The first dirt has officially been spread across the Wallis Annenberg Wildlife Crossing over the 101 Freeway on Monday, March 31, marking a major step forward in the effort to reconnect crucial habitats for Southern California wildlife.
Heavy equipment rolled into position early in the morning, placing a specially formulated mix of sandy loam and lightweight volcanic aggregate across the overpass that spans 10 busy lanes of traffic in Agoura Hills. This unique soil blend will support 6,000 cubic yards of earth — enough to cover a football field with over two feet of soil — creating a deep, nutrient-rich foundation for native vegetation.
Once the soil placement is complete, a variety of native plants including coastal sage, buckwheat, wild grape, wildflowers, and milkweed will be transplanted. These plantings will provide a vital habitat for pollinators and other wildlife. Adjacent to the bridge, an additional 12 acres will be enhanced with oak trees and native vegetation to further restore the natural environment and support wildlife movement.
The $92-million crossing, spearheaded by the National Wildlife Federation and made possible in large part by a generous donation from the Annenberg Foundation, is designed to reconnect critical habitats for mountain lions, deer, bobcats, and other native species. The 200-foot-long, 165-foot-wide structure, standing nearly 22 feet above the freeway, will allow animals to safely travel between the Simi Hills and the Santa Monica Mountains — regions long divided by the heavily trafficked freeway.
For decades, the 101 has been a deadly barrier for wildlife, isolating small populations of mountain lions and other species. Genetic bottlenecks and increasing signs of inbreeding-related birth defects underscored the urgent need for such a crossing. Although the bridge comes too late for L.A.’s iconic mountain lion P-22, whose tragic story helped rally support for the project, it promises a safer, more connected future for other wildlife.
“I imagine a future for all the wildlife in our area where it’s possible to survive and thrive,” said philanthropist Wallis Annenberg in a statement. “This extraordinary structure will serve not only animals — it will reconnect an entire ecosystem and protect this global biodiversity hotspot.”
Originally conceived more than 30 years ago, construction of the wildlife bridge began in 2022 and is scheduled for completion in 2026.
“This moment is symbolic of California’s broader commitment to biodiversity,” said Wade Crowfoot, Secretary of the California Natural Resources Agency. “We’re recognizing that protecting nature also means reconnecting nature.”
As work continues, local residents and travelers are encouraged to follow project updates and witness history in the making — as the world’s largest urban wildlife crossing takes shape over one of Southern California’s busiest freeways.