 4 to 5 years old.
Life History Bald eagles sometimes live 30 years or longer in the wild, and even longer in captivity. They mate for life and build huge nests in the tops of large trees near rivers, lakes, estuaries, or other open water. Nests are often re-used year after year. With additions to the nests made annually, some may reach 10 feet across and weigh as much as 2,000 pounds. Although bald eagles may range over great distances, they usually return to nest within 100 miles of where they were raised.
Bald eagles normally lay two to three eggs once a year and the eggs hatch after about 35 days. The young eagles are flying within 3 months and are on their own about a month later. However, disease, lack of food, bad weather, or human interference can result in the deaths of many eaglets. Typically fewer than half will survive their first year.
Diet The staple of most bald eagle diets is fish, but they will feed on almost anything they can catch or find, including water birds, rodents, turtles, and carrion. In winter, northern birds migrate southward and gather in large numbers near open water areas where fish or other prey are plentiful.
Threats and Concerns Wildlife experts believe there may have been 12,500 to as many as 37,500 nesting bald eagle pairs in the lower 48 states when the bird was adopted as our national symbol in 1782. Since that time, the eagle population has suffered from a number of factors including intentional persecution and degradation of its habitat. In 1940, noting that the national bird was “threatened with extinction,” Congress passed the Bald Eagle Protection Act, which made it illegal to kill, harass, possess (without a permit), or sell bald eagles. By the early 1960s there were fewer than 450 nesting pairs in the lower 48 states. In 1967, bald eagles were officially declared an endangered species under the Endangered Species Preservation Act, a law that preceded the Endangered Species Act (ESA) of 1973. This designation applied to all bald eagles in areas of the United States south of the 40th parallel (see map below).
From the 1940s to the 1960s, the greatest threat to the bald eagle’s existence arose from the widespread use of DDT and other pesticides. DDT was sprayed on croplands throughout the country and its residues washed into lakes and streams. Once in the water, the toxic chemical was absorbed by small animals that were eaten by fish. The contaminated fish, in turn, were consumed by bald eagles, which gradually built up dangerous levels of the pesticide.
DDT interfered with the bald eagle’s ability to develop strong shells for its eggs. As a result, bald eagles and many other bird species began laying eggs with shells so thin they often broke during incubation or otherwise failed to hatch. Their reproduction disrupted, bald eagle populations plummeted. As the dangers of DDT became known, in large part due to Rachel Carson’s famous book Silent Spring, this chemical was banned for most uses in the U.S. in 1972. Federal and state government agencies, along with private organizations, successfully sought to alert the public about the bald eagle’s plight and to protect its habitat from further damage.
Bald eagles have few natural enemies, though males are sometimes mortally injured during territorial disputes. In general, they simply need tall, mature trees in which to construct their large nests and clean waters where they can find food. Though eagles seem to prefer an environment of quiet isolation, in recent years many eagles have demonstrated remarkable tolerance of human activities and are thriving in the face of the development that has impacted so much of their habitat.
Recovery Efforts in Georgia In an effort to restore a healthy bald eagle population to this state, Georgia Department of Natural Resources, Wildlife Resources Division biologists used a method called hacking, a procedure adapted from the sport of falconry. At 8 weeks of age, nestling eaglets, obtained from captive breeding facilities or from wild nests in areas where surplus birds were available, were placed on manmade towers located in remote areas of suitable habitat. The eaglets were kept in an enclosure and fed by the biologists who stayed out of sight. When the birds were capable of flight, at about 12 weeks old, the enclosure around the artificial nest was opened and the birds were free to leave. Food was still provided at the release site until the birds learned to fend for themselves in the wild.
With hacking and other recovery methods, as well as habitat improvement and the banning of DDT, bald eagle populations have steadily increased. There are now nearly 4,500 adult bald eagle nesting pairs and an unknown number of young and subadults in the conterminous United States. In Georgia, there were no known nesting pairs through most of the 1970s, but since then the population has steadily increased to 83 known nesting pairs in 2004.
In 1995 the USFWS downlisted the bald eagle from endangered to threatened to reflect the species’ improved status. In 1999 the USFWS proposed to remove the bald eagle from protection under the ESA. The bald eagle has not yet been de-listed, but that will probably happen soon.
While habitat loss still remains a threat to the bald eagle’s full recovery, most experts agree that its status to date is encouraging. Soon the sight of our national symbol soaring the skies may be available for most Americans to once again behold.
