Why I’m Tracking Bison Herds Across the Prairie

I attended Colorado College for my undergraduate studies in organismal biology and ecology. After graduation, I was lucky enough to intern with Bill McShea at the Smithsonian’s National Zoo and Conservation Biology Institute’s Front Royal, Virginia campus. For nine months, I worked with Bill on mammal camera trapping projects and forest vegetation surveys. Through Bill, I connected with research ecologist Hila Shamon. By that point, I was interested in studying the movement of large mammals, and I was also eager to return to the West, so I jumped at the opportunity to join the Great Plains Science Program as an intern. During that time, my position shifted from an internship to a graduate fellowship, as I am now working on a doctoral degree in ecology and environmental sciences at Montana State University.  

Currently, I am at the American Prairie Reserve in North Central Montana researching bison collective movement. Bison are majestic animals and have an amazing legacy in this landscape. They’re the largest land mammal in North America, and they are highly social herd animals who historically migrated across the Great Plains. 

My research focuses on how social organization of bison influences the way they move across the landscape, select resources and subsequently modify their environment. There’s a lot we don’t know about bison's social organization. Why do they form the groups they form? Today, many bison conservation herds are semi-free roaming, but their movements are restricted by human-imposed barriers such as fencing and land use policies that limit their ability to exhibit historical migratory patterns. How do their behaviors and impact on the landscape differ from their historic patterns?  

We have found that even though bison at American Prairie consistently break off into smaller sub-groups, the sub-groups are not stable over time, and they are not composed of related individuals. We expected to see stable sub-groups based on relatedness because bison are colloquially described as having family groups. We may have seen this result because of the more intensive management practices that are common with modern bison, including smaller pasture sizes and more frequent removal and relocation of individuals. Because their movement patterns were not clearly driven by their social organization, I am now looking into how group dynamics relate to resource availability and other environmental factors.

Over the course of my time in Montana, my “average day” has changed a lot. I’ve spent time driving across the plains, finding bison herds and making behavioral observations to try to identify the social networks and group dynamics of the herds. We use small, unobtrusive GPS ear tags to track the bison, which let us see the movement of both the herd and how individual bison move in relation to each other.  

I am also studying the land-use of bison and other ungulates, or hoofed animals. We have 45 randomly sampled plots on the landscape where we measure forage quality. I fly a drone over each location, to determine forage quality, and I collect grass clippings to analyze nutrient composition of the vegetation. I also review camera trap footage to see how other herbivorous animals like pronghorn, mule deer, white-tailed deer and elk are responding to varying intensities of bison grazing in the plots. 

When you’re out on the plains with bison, you can imagine what it was like for the majority of the country to be covered in huge herds. It makes you think of what was here, what we’ve lost and what we could maybe gain in the future as the species is restored. 

There’s a lot of doom and gloom around conservation and the environment these days, but there are amazing collaborative conservations projects going on and areas where people can make a difference. My advice to people interested in a conservation career is to be persistent and put yourself out there. Find people in the field and tell them what you want to do. Chances are, they will want to help you make connections.