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Wildlife

Wyoming Game and Fish Commission considers migration route data in new policy directives

Written by Natasha Wheeler

Laramie – “If agencies and other stakeholders want to continue to enjoy and sustain the herds we have today, we have to sustain and take care of their migration routes,” stated Western EcoSystems Technology Research Biologist Hall Sawyer during the Wyoming Game and Fish Commission public meeting, held in Laramie on Oct. 5-6.

Sawyer and others presented their positions regarding potential updates in Commission recommendations for gas and oil development in and near big game migration routes.

“Migration promotes abundance, and this is true worldwide,” he explained. “Migratory populations always outnumber non-migratory populations.”

In the past decade, scientists used new tools to understand big game migration patterns and document how animals move across the vast and diverse landscapes of the West.

New tools

“Two things have been game-changers for us in the research community, and the first one, helicopter net-gunning, allows us to capture animals in remote regions that would otherwise be inaccessible,” Sawyer explains.

Secondly, he identified GPS technology as a game-changer in migration science.

“With just one study, we can end up with hundreds of thousands of locations from dozens of animals. This was just unthinkable only a decade ago,” he continued.

With new technology, scientists are better able to determine how animals move between seasonal feeding grounds, including specific routes and resting patterns.

“We can estimate the width of migration routes and also the intensity of use within those routes, or where those animals spend the most time,” Sawyer noted.

Wildlife Division Deputy Chief Scott Smith added, “There are a lot of new details that this research is describing for us to use as land managers. We think that it’s important to embrace this emerging science and update our management recommendations appropriately.”

Defining habitat

Smith also defined a number of terms used to describe big game migration, including migration routes, corridors, stopover areas and bottleneck.

Routes are paths used by individual animals, and corridors are areas across the landscape that whole herds use to move between seasonal habitats.

“Stopover areas are localized areas that ungulates use to rest and feed during fall and spring migrations,” he stated.

Sawyer explained that differentiating stopover habitat from other parts of the migration route is important from a biological management perspective because animals rely on those areas for forage during their migration.

“We now view migration corridors as critical habitat, just like winter range. Mule deer, for example, spend 95 percent of their migration time in these stopover habitats,” he said.

Bottleneck points also impact migrating herds.

As Smith noted, “A bottleneck is any portion of an ungulate migration corridor which physically or behaviorally constrains the animals during migration.”

Bottlenecks may be created by natural means, such as geological features, or by human impacts, such as highways or other barriers.

Multiple use lands

“Most of these migration routes occur in multiple use landscapes that support a variety of uses, such as energy development, livestock grazing and recreation. Anything we can do to better prioritize where our management conservation efforts could be aimed is beneficial,” Sawyer remarked.

Smith asked the Commission to consider oil and gas development constraints and requested that the terms “stopover” and “bottleneck” be added to current mitigation policy.

“This is emerging science that has been collected over the last 10 years, and we are trying to adapt to what we see the science is telling us,” stated Smith.

After Smith and Sawyer presented their arguments, representatives from various interests spoke about their positions in regards to the draft proposal distributed at the meeting.

Wyoming Stock Growers Association Executive Vice President Jim Magagna commented, “As we have seen from the research, human activity and development undoubtedly has some impact on the migration corridors that are important to all of us.”

Yet, the weight of those impacts is still being debated, he argued.

Additional data

“While the proposed changes only apply to public land, given the land ownership patterns that exist in this state, from checkerboard to isolated private parcels, activities that are restricted or allowed on public lands necessarily impact what can reasonably be done on private land,” explained Magagna.

He noted that restrictions for one type of land use often set the precedent for further restrictions in other land uses as well, including livestock grazing, and therefore current regulatory standards should be considered sufficient until more solid data is collected.

“We would encourage the Commission to continue to work in a flexible manner with all interests to make whatever adjustments are necessary and reasonable to be sure that we protect these valuable wildlife corridors,” he said.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at This email address is being protected from spambots. You need JavaScript enabled to view it..