World’s Largest Wildlife Crossing Nears Completion Amid Weather Concerns

The world’s largest wildlife crossing, located over the 101 Freeway in Agoura Hills, is expected to be completed by December 2. Concerns remain about potential delays due to severe winter weather.

The crossing, known as the Wallis Annenberg Wildlife Crossing, is designed to aid mountain lions trapped by urban sprawl and inbreeding. A concrete bridge now spans 10 lanes of busy traffic, topped with a landscape of 6,000 native plants. Recently, work concluded on an additional overpass on Agoura Road. A significant task left is filling gaps with large volumes of soil to link the freeway and adjacent lands for seamless animal passage.

“We’re just hoping El Niño‘s on our side,” said Beth Pratt, president of the Wildlife Crossing Fund.

A super-sized El Niño pattern threatens Southern California, with heavy rain potentially halting work due to slippery conditions of clay and silt soil. Robert Rock, the lead landscape architect, noted that water-logged soil complicates compaction processes needed for construction.

Previous weather delays, such as those during the wet winter of 2022-23, postponed the project’s initial late 2025 completion target. Criticism has mounted over the project’s $114 million cost and its delays, with some detractors labeling it a “bridge to nowhere.” Despite this, a completion date announcement aligns with the period of heightened criticism.

Pratt has faced significant backlash, altering her social media presence. Still, she plans to celebrate the project’s completion, highlighting its importance to the mountain lion population listed as threatened.

Seth Riley of the Santa Monica Mountains National Recreation Area notes that 41% of lion matings involve close relatives, underlining the risk of extinction within 50 years if conditions don’t improve. However, the new crossing offers a chance for these animals to access new mates in the Simi Hills, boosting genetic diversity over time.

Trail cameras have recently captured various wildlife near the crossing, including coyotes, deer, and a female lion with cubs, demonstrating active use even as construction continues. Notably, a lion known as P-113 in the Simi Hills recently had a litter of kittens, which might be among the first to use the new crossing when mature.