Early this spring, a sweet song rang out like a question, filling the air at the Audubon Center at Debs Park early this spring: “Cheedle-cheedle-chee? Cheedle-cheedle-chew!” This fleeting moment of respite came from the migratory Least Bell’s Vireo, a small endangered songbird, likely returning from its southern wintering grounds in Mexico and stopping at the center for fuel. This bird carries an important comeback story that continues unfolding right here in northeast Los Angeles.
Just a few miles around the corner from our center, our team has been hard at work for years at Rio de Los Angeles State Park, a 40-acre urban park in the Cypress Park neighborhood of northeast Los Angeles. With sweeping views of the San Gabriel Mountains and the surrounding urban landscape, the park is a beloved community space with multi-use sports fields, walking and biking paths, playgrounds, picnic areas, and open grassy areas used by local families, schools, and community groups. This park isn’t just a great place for people to walk, relax, and connect with nature; it’s also becoming an increasingly important home for riparian birds. Native landscaping and habitat areas support birds, pollinators, and other urban wildlife, helping reconnect people with the ecology of the Los Angeles River watershed. In recent years, we’ve been focused on one big goal: building denser, more complex habitat.
Why focus on habitat density and complexity? To support the Least Bell’s Vireo comeback. When a vulnerable species like this tiny songbird has what it needs to survive, other birds, wildlife, and people benefit too.
Let’s get to know one of our most charming and motivating wildlife neighbors.
This small, grayish vireo with a soft, melodic voice once filled riparian corridors across California. A subspecies of Bell’s Vireo, they depend on dense, shrubby vegetation along rivers and streams to nest and forage. During the breeding season, they build delicate, cup-shaped nests that hang from forked branches, then spend their days gathering insects to feed their chicks. By the late 20th century, however, habitat loss (especially in urban areas) and additional pressure from nest parasites like the Brown-headed Cowbird pushed the species to the brink of extinction, leading to its federal listing as endangered in 1986.
Restoration along the river brings glimmers of revival
For the Debs Park team, the story of the Least Bell’s Vireo in Los Angeles is becoming one of cautious hope. Along the Los Angeles River, once heavily channelized and stripped of natural habitat, restoration and stewardship efforts are beginning to recreate the conditions this bird needs to thrive. Projects that restore native vegetation, improve water flow, and reconnect fragmented habitat are helping transform sections of the river into viable ecological corridors. Places like Rio de Los Angeles State Park are playing an important role, offering pockets of green space where native plants can thrive, and wildlife can return.
We are seeing the population slowly recover, and the Debs Park team isn’t the only one interested in the Least Bell’s Vireo. Coordinated population monitoring across Southern California shows that the Least Bell’s Vireo is gradually recovering in some areas, thanks to decades of conservation work. eBird Trends also suggests a 25% increase in California, offering another encouraging signal that this endangered songbird is responding to habitat protection and restoration.
While the largest populations remain in places like Camp Pendleton, small but meaningful increases are being observed in restored urban habitats. Along the Los Angeles River, sightings and breeding activity signal that these efforts are working. The key to this recovery seems to be a combination of habitat restoration and active management, including targeted, permitted Brown-headed Cowbird population control and planting native vegetation that supports nesting.
Thanks to all the work our partners are doing, we see and hear more birds (of all species!) each year, not just at Rio de Los Angeles State Park but all along the Los Angeles River corridor. As restoration expands along the river, the potential for a more connected and resilient urban ecosystem grows, benefiting not just the Least Bell’s Vireo, but a wide range of birds and wildlife.
What happens to restoration efforts once the bird is nesting?
Ongoing monitoring ensures that any restoration work immediately pauses or shifts if vireo behavior indicates stress or nesting disruption. Our partners at California State Parks establish zones that we are careful to avoid. This usually means limiting the number of individuals tending to plants and limiting the number of times we set up hoses for watering.
How you can help the Least Bell’s Vireo
You can help support the recovery of the Least Bell’s Vireo right here in Los Angeles by volunteering for habitat restoration events and planting native species at home. Especially in urban areas, we can help the vireos by keeping our beloved dogs on leash. These sensitive songbirds nest closer to the ground, and off-leash pups may accidentally disturb nests, damage nesting habitat, or cause parent birds to flee, leaving eggs or chicks unattended.
With sustained community involvement, the quiet, hopeful song of the vireo can remain a part of Los Angeles’ natural soundscape for generations to come.
Click to Explore What to Do if You Find an Injured or Orphaned Bird
Sources:
Griffith, J. T., and J. C. Griffith (2000). Cowbird control and the endangered Least Bell’s Vireo: A management success story. In Ecology and Management of Cowbirds and Their Hosts (J. N. M. Smith, T. L. Cook, S. I. Rothstein, S. K. Robinson, and S. G. Sealy, Editors) University of Texas Press, Austin, TX, USA. pp. 342–356.
Christine A. Howell, Julian K. Wood, Mark D. Dettling, Kenneth Griggs, Codie C. Otte, Linette Lina, Thomas Gardali “Least Bell’s Vireo Breeding Records in the Central Valley Following Decades of Extirpation,” Western North American Naturalist, 70(1), 105-113, (1 April 2010)
Distribution, Abundance, and Breeding Activities of the Least Bell’s Vireo at Marine Corps Base Camp Pendleton, California—2022 Annual Report
https://pubs.usgs.gov/publication/ofr20241006/full
