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Know the West

Red-legged frogs successfully reintroduced to Yosemite

New egg batches have been spotted, which is unusual.


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In 2001, the U.S. Fish and Wildlife Service designated 4.1 million acres in California as critical habitat for the California red-legged frog, following a federal court order the year before. The once-prolific species had been losing numbers due to habitat loss and an invasive species of bullfrog. At the time, Jan Erik Hasselman, an attorney for the Earthjustice Legal Defense Fund, called it an “important step in getting this frog back on its feet.” (“Red-legged frog habitat slated for protection,” HCN, 9/25/00).


In 2017, wildlife biologists reintroduced red-legged frogs into Yosemite National Park through a partnership with federal and state agencies. This spring, ecologists announced the first signs of successful breeding — egg sacs have appeared in ponds and meadows throughout the park. Since March, 20 egg batches have been spotted, which accounts for approximately 50,000 tadpoles. “It’s unusual to find eggs in any location, and to find them this soon is a strong indication that red-legged frogs are adapting successfully to the riparian areas where we reintroduced them,” Yosemite Superintendent Mike Reynolds said.