At 20 years old, a pioneering La Habra Heights underpass has been a wildlife lifeline

More than 35,000 cars, buses and other vehicles traverse Harbor Boulevard at all hours of the day and night, speeding from Los Angeles to Orange county and back. And for 20 years, a retrofitted underpass in La Habra Heights has allowed wildlife to travel safely too.

The Harbor Boulevard Wildlife Underpass, the first wildlife underpass built in Los Angeles County, turned 20 years old this week, and representatives of the agencies that collaborated in building it marked the occasion with a rare visit to the urban wildlife crossing.

“It’s a great example of successful public projects that combines transportation and conservation,” said Andrea Gullo, executive director of the Puente Hills Habitat Preservation Authority. “We built this to reduce wildlife mortality on Harbor Boulevard and studies show that it has decreased, so it’s working.”

The first and possibly only animal underpass in Los Angeles County was built in 2006 for $1.2 million in grants, plus funds coming from the county, the California Department of Parks and the authority, Gullo said.

Funding also came from the Metropolitan Transportation Authority, Caltrans, and L.A. County Public Works, with experts from multiple agencies helping with everything from construction to scientific studies.

Mary Ann Pacheco, vice chair of the Habitat Authority’s board of directors, was happy to celebrate the authority, its staff, as well as the critters she said should be respected and protected.

“I thought it was very exciting then, and I find it very exciting now to know that it has served the purpose that it was intended for,” said Pacheco, who is also a councilmember on the Whittier City Council. “We lose so much when we lose wildland that we really need. We live in an urban environment where we lose touch with our roots because we’re rooted in nature, and without a place like the habitat to be able to do that, there’s just something missing.”

Cassandra Garcia, director of the authority’s board of directors, said it’s important to remember the underpass was not a mandated environmental regulation.

“It was really a collaboration with all the regional partners involved and it’s created something that’s lasted 20 years and brought immense benefit to the animals and the environment,” Garcia said. “It’s a good indicator that humans and wildlife can coexist in a harmonious way.”

Ecologist Michelle Mariscal describes the underpass as a highway for animals, pointing out how the ground is marked with tracks made by coyotes, deer and raccoons, allowing many species to not only avoid becoming roadkill, but also giving them safe passage to wander and find mates.

The undercrossing was built in 2006 beneath busy Harbor Boulevard and spans 160 feet long, stands 17 feet high and 20 feet across, specifications recommended by a biologist. It links 4,600 acres of publicly protected land to the west of Harbor Boulevard with 14,000 acres to the east of the roadway. It is part of the 31-mile long Puente-Chino Hills Wildlife Corridor that stretches from Whittier Narrows to the Cleveland National Forest.

After construction, the authority landscaped the area around the project with native plants such as chaparral, sage brush and buckwheat.

KennHughes, deputy chief ranger for the Mountains Recreation and Conservation Authority (MRCA), patrols the area. The MRCA contracts with the habitat authority for ranger services.

His work is aided by a wildlife camera, stationed at the underpass since 2020.

Caught on camera: several species of birds, including roadrunners, California ground squirrels, cottontail rabbits, Virginia opossums, striped skunks, bobcats, mule deer, and gazes of raccoons as well as packs of coyotes.

Mountain lions continue to use the corridor, with the authority reporting a mountain lion with a GPS radio collar traversed the corridor in 2022, traveling from the Cleveland National Forest to the Puente Hills Preserve and back again over the span of a couple of months.

Sightings and tracks of wildlife are confirmed by California Department of Fish and Game as well as habitat authority staff.

Mariscal’s favorite surprise appearance, among the 1,800 animals that use the pass each year, came in December 2025, when the wildlife camera caught a gray fox using the underpass. Another gray fox appeared shortly after.

“The gray fox was a really fun surprise,” Mariscal said. “It’s not endangered, just very rare.”

Mariscal started working with the Habitat Authority in 2019, excited to learn about the underpass because she wrote her master’s thesis at UC Riverside on wildlife use of such crossings.

“It’s a wonderful job,” Mariscal said. “I feel like it’s impactful. I’m an advocate for the wildlife and for the habitat and it can’t get much better than that as an ecologist, to be able to make choices that will benefit wildlife and the community.”