With fall upon us, big game animals are on the move from summer ranges in the high country back down to lower elevation winter ranges. That inevitably means elk and deer are crossing highways in greater numbers along their well-established migration routes.
In southwest Colorado, one of those established routes spans the Highway 160 corridor between Bayfield and Pagosa Springs. Thanks to research spearheaded by wildlife biologists with the Southern Ute Indian Tribe, these migration routes are better understood than ever before. Researchers have tracked mule deer that winter in the HD Mountains near Ignacio, and in spring migrate north into the Weminuche Wilderness, even crossing the Continental Divide and summering in the high country around Lake City. In fall, they return south.
The intersections between migration routes and high-speed highways is a recipe for disaster, both for wildlife and motorists. La Plata County has the highest number of animal-vehicle collisions in Colorado.
Statewide, at least 4,000 collisions are reported each year, with an estimated financial cost of more than $80 million, according to the Colorado Wildlife and Transportation Alliance. The cost of a collision with a deer has been tagged at $20,000 per accident, in repair costs and medical bills. For a collision with elk, it ranges as high as $80,000. Those figures attribute a value to the animals as well, given Colorado’s multibillion dollar hunting economy.
The consequences are not lost on wildlife and transportation managers. Two years ago, Colorado Department of Transportation spent $12 million to complete a wildlife overpass and underpass on Highway 160 near Lake Capote. It’s anticipated the structures could reduce vehicle collisions with wildlife by 85% in that stretch.
The first wildlife crossing structures in North America were built along the Trans-Canada Highway through Banff National Park. The success of those structures helped spawn similar interest across the United States. In Colorado, the most ambitious set of underpasses and overpasses for wildlife is located along Highway 9 through the Blue River Valley between Dillon and Kremmling.
Lawmakers are providing increasing amounts of funding for wildlife crossing structures. The Bipartisan Infrastructure Law passed in 2021 included $350 million for a wildlife crossing pilot program, and Colorado established the Safe Passages Fund in 2022 with $5 million in matching funds.
The focus on crossing structures is part of a larger effort to elevate protection of wildlife migration corridors. The federal Bureau of Land Management recently completed a wildlife corridor update to its management plans for 13 million acres across Colorado. The BLM manages lots of lower elevation habitat, places like Animas Mountain outside Durango and many other areas of importance to elk, deer and other migrating species.
BLM’s plan recognizes the importance of the “pinch points” that wildlife crossing structures represent, places where big game herds are particularly focused during their migrations. It’s a crucial part of the bigger picture of ensuring that land management aligns with the crossing structures to best protect migration routes.
If the BLM were to allow development around these crossing structures, like new oil and gas development or intensive recreational trail networks, it could defeat the purpose of providing safe passage zones for wildlife. BLM’s corridor plan is a good example of federal and state agency cooperation to achieve a larger goal.
As highway infrastructure continues to grow, many opportunities are available to improve the ability of wildlife to safely get across highways. When bridges or culverts are replaced, they can be sized to serve double duty as wildlife underpasses. As CDOT expands Highways 160 and 550, look for additional improvements making travel safer for both wildlife and motorists.
Mark Pearson is Executive Director at San Juan Citizens Alliance. Reach him at mark@sanjuancitizens.org.
