Egg-transplanting seems to be succesfull : https://www.usnews.com/news/best-st...rog-discovery-has-researchers-hopping-for-joy
Again egg-masses translocated to the Santa Rosa Plateau Ecological Reserve ( California ) : California red-legged frogs return to southwest Riverside County – Press Enterprise
Article about the return of the Californian red-legged frog : Featured Stories | The return of red-legged frogs