A study from Utah State University found that each year one ungulate dies from getting caught up in fence line for every two and a half miles of fence. There’s been a push recently to remove or replace fences to allow deer, pronghorn and elk to move about and migrate. But one of the biggest hurdles is knowing where all those miles and miles of fence actually are.

Beyond Yellowstone Living Lab’s Kristin Barker is part of a team that mapped more than 150 miles of fence on public lands east of Yellowstone near Cody last year. Data was shared in the Absaroka Front Fence Inventory 2024 summary report.

Wyoming Public Radio’s Olivia Weitz spoke with Barker about how she hopes the map will be used to help wildlife, while also balancing the needs of working cattle lands.

Editor's Note: This story has been edited for clarity and brevity.

Kristin Barker: As someone who's newer in the fence ecology world, I did not realize how many fences there are on the landscape. It is just mind blowing how many miles of fences there are.

I also didn't understand that nobody has any idea where they are or what conditions they're in.

There have been a couple of studies trying to look at fences, and it's hard because we don't have the information. There have been some conservative estimates of over 150,000 miles of fences just in elk wintering habitat in the Greater Yellowstone Ecosystem.

There's been a collared pronghorn that was noted navigating 250 fence lines in a single year, so they're really pervasive across the landscape, and there are a lot of groups working to make sure those fences are safe for wildlife, but we just really don't have all the information.

Olivia Weitz: Why is all this fence here? When and why was it installed? What kind of fence are we talking about? And do we know anything about the ratio of used to unused fence?

KB: I can't speak to the ratio of used to unused. I can say that fences have been out on the landscape for over 100 years.

There was the, they call it the barbed wire boom of the late 1800s, when the use of barbed wire fence just exploded throughout the West. So fences really started going up in earnest then, and of course, they've continued to be built and put out on the landscape since then.

There are definitely fences that were built a long time ago that aren't needed anymore, and it's helpful to get those off the landscape. There are also fences that are old and kind of not in great shape, but they are still being used. And those are actually extra important to try to deal with, because it’s especially when the top wire gets really loose or when the top two wires get loose is when it's really easy for animals to get snagged when they're trying to jump over the fence. The older fences that are in kind of rough condition are actually quite hazardous when wildlife are trying to cross them.

OW: I know you were working with a crew that was helping you help map the fences. Did you encounter any wildlife that was caught in a fence trying to cross the fence or anything like that?

KB: The crew found five wildlife mortalities that were definitively caused by fences, animals that got tangled up in fences and died there. And we were very conservative on what we considered a mortality.

There were some other pieces of animals and dead things that were likely attributable to fences, but five of them were very clearly just killed by the fence itself.

OW: What did the field crew find in terms of the condition of some of these fences, the height of some of these fences? How will that information be used to potentially modify fences in the area in the future?

KB: They found a range of fences from following very wildlife-friendly specifications to less so. For instance, there is a really long drop fence, which is very cool. Game and Fish can drop the entire fence down onto the ground during wildlife migration time, so the animals can pass through.

That's an example of a fence that they found that's really great for wildlife.

Anything under about 38 inches high is decent for animals to jump over. The bottom wires are what's important for pronghorn because they typically scoot under fences instead of jumping over them, so you want the bottom wire to be like 16 to 18 inches above the ground.

They found a range of fences, some that were built to those specifications, but most fences historically haven't been built to those specifications because they only learned those numbers recently.

One of the things that the data are being used for right now is an effort by AFI [Absaroka Fence Initiative] to do some range-wide improvements specifically targeting the Carter Mountain pronghorn herd.

Pronghorn just have a harder time crossing fences and they’re really susceptible to other things like deep snow, so trying to make sure that habitat is easy for pronghorn to move through as possible is really important moving forward.

AFI is using the data we've collected to identify fences that could be modified, so that it's easier for pronghorn to cross them.

OW: Some of what you were doing out in the field, as you were looking at where the fences are located, is that you were cleaning up prior data on where the fences were located. What did you do there in terms of updating what's out there for mapping?

KB: Essentially, the field crews would walk the boundaries of all of the grazing allotments and pastures on the Forest Service, and if those were not surrounded by fence, then they would remove that from the existing database that we had pulled together.

OW: Are you working with private landowners to document fence locations? And how is that going?

KB: We are very happy to work with private landowners. In our first year, we decided to stick with public lands entirely for two reasons. One is because those are the places where fences are the least well known and least mapped. A lot of private landowners know where their fences are.

Number two, we wanted the data we collected to be broadly accessible and we didn't want to share any private landowner data without their express consent. We just focused on public land for now, but we are definitely interested and excited to work with anyone who would like to work with us in the future.

OW: Has there been any fences that have been modified or removed at this stage? Tell us what the next phase of the project is going to look like.

KB: AFI is currently working on the modification and removal end, so that's sort of their expertise is doing physical fence work. We are continuing our fence mapping project to inform current and future work. As they are developing plans and modifying fences that we've already mapped, we're going to continue mapping more.

Based on our first season of work, they've identified the Carter Mountain pronghorn herd range as a really particularly good focal point for them to start on. And so we are supporting that work by also focusing on that range for our next phase of work.

This summer we're going to do what we can to map all the fences across the entire range of the Carter Mountain pronghorn.

OW: Is there anything else I should have asked? Anything else that you want to highlight or that the public should know at this juncture?

KB: I would love it if people knew that the places where folks are running cows and need fences, those fences are still really important, and we're glad they're there. There are also ways that you can still retain livestock just as effectively and make it easy for other wildlife to cross the fence.

There are a lot of cost share programs, for instance, through the NRCS, where you can actually get money to repair your fences. If there's a fence line that you want to replace anyway, you could go for cost share to replace it. And you could have it replaced to two wildlife friendly specifications. So it's kind of a win-win.