Golden Eagle Redux
In case you’ve been wondering about the photo of me in the sidebar, here’s the story, from my November column in Pennsylvania Game News.
The phone rang just as we were in the midst of eating dinner.
“I’ll bet that’s Trish and she’s got an eagle,” I said.
Bruce answered the phone.
“You’ve got an eagle,” he repeated. “You’ve got a problem. What is it? Steve and Dave are here too. I’ll send them both up.”
It was the last day of daylight saving time, and at 6:15, the sun had already set. Trish Miller, a golden eagle researcher working on her Ph.D. at Penn State, had arrived at the new trapping site on our mountain in the morning. Luckily, she had come by herself, because I had often encountered her with her little daughter Phoebe on her back heading to the site.
Unlike the previous year’s site, this one was a steep climb up Sapsucker Ridge and then a precarious climb down into the middle of a rock slide where her husband, Mike Lanzone, assisted by interns from the Powdermill Nature Reserve, had designed and built a blind and live trap.
During their first trapping season here, they had discovered that the golden eagles, after crossing the Tyrone Gap in Bald Eagle Mountain, would drop below the ridge on the northwestern side and not soar above it until they reached the top of First Field. On the rock slide, the eagles often flew past at eye level.
The day she called us, the northwest wind had picked up at noon, and Miller had watched nine golden eagles fly over. Every eagle was escorted through his territory by the resident red-tailed hawk, which picked them up on the far side of the gap, near a cell phone tower, and accompanied them on along the ridge.
Then the tenth golden eagle struck the bait. One of the lines to the bait broke, and the eagle hung on to it while flapping half off the trapping platform. Afraid to spring the bow net, Miller waited, hoping the eagle would flap back on to the platform. When it did, she sprang the net and had a perfect catch. She managed to get the eagle into a large carrying case she had brought along, but she couldn’t haul it up the rock slide and down the trail to our place, a good half-mile away, before dark. That’s where our sons came in.
Bruce and I waited and waited. It grew dark and still we waited. Finally, in they came, our two sons and Miller, bearing the eagle in the carrying case. After giving us a chance to look in and see the magnificent bird, they carried the case down to our cellar and covered it with a sheet for the night to keep the bird calm.
The following morning researchers and bystanders began assembling to work and watch by 8:00 a.m. It was a cold, damp and overcast 37-degree Sunday morning. Dr. Todd Katzner, Director of Conservation and Field Research at The National Aviary, arrived from Pittsburgh first. The Scott family, who had been packing up from a day of hunting when they brought the eagle down off the ridge, was also here, as well as our sons.
Before the other researchers arrived, Katzner carried the case into our shed. He carefully opened it and climbed halfway inside the case to grab the feet of the eagle and pull it out.
“I think this a first year female,” he said and gave us a lesson on golden eagle biology. He spread her tail to show the white on it and her more than five-foot wingspan to display the white underneath. Both were signs of her age. But her massive golden head was already its golden adult color. Although her beak looked dangerous, it was her taloned feet that were. She had been hatched sometime last April or May in northern Quebec or Labrador, he thought.
Miller, Lanzone, their children Jeffrey, Ashley and Phoebe arrived at 8:30, followed by Dan Ombalski, another researcher, from State College.
Once everyone was assembled on our veranda, the work began. They put a cap over the eagle’s head so she wouldn’t be too stressed, although Katzner told us that her cortisone level was high.
They measured her wings and tail and brought out a chart to check sizes against what would determine the sex of the bird. Her legs were thick; her bright yellow talons huge. “Fresh, happy feet,” Miller called them.
She weighed 41.20 grams or 8.4 pounds, which definitely made her the bigger, heavier female–the first female eastern golden eagle ever radio tagged.
It took hours to fit the harness and radio transmitter over her abundant feathers and impressive breast, and they shook her several times so she would flap wildly. Then they would once again adjust the harness. They sewed a section on with thread so that the transmitter would fall off in a year or two. All of this was part of a new kind of transmitter, and Lanzone had been up all night tweaking it, perfectionist that he is. Instead of transmitting data once an hour, as the other transmitters did the previous year, this one was made to transmit every thirty seconds.
Finally, all the actors were ready. That was when the researchers decided that the eagle would be released on the rock slide where she had been trapped, so she would resume her migration with as little disruption as possible.
All of us hiked to the site except for Katzner who drove The National Aviary truck that held the golden eagle in the carrying case. By then three Powdermill interns had joined us as well. What a crowd to usher off an eagle.
I picked my way down the rock slide to the first open area where they planned the release. Everyone had cameras and surrounded the eagle and Lanzone who was holding her.
At that moment, Miller came over to me and said that they would like me to release her. It had never crossed my mind that they would honor me in such a way. Looking at her talons, I gulped and agreed. How could I turn down a chance to hold this incredible bird?
Miller showed me how to grasp her feet and then carefully transferred the eagle to me. Her eight pounds seemed light despite her massive size.
I held her for what seemed many photos and videos.
“Just throw her lightly into the air,” they told me. When I yelled “Ready,” Katzner responded “Go!” And just as we had rehearsed — off she flew. I felt as if I was releasing air.
But instead of streaking away, she flew into a nearby pine tree. Our son Dave and Lanzone ran through the underbrush to take more photos and watch her as she ruffled and smoothed her feathers, grooming off the feel of humans who had insulted her dignity. Once she reached behind her back and pulled repeatedly at the transmitter. There were a few tense moments until she gave up trying to remove it and went back to grooming.
Then she rose into the air again, and instead of continuing down the ridge, she returned to circle above us twice, as if in farewell, before she headed south to our collective applause. We wished her a safe trip and hoped all would go well with the transmitter so we could watch “our” eagle’s journey.
But months dragged on and we didn’t hear anything. I finally contacted the researchers and learned from Katzner that “the prototype transmitter had worked very well and provided initial data for a few days before it failed” and they had lost track of her. What a disappointment!
But Miller told me that they had learned more, during that short time, about how she used the ridge during her flight, than they had from the other eagles they had tagged with transmitters the previous year. Because their research project goal is, in Katzner’s words, “to provide informed science and generate key information so that raptor friendly wind farms can be built in Pennsylvania,” they must know how high eagles fly above the ridges.
Nothing in the evolutionary history of birds or bats has prepared them for industrial-sized wind mills, what some folks call “eggbeaters in the sky.” Each 150 foot blade, 300 feet in diameter, weighs 9 tons and the blade tips move 200 feet per second, Katzner says.
The researchers also must identify primary migrating routes and wintering sites and identify the eagles’ behavior on migration and during the winter. Eventually they plan to produce maps that show the relative risk to the birds from the development of industrial wind farms.
All of this scientific information was impressive, but we couldn’t help wondering about our own golden eagle. What had happened to her? Where had she gone?
Then, on Valentine’s Day, we received an e-mail from Lanzone.
“Got a call today from someone helping with a PGC study about an eagle that looked like the one in the Game News. Turns out it was the golden eagle you released. It looks very healthy from the pictures and has been visiting the deer [dump] for just over two weeks (they had thought it was a bald eagle until the other day)…it is visiting their study area on private land just north of Greensburg in Westmoreland County about 25 miles from my office.”
They hoped to re-trap her and put on a new transmitter, but she was having none of that. Once trapped, twice shy. But what a relief it was to learn that she was fine and that she hadn’t even left Pennsylvania. And she wasn’t the only golden eagle to winter in our state. At other deer dumps in other parts of the state stationary cameras captured photos of golden eagles feeding on deer carcasses.
There is much more to learn about eastern golden eagles. Katzner estimates that from 1000 to 1500 golden eagles pass through Pennsylvania during migration, which is 90 to 95% of the population. So far, it seems as if in the autumn most pre-adults migrate through eastern Pennsylvania along Hawk Mountain (the easternmost ridge in the ridge-and-valley province) and adults through western Pennsylvania, primarily along the Allegheny Front and our own Bald Eagle Ridge, the westernmost ridge in the ridge-and-valley province. Southern West Virginia appears to provide key wintering habitat.
In spring, adults migrate mostly from the Allegheny Front to about 60 miles east, although Tussey Mountain, the next ridge to the east of Bald Eagle, seems to be the major ridge. There is also evidence that some pre-adults stay in Virginia for the summer.
With the help of Quebec collaborators, they now have radio transmitters on 15 eastern golden eagles. Using GPS satellite telemetry, which is solar powered and should last one to three years, GPS data points at regular intervals are transmitted to a server by satellite. And those points should give them all the information they need about the eastern golden eagles’ flight speed, elevation, and timing during migration.
As Miller continues her “Wind Power and Eagle Migration” Ph.D. work, we hope she traps and radio tags many more golden eagles on our mountaintop and on the Allegheny Front so we can learn more about the life history of this distinct, poorly-known, small population of eastern golden eagles.