Conservationists have re-released a swarm of mountain yellow-legged frogs into the wild hoping the natural habitat will help in the growth of their numbers.

The mountain yellow-legged frogs have been listed as the most endangered amphibians in California, once found in abundance in the streams of San Gabriel, San Bernardino and the San Jacinto mountains. In 2001, the United States Fish and Wildlife Service listed these frogs in the endangered list of species after their numbers dwindled to less than 200, according to a report from Science Recorder. Many affecting factors such as habitat loss, human-driven development, increased wildfires, drought, predators, and emerging disease played a major role in the decline.

San Diego Zoo Institute for Conservation Research released a swarm of 65 one year-old juvenile frogs into the shallow ponds at the James San Jacinto Mountains Reserve, says a report from Nature World news. This is the first time that the mountain yellow-legged frogs have been re-released into the wild. The report says that additional 40 frogs will be released later this week.

The San Diego Zoo Institute for Conservation Research has been working for nearly seven years to maintain a recovery program for these endangered species. Previously, conservationists released mountain yellow-legged tadpoles into the wild which did not survive. Tadpoles are often prey for fishes like trout. Adult frogs are hunted by snakes, birds and raccoons.

Besides being hunted by their predators, these mountain frogs are exposed to deadly fungal diseases. But to ensure the prolonged existence of these frogs, which have a life-span of about 14 years, conservationists bathed the frogs in bacterial solution to keep them immune from infections. Furthermore, the frogs are fixed with tracking devices to monitor their movement and learn more about their survival.