Mountain yellow-legged frog conservation efforts

The Southern Mountain Yellow-legged Frog Recovery Program has reached significant milestones through a collaborative effort involving the Los Angeles Zoo, the Aquarium of the Pacific, and the U.S. Geological Survey.

In August 2026, the Los Angeles Zoo released 653 zoo-bred frogs into the San Gabriel Mountains in two stages. Many of these individuals were raised in a specialized, bio-secure amphibian headstarting facility designed to increase survival rates during early development. Of the August release, nearly 400 individuals had been head-started at the Aquarium of the Pacific.

As the program enters its fifth year, biologists report that more than 1,000 frogs have been successfully raised and released into the wild since 2020. This number exceeds five times the estimated population remaining in natural habitats as of 2019. The recovery process utilizes a pipeline where frogs are bred at the Los Angeles Zoo, transferred to the Aquarium of the Pacific as tadpoles to undergo metamorphosis, and subsequently returned to mountain streams in the San Gabriel, San Bernardino, and San Jacinto Mountains. This effort is conducted in coordination with the U.S. Fish and Wildlife Service.

The species, listed under the federal Endangered Species Act in 2002, has faced population collapses due to wildfires, mudslides, pesticides, fungal diseases, habitat loss, and nonnative predatory species. Specifically, the devastating Bobcat Fire destroyed approximately 95% of the species' habitat, contributing to a decline where the population dropped to fewer than 200 individuals by 2021. The frogs are considered vital to their ecosystems, helping maintain clean waterways by consuming algae and organic matter.