Raptor researchers head down Montana's Rogers Pass at dusk, Oct. 24, 2019. The team counted birds on top of a nearby ridge trying to determine why migratory golden eagle counts in Montana have dropped in recent decades. CREDIT KYLIE MOHR
Research Shows Big Drop In Golden Eagle Migration Over Montana
The sky of west-central Montana turns into a highway for migrating golden eagles this time of year. And as the birds fly south, researchers are counting. Local researchers say annual counts show North America’s largest bird of prey’s migratory population is struggling in Montana.
We’re crouching in a camouflaged hut atop Rogers Pass. It’s cold, with gusty winds and several inches of snow on the ground.
Rob Domenech, executive director of Missoula’s Raptor View Research Institute, grabs his binoculars. He and other field biologists are trying to spot eagles. It’s their last count of the season and all are staring intently across the valley.
Migration monitoring helps scientists get a population count on the birds, who usually nest in remote northern locations and are hard to study during other times of the year.
"What we do is just scan these hillsides constantly," Domenech says. "These guys are scanning up there, we have radios, if they see something they’ll let us know."
Decades of migration counts of the birds above Montana indicate that the golden eagles that travel have declined here.
Domenech and others spend weeks on ridge lines this time of year trapping and banding birds, outfitting them with tracking tags and collecting data. This helps them monitor trends and follow migration paths. Not unlike a puppeteer, Domenech pulls strings to manipulate a pigeon outside the hut in hopes of catching a bigger bird’s eye.
"Now we’ll just do some periodic luring and hopefully in about five minutes it’s here," he says.
"It’s those migratory populations that are throwing up a red flag to researchers and conservationists," Domenech said, speaking on the phone before the counting trip.
Are the birds dying during migration? Are they not not migrating as far south as they used to?
"What exactly is going on is hard to say. And that’s part of what we’re trying to figure out with our telemetry work."
Golden and bald eagles are protected under federal law and people face fines and potential jail time for killing, wounding, or disturbing the birds.
Researchers say migrating golden eagles face a unique set of challenges that include habitat loss, car collisions, power line electrocutions, wind turbines, traps and lead poisoning, to name a few. The birds come from as far north as the Brooks Range in Alaska and tagged birds have wintered as far south as Mexico.
While some Montana researchers say they’re seeing a decline in eagle numbers, other available research from across the West shows the non-migratory population is more stable. The 55th parallel delineates the two populations, with those that breed in harsher northern climates needing to migrate to follow food sources. This potentially puts them in more danger.
Some recent reports indicate researchers may have reason to believe the bird’s dipping migration numbers are stabilizing in Montana. A Hawk Watch report from 2016 says recent counts give "reason for some optimism," with the highest number of golden eagles tallied in the region since 1998.
Missoula’s Rob Domenech and his team will add this year’s bird watching data to the picture soon. Domenech says a healthy golden eagle population often means a healthy ecosystem, or vice versa.
"So what’s happening with golden eagles could be in fact indicative of the ecosystem as a whole. They are sort of the canary in the coal mine of ecosystem health, let’s say."
Counting time is coming to a close. While the team wasn’t able to catch a golden eagle on the last day of the 2019 season, they did count 15, and managed to trap a goshawk. The field biologists quickly banded the bird.
Researchers are packing up their work site before snow makes it inaccessible. It’s too soon to tell if the migratory golden eagle decline in Montana has stabilized for good. But scientists are working to learn what they can from the birds soaring overhead.
Scientists Forced To Adapt As COVID-19 Complicates Long Term Research
Kayla Ruth and Samantha Bundick look through binoculars in 2016 while doing research aimed at determining the species of songbirds they're observing on private lands in Eastern Montana. COURTESY UM AVIAN SCIENCE CENTER
Scientists' spring and summer field seasons are being postponed, altered or cancelled completely in the face of COVID-19. Time sensitive research is the most vulnerable.
This story is another in our series looking at the impact of the novel coronavirus pandemic on scientific research efforts in Montana.
[Songbirds singing]. This is what songbirds sounded like a year ago in eastern Montana’s sagebrush. But Victoria Dreitz and her 20 field techs aren’t there to finish recordings for the final year of their decade of research into the birds. Concerns about spreading the virus to rural communities cancelled the season.
"It doesn't feel good losing field data, but everybody's health comes first before the data collection."
Dreitz is the Director of the University of Montana’s Avian Science Center. Her research is time-sensitive. She and her students need to be in the field when birds migrate, and when their eggs hatch. That time is now.
"The animals don't wait just because we needed to figure out our processes."
Some field seasons are proceeding roughly as planned, while other far flung trips were already scratched. But the natural world doesn’t pause for a pandemic. PhD student Claire Rawlings Gilder studies fluvial geomorphology at UM. That's a fancy way of saying she looks at how landscapes change in response to forces like water. The state’s stay-at-home order in March quashed plans to place equipment in the Middle Fork of the Flathead River this spring.
"Once the flows start going up during spring snow melt, it's not safe to be on the river if you’re trying to do data collection. I mean, if you're doing whitewater rafting, it might be great. But that was not our hope."
Missing that information could compromise her overall study. "So we're gonna have to come up with some more creative ways to think about how the river’s behaving."
Thatcher Montgomery records songbird data collected on private lands in Eastern Montana in 2014. CREDIT COURTESY UM AVIAN SCIENCE LAB
The impact of losing or postponing a summer in the field varies. PhD students might have time to cope with delays, but master’s students and undergrads have a shorter window before graduation. University guidelines to keep people safe, although relaxed slightly May 4, are adding logistical and financial challenges. Crews need plans for social distancing during travel, research, sleeping, cooking and living in the field. Stringent cleaning of shared spaces and gear, plus wearing face masks and taking temperatures every 12 hours, is also suggested.
Associate professor Andrew Whiteley says he’s working through these complications to keep his students’ upcoming field seasons on track. One study on westslope cutthroat trout, for example, requires that each generation of offspring be caught.
"It just takes a long time for us to understand patterns. A missing year could have a big effect."
So Whitely and others are getting innovative, tapping students’ roommates or married couples as field helpers to get around social distance hurdles. They say adaptability is just part of doing science.
This story and our series this week looking at how the novel coronavirus pandemic is changing scientific research is supported by a grant from the National Geographic COVID-19 Emergency Fund for Journalists.