Issue Date: Chesapeake Bay Magazine - February 2007,
FEATURE DESTINATION: Have Eagles, Will Donate
With its robust and growing population of bald eagles, Blackwater National Wildlife Refuge helps out other locales by donating surplus chicks.
--by Melanie Lynch
Three years ago, I saw my first eagle--and nearly caused an accident. I was sitting in the passenger seat of my friend's Suburban, and we had just crossed the Route 301 bridge over the Potomac River into Virginia. And there it was, a bald eagle--perched regally in a bare snag, about 50 feet up, white head and tail feathers shining like a beacon.
"Stop!" I yelled.
My friend reflexively hit the brakes and wrestled the truck over to the shoulder, narrowly missing a light pole. "Did I hit something?" he asked, twisting around to see what it might have been.
"No!" I said. "There's an eagle back there! Back up!"
"Oh," he said, relaxing his grip on the wheel. "That old thing? . . . They're all over the place down here!" he said. But he indulged me. He backed up the truck and gave me time to revel in something that had taken a half century to happen: my first sighting of Haliaeetus leucocephalus, the bald eagle, the only eagle uniquely native to North America.
I was already in thrall to another of the Bay's raptors, the osprey ["The Osprey Fix," May 2006]. I had taken part in an expedition to band osprey chicks on the Patuxent River, and I had gotten quite hooked on, among other raptor reality shows, the osprey web camera at Blackwater National Wildlife Refuge near Cambridge, Md. And it was only a matter of time before I learned there was also an eagle cam at Blackwater (www.friendsofblack water.org/camhtm2.html), which I now regularly monitor.
Like many people, I suppose, I was surprised to learn that the bald eagle--all but wiped out in the lower 48 in the 1950s and '60s by the insecticide DDT--has been staging a remarkable comeback in the last two decades. And the numbers have been particularly good at Blackwater--27,000 acres of protected marshlands overseen by the U.S. Fish & Wildlife Service. In 1976, just four years after the EPA finally banned the widespread use of DDT, there were only four active eagles' nests (with mating pairs) at Blackwater; by the mid-'90s, the number was up to a dozen or so, and now there are at least 21 nesting pairs in the refuge--each producing one to three offspring per year.
Blackwater has been so successful, in fact, that it has been donating chicks to Vermont--the only state in the continental U.S. that is still without a successful nesting pair of bald eagles. Over the last three years, some 15 eagle chicks have been taken (or "hacked," as they call it) from around the Bay and relocated to the Dead Creek National Wildlife Management Area at Addison, Vt., a few miles from Lake Champlain.
Last spring, when my friend Lisa Mayo, webmaster for Friends of Blackwater, tipped me off that the last of these hacking expeditions was about to take place, I lost no time in wangling an invitation. And soon I found myself tagging along with a crew of Fish & Wildlife bird-nappers from both Maryland and Vermont. At the site of the first nest, though we had parked the trucks a good hundred yards from the tree, the adult eagles began to raise a ruckus, as if they knew we had come to snatch their young. They took off from their nest and circled overhead, clucking up a storm. Not screeching fiercely, as I'd expected, but . . . well, clucking, like really angry turkeys. (Eagles do sometimes screech, but not like you hear on TV, I've since learned. When you hear an eagle screech on TV or in a movie, chances are it's not an eagle at all; it's a voice-over, usually by a red-tailed hawk.)
It wasn't hard to tell when we'd arrived below the first nest. There was a veritable dumping ground at the base of the tree: long primary feathers, sticks, picked-over fish carcasses, and of course "whitewash" from the birds' excretions over the sides. Like ospreys, eagles are smart enough not to soil their own living quarters; they are experts at projectile pooping, up and out of the nest every time.
Craig Koppie, a Fish & Wildlife biologist based in Annapolis, was today's designated climber. After attaching a dual set of climbing ropes to his belt and a pair of climbing spikes to his boots, he shimmied quickly up the tree, pausing only to loop a new rope over a branch and detach the one beneath. When he arrived at the roughly twelve-foot-wide nest, he had to literally break into it, tearing through the sticks and grass to get at the chicks. They hissed at the intruder and backed away, naturally, but he spoke calmly to them. ("Just what do you say to a baby bald eagle when you climb into its nest?" I asked him later. "Don't jump," he deadpanned.) Too young to fly, the chicks could be killed or badly injured if they hopped out of the nest and fell before he could get to them. Using his bare hands, without the heavy leather raptor gloves I had expected, Koppie then grabbed one of the three chicks, held its wings close to its body, wrapped it in a towel and then put it in a duffle bag and lowered it on a rope to waiting staff on the ground.
After banding the chick, the ground team let it sit on the ground unrestrained while the next one was lowered. The first chick was surprisingly calm about its situation, barely moving its head enough to look around. It was big enough to peck at my knee if it had wanted to--and, given its adult-size beak, it could have easily done serious damage to said knee. But it didn't stir. Its sibling, though, was quite feisty and therefore kept in its improvised straightjacket until it could be stowed in one of the large pet carriers the team had brought along. As we drove away, Mom and Dad returned to their nest and were--I like to think--relieved to find that we'd left one of the chicks behind. At another nest a couple of miles away, we repeated the process, snatching one chick and leaving one behind.
The three captured Blackwater chicks, together with three that had been nabbed the day before from the Eastern Neck National Wildlife Refuge on the Chester River, would now be loaded in a truck for the 15-hour trip to Vermont. There they'd spend a few weeks in pens large enough to allow them to exercise their wings--and then, once imprinted with their new surroundings and neighborhood and having shown they're ready to fledge, they'd be released into the wild. Since bald eagles take five years to mature--and because these chicks were taken too young for Fish & Wildlife to determine their gender--it will still be awhile before Vermont can begin to measure the success of the project.
Back here on the Bay, the outraged eagle parents--who mate for life--are most likely raising more chicks as you read this. The female lays as many as three eggs in mid-January and then stays on the nest almost continuously for about five weeks. During this time, the male is responsible for gathering food, though he will occasionally take over incubating duties, giving the female a chance to stretch and spread her wings. Each parent has a "brood patch," a bald spot on the lower breast that helps transmit body heat to the eggs, which hatch in late February or early March.
At first the chicks' beaks grow more quickly than anything else, so by three weeks they are cartoonishly out of proportion with the birds' little bodies, still covered in white down. Soon, though, the proportions begin to balance out, and the white down gives way to black feathers, from head to tail. The distinctive white head and tailfeathers do not completely fill in until the eagle reaches maturity.
If food resources are good and the predators few, all three chicks will likely fledge. If, on the other hand, food is scarce, things can get dicey for the smallest chick. It's not uncommon for the smallest chick to die of malnutrition, or to be mortally injured by a larger sibling. At this stage of their lives, the whole brood is also vulnerable to outside predators. Raccoons may drag a young chick out of an unattended nest. Great horned owls can swoop in and snatch a chick without a sound.
If all's going well, though, chicks grow at a rate of a pound and a quarter every week. Once they are roughly the size of roosters, they are old enough to be left unattended, and the mother can join in the hunting responsibilities. It will now take the efforts of both adults to keep the chicks fed. Mom and Dad will spice up the mostly fish buffet with ducks, rabbits, lizards, snakes and turtles, and even a little road kill. While the chicks are very young, the mother will feed them, but they soon learn to rip and tear and feed themselves. An eagles' nest quickly becomes crowded with the growing chicks--which stand nearly two feet tall at just eight weeks and keep busy by stretching wings with a five-foot span.
As the chicks grow, the adults spend more and more time away from the nest--and the chicks, like any adolescents without parental supervision, begin to explore their world. They'll start "branching"--perching on the very edge of the nest, or even on the supporting branches, and testing those great wings. Once they actually launch themselves, they will still hang around, increasingly exploring their neighborhood. The youngsters are not particularly graceful when taking off, their huge wings beating the air stiffly and with great effort. ("They fly like plywood," one naturalist told me.)
Bald eagles do migrate, but they don't make the long, Homeric journeys--thousands of miles, over open ocean--of which their crazy osprey cousins are so fond. In the winter they're happy with a reasonably temperate climate (like here) where there is open water and plenty of fish (like here). On the Bay they are partial to roosting in loblolly pines, which rise to 100 feet and give the eagles a sheltering canopy above and a clear view below.
The nesting season begins in late November, when mates renew their pair bonds with daredevil and dramatic sky dances. A breeding pair will soar up to a great height, intertwine talons and twirl around while plummeting toward the ground, separating only at the last moment--seemingly a gesture of total trust in each other. The eagle cam, unfortunately, cannot capture this, but it does allow us to witness the couple's tender billing and cooing (who knew?) when the male brings food gifts to his mate. The pair carefully renovates the nest, adding more sticks and preparing the bowl for the eggs--building up a cup and lining it with soft grasses in the center of the nest.
During this time, the pair becomes very particular about its territory, driving off other bald eagles who get too close. Another fascinating tidbit: There are no opposite-sex battles--the male fights off the male intruders and the female takes on the females.
Eagles also apparently get a kick out of stealing meals from ospreys. If they see an osprey with a fish, they'll feint an attack until the osprey drops the fish--which the eagle then steals. This often requires much more effort by the eagle than if it simply caught its own fish, so one has to wonder if it's not a matter of pure sport.
None other than Benjamin Franklin took an even dimmer view of the practice, considering it a character flaw--and good reason to disqualify the eagle as a candidate for national bird. "For my own part I wish the bald eagle had not been chosen the representative of our country," he wrote in a letter to his daughter. "He is a bird of bad moral character. He does not get his living honestly. You may have seen him perched on some dead tree near the river, where, too lazy to fish for himself, he watches the labour of the fishing hawk [osprey]; and when that diligent bird has at length taken a fish, and is bearing it to his nest for the support of his mate and young ones, the bald eagle pursues him and takes it from him."
Franklin was not alone in his low regard for bald eagles. Until a federal law was passed in 1940 protecting them, they were considered a nuisance and commonly shot by hunters, farmers and fishermen. Then DDT, a potent insecticide, came into the picture. It was made available for public use in 1945 and used extensively after that. By 1963, the nation's bald eagle population--which might have once been half a million--was down to about 400, according to researchers at Vanderbilt University. Meanwhile, Rachel Carson, who had been chief editor of publications at the U.S. Fish & Wildlife Service in the early 1950s, argued in her 1962 book, Silent Spring, that raptors at the top of the avian food chain were particularly affected by heavy use of DDT. Dosages accumulated in their systems, the theory went, causing the eggshells to thin to the point that the weight of the incubating adult raptor crushed the eggs. President Kennedy ordered the President's Science Advisory Committee to investigate, and much of the research ordered by the committee was done at the Patuxent Wildlife Research Center in Laurel, Md. The eagle was declared endangered in 1967, and DDT was finally banned in 1972.
Today there are an estimated 7,066 nesting pairs in the lower 48, and the future of the bald eagle seems solid enough that the government is seriously considering taking it off the Endangered Species list. The biggest challenge the bald eagle still faces is loss of habitat. The birds themselves would still be protected under the Bald and Golden Eagle Protection Act, which prohibits hunting them or tampering with their nests, and there are guidelines--however voluntary--for buffers that protect nests from human activities likely to disturb them--defined as actions that disrupt their breeding, feeding or sheltering practices, or causing injury, death or abandonment of nests.
While eagles were expected to avoid close proximity with humans, they are now often reported nesting just a hundred yards or so from houses. One of the nests that the Fish & Wildlife team had visited was at the water's edge--near a house under construction. The homeowner was intent on laying hardwood floors while the female eagle was intent on laying her eggs. The noise proved too much, and she would not stay on the nest. The owner saw that the noise was driving her away and, after a consultation with Fish & Wildlife, decided to postpone the flooring project. The female eagle returned and got down to the business at hand.
That particular nest was about 15 feet from a rapidly eroding shoreline and was in danger of falling into the Bay--as the nesting pair's previous tree had done. But, judging by the pile of rip-rap deposited nearby, the homeowner was working on slowing down the erosion. A win-win situation, I'd say: The eagles get to keep their nest, and the humans get the treat of having the national bird as a neighbor.
Although I have now gotten over my eagle naivete, I haven't lost my sense of wonder when I see one. I still treasure that first sighting on the Northern Neck of Virginia. That bird obliged me by staying put, allowing me a solid two minutes of admiration. Then, as if he'd suddenly decided he'd had enough of the nosy birdarazzi, he spread his wings and flew away.
At the time, still unaware of the bird's improved circumstances, I thought it might be not only the first eagle I'd seen, but also the last. Happily, it was the first of many. And nowadays, I'm much less likely to come to a screeching halt in the middle of the road everytime I see one--though I'm not making any promises.