When herpetologist Brad Hollingsworth heard the quiet, distinct grunting of a red-legged frog’s breeding call on January 30th, it felt like “a big burden off his shoulder” because he thought the project might be failing after years of painstaking work. The sound, captured by AI technology analyzing pond recordings, proved that red-legged frogs transported as eggs from Mexico during the COVID-19 pandemic had not only survived but were now breeding in Southern California ponds where they had disappeared from 95% of their historical range. This remarkable conservation success story began when scientists discovered that Southern California’s last red-legged frogs were more genetically similar to a small population of about 20 frogs found in Baja California than any remaining in the state.
Despite pandemic border restrictions, dedicated researchers scrambled to secure permits and pilots to airlift coolers of precious frog eggs across the U.S.-Mexico border, with the eggs even passing border guard inspection on their journey north. The collaboration between American and Mexican scientists, led by passionate conservationists like Anny Peralta who dedicated her life to the species after joining the search in 2006, has already restored the Mexican population from 20 to 400 adult frogs. Now, with over 100 adult red-legged frogs estimated in Southern California ponds and tadpoles appearing at new sites, this binational effort proves that when it comes to saving species, borders and walls can’t stop the power of scientific cooperation and determination. As Peralta beautifully put it, the frogs “don’t know about borders or visas or passports” because “this is just their habitat and these populations need to reconnect.”