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Photo: Julie Mitchell

If you’ve ever driven along the Going-to-the-Sun Road, gone for a backcountry hike in Glacier, or experienced the grandeur of Hidden Lake, there’s a good chance you’ve seen one of the park’s most majestic species: Glacier’s bighorn sheep.

With an athletic disposition and large curved horns weighing up to 30 pounds on males, the bighorn is a staple throughout the park. Despite these impressive characteristics, Glacier’s bighorn sheep face many risks. Respiratory disease can decimate bighorn populations, impacting the survival of lambs for many years to come. There are also connectivity concerns in particular corridors, due to evidence of increasing traffic, recreation, and development. That’s why the park is hard at work studying bighorn movement across Glacier and Waterton Parks, identifying potential areas of disease migration between park herds, and providing connectivity with the larger region.

Your donations to the Glacier Conservancy are supporting this multi-year study on Glacier’s bighorn sheep, giving park managers the tools they need to better understand and protect bighorn sheep for years to come.

Research Helps To Better Understand and Protect Glacier’s Bighorn Sheep

In an effort to learn more about Glacier’s bighorn sheep and how your donations are making a difference, we caught up with Elizabeth Flesch, the postdoctoral researcher assisting with the current bighorn study in Glacier National Park. Keep reading to get the inside scoop and see some amazing photos from this study your support is making possible.

Glacier National Park Conservancy (GNPC): Can you tell us a little bit about you, where you’re from, and your educational background?

Elizabeth Flesch (EF): Originally from the flatlands of Iowa, my interest in the natural world developed from a young age through visits to Yellowstone National Park with my family. Nose pressed against the car window, I marveled at the bison, elk, and grizzly bears in the wilderness, and a lifelong fire of curiosity and passion for ecology was ignited. Consequently, I earned a degree in Biological Sciences with a concentration in Fish and Wildlife Management at Montana State University (MSU). My studies culminated in my honors senior research thesis regarding bighorn sheep and mountain goats in the Greater Yellowstone Area, which involved backpacking in rugged terrain to map where they were located.

After graduating, I worked seasonally on wildlife projects in multiple locations, including surveying for pikas among the volcanic rocks of Lassen Volcanic National Park. My heart was always in the Rocky Mountains, and I returned to MSU for graduate school, where I completed my PhD on bighorn sheep genomics in 2020.

A woman smiles while standing along a trail in the alpine landscape of the Rocky Mountains

Postdoctoral researcher, Elizabeth Flesch, is leading the genomic analyses and GPS collar analyses for bighorn sheep in Glacier National Park.

Photo: U.S. Geological Survey

GNPC: What led to your interest in studying bighorn sheep? How did you end up in Glacier National Park?

EF: I’ve always been inspired by animals that thrive in the rugged mountains. I was fortunate to serve as the High Country Citizen Science Coordinator in Glacier National Park for three summer seasons, where I fostered public engagement in research concerning pikas, mountain goats, and bighorn sheep. This program of course is made possible by the generous support of the Glacier Conservancy. In this role, I worked to partner public interest with scientific inquiry, in order to promote both environmental education and the advancement of understanding regarding alpine species.

When I started graduate school, I stayed in touch with my collaborators in Glacier and we integrated on Glacier’s bighorn sheep herd into my statewide evaluation of bighorn sheep herd genetics, thanks also in part to the generous support of the Glacier Conservancy! I am quite happy to continue to work on Glacier bighorn sheep research as a postdoctoral researcher at Montana State University, in collaboration with the National Park Service and U.S. Geological Survey.

A flock of bighorn sheep traverse a road with snowcapped mountains in the distance

Photo: Elizabeth Flesch

GNPC: What is the most interesting bighorn story that you’ve heard and/or experienced?

EF: My nostalgic bighorn sheep recollections are general impressions: a group of lambs galloping across green meadows of springtime; the silhouette of rams on a ridgeline at sunset; a group of ewes and lambs darting to avoid a curious coyote. One interesting bighorn encounter was when we were darting bighorn sheep in the Greater Yellowstone Area to deploy GPS collars and collect genetic samples. The bighorn sheep in this particular area were often found along the road in winter, so we would try to dart them from the pickup truck to avoid spooking them from walking on foot. However, after a few visits, one group of bighorn sheep we had been stalking appeared to remember us. As soon as they spotted our truck, they ran for the hills!

GNPC: What is something that most people don’t know about bighorn sheep?

EF: Historically, bighorn sheep populations were relatively widespread across western North America. However, European colonization of the West brought market hunting and domestic sheep, which provided direct competition and new diseases. These influences resulted in the decline and complete disappearance of many bighorn sheep populations. Over the past century, wildlife managers moved bighorn sheep to previously occupied areas and supplemented small populations in translocations, in an effort to restore the species to its former range.

For my dissertation research, we evaluated the genetics of source and recipient populations of translocations to determine the success of these past efforts. We discovered that translocations of larger groups, including males and females, were more successful in providing gene flow than small translocations of a few rams. Interestingly, Glacier’s population is unique in that it has never been extirpated or supplemented with external translocations. This means that the bighorn sheep we see in the park today have lived continuously in the area for many generations!

A bighorn ewe and lamb graze along a meadow in the alpine of the Rocky Mountains

Photo: Elizabeth Flesch

GNPC: Why is this study important for the viability of Glacier’s bighorn population and bighorn populations as a whole?

EF: A major limiting factor for bighorn populations is respiratory disease. Understanding what facilitates or impedes movement is imperative for identifying management options in the event that pneumonia strikes one or more of the herds within Glacier and Waterton Lakes National Parks. Glacier has one of only two large native populations of bighorns in Montana with multiple loosely connected herds. However, their patterns of movement and the environmental characteristics affecting their movement are poorly understood. Using GPS collar and genomic data from nearly 100 bighorns collared by USGS across the eastern side of the park (from 2002-2011), we will assess the factors influencing their movements, including roads, trails, mineral licks, and habitat.

When we know how much different conditions influence bighorn sheep movement, we can create a map showing the places where bighorns are more and less likely to move across Glacier and Waterton Parks. This will let us identify potential areas of disease migration between park herds, which is key to reducing the likelihood that disease will affect more than one bighorn herd. The map can also be used to inform planning for maintaining connectivity across the US Highway 2 corridor that runs along the southern border of the park. The Glacier Conservancy’s support is making this project possible!

A herd of bighorn sheep graze alongside a road with a lake and mountains in the distance

Photo: Elizabeth Flesch

GNPC: Is there anything you’d like to add about the importance of this program?

EF: This research includes ground-breaking genomic and GPS collar analyses that will extend far beyond Glacier. It develops a framework for multiple parks and other management agencies with questions about movement and disease. In Glacier, it will inform options for mitigating potential respiratory disease outbreaks and plans to manage connectivity of bighorn sheep herds within the park and with neighbors. It will also provide baseline data on patterns of movement and genetics in a large native herd that coexists with mountain goats. If changes in mountain goat or bighorn sheep populations occur, this might help us understand how or why they are changing.

Protecting Glacier’s Bighorn Sheep For Future Generations

There are few animals that can match the majesty found in the herds of bighorn sheep that populate Glacier National Park. The sheep’s namesake horns make them a classic symbol of the park. Glacier has one of only two large native populations of bighorns in Montana with multiple loosely connected herds.

Thanks to your support, the park is exploring options for mitigating potential respiratory disease outbreaks, developing plans to manage connectivity of bighorn sheep herds within the park and with neighbors, and providing baseline data on patterns of movement and genetics in a large native herd of bighorn sheep that coexists with mountain goats. This work also continues a cooperative partnership with Montana State University on a statewide study of bighorn sheep.

A bighorn stands on the edge of a cliff face

Photo: U.S. Geological Survey

How You Can Help Glacier’s Bighorn Sheep

Ewe (get it?) can help protect Glacier’s bighorn sheep by making a donation today, sharing this blog post with a friend, or following the Glacier Conservancy on social media. We appreciate your support!

A bighorn sheep with large curved horns look at camera with snow and trees in the background

Photo: NPS

Your Support Makes A Difference

This project and many other critical projects would not be possible without your donations to the Glacier Conservancy. Learn more about how your support is making other scientific research projects possible in Glacier National Park.