Discovering Ungulate Migrations

Dr. Kevin Monteith of the University of Wyoming and the Wyoming Migration Initiative uses ultrasound to check the pregnancy status of a mule deer doe after affixing it with a GPS collar to document its migration movements.

Excerpt from Spring 2019 issue of Fair Chase

Animal migrations have long fascinated people and been a focus of biological research. Bird migrations, notably, have interested people of all ilks as their seasonal journeys have been the most visible (and audible). Mammal migrations have held less popular appeal and awareness among the general public, largely due to the fact that they tend not to be observed from one’s backyard, they are not as visible in the remote landscapes where many occur, and scientists still have much to learn and describe. Notable exceptions are the caribou migrations in arctic North America and wildebeest and zebra migrations in East Africa. Over the last two decades, groundbreaking research has documented dramatic migrations of some of North America’s most iconic ungulate species in the West—mule deer, pronghorn, and elk. The story that has unfolded has been revelatory not just in documenting the migrations, but in explaining the nature of them. A new book, titled Wild Migrations: Atlas of Wyoming’s Ungulates (Atlas), brings this story to life.

The Atlas itself can serve as a textbook or a coffee-table book and pretty much everything in between. Edited by a team of scientists and publishing professionals, led by Dr. Matt Kauffman of the U.S. Geological Survey’s Wyoming Cooperative Fish and Wildlife Research Unit, the book synthesizes decades of research in Wyoming and the Greater Yellowstone Ecosystem. It comes at an opportune time, soon after issuance of Department of the Interior Secretarial Order 3362 that directs Interior agencies to collaborate with 11 western states in identifying and protecting big game migration corridors.

The Atlas begins with a lengthy introductory section that gives the reader background information on migrations, habitats, and the natural history of Wyoming’s ungulates. A section on history chronicles ancient rituals, hunting, and the emergence of the conservation movement, including the role of the Boone and Crockett Club in the recovery of populations following the market-hunting era. A section on science details how biologists actually discover and map migrations—a complex endeavor described for the lay reader. A section on threats details the numerous challenges migrating ungulates face. Another section on conservation identifies ongoing measures and those that are needed in order to sustain these migrations. Throughout, the Atlas is liberally illustrated with breathtaking photography, artwork, and groundbreaking maps.

Some key findings from this umbrella effort, known as the Wyoming Migration Initiative, include the following:

• Migration corridors are not just a transportation route; they are habitat unto themselves, where ungulates moving from winter range to summer range “surf the green wave” of nutritious vegetation as it emerges phenologically from south to north. Many points along the route are key stopovers for animals where they may stay and fatten up for days or even weeks.
• These migrations, including the longest ever documented for mule deer (150 miles) are not hard-wired; they are culturally transmitted, meaning the routes are passed down from generation to generation from mothers to their young. The implications of this are profound; if human-caused or other disturbance disrupts migration for a period of years, the use of the corridor may be lost with likely negative consequences to the fitness of the herd.

The good news here is that attention is being directed to conserving these corridors across the West, thanks to leadership provided by the Wyoming Migration Initiative and its participating partners, most notable the Wyoming Game and Fish Department and the USGS Coop Unit at the University of Wyoming. We have the techniques and means to identify these corridors and growing awareness and support to enact conservation measures.

In the 1890s, the Boone and Crockett Club created the Bronx Zoo so that future generations of Americans could see living examples of big game. This was based on the sobering thought of the time that these animals would disappear from the landscape. The story of the emergence of the conservation movement and recovery of populations thankfully put that concern to rest. Now we have another story emerging, one that is fascinating seasoned biologists, hunters, and wildlife watchers alike. This new chapter in our efforts to sustain these magnificent animals will be an important one to follow. One can learn more by visiting the website
migrationinitiative.org.