A hummingbird has already checked out California’s biggest wildlife crossing project, even though the overpass is still being built.

The Wallis Annenberg Wildlife Crossing in Agoura Hills is expected to be finished on December 2, 2026, after four years of construction and 30 years of planning. California began building it over the 10-lane U.S. Route 101 freeway in 2022.

When it is complete, it is expected to be the largest wildlife crossing in the world.

Southern California is home to animals including mule deer, foxes, coyotes, bobcats, mountain lions, black bears and desert bighorn sheep, but their habitats are heavily fragmented by roads, highways and freeways. U.S. Route 101 stretches about 1,300 kilometres from Oregon to downtown Los Angeles, and while the speed limit is 105 kilometres per hour, traffic often moves at about 121 to 129 kilometres per hour.

The Pew Research Center estimates 1 million to 2 million wildlife-vehicle collisions happen each year in the United States, causing about 200 deaths, 26,000 injuries and more than $8 billion in costs.

The crossing is designed to help wildlife move across one of the busiest freeways in the country. It will be covered with native vegetation and built to resemble a natural habitat, rather than a simple bridge.

“This is a vital crossing in one of the last undeveloped areas on the 101, and building a safe passage gives us a chance to ensure the future of the mountain lions in the Santa Monica Mountains and Los Angeles area,” Dr. Seth Riley, the wildlife branch chief of the National Park Service’s Santa Monica Mountains National Recreation Area, said in a press statement.

The project was inspired in part by the deaths of mountain lions, including Los Angeles cougar P-22, whose story helped build public support.

“You’re going to see this ecological transformation. And that part of it is going to be over one of the busiest freeways in the world, that, to me, is just such a hopeful statement for what’s possible,” said Beth Pratt, California’s regional executive director for the National Wildlife Federation. “We can redeem a freeway.”

On Earth Day, April 22, Pratt announced the updated deadline for the project.

“The project will be officially ‘open for animal business’ on 2 December,” Pratt said.

On May 31, the Wallis Annenberg Wildlife Crossing Facebook page said the project had received its first animal visitor as crews neared completion of the “secondary structure” of the overpass.

“We saw our first hummingbird on the habitat in the 101 structure,” the page said.

Another wildlife overpass in California also recently got its first animal visitors. Three mule deer were seen crossing over Route 97 in Siskiyou County while that bridge was still under active construction.

“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 2 said in a Facebook post. “This wildlife overcrossing was designed to provide animals with a safer way to cross the highway while helping reduce wildlife-vehicle collisions for motorists traveling through the corridor.”

Read more from GoodGoodGood.