Mule deer have begun crossing a $20 million wildlife bridge over Route 97 in Siskiyou County, California, even as construction continues. Camera traps documented three deer using the structure within recent days, providing early evidence that the crossing works as intended.
The bridge represents California's first wildlife passage built directly over a major highway. Caltrans designed the structure with accompanying fencing to guide migrating mule deer, elk, and other species away from vehicle collisions on Route 97.
The project addresses a documented problem. Highways fragment wildlife habitat and kill thousands of animals annually through vehicular strikes. Mule deer migrations across northern California highways face particular pressure as populations move seasonally between winter and summer ranges. The Route 97 corridor has seen documented wildlife mortality, prompting state transportation officials to pursue the crossing.
Construction remains incomplete, yet animals are already adapting to the passage. The early adoption by mule deer suggests the bridge's design succeeds in channeling wildlife safely across the roadway. The structure's effectiveness will hinge partly on the accompanying fencing system, which directs animals toward the crossing rather than forcing them to navigate the highway directly.
Wildlife crossing projects exist elsewhere in North America and Europe, but California's bridge fills a gap in the state's highway infrastructure. Other wildlife overpasses exist across the country, yet constructing one over a high-traffic route like Route 97 required securing funding, environmental review, and coordination between transportation and wildlife agencies.
The $20 million investment reflects both the project's scale and California's commitment to reducing human-wildlife conflict. If the crossing performs as designed, it could serve as a template for similar projects on other fragmented routes. Caltrans will likely monitor wildlife use patterns, vehicle strikes, and population impacts to assess long-term outcomes.
The mule deer sightings offer an early validation. Animals proved willing to