Eagle B-75 spends most of her time in Durango, fishing the Animas River and picking off easy prey – usually prairie dogs – in surrounding farmlands. But a few summers ago, the female bald eagle treated herself to a bit of a vacation.
The 11-pound eagle started north, taking just six hours to fly to Grand Mesa (the trip takes about 4½ hours in a car). She then spent some time at Flaming Gorge Reservoir, likely feasting on the waterway’s renowned trout and salmon, before taking off toward Wind River in Wyoming.
Like most tourists, Eagle B-75 stopped in Yellowstone National Park. But unlike other tourists, she probably ate rodents for dinner. She then soared the skies of Idaho before deciding it was time to get home, taking nearly the exact same path back to Durango.
The entire journey, which covered more than 1,500 miles round-trip, took Eagle B-75 just about 40 days.
The details of her flight come from a Colorado Parks and Wildlife tracking study that aims to tag eight bald and/or golden eagles in Durango to gain a better understanding of the birds’ migration and behavior habits.
“Without having those transmitters on it, we would never have known where that eagle was,” said Brian Magee, a land-use coordinator with CPW. “We would just assume we missed it.”
A need to trackIn 2011, BP American Production Co. signed a sort of good faith agreement with CPW vowing to minimize its impacts to wildlife and habitat loss from oil and gas extraction in the San Juan Basin. Part of that agreement had BP donate funds for wildlife study, some of which are now being used for the eagle tracking project.
A spokesman with BP did not return requests seeking comment.
Though eagles were taken off the endangered species list, the iconic bird is still under federal protection. So when any project is proposed that would alter the landscape, such as drilling new wells, building a new road or putting in a subdivision, potential impacts to eagles have to be considered.
In Colorado, that task usually falls to CPW, which must provide recommendations to best protect eagles from new developments. This tracking study, which will provide insight for wildlife managers about how eagles use the landscape, will better inform those recommendations, Magee said.
“Millions of dollars of economic activity are tied up in our recommendations, so we want to have the best information out there,” he said.
The first eagles in this part of Southwest Colorado were collared with tracking devices in 2014. One more or less stays in a 5-mile radius around Durango year-round and doesn’t like to leave its nesting territory. The other, Eagle B-75, is the traveler.
From 2014 to 2018, CPW tried to tag more eagles, unsuccessfully.
Capturing a live adult eagle, a smart and cunning hunter that can weigh up to 15 pounds and unleash piercing talons, is pretty difficult, said CPW’s Jon Holst,
As a result, wildlife officials changed their capturing tactics. Now, Holst said CPW goes out in winter, using bait when other easily available food sources, such as prairie dogs, are under the frozen ground.
Already, CPW has tagged three more eagles, bringing its total to five bald eagles and one golden. The project has funding for two more taggings. The transmitters, which are expected to last at least five years, send a signal back to CPW offices, allowing wildlife officials to see where the birds are about every hour on an interactive map.
Back from the brinkBy the 1970s, hunting and agricultural pesticides had driven the animal that is America’s national symbol to the brink of extinction. But in recent years, eagle populations have rebounded and stabilized. In 2007, bald eagles were taken off the endangered species list.
“Twenty, 30 years ago, it was a big deal to see an eagle, and now it’s relatively common,” Holst said. “It’s one of the great conservation success stories in America.”
Robert Segin, a spokesman for the U.S. Fish and Wildlife Service, said a 2016 report estimated there are 40,000 golden eagles and 143,000 bald eagles throughout the United States. It also concluded bald eagle populations are increasing at about 5 percent every year while golden eagle populations appear to remain stable.
In Colorado, more specifically, only one bald eagle nest was documented in a 1974 study. In 2017, however, CPW reported nearly 200 nests.
But there are continued risks to the eagle as more land is developed.
On Colorado’s Front Range, for instance, increasing population growth, resulting in rapid construction of housing developments, along with a booming oil and gas industry pose real threats to eagles, said Dana Bove, a retired federal geologist who founded Front Range Nesting Bald Eagle Studies, a nonprofit eagle advocacy group.
While CPW can make suggestions about how new developments can ease their impact to eagles, Bove says more enforceable measures need to be put in place.
“It’s an issue everywhere in Colorado,” he said. “And it’s something we’re certainly looking to address to see if there’s a way we can make some changes in state law that would give recommended buffers some real teeth.”
Southwest Colorado’s eaglesCPW’s Holst said it’s too early to draw any conclusions from the eagle tracking study in Southwest Colorado, but already, wildlife managers are witnessing behaviors that go against previous thinking.
CPW has documented anywhere from 16 to 20 active bald and golden eagle nest sites throughout La Plata and Montezuma counties, as well as hundreds of bald eagles that spend winters in the area.
“We’ve never had transmitters on eagles down here before, so we thought the eagles nesting here in the winter went north in the summer,” Holst said.
Instead, trackers show nesting eagles typically stay around the region.
Ultimately, with the new information in hand, CPW may be able to identify a site where eagles go to hunt. Then, in the future, if any projects were proposed there, the agency could recommend avoiding the area.
“If we see a spot where an eagle goes to hit spawning trout, maybe that’s a place we need to protect,” Holst said.