Our single-engine Cessna cruises about 400 feet above Virginia’s Rappahannock River, carrying out an unusual mission: counting eagles. Having lifted off from a small airstrip near Fredericksburg, we are headed downriver toward the town of Tappahannock.
Before we spot any of the birds, there are reminders of how much of the Northern Virginia countryside has been taken over by humans. We fly over a subdivision of new homes as well as a Food Lion, a lumberyard, a golf course, and a power plant. Those give way to farms with fields ready for planting, pastures dotted with beef cattle, and the occasional manor house.
The Rappahannock, which lies gray and choppy below us, is a tidal river that flows into the Chesapeake Bay, narrow and meandering at first but wider and straighter the farther we fly. Our eyes are focused on the river’s edges, where hardwoods and pines are mixed with open wetlands decorated with marsh grasses, muskrat mounds, and a few duck blinds. This wilder stretch of the river is home to one of the East Coast’s largest concentrations of bald eagles—so many that boat tours are available out of Tappahannock for those who want to see the national symbol close up.
The man in charge of our flight is Bryan Watts, an avian ecologist who is director of the Center for Conservation Biology at the College of William and Mary. A West Virginia native, Watts has been making such flights for 15 years as part of the official census of Virginia’s eagles. He is following his mentor, retired William and Mary biology professor Mitchell Byrd, who began the flights in 1977, when you could fly for miles and see no trace of an eagle’s nest with eggs or chicks.
Watts makes two passes a year over the Rappahannock as he does over the shoreline of the bay and the James, Potomac, and other rivers. The first, in early March, is to look for new nests and to see which old nests have adult eagles in them, a sign that they are incubating eggs. The second is this trip on a bright morning in May to count the number of chicks in each nest. Every nest is numbered and pinpointed on a map.
After so many surveys, Watts uses memory and his eye as much as the maps to find the nests: “You get so you see the landscape as an eagle does.”
For a novice, the nests are harder to spot, disappearing quickly as we fly just above the treetops at 90 miles an hour. It gets easier with practice, thanks to the fact that eagles build huge nests—“a person can lie down in one and not hang over the edge,” says Watts—and that they build them near the top of the trees.
Matt Crabbe, a pilot who honed his skills as a crop-duster, has flown Watts on the eagle census for more than a dozen years. Watts points with his hand to give him a heading, and in a few seconds he’s dipping the right wing to give us a look at a nest.
Adult eagles, distinctive with their brown bodies topped by a white crown, sit perched near nests, perhaps scanning for fish in the river. Here’s one nest near Tappahannock that sits in a pine tree right over someone’s cottage. And here’s one 75 feet above the ground that Watts climbed up to last week to band some eaglets for research.
Most nests have one, two, or three eaglets, and Watts can tell from their size and plumage, which changes rapidly at this stage, how old they are within a day or two. They will not leave the nest until their first flight in June, dependent until then on their parents to bring them food. Like the adult eagles, the young ones are unaware that they are being watched, unaware they are part of a great conservation effort.
In the saga of the bald eagle—both as a wild creature and as a national symbol—a moment of irony unfolded one night in 1969. Astronauts landed for the first time on the moon, reporting the touchdown of their spacecraft with a declaration of American pride: “The Eagle has landed.” Back on earth, meanwhile, eagles themselves were struggling through dark times, their number diminished in the lower 48 states to a few dozen pairs.
The eagle has lived with such contradiction since it was chosen to grace the Great Seal of the United States shortly after the American Revolution.
Everybody loves the eagle: Admired for its imposing size, striking visage, and ability to soar. Glorified on our money, government buildings, and military insignia. Adopted in the names and logos of hundreds of businesses and organizations.
But the eagle also has suffered from shabby treatment—a loser in the conflict between humans and wildlife. Eagles were shot and fed to hogs in colonial times, were killed by farmers who accused them of attacking livestock, had their eggs stolen from nests to decorate parlors, and were subjected to a bounty for snatching too many salmon in Alaska. In the deadliest threat of all, they were almost obliterated by insecticides after World War II.
The 126 nesting pairs of eagles along the Rappahannock are evidence of one of the most significant wildlife conservation achievements in the nation’s history. Eagles have rebounded throughout the lower 48 states, and soon, if all goes as planned, the species will be removed from the federal government’s list of threatened species. That will test whether eagles—still in competition with real-estate developers for shoreline habitat—can hold their own.
The changing fortune of the eagle has a strong connection to Washington. Studies linking insecticides and eagle mortality were done by government scientists at the Patuxent Wildlife Research Center near Laurel, and Silent Spring, the book that called attention to the problem, was written by Rachel Carson, who lived in Silver Spring. Federal policies initiated in the 1970s that put the eagle on a path to recovery, including the banning of certain insecticides and passage of the Endangered Species Act, were hammered out in Congress and administered by federal agencies.
Washington’s inclusion in the Chesapeake Bay watershed puts it in the middle of prime eagle habitat. Most of the birds live in remote locations along the shores of the bay and the rivers that flow into it. But they are plentiful enough now that you may see them in less likely places—perhaps perched at Mount Vernon as if conscious of their patriotic role.
Loving the National Mascot
Everywhere George W. Bush goes, he is accompanied by the eagle, whose image—grasping in its talons the arrows of war and the olive branch of peace—dominates the presidential seal. The seal is woven into the carpet of the Oval Office, emblazoned on the side of Air Force One, and appears on the White House M&Ms.
The presidential seal is a version of the Great Seal adopted by the American colonies in 1782, shortly after the war for independence from the British.
The American revolutionaries probably were aware that the eagle—there are about 60 species worldwide in addition to the bald eagle—had long served as a powerful symbol in Europe. Zeus, chief god of the Greeks, was said to keep an eagle on Mount Olympus because it was the only bird with the strength and speed to catch his thunderbolts. An eagle was released from the funeral pyre of the Roman emperor Augustus, symbolizing the ascent of his soul to the gods. Early Christians, adapting stories from the Greeks about an eagle being renewed by plunging into a fountain of youth, saw the eagle as a symbol of eternal life; it was sometimes carved into baptismal fonts and was featured on the flag of the Holy Roman Empire.
But the appeal of the bald eagle as a symbol of the United States was heightened by the fact that it was native to the New World. It was a common sight: Thousands of the birds existed along the Eastern seaboard when European colonists arrived in the early 1600s. Its full range ran down into northern Mexico and up into Canada and Alaska. Its relative the golden eagle was most numerous west of the Mississippi River.
The bald eagle also underscored the political statement the American revolutionaries wished to make. Soaring high in the sky without restraint seemed to embody freedom and independence. With its great size, sharp talons, and hunting skills, the eagle symbolized that the colonies were strong, courageous, and not to be taken lightly by other nations. An eagle with a talon grasping arrows was more subtle than a snake, which had appeared on colonists’ flags with the words don’t tread on me, but the eagle had enough edge to make the same point.
Benjamin Franklin raised objections to the eagle, though his dissent may not have been entirely serious. In a letter to his daughter in 1784, he dismissed eagles as birds of “bad moral character.” He claimed that their habit of snatching fish from ospreys made them thieves. Franklin preferred the turkey—a “respectable bird” with the courage “to attack a grenadier of the British Guards.”
When the Founding Fathers were adopting the eagle as the national mascot, Native Americans already had hundreds of years of experience with both bald eagles and golden eagles as cultural icons. The mythic thunderbird, which was believed to cause thunder as it flew, appeared on totem poles. Eagles, roaming high in the sky, were thought to be spiritual messengers from the Creator. Eagle feathers were believed to have great power and were regarded with reverence. They often were used in religious ceremonies and awarded to warriors for acts of valor.
While the eagle gets a workout across the country on the Fourth of July and other patriotic occasions, Washington’s position as the national capital makes it the source of much eagle iconography. The eagle appears on the quarter and the one-dollar bill and on postage stamps, Social Security and Medicare cards, income-tax forms, and passports. The bird is part of the official seals of the president, the vice president, the House, and the Supreme Court as well as of departments and agencies, including State, Defense, Justice, and the Postal Service. One exception is the Department of the Interior, whose Fish & Wildlife Service administers the Endangered Species Act. Its logo features a bison.
The eagle also is a decorative figure in much of Washington’s official architecture, including the US Capitol, the Library of Congress, the Old Executive Office Building, Constitution Hall, the World War II Memorial, and Arlington Memorial Bridge. The National Galley of Art has nearly 200 works of art featuring eagles, from a 16th-century Titian drawing to a 1999 print by Robert Rauschenberg. Most famous is an 1828 print of the bald eagle included in naturalist John James Audubon’s The Birds of America. Like Franklin, Audubon considered the bird cowardly: “I grieve that it should have been selected as the emblem of my country.”
That is very much a minority view, because the eagle is widely used by the American military to symbolize strength, courage, and ferocity. The bird appears on the logos of the Navy, the Marine Corps, and the Air Force, and it’s an eagle that signifies “full bird” colonels. Several services have units that incorporate the eagle in their logos or names, including the Screaming Eagles of the Army’s 101st Airborne.
The eagle has migrated into other corners of American popular culture and commerce. Generous donors to the Republican Party are called Eagles; there are a million members of the Fraternal Order of Eagles; earn a merit badge in environmental science and you’re on the way to becoming an Eagle Scout; the Eagle is DC’s leading gay leather bar; and the eagle is on display in everything from high-end jewelry to menacing tattoos.
More than 50 colleges use the eagle as a mascot, including Boston College and American University. Philadelphia’s pro football team became the Eagles in 1933 in honor of Franklin Roosevelt’s New Deal and the National Recovery Act, whose symbol was an eagle. Screech, the eagle mascot of the Washington Nationals, was introduced when baseball returned to the city.
Washington is loaded with “legal eagles,” and cops make suspects do the “spread eagle.” Charles Lindbergh’s solo transatlantic flight in 1927 was an expression of aviation skill and grit that earned him the nickname “The Lone Eagle.”
Eagles have been a favorite of poets and songwriters, and the Eagles have long been a popular rock band. Even former attorney general John Ashcroft wrote a patriotic song about them, which he tried with little success to get employees of the Justice Department to sing: “Let the mighty eagle soar. Soar with healing in her wings. As the land beneath her sings: ‘Only God, no other kings.’ ”
The eagle really soars in the hands of marketing experts. More than 1,300 companies have registered trademarks protecting the use of the eagle in their names, logos, and advertising—far more than the fox (900), wolf (550), deer (280), or whale (120). Some of this branding is well known: American Eagle Outfitters, Harley-Davidson, Goodyear, Chrysler, Anheuser-Busch, American Airlines. The eagle also is used by wineries, newspapers, banks, fireworks makers, and resorts.
Secret Life of the Eagle
When you see eagles perched in the wild, it’s easy understand how much of their reputation for strength, beauty, and magnificence depends on their size and coloration. No wonder they are known among naturalists as “charismatic megafauna.”
Bald eagles are among the largest birds of prey in North America. Adult females, about 30 percent larger than males, weigh up to 15 pounds and measure more than three feet from head to tail. They may have a wingspan up to seven feet, which has benefits for soaring but limits their ability to maneuver in deep forests. Juvenile eagles, from their first flight at three months to five years of age, weigh more than adults because they have longer and thicker feathers. Eagles in Alaska and Canada are bigger than those farther south, enough so that scientists used to think they were separate species.
Much of the adult bald eagle’s body is covered with dark-brown feathers—7,000 in all—that are crucial to flight and serve as waterproofing and insulation. Their beak and legs—even their eyes—are bright yellow, and they are accented with white feathers on their tails and around the crown of their heads. “Bald” is a misnomer—their heads aren’t bare—but comes from the old English word “balde,” which meant “white” to early colonists. The white is acquired when they are about five years old—before that all their feathers are mottled brown, which makes them hard to distinguish from golden eagles, hawks, osprey, and vultures.
Seeing eagles in flight suggests why the American colonists considered them an ideal symbol of freedom. With hollow bones—about 5 percent of their total weight—and those long wings, they are capable of flying as high as 10,000 feet. They are at their most graceful when they soar into rising currents of warm air, flap their wings intermittently, and go into an energy-saving glide.
Much of the biological glory of the eagle is hidden from the casual observer with a set of binoculars and a camera. It unfolds when you begin to understand some of its secret life, to appreciate the adaptations that have helped it survive for thousands of years, and to recognize the niche it occupies in the ecological scheme.
A flight with Bryan Watts hints at the fact that eagles thrive in a habitat that offers three essentials. They need to live near rivers or other open waters with plenty of fish. They need trees that are strong enough to hold their nests and tall enough to offer a clear path for flight. And they need space that isolates them from the noise and disturbance of humans.
All of these conditions prevail in the Chesapeake Bay ecosystem. While some eagles nest along a thin strip of woods and marshes on the edge of the bay itself, many others exist on both banks of the Potomac River as well as such Virginia rivers as the James, Rappahannock, and York and Maryland rivers including the Choptank, Chester, Pocomoke, Patuxent, Wicomico, and Nanticoke. Lesser populations live inland along the shores of reservoirs.
Eagles belong to a group of carnivores known as raptors, and much of their time is spent in the hunt for food. Fish make up the bulk of their diet, especially catfish, shad, and herring. But they also prey on waterfowl, seagulls, muskrats, rabbits, squirrels, and small turtles, whose shells collect in their nests. They’re also scavengers who feast on carrion, including dead deer, pets, and other roadkill.
One of the adaptations that serves eagles well is their astonishing eyesight. “Eagle-eyed” is for real. Their vision is several times sharper than that of humans, allowing eagles to spot a fish from hundreds of yards away. Their frontally set eyes are large, with oversize retinas; they have twice as many cones as humans, allowing for better visual accuracy and color perception; and they are able to rotate their heads 270 degrees. The downside: They cannot see that well at night, so all their hunting is done during the day.
Eagles play a waiting game when they hunt, spending hours perched on a tree near the water scanning for a fish near the surface. Spotting prey, they go into a dive that may reach 100 miles per hour. They snatch the prey in sharp, viselike talons, often killing it instantly. Their downward-curving beak is used to tear apart flesh and bones into bites for themselves or their young. They have limited lifting power but are so tenacious that they have been observed using their wings to swim to shore if they get hold of too heavy a fish.
Bald eagles reach sexual maturity at about five years, their readiness for mating signaled by the emergence of their white plumage. They are usually monogamous, mating for life, though some “divorce” and “remarry” or find a new mate if an old one is killed. They may live more than 20 years in the wild—the known record, held by two eagles in this region who were banded as chicks and captured as adults, is 28 years.
The devotion of eagles to their mates lent poignancy to the story of Martha and George, who have become famous for nesting the past few years in the shadow of Woodrow Wilson Memorial Bridge even as it has gone through noisy reconstruction. Martha was involved last spring in a bloody fight with an intruding female eagle. Badly injured, Martha was captured and taken to a Delaware rehabilitation center. George stayed at the nest incubating their eggs, but none hatched. Released in Delaware, Martha found her way back to the area and has been seen perching and flying with George.
During courtship, eagles are noted for a ritualized behavior known as “cartwheeling,” which is the subject of a poem by Walt Whitman called “The Dalliance of the Eagles.” It begins with a male and female soaring to great heights, where they lock talons and begin a tumbling, gyrating free fall toward the earth. Just before hitting the ground, they disengage, then soar upward—and do it again.
Once paired off, the next order of business is to find a nesting site. Scientists presume the choice is by mutual agreement, and it’s likely to be within several miles of the place where either the male or female was hatched. They always choose one of the largest trees available, often one that stands a little taller and is on the edge of a field, woods, or marsh. In this region, about 60 percent of nests are in loblolly pines.
The nests must be big enough to accommodate two adults and their young. They may be six to eight feet in diameter, four to six feet deep to keep chicks from falling out, and weigh several hundred pounds, occasionally as much as a couple of tons. Shaped like a cup, they are assembled from sticks about three feet long and lined with soft materials such as pine boughs, grasses, and corn husks. They are reconstructed, enlarged, and reused every year, usually by the same pair.
The female lays one to three eggs between mid-January and late March. She takes primary responsibility for incubating them during the 35 days until they hatch, though the male takes part as well. Because the birds are tied to the nest, this is the time when Bryan Watts and Mitchell Byrd take to the air to make the first census. The view, Watts says, is especially striking after a snow, with white-headed eagles sitting there high above a white landscape.
Baby eagles break out of their eggs in March or April as wet, closed-eyed, cheeping little creatures with fuzzy white down. Father and mother alternate between bringing them food and brooding, contributing to a growth rate that is among the fastest of North American birds. They are fully developed by the age of three months, when they take their first flight. Within weeks they are on their own.
These juvenile eagles are free to roam for the next few years before reaching maturity. Some scatter along the Atlantic coast from Canada to Florida. Others stay near the bay.
Here they merge into a population that swells at certain times of the year because the region’s mild climate and abundant supply of fish make it a “convergence area” for eagles. That means the bay—in addition to its own juveniles and adults—attracts migratory eagles from up and down the Atlantic coast. In winter they come from Canada and New England, in summer from Florida and the Southeast. When local and migratory eagles come together in roosting sites, the numbers can be impressive—500 or more along the Potomac, 450 along the James, 320 along the Rappahannock, 150 along the Nanticoke, and 100 at the Aberdeen Proving Ground.
Heading Toward Extinction
Hundreds of years ago, when pristine nature prevailed throughout North America, the bald eagle was well positioned for survival. It stood at the top of its food chain, a large predator with no natural enemies. Though Native Americans killed a few eagles for feathers to use in ceremonies, their reverence for eagles and their lack of rifles limited the killing. With the arrival of Europeans in the early 17th century, all this began to change.
Some of the threat to the well-being of eagles came from loss of habitat as settlers claimed land along the Atlantic coast and eastern rivers. Around the Chesapeake Bay, where the land was then about 95 percent forested, trees that eagles depended on for nesting and perching were cleared by farmers to grow tobacco, corn, and other crops. Other trees fell to the ax for firewood and for logs and lumber to build houses, barns, and towns. âž
As agriculture pushed westward into the North American interior, farmers and ranchers came to regard both bald eagles and golden eagles as nuisance species that threatened their livestock. Thousands of eagles were shot in the name of protecting chickens, lambs, calves, and pigs, though it’s unclear that eagles were capable of the widespread marauding blamed on them. Eagles also were killed to protect fishing stocks—in the trout streams of upstate New York and in Alaska, where they feasted on salmon. Bounties were paid in Alaska on 115,000 bald eagles between 1917 and 1952. There also were wild rumors of eagles snatching household pets and babies—something wildlife biologists dismiss as pure myth.
Even city dwellers threatened eagles. Eggs were stolen from nests and sold as collectibles that became a status symbol in upper-class urban homes. Other birds—especially egrets, herons, and songbirds—were shot in large numbers for colorful feathers to decorate women’s hats. This slaughter was an impetus for creation of the National Audubon Society, one of the country’s first wildlife conservation groups, in 1886.
Bald eagles also faced dangers that were less obvious. Some died of lead poisoning after eating dead or crippled waterfowl wounded by hunters using lead shot. Others were killed when they were caught in traps or ate poisonous bait intended for wolves and coyotes.
Bald eagles gained some protection under the Lacey Act of 1900 and the Migratory Bird Treaty Act of 1918, which regulated trade in wildlife across state and international borders. The big breakthrough came in 1940 with passage of the Bald Eagle Protection Act, which sought to protect the national symbol and made it illegal to kill them, capture them, or destroy their eggs or nests. The protection was extended to Alaska, which has the world’s largest concentration of bald eagles, in 1952, and to golden eagles, which were being killed by the thousands, in 1962.
The legal protection afforded bald eagles in 1940 came just as a more devastating threat was arising in the form of the insecticide known as DDT.
That was short for dichloro-diphenyl-trichloroethane, a compound created by a German chemistry student, Othmer Zeidler, in 1874. It had remained a laboratory curiosity until 1939, when Swiss chemist Paul MÃ¼ller discovered that it was capable of killing dozens of kinds of insects. Introduced during World War II, DDT proved efficient in killing malaria-carrying insects for US troops in the islands of the South Pacific and as a delousing powder for soldiers in Europe. The chemical was so successful that MÃ¼ller was awarded a Nobel Prize in 1948.
After the war, DDT was sold for civilian use and became the dominant insecticide applied in the United States. Public health departments sprayed coastal marshes to control disease-carrying mosquitoes, and farmers used it on insects that threatened their crops and livestock. In an era when there was wide public respect for the benefits of chemicals, weak government regulation of their safety, and little suspicion of their side effects, DDT was hailed as a miracle. Popular Science predicted it would lead to “total victory on the insect front.” A Time ad in 1947 depicted cartoon versions of a cow, an apple, a chicken, and a housewife singing “DDT is good for me-e-e!”
But concerns about DDT began to arise, some related to the bald eagle. Ornithology is one of the few scientific fields where amateurs can make important discoveries, and bird watchers were among the first to worry about the effects of DDT. One of the first to record a dramatic decline in the number of bald eagles was Charles Broley, a retired banker from Winnipeg, Canada. He undertook a survey of the eagle population in Florida in the late 1940s. In 1946, he recorded 56 nests with 103 young along a 100-mile stretch of coast south of Tampa, but by 1957 he found only seven active nests with eight young.
Some eagles were killed directly by DDT. Mitchell Byrd, the William and Mary biologist, remembers a sick, trembling eagle found under a nest tree on Jamestown Island in the early 1960s that later died and was found to have very high levels of the chemical in its brain. But much of DDT’s effect on eagles—as well as on ospreys, brown pelicans, and peregrine falcons—was indirect. The problem was that DDT persisted in the environment long after the initial spraying—washing into waterways with each rain and working its way up the food chain.
The effect on bald eagles was insidious. DDT in the water was absorbed by small fish and other organisms, which were then eaten by larger fish. In a process known as bioaccumulation, DDT built up in the fatty tissue of these fish, which were then caught and eaten by eagles. In eagles, the DDT inhibited hormones responsible for releasing the calcium required for sturdy eggshells. When eagles sat on their eggs to incubate them, the shells collapsed or the embryos inside were not viable—and another year passed without any young.
Rachel Carson, who did more than any single person to publicize the damage wrought by DDT, spent most of her professional life in Washington. Born on a farm in Pennsylvania, she earned a master’s degree in zoology at Johns Hopkins in Baltimore, taught at the University of Maryland, and worked as an editor here at the US Fish & Wildlife Service. By the late 1950s, while living in Silver Spring, she already was a famous author, having written three books on the natural world, one of which, The Sea Around Us, stayed on the New York Times bestseller list for 86 weeks.
Carson’s interest in writing about DDT was aroused in 1958 by a letter from a friend in Massachusetts describing widespread bird deaths there following DDT sprayings. Reader’s Digest rejected a story proposal, but Houghton Mifflin offered a book contract. Four years later, in 1962, the results of her research were published in Silent Spring.
The book espoused the idea that all of nature is interconnected and that humanity can upset its balance with the unwise application of technology. The book’s most powerful chapter presented an apocalyptic vision of a nameless town where all life, from fish and birds to human children, had been silenced by DDT. The link between DDT and weak eggshells in eagles was not yet firmly established, but Carson suggested that their decline might make it necessary to find a new national symbol.
The book became a bestseller . Chemical companies and farm groups launched attacks to discredit Carson, including a rebuttal by Monsanto called “The Desolate Year” in which insects, disease, and famine devastate a world in which insecticides are banned.
Carson died of breast cancer at age 56, two years after the book’s appearance, not living to see its full impact. Eventually it was hailed as a seminal work of environmentalism and a landmark of muckraking on a par with Harriet Beecher Stowe’s Uncle Tom’s Cabin and Upton Sinclair’s The Jungle. Locally, her memorials include an elementary school in Gaithersburg.
The bald eagle continued its slide toward oblivion. An aerial survey in 1962 by Jackson Abbott, an amateur naturalist who worked as a civilian employee at Fort Belvoir, suggested there were only about 150 breeding pairs left in the Chesapeake Bay watershed—far fewer than the 600 to 800 estimated in 1936. Even more ominous: While each nest in 1936 produced 1.6 chicks on average, by 1962 only one nest in five produced a single chick.
Along the James River, the decline was catastrophic. During the 1950s, there had been 23 nesting pairs, but that dropped to 13 pairs in 1964, seven in 1966, four in 1970, two in 1971, and then just one. In 1975, there were no breeding pairs along the banks of the James.
The story was much the same elsewhere. Around the Chesapeake Bay the low point is thought to have been the early 1970s, with about 60 nesting pairs. Nationally, in 1963, a study estimated there were 417 pairs in the lower 48 states.
While Carson’s book took withering fire from DDT’s producers and users, it helped trigger a change in the country’s approach to pesticide regulation. President John F. Kennedy ordered his science advisory committee to study the issue in 1963, and its report vindicated her alarm. In 1970, during the presidency of Richard Nixon, the creation of the Environmental Protection Agency gave the federal government new power to regulate the sale of pesticides. One of its first acts, in 1972, was to ban the use of DDT in the United States.
The banning of DDT was the single most important move leading to the recovery of bald eagles, but much credit also belongs to the Endangered Species Act. It was passed in 1973—though a similar but weaker law had been on the books since 1966—and the bald eagle was on the “endangered” list from the beginning, along with the California condor, the whooping crane, the timber wolf, and the grizzly bear. The act set up two categories—“threatened” and “endangered,” the latter more dire. The eagle was listed as endangered in the lower 48 states except for Michigan, Minnesota, Wisconsin, Washington, and Oregon, where it was listed as threatened. The practical effect was to give eagles more protection, mainly by making sure their well-being was taken into account when permits were sought to build on land near their nests and roosting areas.
The bald eagle’s designation as an endangered species—on top of its status as national symbol—made it a celebrity. The media produced features on the eagle’s plight, and an orphaned eagle named Challenger made appearances everywhere from the White House and the World Series to Late Night With David Letterman. Corporations used the eagle’s cause to create goodwill, including an airline that flew injured birds without charge to rehabilitation centers, and conservation groups featured eagles in fundraising appeals. Children waged campaigns, writing letters of protest against developers building too close to nests and raising money for sanctuaries.
The campaign to save the bald eagle became one of the biggest conservation efforts in history—a campaign powered by money, research, and passion. The US Fish & Wildlife Service was the lead federal agency, with additional work by state agencies such as the Maryland Department of Natural Resources and the Virginia Department of Game and Inland Fisheries. Scientists, both at universities and in the federal government, conducted studies that shaped conservation efforts, and private groups from zoos to rehabilitation centers pitched in.
Wildlife officials encouraged landowners with eagles on their property to take pride in them as status symbols. This worked especially well with the landed gentry, but even some real-estate developers came to see that eagles could be turned into a marketing advantage by incorporating the bird into the name of a subdivision or street.
Eagles also found protection in hundreds of acres of habitat set aside in the Chesapeake Bay watershed as national wildlife refuges. One of the most important, the Blackwater refuge on Maryland’s Eastern Shore, had existed since the 1930s. But new federal sanctuaries perfect for eagles were created during the past 40 years, including ones along the James, the Rappahannock, and the Potomac at Mason Neck in Fairfax County.
Virginia protected two important new natural areas, one at Mason Neck and another farther south on the Potomac called Caledon. The undeveloped land on military bases offered additional sanctuary, including Aberdeen Proving Ground, Marine Corps base at Quantico, Fort Belvoir, and Fort A.P. Hill.
One of the most innovative conservation efforts was the National Eagle Repository, located on a former military base near Denver and designed to discourage Native Americans from killing eagles for feathers and other parts used in ceremonies. Bald eagles and golden eagles that die or are killed in accidents are shipped from around the country to the repository, where they are logged in and sorted, then given to those who file a request. Only Native Americans are eligible, and only one eagle per person is allowed per year—last year about 1,000 bald eagles were dispensed around the country.
Scientific support for the bald eagle came from the Patuxent Wildlife Research Center in Maryland, then a unit of the US Fish & Wildlife Service. It was a pioneer in the captive breeding of eagles, which were released into the wild to build up populations where the species had become extinct. Beginning in the mid-1960s, scientists at Patuxent raised 124 eagles using a variety of techniques. If they climbed up to a nest and took eggs to be hatched in captivity, for instance, they discovered that the eagles would lay another clutch.
Research at Patuxent also was central in linking DDT with the decimation of eagles and other birds. Scientists there began studying the effect of pesticides in the 1940s and at first concentrated on what dosages of DDT were lethal. The big breakthrough came in 1969, when they confirmed that DDT’s threat to eagles and other raptors was mostly due to eggshell thinning.
Patuxent also did studies on lead pellets in shotgun shells, which had been used by hunters for generations. These studies proved that waterfowl could be poisoned if they were wounded by lead pellets or ingested spent pellets from marshes, with the effect magnified up the food chain as eagles ate the waterfowl. The issue was settled in the late 1980s, when a National Wildlife Federation lawsuit forced the US Fish & Wildlife Service to phase in a ban on lead pellets.
In the three decades since the banning of DDT, the recovery of the bald eagle has been remarkable, both around the Chesapeake Bay and elsewhere in the country. Seeing an eagle in the wild remains a thrill—many people describe their sightings on www.baldeagleinfo.com. But this experience, once so rare, is now fairly common, not just in remote areas but in places nearer the heart of Washington. Eagles are now seen soaring above Chain Bridge, the Chesapeake & Ohio Canal, Roosevelt Island, Hains Point, Reagan National Airport, and the Alexandria waterfront.
The number of nesting pairs in the Chesapeake region, down to 60 in the early 1970s, is estimated this year to be more than 900—producing nearly 1,500 chicks. In the summer, when migratory eagles arrive from the south to join local birds, the number of adult and juvenile eagles around the bay may be as high as 5,000.
In other states, the recovery of bald eagles is equally strong. The number of nesting pairs in the lower 48 states, estimated at just 417 in 1963, has risen to more than 8,000, with many more juvenile eagles on their way to maturity over the next few years. Florida has the most pairs (631) followed by Minnesota, Wisconsin, Michigan, Oregon, and Washington. Alaska—where bald eagles thrive on an abundance of fish and wilderness—is thought to have about 35,000 eagles, with another 20,000 in British Columbia.
The numbers are so good that victory for the bald eagle is about to be declared officially. Maryland’s Department of Natural Resources, which did annual aerial surveys like those in Virginia, stopped after 2004 on grounds that the eagle population is fully recovered. In 1995, the US Fish & Wildlife Service reclassified the bald eagle as merely “threatened” in the 43 states where it had previously been considered endangered. And earlier this year it announced its intention to remove the “threatened” designation.
Competing With Humans
Amid their remarkable recovery, eagles still face threats from the vagaries of nature. Nest trees, which often stick up above their surroundings, are susceptible to lightning strikes. And nests are sometimes dislodged by windstorms, destroying eggs and killing chicks—a phenomenon wildlife biologists call “wind throw.” In the Chesapeake Bay region, one of the few declines in active eagle nests in the past three decades occurred between 2003 and 2004 after Hurricane Isabel.
Eagles also are susceptible to an avian version of cholera and to West Nile virus. Raccoons sometimes invade nests and eat eggs or chicks, and great horned owls sometimes take over eagle nests. About 25 percent of eagles do not survive their first year of life, though that is a high survival rate in comparison to many other species.
Bigger threats to bald eagles come from entanglements with humans and their technology. Some are electrocuted or crippled by flying into power lines. Some are killed or injured when hit by cars and trucks, often as they are feasting on roadkill. Occasionally one is killed in a collision with a small airplane, and there is some smaller danger from entanglement in plastic fish line and netting. Glenn Therris, top eagle expert at the Maryland Department of Natural Resources for the past two decades, says the leading cause of death in his state has been electrocution, with 36 deaths over the past 17 years. Only five eagles were illegally shot during that period.
In the Chesapeake Bay region, a more diffuse threat comes from losing habitat to an ever-growing population of humans. At a time when Americans are more respectful of eagles than ever, they also are spreading into undeveloped territory the birds have reclaimed in the post-DDT era. That means more cutting of trees and construction sites to build houses, offices, shopping centers, and roads as well as an increase in boating, fishing, and waterfowl hunting.
The most intense competition between eagles and humans is likely along the thin strip of shoreline around the bay and the rivers that flow into it. It’s prime habitat for eagles but also coveted by developers.
As this land is developed, says Bryan Watts, eagles are likely to abandon their nests, and the “carrying capacity” of the region will decline. That’s one reason he worries about removing the bald eagle from the endangered-species list, fearing that existing restrictions on construction within several hundred feet of eagle nests will be weakened.
While most eagles prefer nesting in wilderness, some are locating surprisingly close to human activity. Besides George and Martha at the Wilson Bridge, nesting eagles have been found on the grounds of St. Elizabeths Hospital in DC and in Baltimore Harbor. Nests have been spotted on the edge of backyards; in cemeteries; near rock quarries; along highways, railroad tracks, and runways; on high-voltage transmission towers; and near military training sites, including tank firing ranges and helicopter landing zones.
Not all these nests remained occupied, and biologists are unsure whether the up-close-with-humanity trend is a sign of desperation or adaptability. But it seems certain that we will be seeing more of these startling juxtapositions.
In southern Maryland, on the banks of the Potomac River, there’s an eagle nest not far from the 18th hole of the exclusive Swan Point Yacht and Country Club. The golfers and America’s symbol have fashioned a rapprochement: It’s good to shoot an eagle, but nobody would dare shoot an eagle.
Senior writer Larry Van Dyne wrote about the bridges of Washington in the March issue.