A single house rising from an open Wyoming meadow might seem like nothing — a modest footprint in a vast landscape. But for elk, mule deer, moose, and pronghorn threading their seasonal migration routes, even isolated rural buildings can quietly close off the path ahead. Conservationists have long suspected that rural housing fragments these corridors, but lacked the precise measurements to make that case to planners and zoning boards. A new study has now produced those numbers.
A problem hiding in plain sight
Rural housing has long raised concerns among wildlife biologists, but its precise impact on big game migration remained poorly understood compared to more visible threats. Highways get overpasses. Fences get retrofitted. Energy infrastructure draws regulatory scrutiny. Rural subdivisions, by contrast, spread quietly across the landscape with few clear standards for how much open space they must leave behind.
Earlier research offered troubling hints. Studies showed mule deer rushing through rural developments without stopping to rest or feed — a behavioral sign of stress. Other work documented how deer actively avoid densely packed houses, and a 2016 paper suggested that housing could be even more harmful to migrating mule deer than energy development. Yet none of those findings gave planners or zoning boards a concrete number to work with. Closing that gap is exactly what the new research set out to do.
How the researchers built the picture
University of Wyoming associate professor Jerod Merkle and his colleagues started with an unusual dataset: a Microsoft mapping project that documented the footprint of every building across the Cody and Jackson, Wyoming, areas. From that data, the team constructed a spatial grid showing the minimum distance between structures at any given point in the landscape.
They then layered in hundreds of thousands of GPS collar data points collected from elk, mule deer, pronghorn, and moose. The collar data let researchers track not just where animals traveled, but how they moved — an animal meandering slowly and pausing to graze signals comfort, while one moving fast and straight signals fear-driven transit through an unwelcoming space. By combining building locations with movement behavior, the team could identify both the corridors animals used and the gaps they avoided entirely.
The numbers that planners have been waiting for
The results are direct. In rural areas where structures appear roughly every 190 acres on average, wildlife avoided corridors narrower than 1.2 miles wide and never squeezed through gaps under approximately 150 feet. Animals more accustomed to suburban settings tolerated slightly tighter passages, but still steered clear of the narrowest openings.
Merkle is careful to note what the findings do not require. Houses do not need to sit a mile apart from one another. The key insight is about clustering — a developer placing 50 homes on one-acre lots, concentrated in one corner of a property, can leave the remaining land open and functional for migration. Spreading those same 50 homes across five-acre lots fragments the whole landscape instead. The study, published May 11 in the Journal of Applied Ecology, translates that principle into a science-based standard that county planners and developers can actually apply.
An interactive tool puts the data to work
The research team did not stop at publishing numbers. They built an interactive map that lets planners, landowners, and developers input proposed residential lots and see in real time how those placements would affect known migration routes. The tool moves the conversation from abstract principle to concrete decision-making.
Jill Randall, Wyoming Game and Fish Department’s big game migration coordinator, described the specific data as “something we’ve been really lacking.” Bettina Cameron, president and co-founder of the Eagle Mountain Nature and Wildlife Alliance in Utah — a group that has spent years pushing back against development pressure on migrating mule deer — was equally direct: “When you’re dealing with landowners and legislation and local planners, you need scientific information. Without the science, we’re not going to get anywhere.” For wildlife-minded landowners who want to act responsibly, the tool now provides a practical blueprint where none previously existed.
What the study does not yet answer
The research comes with acknowledged limits. The dataset cannot distinguish between a rarely visited barn and a busy household surrounded by dogs, livestock, fences, and daily foot traffic. Both register as structures, but their effects on passing wildlife are likely very different. Lead author Ben Robb flagged that gap as a target for future work.
Geographic scope is another constraint. Merkle notes that animal behavior may differ in other regions, which limits how directly these Wyoming-specific thresholds apply elsewhere. Even the best science cannot compel action in a part of the country where property rights carry deep cultural weight, and not every rural landowner will follow voluntary guidance — the researchers acknowledge that plainly.
Still, the current findings represent a meaningful advance. The field now has a quantified baseline where it previously had only suspicion. Researchers hope future studies will refine the model, account for the intensity of human activity at individual structures, and expand the geographic reach of the analysis. As that work develops, the interactive mapping tool is already in the hands of the planners, developers, and landowners best positioned to use it — and the migration corridors those animals depend on may be a little harder to close off quietly.