Proposed project would trap, move, track lamb-hunting eagles

Update — The Wyoming Game and Fish Commission approved the proposal April 22.

The Wyoming Game and Fish Department is backing a plan to trap 16 sheep-hunting golden eagles and move them up to 400 miles away, including out of Wyoming.

The plan is both a research project and a way to “alleviate conflicts” with domestic livestock, according to a memo to Game and Fish commissioners from the chief of the agency’s wildlife division. The matter is scheduled for consideration and potential approval by the commission Thursday at its Jackson meeting.

The goal of the research is to identify best practices for relocating depredating golden eagles and reduce conflicts, said Nate Bickford, a Colorado State University professor in Pueblo, Colorado, who proposed the project. With today’s tracking technology enabling researchers to fit devices on birds, the project could benefit both eagles and stock growers, he said.

“We can move these eagles and, with telemetry, actually track their movements after they are released,” Bickford said. Bickford and associates may identify the environments where relocated eagles stay and possibly figure out why. At the same time, the project could determine what factors influence eagles to take wing and return to lambing areas after being relocated, he said.

Something as simple as an abundance or scarcity of natural prey, such as rabbits, in any given year could be a factor in relocation success, research has suggested.

A dozen eagles could be relocated this year, and four more in 2022, Bickford said. Neither he nor the U.S. Fish and Wildlife Service could say by deadline how many eagles, if any, were moved last year.

Ranchers and their certified eagle trappers “would be doing some of that work regardless of our project,” Bickford said. The proposal appears to contemplate giving some birds to raptor handlers — falconers and austringers — with the result of those birds being removed from the wild population.

Researchers would move eagles up to 400 miles, Wildlife Division Chief Rick King’s memo to the Game and Fish Commission states. “Careful consideration is given to the release sites and researchers are evaluating several locations outside of Wyoming.”

Game and Fish will collaborate with the Wyoming Animal Damage Management Board, U.S. Department of Agriculture Wildlife Services, Wyoming Wool Growers Association, International Eagle Austringers Association, North American Falconers Association and Colorado State University, according to agency documents. The Wyoming Animal Damage Management Board funded the project, according to Bickford’s research application.

Tracking a key element

Bickford must share tracking information and possibly blood samples with the Game and Fish, according to a Wyoming research permit dated April 6 and signed by Scott Edberg, deputy chief of the agency’s wildlife division. Where the eagles will be trapped will depend on what ranches secure depredation permits from the federal government, Bickford’s application states.

Most likely the project will center on three ranches in the Green River region, three in the Powder River Basin and one in the Shirley Basin, the application states.

Research would take place for three years, according to a separate application for funding to the Wyoming Animal Damage Management Board. The undertaking would cost some $60,920 a year and employ non-lethal management methods, that application states.

Bickford will receive $45,000 a year from the ADM board, according to the organization’s website. The application in 2020 shows he was seeking, $2,500 a year each from Wyoming Wool Growers Association and North American Falconers Association and $5,000 from the International Eagle Austringer Association.

CSU would make $5,920 a year in in-kind contributions, according to Bickford’s ADM grant application that was copied to Game and Fish. There is no indication of any funding from Game and Fish.

Golden eagles are adept at killing lambs and can inflict significant losses. Since lawmakers in 1962 amended the 1940 Bald Eagle Act to protect golden eagles, researchers and ranchers have tried various methods for protecting sheep without harming the raptors.

A 1988 paper by federal researchers Robert Phillips and F. Sheridan Blom of the U.S. Department of Agriculture said eagles can have “substantial economic impact on individual producers.” They cited a 1975 case documented by B.W. O’Gara at the University of Montana in which two neighboring Montana ranches lost $48,000 worth of lambs that year.

More recently, a Johnson County rancher in 2019 complained that eagles took all but 25 of his 200 lambs, killing some of them “just for the fun of it,” according to reporting by the Buffalo Bulletin.

Investigations in the 1970s by O’Gara suggested ranchers would take matters into their own hands and kill eagles, despite federal laws, if predation by eagles could not be prevented by other means.

In 2020 the U.S. Fish and Wildlife Service along with Wyoming Game and Fish investigated the poisoning deaths of a golden eagle and ravens near Wamsutter. Investigators found poison-laced baits along with the dead birds.

Historic research 

By 1987, O’Gara and W. Rightmore determined scarecrows and harassment of eagles offered “the most feasible means of protecting lambs under range lambing conditions,” in Montana. Range lambing occurs when sheep give birth in open pastures instead of in sheds.

Bickford discounted that technique, saying golden eagles become habituated to scarecrows and hazing.

Live trapping and moving golden eagles became the most common method to alleviate ranchers’ problems, USDA researchers Phillips and Blom wrote in 1988. On one Montana ranch, trappers moved 430 eagles during the period 1975 to 1983.

“Most field investigators who have dealt with eagle depredation problems feel that where eagles are preying on lambs in large open range pastures, scare tactics and the general live-trapping and relocation of eagles have been ineffective,” they wrote.

Other research had different results. Starting in 1999, a group of California researchers trapped and relocated golden eagles from the Channel Islands off the state’s southern coast to stop a “catastrophic decline” in three subspecies of island fox.

Live-trapping and moving the eagles was an “effective non-lethal method of reducing the island golden eagle population,” they wrote.

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But by 1991, Phillips had found the method somewhat ineffective when dealing with breeding golden eagles near Sheridan. “Our observations of 14 relocated resident golden eagles showed a well-developed homing instinct for this species, with 12 of 14 individuals returning to their former territories,” he wrote.

Some were back within 11 days. Two came back after being moved twice, each time in different directions.

“Because most relocated birds reestablished their territories, it appears that relocation of breeding adult eagles offers, at best, only a short-term solution to the problem of eagle predation on livestock,” Phillips wrote.