BRIGHTON, Colo. (KDVR) — The number of bald eagles in the U.S. has quadrupled in nearly a decade, and Colorado has also seen a spike.
Experts are now stepping in to understand bald eagle population trends, habitat use and impacts from human disturbance.
In Colorado Parks and Wildlife’s raptor-nest database, there were more than 90 breeding pairs of bald eagles in the Denver metro area to the Wyoming state line as of 2020.
“The reason we are focused on this area is the concentration of bald eagles along the Front Range, juxtaposed with the concentration of humans and human infrastructure along the Front Range,” CPW avian researcher Reesa Conrey said in a press release. “That intersection is a huge part of this project, in addition to monitoring what the eagles are doing in terms of their nest numbers and nest success.”
Conrey is among the group of avian researchers, placing a small transmitter on the back of the the birds’ necks to get minute-by-minute data wherever they may fly.
The study is expected to last four years and will be the most comprehensive bald eagle monitoring project ever done by CPW.
“We are looking at nest sites along a gradient of human activities and disturbances from urban to rural areas,” Conrey said. “We are especially interested in comparing areas expected to remain stable with those expected to see new development within the next few years.
“We can use spatial data over the past several decades to get at land use change, as this area has been developed for residential and commercial uses, agricultural conversions, sand and gravel mining and energy — including oil and gas wells, solar and wind energy facilities. We’re getting more transmission lines, cell towers, road traffic, use of trails and boating areas and all the other things that go along with human activity and an increasing human population,” Conrey said.
Currently, 14 bald eagles have trackers on them, but the goal is to trap between 25-30 birds for the study, releasing them all back out into the wild after the transmitters are installed.
“We’re thrilled to see data collected by our volunteers contribute to this research effort,” Matt Smith, outreach biologist with the Bird Conservancy of the Rockies, said in the release. “Bird Conservancy has been monitoring the expansion of the bald eagle nesting population across the Front Range for 30 years, and while eagle numbers have steadily increased during that time, so has the human population of the region.
“This gives us an opportunity to put those data to work and learn more about how eagles are adapting to the changes we’re making to the landscape,” Smith said. “Hopefully, this will tell us more about what the future looks like for bald eagles in the years to come and what management actions can be undertaken to ensure a healthy population of this iconic bird in our state in perpetuity.”