On the Santa Ana River Trail construction site, an endangered vireo bird is nesting, temporarily stopping all work.

The Santa Ana River Trail is said to be the longest multi-use trail in Southern California.

Santa Ana River Trail Construction Halts

A Least Bell's Vireo was discovered nesting in the project's boundary in San Bernardino County while workers were working on Phase III of the Santa Ana River Trail project, which has four phases. In 1980, the Least Bell's Vireo was added to California's list of endangered species and is still state-protected.

According to the US Fish and Wildlife Service, the birds breed in Southern California from mid-March to early April and typically stay there until late September. They occasionally depart as early as the end of July.

On January 30, 2023, in Redlands, construction on the 3.8-mile Santa Ana River Trail officially began. The 110-mile project will connect Orange, San Bernardino, and Riverside counties once the multi-use trail is finished.

There will be trails that allow hikers, cyclists, and even horses access to the Pacific Ocean in Huntington Beach from the San Bernardino County National Forest, according to Riverside County.

According to county officials, the Santa Ana River portion was expected to be completed in August, but the area needs to be inspected in July or August to see if the project duration needs to be revised. Based on the findings, the Department of Public Works, together with the construction company, will decide whether or not construction can proceed, the officials said.

If not, the project will be postponed until September, the end of the endangered bird's breeding season, when it is anticipated that the birds will migrate. Phase III of the trail won't be completed until at least February 2024 as a result of the delay.

Funding for Phase III came primarily from two sources, according to the county: $6.9 million in state Proposition 84 funds from the California Coastal Conservancy and $1.1 million in federal Active Transportation Program grant funds. The project is a partnership between the San Bernardino County Department of Regional Parks and the Department of Public Works. The Department of Public Works and the Regional Parks Department of San Bernardino County are working together on the project, KTLA 5 reports.

Endangered Vireo Bird

Small birds measuring only 4.5 to 5.0 inches, Least Bell's vireos are among the least common endangered species. They have short, straight bills and short, rounded wings. They have feathers that are predominantly gray above and pale below, and they have a faint white eye ring. This is a typical form of bird protection marking. The bird disappears into the clouds when viewed from below. And, according to data from the US Fish and Wildlife Service, it blends into the land cover when viewed from above.

This is a typical form of bird protection marking. The bird disappears into the clouds when viewed from below. According to data from the US Fish and Wildlife Service, it blends into the land cover when viewed from above.

The least Bell's vireo is a neotropical migrant that travels 2,000 miles annually between its breeding and wintering grounds.

Males arrive in breeding areas before females do, and they use their song to create territories that can be as large as three-quarters of an acre. Within a few days of choosing a mate, the pair will start building a low-lying, open-cup nest, and three eggs will typically be laid. This breeding behavior lasts from the middle of March until late September, according to Center for Biological Diversity.