Wallis Annenberg Wildlife Crossing Enters its Second and Final Construction Stage as Work on the Structure That Will Span Over Agoura Road Is Ready to Begin

By The National Wildlife Federation

The National Wildlife Federation’s #SaveLACougars campaign and project partners are celebrating the second and final stage of construction on the Wallis Annenberg Wildlife Crossing. Crews are preparing to build a secondary structure over Agoura Road that will add to the crossing’s current span across ten lanes of the U.S. Highway 101 freeway in the City of Agoura Hills.

This year, the project achieved a big milestone in the completion of the structure over the 101 — the result of more than 26 million pounds of concrete poured, the completion of vegetated sound walls, the placement of the planting soils, the installation of natural stone habitat elements, and the unveiling of the crossing’s name, now visible every day to the over 300,000 drivers that use the 101 freeway.

Although the structure over the 101 freeway is larger than the one being built over Agoura Road, this final phase of construction is much more complex. The Agoura Road structure spans a smaller two-lane local road, but is as wide as the structure over the 101 freeway—and requires a more extensive foundation. To connect the habitat areas north and south of the freeway and enable animal crossings, a large amount of earthwork is necessary. The landscape connects to the freeway and must reconstruct critical hydrology and restore habitat while protecting the existing creek watersheds and several large, heritage oak trees. In addition, a series of important utility lines parallel to the freeway must be relocated — a monumental, multi-agency effort.

“Today, the state is beginning the final phase of construction for what will soon be the largest urban wildlife crossing in the world – all thanks to the visionary work of state, federal, and private partners,” said California Governor Gavin Newsom. “The Wallis Annenberg Wildlife Crossing will soon protect Los Angeles’ native wildlife and over 300,000 drivers daily, as well as provide a cutting-edge model for urban wildlife conservation.”

“Every stage of construction of this vital crossing is another step toward the survival of the vibrant animal and plant life that form the remarkable ecosystem of this region,” said Wallis Annenberg, chairman, president and CEO of the Annenberg Foundation. “The sophistication of the structure reflects the immense care and attention to detail that have brought us to this final phase. I am so proud to partner with and to champion the efforts and excellence of everyone involved.”

“The City of Agoura Hills founding Councilmembers had the foresight to secure open space on both sides of the 101 freeway to ensure a future for wildlife connectivity and a possible wildlife corridor. Our city is so proud to see that dream become a reality. This crossing sets an example for the whole world of what can be done to protect wildlife and biodiversity,” said City of Agoura Hills Mayor Penny Sylvester.

“We’re honored to continue our work on the Wallis Annenberg Wildlife Crossing as the contractor for both phases of this landmark project. As a local contractor with over 60 years of experience, it’s especially meaningful for our team to contribute to something that will benefit both our community and California’s wildlife for generations to come. We’ve been proud to work closely with Caltrans and the National Wildlife Federation to help move this effort from vision to reality,” said Adam Rasmussen, president of C.A. RASMUSSEN, INC.

“The Santa Monica Mountains Conservancy and Mountains Recreation and Conservation Authority (MRCA) are eagerly anticipating working with our partners in this next milestone to fully complete the Wallis Annenberg Wildlife Crossing. Protecting this crucial wildlife habitat linkage has been in our dreams and plans for 45 years of land protection work,” said Rorie Skei, chief deputy director of the Santa Monica Mountains Conservancy.

The project’s final stage follows the placement in April of 6,000 cubic yards of living soil on the crossing, in preparation for thousands of native plants being grown a few miles to the east at the project’s native plant nursery. These elements will create a nearly one-acre wildlife habitat over the surface of the crossing. Although originally projected for placement on the crossing this spring, supply chain issues and construction scheduling led to the planting effort being pushed to this fall to optimize success by avoiding the summer heat.

To support the fall planting and all future planting efforts, a dedicated and Indigenous-led nursery team has, over the last three and a half years, hand-collected well over 1.1 million hyper-local seeds representing over 50 distinct native plant species from distinct Santa Monica Mountain plant communities that have been grown in the native plant nursery. The collection of seeds and work at the nursery is on-going and also part of a future and broader ecological restoration that will revitalize acres of open space in the Santa Monica Mountains and require 50,000 native plant and tree species. Envisioned by Rock Design Associates — the innovative, living soil and native plant species work is the result of more than three years of meticulous and close collaboration with renowned experts in wildlife biology, engineering, horticulture, soil science, soil biology, and mycology. Partners on the plant nursery include the Santa Monica Mountains Conservancy, the National Park Service, the Santa Monica Mountains Fund, Rock Design Associates, and the National Wildlife Federation’s #SaveLACougars campaign, which funds the nursery.

“This native plant nursery is a key piece of this tremendous effort,” said Robert Rock, president and CEO of Rock Design Associates. “It is important to highlight these local plants and the soil biology that will do the noble job of restitching this fragmented landscape, but it is even more important to highlight the dedicated work of so many who are making this happen. Being able to share the story of the nursery with this series of videos marks a special moment for all of us.”

To prepare for planting in the fall, the National Wildlife Federation’s #SaveLACougars campaign is releasing a series of fun and educational videos about the project nursery. This includes short videos with the Indigenous nursery staff introducing people to ten of the native plants that will be placed on the crossing. The campaign is also now offering for purchase a new seed packet representing six native plants that will be grown on the crossing. All proceeds from the sales of the packets will benefit the plant nursery and crossing project.

Communities are invited to view the videos across all of the P-22 Mountain Lion and Wallis Annenberg Wildlife Crossing social channels and can purchase the native seed packets on the #SaveLACougars campaign store. Members of the press can also access the videos for editorial purposes here.

“This crossing is a story of hope — a hope for a better future for wildlife. And a story of partnership and collaboration. Building a wildlife crossing over one of the largest and busiest freeways in the country, and in one of the most densely populated areas in the United States, came with immense challenges. But because so many people — the agency teams, elected officials, scientists, donors, artists, volunteers, the communities, and the public at large — united around the important cause of protecting mountain lions and all wildlife in the Santa Monica Mountains, this visionary dream has become a reality,” said Beth Pratt, California regional executive director of the National Wildlife Federation and leader of the #SaveLACougars campaign.  “To see the Wallis Annenberg Wildlife Crossing enter its final phase and near completion, means we are closer to having that first mountain lion cross the bridge. I cannot wait to see that first photo of a cougar on the crossing — what a moment that will be for us all!”

Work on the visionary Wallis Annenberg Wildlife Crossing is scheduled to be complete in 2026. When it’s completed, it will be the largest bridge of its kind in the world and a global model for urban wildlife conservation. The core project partner team includes Caltrans, the National Park Service, the Santa Monica Mountains Conservancy and Mountains Recreation and Conservation Authority, and the National Wildlife Federation. The project partners also work with a world-renowned design team led by a landscape architectural practice, Rock Design Associates, that collaborates with Caltrans and coordinates with a broad team of wildlife crossing experts in the planning, design and construction of the wildlife crossing.

Newly unveiled renderings of the Wallis Annenberg Wildlife Crossing’s secondary structure, diagrams of the innovative engineering and science behind the living soil placement over its surface earlier this year and drone footage over its construction are available here.

Docent tours of the Wallis Annenberg Wildlife Crossing are available to the public and open for registration and are a great opportunity for everyone to learn about how the crossing will protect local wildlife populations. Details on the tours and how to register can be found on the reservations page.

Everyone is invited to follow construction on the bridge in real-time through its dedicated webcam and learn more about the Save LA Cougar’s #P22Legacy Campaign phase here and the Wildlife Crossing Fund here.

The National Wildlife Federation is America’s largest conservation organization with over 6 million supporters nationwide, uniting all Americans to ensure wildlife thrive in a rapidly changing world. Follow us on Facebook, Twitter, and Instagram. To learn more about the #SaveLACougars campaign to build the Wallis Annenberg Wildlife Crossing visit https://savelacougars.org/