Monarch Of The Skies: How Golden Eagles Reveal The Intricacies Of An Entire Ecosystem

May 18, 2018

The Draper Natural History Museum at the Buffalo Bill Center of the West will open a new permanent exhibition on June 10. The exhibition focuses on the last ten years of research on golden eagle activity in the Bighorn Basin. Golden eagles are a top predator so by studying the top of the food chain, researchers are learning not just about the bird but also about the dynamics of animals they eat and the ecosystem they live in.  

In mid-March, I tagged along as the golden eagle research study group from the Draper Natural History Museum in Cody scouted for eagles in the Big Horn Basin. Corey Anco, the assistant curator at the Draper, spotted an eagle.

“And there’s one sitting on a nest there,” exclaimed Anco.

Anco works with senior curator Charles Preston, whose team has been researching golden eagles for the past 20 years. When Preston first arrived in Cody, there was no data on the eagle.

“We realized we had no idea what was going on in our own Big Horn Basin here,” said Preston. “And so I thought that it was important to document [it] and so we can not only compare it with other sites but we have a baseline, and find out if there is a trend of increasing or decreasing population or reproduction.”

The word baseline is key. Preston hoped to tie his research in with other golden eagle studies.

“What we're trying to do is develop a network of monitoring sites,” said Brian Woodbridge of the U.S. Fish and Wildlife Service. Woodbridge is in charge of leading the Western Golden Eagle Team which is a west-wide group of dispersed teams focusing on golden eagle conservation and management. He said the baseline research is what allows golden eagle studies throughout America to become a unified network.

“Where they share results and methods and try to develop a more comprehensive picture of what's going on with golden eagles in the West,” said Woodbridge.

Starting in 2008 after winning enough grants to support the basic amount of research, Preston began to collect the bare minimum data. This included monitoring reproduction and the food remains in the nest. Then depending on the amount of funding, some eaglets received a satellite tracking device as well as leg bands. And with constant collection of what seems like not that much data, patterns began to pop up.

“We found very early on that the diet is absolutely dominated by cottontails in our area, not many jackrabbits. We found a very strong relationship between golden eagle reproduction in a given year and cottontail abundance in that year,” said Preston.  

Basically, this means that the golden population heavily depends on one species for food: cottontail rabbits.  And this led Preston to even more questions.

“What may cause that and what the implications of that [are] not just for golden eagles but for other predators, but also for the vegetation and maybe even the quality of graze for domestic livestock?” 

Preston's colleague Corey Anco said the initial data collected gives a clearer image of the dynamics of the Bighorn Basin Ecosystem.

“Every species, every ecosystem here is a big part of that puzzle so you kind of take a step back and look at the big picture of what’s happening in the sagebrush steppe ecosystems, what’s happening in the Intermountain West and what’s happening as climates begin to shift or adapt,” said Anco.  

As we were driving through the area, the researchers explained that sagebrush is the ideal habitat for goldens since they can easily spot their prey but Preston said eagles are not the only ones that could be impacted by a change in the ecosystem. So he envisions creating discussions and conversations on the sagebrush steppe ecosystem itself.

“It's all the same big piece of landscape and it affects lots of people and of people affect it. And we have this opportunity to look at conservation on a large scale and a real big picture with all the stakeholders in the room," said Preston.  

The Monarch of the Skies exhibition will hopefully continue this dialogue, as the exhibition educates the public on the importance of studying the diversification of an ecosystem.  

This is the first part of a two-part series focusing on the Monarch of the Skies exhibition at the Buffalo Bill Center of the West. Next, we’ll delve into cultural significance of golden eagles to the Plains Indian people.