UPDATE: Researchers trapped one bald eagle Saturday somewhere along Pool 16 of the Mississippi River between Muscatine and Rock Island. Handlers attached a transmitter to the bird and plan to track its travels.
PREVIOUS STORY: It’s no mystery that scores of bald eagles congregate this time of year along the Mississippi River corridor in the Quad-Cities, but where exactly will they fly off to once the weather turns in the spring?
“Each bird takes on its own personality,” said Sara Schmuecker, biologist for the U.S. Fish and Wildlife Service’s Rock Island Field Office.
To study their migratory patterns, Schmuecker and other researches with the federal agency and West Virginia University set out this week to trap birds and outfit them with tracking transmitters.
Using deer carcasses as bait, crews set up rocket net traps at seven land-based sites in the area, from Exelon’s nuclear power plant in Cordova to about 80 miles southwest in the Port Louisa National Wildlife Refuge in Wapello, Iowa. Boat crews also deploy homemade water traps to lure eagles near area locks and dams.
They hit the ground running on Tuesday, but as of Friday afternoon, they had yet to catch any birds.
“It’s been very tough,” said Dr. Trish Miller, a wildlife biologist at West Virginia University who has studied and tracked eagles for more than a decade. “The animals don’t always cooperate.”
However, they’re currently collecting data from about 30 eagles they’ve captured and released in the Quad-City area since launching the Midwest Bald Eagle Project four years ago.
Researchers primarily want to study how the iconic animals navigate the landscape and conflicts with human activities — mainly wind turbines, communication towers and other structures — when they take flight.
Once they trap an eagle, handlers place tiny leather hoods over the bird's head and beak to protect themselves and the eagles.
They then attach the transmitter, a GPS-GSM telemetry unit, to the bird's body. Using Teflon ribbon, a non-abrasive material, they secure the transmitter like a backpack, using the ribbon to create a harness.
The tiny transmitter, which weighs between 60 and 70 grams, allows researchers to follow the migration path of the eagles, as well as their speed and altitude.
Each bird also receives a silver band around its leg that includes an identifying number.
Additionally, researchers take several measurements of the birds' beaks and legs, pull feather samples and draw small samples of blood to confirm the sex of the bird and detect any lead contamination. Lead likely comes from the animals they eat, including deer or other animals that have been shot or fish with lead sinkers.
On Monday, as Schmuecker geared up for her "favorite week of the year," her hands reeked of fish from tying noose-like wire snares to gizzard shad her team uses to draw eagles on the water. It's their most successful trapping method.
They link the dead fish to a wooden block and drop the contraption in the water. When an eagle attempts to grab the fish, the snares tighten its talons and pull it into the water. The wood acts as an anchor, preventing it from flying away.
Jeremiah Haas, the fishery biologist at Exelon’s Quad-Cities Generating Station, said the plant donates fish from its hatchery for the cause. Haas, who is assisting the visiting researchers, said he also gathered roadkill for the land-based traps.
"It’s a long week for me, but it's fun," he said. "There are a lot of folks working to try and make this happen."
In March 2015, a river crew trapped one bird near Modern Woodmen Park and nicknamed it Ferris. That spring, Ferris flew to Cambridge Bay in the Northwest Territories of Canada and back to the Quad-Cities the following winter, totaling about 8,300 miles of travel.
In the spring of 2016, it flew farther north — across Cambridge Bay.
Earlier this week, Schmuecker pulled out her smartphone and checked on Ferris' status. Sure enough, she discovered the bird returned to the Quad-Cities yet again.
"He is on Arsenal Island right now," she said.
Miller, who lives in West Virginia with her husband and has family in the Quad-Cities, called Ferris' journey a "testament to what incredible flyers they (eagles) are."
Last spring, a team removed Arconic's two juvenile eagles from their nest, and Miller fastened tracking devices to both of them.
This year, Schmuecker said they hope to band another 30 birds and eventually bring their total to as many as 100 eagles.
They will continue their work through Sunday and return again for another week of trapping in February.
To 'learn' and 'protect'
Beginning Jan. 17, wind turbine farmers can apply for 30-year permits that allow them to kill or injure a certain amount of eagles every year without fear of prosecution.
The birds are not endangered species but are protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act. The laws prohibit killing, selling or otherwise harming eagles, their nests or eggs without a permit.
Specifically, the new regulation will allow wind companies to operate high-speed turbines for up to 30 years and kill up to 4,200 bald eagles.
As populations of the species increase, so do the number of developments that threaten the birds, said Kraig McPeek, supervisor of the U.S. Fish and Wildlife Service’s Rock Island Field Office.
"We think wind energy is a valuable resource, but we also think protecting bald eagles is a valuable way to spend taxpayer dollars," he said, calling their project more "relevant" now than ever. "Without a doubt, we’re beginning to reap benefits from our investments."
Miller said their data will help them devise ways to mitigate the dangers eagles face.
“Bald eagles are amazing birds," she added. "We need to learn more about their behavior in order to protect them."