Yellowstone Winter Ecology

We set out to establish patterns of large mammalian behavior in the Lamar River Valley region of Yellowstone National Park during winter. As a region of significant ecological impact, understanding the movements and preferences of species of concern aids in informing management decisions.

Winter research presents varied and unpredictable challenges at every turn. In order to reach our study sites, we utilized backcountry ski equipment and sleds to ensure we could carry enough supplies to support ourselves.

Observational evidence suggests a wide variety of unique behaviors are used to survive the challenging winters, especially among Bison. Resource and elevation gradients are present along the plowed road and deeper into the park. Bison looked healthier, with thicker coats, fewer ribs showing, and more calves, at lower elevations, indicating a strong elevational gradient. Further from the road, small groups of males predominated, following paths established over weeks or months of repeat travel. Paths of least resistance became a dominant feature of travel, with wolves frequently appearing to travel in or alongside Bison tracks. As he was leaving the field Shane found that most of his tracks were used, likely by wolves or coyotes the previous day. We found little evidence of preferential use of geothermal features, but without further research it is impossible to establish whether that is a result of proximity to roads, movement patterns, time of year, or any other combination of confounding variables. However, this preliminary research demonstrates trends towards habitual path use, group movement, and multi-year food locations, which can be applied to conservation strategies in the Greater Yellowstone Ecosystem (GYE).

Without this grant, obtaining the funds for this trip would have been nearly impossible. The experience we were able to gain in the field was challenging, unique, and something neither one of us had ever been able to do before. Engaging in the environment in this way was amazing, and created so many fantastic memories. Hearing a wolf pack howling next to our tent our first night in the field provoked such a strong sense of awe and connection to the space we occupied. So too did our standoff with four massive bison, who wanted to take the same path we had just came in on. We'll never forget the fear, wonder, joy, and exhilaration of those moments in our journey, and the lasting impact it has had on us.

Our next steps are to expand research to incorporate more sites, particularly in the Pelican Valley area, and incorporate sites that we were unable to access during this expedition. With increased logistical support, a longer term study of major geothermals would be possible, incorporating multiple sites over several years, although snow machine use would have to be added to the access plan.

Special thanks to the Venture Grant Committee, the Keller Family, and Dr. Brian Linkhart for sponsoring this research. Additionally, we acknowledge that this work took place on the ancestral lands of the Eastern Shoshone, Umatilla, and Crow Peoples. We have a responsibility to acknowledge our Indigenous connections, as well as the histories of dispossession and forced removal that have allowed for the growth and survival of institutions like the National Park Service and the advancement of research like ours.