Researchers to track 20 to 25 bald eagles during the four-year study.

Colorado's most populous corridor, the Front Range, has grown in human population by 18 percent since 2000, and there is no end in sight. The area also happens to be home to a high concentration of bald eagles, with around 90 breeding pairs from the Denver metro area to the Wyoming state line. 

To understand the effects of the growing human population on those eagles that live in the area, Colorado Parks and Wildlife officials have embarked on a four-year study that will measure current population trends, habitat use, and impacts of human disturbance on bald eagles.

“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,” said CPW Avian Researcher Reesa Conrey. “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.”

The study is particularly important as bald eagles were at one point critically endangered in Colorado, with only three known eagle nests in the whole state in the 1970s. After significant revitalization efforts, the eagle population has increased to healthy levels, but researchers are seeing them move into areas far removed from conventional nesting locations. 

Around 20-25 bald eagles will be tagged with a transmitter that connects to a cellular communications network and provides location data of each eagle. CPW has marked and released eagles for the study since July 2020. 

Bruce Snyder of the Bird Conservancy of the Rockies releases a bald eagle that researchers placed a GPS-GSM transmitter on in Golden on June 5, 2021. (Courtesy of Jason Clay/CPW)

“The transmitters that we are using for this project are different from what typically have been used,” Conrey said. “Previous generations of wildlife transmitters required biologists to use antennae to pick up the signals or they connected to satellite networks. But these transmitters connect to the cellular communications network. It allows our transmitters to be lighter in weight. That reduces potential stress on the eagles and it was a good choice for us in the Front Range because we have a lot of cell towers in this area.” 

Researchers and volunteers will be collecting data and observations for the study. Results will be used to model the eagle population trajectory and expected impacts of human populations, which will be used to formulate recommendations to minimize disturbances in the eagles' environment. 

“We’re thrilled to see data collected by our volunteers contribute to this research effort,” said Matt Smith, outreach biologist with Bird Conservacy of the Rockies whose volunteers are helping with the study. “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. 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."

You can learn more about this important study on the Colorado Parks and Wildlife website.

Take a look at the live eagle cam and tell us in the comments what you see.