A threatened species shows signs of recovery through joint efforts
After decades of absence, the California red-legged frog has been heard again in the wild in Southern California. This milestone is the result of a collaborative conservation effort involving habitat restoration, cross-border egg translocation, and advanced artificial intelligence (AI) monitoring.
Listed as threatened since 1996, the frog was once common from northern Baja California up to the Sierra Nevada. Its decline was driven by habitat loss, invasive species, disease, and human activity.
Relocation from Mexico and AI audio detection
Beginning in 2020, biologists from Mexico and the United States worked together to move red-legged frog egg masses from a pond in Baja California to restored wetland areas in San Diego and Riverside counties. These sites had been cleared of invasive predators like the American bullfrog.
To monitor reproduction, the team installed microphones that captured thousands of hours of audio during the mating season. A custom machine learning model was trained to detect the specific mating calls of the male red-legged frog, distinguishing them from similar sounds like bird calls.
Positive signs after years of waiting
After several years without confirmation of breeding, researchers identified the vocalizations of adult frogs. Shortly after, a new egg mass was discovered, marking the first natural reproduction of the species in the area in decades.
This finding marks a significant step in the species’ recovery. While gaps in the frog’s historic range remain, the success of this project demonstrates how targeted conservation, supported by AI, can help reestablish threatened species in their native ecosystems.
