Yosemite marks release of 10,000th California red‑legged frog in major recovery milestone
Yosemite National Park marked a decade of recovery work on May 7, 2026, releasing its 10,000th zoo‑reared California red‑legged frog — nicknamed “Twain” — near Yosemite Falls, celebrating the species’ return to the valley after years of coordinated conservation efforts.
Key takeaways
- Milestone release: On May 7, partners released several zoo‑reared juvenile California red‑legged frogs in Yosemite Valley, including the program’s symbolic 10,000th frog, “Twain,” at a public Stewardship Series event (National Park Service event page).
- Collaborative effort: The recovery is led by the National Park Service with the U.S. Fish and Wildlife Service, the CDFW release, Yosemite Conservancy and the San Francisco Zoo & Gardens.
- Method mix: Success combined invasive bullfrog removal, habitat restoration funded by voter‑approved grants, captive rearing and sustained monitoring to reestablish self‑sustaining frog generations.
A species driven from the valley
For decades, Yosemite Valley lacked California red‑legged frogs (Rana draytonii). Invasive American bullfrogs and elevated raccoon numbers tied to open refuse sites in mid‑20th century Yosemite devastated local populations. Bullfrogs both preyed on and competed with young red‑legged frogs, making removals essential before reintroduction could succeed.
“After invasive bullfrogs eliminated red‑legged frogs from the area decades ago, we removed those threats and created conditions for recovery,” said Rob Grasso, aquatic ecologist at Yosemite National Park.
How the comeback was done: methods and partnerships
The recovery blends long‑term fieldwork, engineered habitat improvements and captive rearing. Key elements include:
- Bullfrog removal: Yosemite staff spent years eradicating invasive bullfrogs that once drove native frogs from the valley.
- Habitat restoration: Projects tied to the Merced River Plan rebuilt wetlands, streambanks and river systems critical for breeding and shelter; voter‑approved grants administered by CDFW funded many efforts. As Laura Patterson of CDFW noted, the agency is proud to have assisted recovery efforts (CDFW release).
- Captive rearing facility: In 2016 the National Park Service partnered with the San Francisco Zoological Society to open a rearing facility in San Francisco, raising frogs from wild‑collected eggs to juvenile stages before release.
- Monitoring & research: Yosemite Conservancy funded post‑release studies and UC Santa Barbara provided technical support on reintroduction techniques (National Park Service event page).
From zero to thousands: resilience amid hardship
When the program began in 2016, Yosemite Valley had effectively zero red‑legged frogs. Over ten years, partners reintroduced tens of thousands of animals and documented natural breeding. The result: multiple self‑sustaining generations now persist in the valley despite droughts, harsh winters and floods that tested adaptive management.
“Partners have been essential,” said Kim Turner, acting field supervisor for the Sacramento Fish and Wildlife Office. “We appreciate the progress made over the past decade and remain committed to this collaborative effort.” (Quoted in CDFW release)
Event day: Twain and the public ceremony
On May 7, park officials, agency partners and the public gathered near Yosemite Falls. Speakers described the science and long work to remove threats and restore habitat, then released several zoo‑reared juveniles — including the symbolic 10,000th frog, nicknamed “Twain.” The event was part of the park’s Stewardship Series (National Park Service event page).
Why this is a model for other parks
Biologists say Yosemite’s approach — invasive species removal, habitat restoration, captive rearing and community partnerships — offers a blueprint for restoring amphibians and other species. Localized, targeted action produced measurable ecological gains and demonstrates how pragmatic conservation can recover species once thought lost.
Implications for Paso Robles, California
Economic impact:
- Tourism draw: Yosemite’s recovery story can boost visitation to gateway communities such as Paso Robles, supporting local hotels, restaurants and tours.
- Funding model: Voter‑approved grants that funded habitat work in Yosemite offer a replicable financing approach for local conservation and water‑supply projects.
Political and governance takeaways:
- Local stewardship works: The program was built on partnerships among federal, state, zoo and local funders — a model that aligns with community and fiscal accountability values.
- Practical conservation: Targeted, science‑based actions (remove invaders, fix habitat, rear animals) delivered results preferred by many voters.
Social and community effects:
- Jobs & volunteers: Restoration and monitoring create seasonal positions and volunteer opportunities for nonprofits and schools.
- Education: Partnerships like the San Francisco Zoo rearing program can inform local exhibits, talks and field trips.
Environmental and practical applications:
- Invasive control: Bullfrogs are a statewide problem; Yosemite’s methods can inform local pond and stream management in Paso Robles.
- Waste management lessons: Elevated raccoon numbers in Yosemite were linked to open refuse sites. Secure waste practices protect wildlife and reduce conflicts.
Cultural relevance: As California’s state amphibian, the red‑legged frog’s return to a national park is a source of state pride and a rallying point for pragmatic conservation across rural and outdoor communities.
Sources and further reading
- California Department of Fish and Wildlife release on the 10‑year milestone
- National Park Service event and Stewardship Series
- ABC30 coverage of the recovery effort
- NBC News video on the reintroduction work
Reporting contacts
Agency media contacts at Yosemite National Park, the San Francisco Zoological Society and CDFW are listed in the linked agency statements and event materials above. For event background, see the National Park Service event page and the CDFW release.
