Before their trailblazing research around grizzlies, John and Frank Jr. had conducted a survey of various bird species around the Blacktail Butte area near Kelly. When Derek compared that study to his more recent work, he saw a troubling trend. “The population has shown some decline since the ’40s and ’50s. I hypothesized that it could be due to the change in the land use practices around Kelly and Moose. At that time, there was quite a bit more ranching and farming, which kept fields open, providing good habitat for ground squirrels and hunting opportunities for red-tails.”
But, he wondered, what if this decline had less to do with the half of the year they spent in the Tetons, and more to do with the half of the year they spent elsewhere?
The first thing he had to figure out was where “elsewhere” was. At the time, nobody knew for certain. “We wanted specific information, so we put lightweight satellite GPS transmitters on some of the adult red-tailed hawks. We were fully expecting them to migrate down to Utah or Arizona, and we thought it would be really cool if they got as far as Texas. Well, we were really surprised when they went to Mexico; we even had one bird go as far as Nicaragua. So they were migrating 2,000 miles.”
Subsequent years revealed that the hawks returned to the same wintering grounds each year. While Derek’s team found no evidence of drastic habitat degradation in Mexico, they did observe a similar trend of land use slowly, generationally changing. Ultimately, he says, the combination of changes likely contributed to the decline in the raptor population, but the precise nuances are still unclear.
While an improved understanding of red-tailed hawk migration may seem hyper-specific, Derek explains that this kind of research is critical when it comes to advocating for wildlife.
“I really want to understand our wildlife well enough and intimately enough that I can be a voice on their behalf. To communicate what the wildlife needs, what’s important to them, and what it’ll take for them to survive. So part of that’s learning a lot about this species, but the next step, which is just as important, is getting that information out to not only other resource managers, but to the general public in a way that’s both interesting and accessible.”