Endangered Species Protection: The Fall and Rise of the Bald Eagle
(Originally published by National Geographic News on June 20, 2002. Updated on June 28, 2007.)

By Robert Winkler
About the Author

wo hundred and twenty-five years ago—on June 20, 1782—the bald eagle became an American icon when the Second Continental Congress decided to use its image on The Great Seal.

The Congress had considered another bird—not the wild turkey championed by Benjamin Franklin, but a fanciful eagle inspired by the imperial eagle of the Eastern Hemisphere. In altering the earlier design, Charles Thomson, secretary of the Congress, substituted the native bald eagle suspended on spread wings, "to denote," he said, "that the United States of America ought to rely on their own Virtue."

Incensed by the decision, Ben Franklin would become the bald eagle's greatest detractor. Viewing the national bird through overly anthropomorphic spectacles, he judged it immoral because it pirated fish from the osprey, cowardly because it retreated from the aggressive, yet comparatively small, Eastern kingbird.



Time, of course, would prove Franklin wrong. In the minds of many Americans, North America's second largest bird of prey (after the California condor) is a fitting symbol for a republic founded on lofty democratic principles. Its image graces currency, stamps, art, architecture, and corporate logos. As the subject of more than 2,500 published papers and books, the bald eagle, moreover, is probably the most extensively studied North American bird.

Attitudes like Franklin's, however, prevailed for the eagle's first 175 years as the national bird. To settlers, the eagle's seven-foot wingspan, fierce gaze, and crushing talons symbolized a competitor bent on depriving them of fish and game, and on depleting their livestock. They also killed eagles for sport. Meanwhile, Native Americans trapped and killed eagles to obtain ceremonial feathers. 

While shooting, trapping, and poisoning took their toll, human population growth and land-clearing along navigable rivers and estuaries destroyed prime eagle habitat. Before European settlement, 250,000 to 500,000 bald eagles ranged across North America, and as late as the mid-1800s, wintering eagles reportedly fished the waters off New York's Manhattan Island by the hundreds, sometimes devouring their catch in Central Park.

"The relationship between human development and the absence of bald eagles has been documented in various places across the country," said David A. Buehler, author of the bald eagle monograph in the recently published Birds of North America: Life Histories for the 21st Century.

"In general," Buehler added, "eagles avoid developed areas, where their risk of mortality rises. Shooting, trapping, poisoning, collisions with man-made structures, scarcity of prey, and poor nesting and roosting habitat are among the dangers. I think it was the human persecution, however, that ultimately 'taught' eagles in an adaptive sense to avoid people."

With the westward expansion of human settlements, persecution and habitat destruction whittled away at eagle numbers. By 1940, the bird's rarity compelled Congress to pass the Bald Eagle Protection Act, which outlawed the killing and disturbing of eagles, as well as the possession of eagle parts, including feathers, eggs, and nests.

After studies showed that salmon populations were not harmed by eagle predation, this law ended a bounty system in Alaska that claimed 128,000 eagles between 1917 and 1952. The actual number of slaughtered eagles probably exceeded 150,000, since many bounties were never collected.

For a long time, the Bald Eagle Protection Act, designed also to protect the beleaguered golden eagle, was not strictly enforced. At one Wyoming ranch, for example, eagles were systematically shot for their perceived threat to livestock. According to a 1970 report, more than 770 bald eagles were shot at this ranch, and hunters were paid $25 for each carcass. Responding to a public outcry over such flagrant violations, the government began to crack down.

Just when it was finally benefiting from legal protections, the bald eagle took a heavy blow from DDT, a pesticide that enters the food chain and causes reproductive failure. Widely used after World War II to control mosquitoes and other insects, DDT was wreaking havoc among many bird species. Raptors were particularly vulnerable—over time, animals higher in the food chain accumulate more DDT.

New research on the effects of DDT challenges the long-held belief that eggshell thinning was the primary cause of reproductive failure in birds. "The thinning did occur," said Buehler, "but it was probably not actually responsible for the reproductive failure."

Rachel Carson exposed DDT poisoning in her 1962 book, Silent Spring. The pesticide was banned in the United States in 1972, but by then, over a period of about 20 years, it had done grave damage. The bald eagle hit a low point in 1963, when a nesting survey in the lower 48 states found only 417 pairs.

The most sweeping protections took effect in 1978, when, under the Endangered Species Act of 1973, the bald eagle was listed as endangered in 43 of the lower 48 states and as threatened in the rest. The 50,000 to 70,000 bald eagles in Alaska are not at risk; therefore, they have not received protection under the act.

Enforcement of the Endangered Species Act; cooperation among wildlife agencies, conservation organizations, and Native American tribes on captive-breeding programs and reintroductions; and citizen support led to a fourfold increase in the Lower-48 breeding population between the mid-1970s and mid-1990s. In 1995, the U.S. Fish and Wildlife Service downgraded the bald eagle's endangered-species status to "threatened" in all of these states. Plans to remove the eagle from the threatened list were announced in 1999, but the service stalled until 2005, when a Minnesota landowner sued to force a decision. An active bald eagle nest on his undeveloped property had long precluded him from building homes there. The court ruled in the landowner's favor, ordering the Fish and Wildlife Service to make a final decision by June 29, 2007.

With the number of nesting pairs at 9,789 as of 2006—every state in the Lower 48 has a breeding population—the service "delisted" the bald eagle entirely on June 28, 2007, though it continues to work on details of post-delisting management. Citing the eagle's 25-fold population growth over the last 40 years, Dirk Kempthorne, secretary of the Department of the Interior, which oversees the Fish and Wildlife Service, announced the decision at the Jefferson Memorial in Washington, DC.

"Based on its dramatic recovery, it is my honor to announce the Department of the Interior's decision to remove the American Bald Eagle from the Endangered Species List," he said.

The ceremony's honored guest: a 19-year-old male bald eagle named Challenger, who flew across the memorial steps on cue, returning on six-foot wings to the forearm of Al Cecere, president of the American Eagle Foundation. Challenger had traveled to Washington by van from the foundation's headquarters at Dollywood in Pigeon Forge, Tennessee. Orphaned when blown from his nest in a windstorm, Challenger was hand-raised, which made him "human socialized." He remains in captivity because two release attempts failed—instead of fending for himself, Challenger both times approached humans to beg for food, proving he could not survive in the wild.

"From this point forward," said Kempthorne, "we will work to ensure that the eagle never again needs the protection of the Endangered Species Act."

The Center for Biological Diversity, an Arizona-based conservation group, estimates the 2007 breeding population of bald eagles at 11,400 pairs, nearly a 13 percent increase over the Fish and Wildlife Service's 2006 census figure. In a statement issued by the White House press secretary, President Bush called the eagle's recovery an "overwhelming success." He added, ''This great conservation achievement means more and more Americans across the Nation will enjoy the thrill of seeing bald eagles soar. What a wonderful way to celebrate this Fourth of July.''

The bald eagle joins 20 species whose recovery has led to their removal from the Endangered Species List. Among this small fraternity are the American alligator, Yellowstone grizzly bear, American peregrine falcon, Aleutian Canada goose, brown pelican, and gray wolf. At last count there were 1,177 animals and 749 plants still on the Endangered Species List. Species are added periodically—a new candidate is the polar bear, which the Fish and Wildlife Service, acting under duress, plans to list as a threatened species because global warming has severely reduced sea ice that the bear relies on for survival.

Between 1987 and 2004, the Western Hudson Bay polar bear population declined from 1,200 to fewer than 950 due to the melting of sea ice. In 2006, winter sea ice shrank by more than 115,000 square miles, an area roughly the size of Arizona. The Center for Biological Diversity, the Natural Resources Defense Council, and Greenpeace successfully sued the federal government to force action on the polar bear's predicament.

Eagles remain protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act. To banish any impression that delisting opens the door to mistreatment, and to ensure that people understand what it means to disturb an eagle, which the Eagle Act prohibits, new regulatory language defines "disturb" as " to agitate or bother a bald or golden eagle to a degree that causes, or is likely to cause, based on the best scientific information available, 1) injury to an eagle, 2) a decrease in its productivity, by substantially interfering with normal breeding, feeding, or sheltering behavior, or 3) nest abandonment, by substantially interfering with normal breeding, feeding, or sheltering behavior."

Still, the Center for Biological Diversity argues that completely lifting endangered species protection will jeopardize eagle habitat. Kieran Suckling, the center's endangered species expert, points out that the Bald and Golden Eagle Protection Act, a 67-year-old law, won't keep real estate developers from destroying previously protected land and water that eagles need for future population growth.

"The Department of Interior rejected a U.S. Fish and Wildlife Service proposal to interpret the Bald and Golden Eagle Protection Act in a way that directly protected eagle habitat," said Suckling. "Thus, developers can destroy important habitat if eagles are not nesting there in a particular year, or even if they have just migrated away for the winter."

The Fish and Wildlife Service counters that, although the Bald Eagle Protection Act of 1940 originally applied to shooting, killing, and hunting, the U.S. Congress has amended the law over the years to broaden its protective mantle and to include golden eagles and eagles in Alaska. According to service spokesman Nicholas Throckmorton, "Now, the service is working—by defining 'disturb,' issuing management guidelines, and considering a managed-take permit—to make this law relevant in today's world."

On June 5, 2007, the service opened a 90-day public comment period on a proposal to authorize limited “take” of bald and golden eagles through a permit process. Similar to the "incidental take permit" issued under the Endangered Species Act, the new permit would shield from prosecution people who unintentionally harm eagles while otherwise acting lawfully, so long as they agree to implement specified conservation measures.

The proposal includes a provision that in certain instances would allow removal of eagle nests, such as when a nest's location (say, near an airport runway) poses a safety risk to people or to the eagles themselves. At present, the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act prohibit any form of taking—the killing, selling, or otherwise harming of eagles, including harm to their nests or eggs. It's unclear whether the Minnesota landowner whose lawsuit prompted the delisting can now build homes on his eagle-occupied property.

The current bald eagle population is estimated at over 100,000; more than half the birds are found in Alaska and British Columbia. Eagles will never be as abundant as they were before the arrival of Europeans. Nonetheless, their comeback is one of the great conservation stories.

Their continued success requires vigilance: Threats include oil spills—the Exxon Valdez spill in 1989 killed some 250 eagles, and the local population did not recover until 1995. As humans encroach on eagle habitat, and vice versa, collisions with made-made structures and with vehicles are expected to rise.

Meanwhile, the National Wildlife Health Center in Madison, Wisconsin is monitoring outbreaks of avian vacuolar myelinopathy (AVM), a fatal neurological disease that first showed up in bald eagles and American coots wintering at DeGray Lake in Arkansas in 1994. Twenty-nine eagles died that year; the disease has since been identified at 11 lakes and reservoirs in 5 states. In total it has killed more than 100 eagles and thousands of coots, as well as Canada geese, mallards, ring-necked ducks, buffleheads, killdeer, and great horned owls. Eagles get the disease after consuming affected coots and waterfowl.

Hydrilla verticillata, an invasive aquatic plant introduced to the United States in the 1960s, has been linked to AVM. At reservoirs where AVM has occurred, a newly discovered cyanobacterial species has been found to cover as much as 95 percent of hydrilla leaf surfaces. The cyanobacteria is believed to produce a neurotoxin that causes AVM in water birds. After feeding on contaminated hydrilla, these birds can pass along the disease if eagles catch and eat them or scavenge their carcasses. In late stages of the disease, infected eagles look ruffled and may fly and walk erratically. A researcher has described the brain of an infected eagle, viewed under a microscope, as resembling lace.


Army Corps of Engineer personnel collect invasive hydrilla from Lake Seminole in Florida

As their numbers grow, bald eagles can be expected to expand their breeding range, within limits imposed by habitat destruction, human disturbance, and environmental contamination. "Persecution from humans has declined in the last 20 years, and prime wilderness habitat has become occupied," said David Buehler, "so eagles have started moving back into human-developed areas." Many states have laws that continue to protect the eagle as an endangered, a threatened, or a "special concern" species.

Bald Eagle (Haliaeetus leucocephalus) Facts

- Named for its head of white (balde in Old English), the bald eagle is one of eight species in the genus Haliaeetus—the only sea, or fishing, eagle found regularly in North America. It is largely confined to Canada, the United States, and northern Mexico.

- Bald eagles acquire their distinctive adult plumage—white head and tail, dark-brown body—at about 5.5 years.

- Females are larger than males.

- The largest breeding populations occur in coastal areas of southeast Alaska and British Columbia; around the Chesapeake Bay and Great Lakes; in Minnesota, Florida, and coastal Maine; and in the Maritime Provinces.

- The eagle's preferred food is fish. If live fish are available, it will hunt them, but it readily takes dead and dying fish. In winter, birds (mainly waterfowl), mammals, and carrion account for a higher proportion of the eagle's diet. The eagle often pirates food, especially from other eagles and from the osprey, a more skillful catcher of fish.

- Eagles migrate south or to coastal areas when their food becomes scarce or, because of freezing, inaccessible. In the fall, as many as 3,000 eagles may appear on Alaska's Chilkat River to feast on spawning salmon.

- In the wild, eagles live for up to 28 years; a captive eagle lived for 36 years.

- Eagles are thought to mate for life; lost mates may be replaced quickly. Courting eagles lock talons briefly and engage in chases. The cartwheel display, in which two eagles lock talons and tumble toward the ground, can be a courtship act or a ritualized battle between territorial males.

- Pairs generally nest in a large tree on forested land near water, often reusing, and adding to, the nest from year to year. The largest bald eagle nest on record was in Florida—9.5 feet wide and 20 feet high, it weighed more than two tons.

- Ornithologist Arthur Cleveland Bent described the eagle's voice as "ridiculously weak and insignificant . . . quite unbecoming a bird of its size and strength." Filmmakers have been known to replace the eagle's high-pitched, gull-like cackle with the more robust voice of a red-tailed hawk.

- On The Great Seal, the eagle faces the talon holding the olive branch. The eagle on The Presidential Seal faced in the opposite direction—toward the talon holding the arrows—until 1945, when Harry Truman had it redesigned to face the olive branch as well.

More info:
U.S. Fish and Wildlife Service Draft Post-Delisting Monitoring Plan for the Bald Eagle (PDF file published June 15, 2007)
U.S. Fish and Wildlife Service Bald Eagle Web Site
Most Recent Count of Bald Eagle Pairs in the Lower 48 States (Compiled June 22, 2007 by the Center for Biological Diversity)
Threatened and Endangered Animals and Plants (U.S. Fish and Wildlife Service)
Recovery and Delisting of Endangered Species (U.S. Fish and Wildlife Service)

Related article: Zen in the Art of Finding a Wintering Bald Eagle

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A message from Robert Winkler

Jeff Brush/Connecticut Post (used with permission)

If you enjoyed this article, I know you'll enjoy my critically acclaimed book, Going Wild: Adventures with Birds in the Suburban Wilderness (National Geographic), which expands on many of the short pieces I've posted here. Why do I write about birds? Because they represent the wild in all its glory. They're numerous, diverse, intelligent, talkative, and beautiful; their power of flight never ceases to amaze; and they're the most conspicuous class of wild animal—even in the suburb, they're just about everywhere. Whether you're a beginning or advanced birder, a fan of nature writing, a curious suburbanite, or a reader in search of that rare bird known as a good book, Going Wild could very well change how you view your world. So get your copy now, or buy one for your favorite birder or nature lover. Best deal on the Web: brand new, perfect copies $5 each (69% off) at National Geographic Books.

"White-Headed Eagle, Male" (Adult Bald Eagle) by John James Audubon, plate #31 in his Birds of America (1827-38)
"White-Headed Eagle, Young" (Immature Bald Eagle) by John James Audubon, plate #126 in his Birds of America (1827-38)
"Bald Eagle" by Louis Agassiz Fuertes (date unknown; watercolor)
Hydrilla photo by Stephen Ausmus, USDA 
Text Copyright © 2002-2007 Robert Winkler

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