Mule deer already using incomplete $20m wildlife bridge in California

Within the last few days, a camera trap caught images of three mule deer using structure for the first time

A trio of mule deer have already scuttled across a not-quite-finished $20m wildlife bridge in Siskiyou county, marking a triumph for the California department of transportation (Caltrans).

The bridge and accompanying fencing over Route 97 in Siskiyou county is the first wildlife crossing constructed over a major highway in California. The project promises to both improve driver safety and reduce mortality for migrating mule deer, elk and other animal species.

“This is our first over-crossing laboratory in California,” said Fraser Shilling, the director of the Road Ecology Center at the University of California, Davis. “It gives us a structure to learn how to make them better.”

Within the last few days, a camera trap caught images of three mule deer using the structure for the first time.

“While the contractor is still completing final touches, it’s incredible to see wildlife already embracing the new structure, even with workers still in the area,” Caltrans district two posted in a message to Facebook . “In addition to deer, a bobcat and other wildlife have also been spotted using it.”

The bridge itself is completed and ready to use. The only thing that remains is some final touches on the adjacent fencing, which is needed to funnel wildlife toward the crossing, said Shilling.

“Wildlife crossings by themselves do not stop roadkill,” Shilling said in an interview. “It’s the fencing associated with them that stops roadkill.”

A 2024 report by the Road Ecology Center that Shilling co-authored called vehicle crashes into wildlife “a damaging and preventable natural disaster” wrecking havoc on both animals and drivers.

California drivers kill nearly 50,000 mule deer annually, according to the report. That figure accounts for roughly 10% of the state’s deer herd. Nearly 100 mountain lions died every year in car crashes, the report says, along with thousands of other animals from a wide array of species.

The new crossing takes a step toward mitigating those preventable deaths. Some 50 deer and 16 elk died at the site of the crossing from 2015 to 2020, according to Caltrans.

More crossings are scheduled to open in the near future. The largest of them, the Wallis Annenberg wildlife crossing in southern California, will become the world’s largest after its scheduled opening at the end of the year. The bridge spans the breadth of the 10-lane 101 freeway.

Shilling praised Caltrans for taking the bold step of using its own funds to implement the trailblazing crossing over Route 97 that will make the roads safer, while improving wildlife populations.

“They’re heroic,” Shilling said of the Caltrans staff. “Within agencies like that, doing anything different means you’ve got big ovaries.”