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

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.

Over-crossing construction at a wildlife bridge in Siskiyou county, California, in 2025. Photograph: Katherine E Kerlin

“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.