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Biologists Bring Red-Legged Frog Back To San Diego, Days Before Virus Could Have Derailed Plans

Associated Press
This March 20, 2017 photo from the National Park Service shows a California red-legged frog (Rana draytonii), found in the Santa Monica Mountains near Los Angeles.
Biologists Bring Red-Legged Frog Back To San Diego, Days Before Virus Could Have Derailed Plans
Listen to this story by Shalina Chatlani.

When the U.S.-Mexico border shut down in March, many plans, including some conservation efforts, were put on hold. But at the last minute, San Diego researchers and biologists were able to bring the California red-legged frog from Mexico back to Southern California, where it had been gone for almost two decades.

Though its song hasn't been heard throughout San Diego since the 1970s, herpetologist Bradford Hollingsworth of the San Diego Natural History Museum is familiar with the California red legged frog's talkative spirit.


"We can all mimic the sound," said Hollingsworth, who when challenged (and KPBS did challenge him) can easily voice the guttural and choppy call of the frog. "Culturally, this is the frog that Mark Twain wrote about over 130 years ago: The Celebrated Jumping Frog of Calaveras County."

"It might be a parrot, or it might be a canary, may be, but it an't, it's only just a frog," Twain wrote.

But, the frog didn't just play a cultural role. It used to be an important part of the food web in Southern California. The frog would bring nutrients from wetter regions to dry areas, where animals there could chomp on the frog and gain that nourishment. The frog population started declining in the region in 1970s because of habitat destruction and invasive species, like the bullfrog.

"The whole idea of having them back here in Southern California was a dream of many of us," Hollingsworth said.

In 2006 the museum and federal biologists began studying ways to bring the frog back, and soon partnered with a nature group in Baja California, where the frog population was thriving. In March the team could finally transport frog eggs across the border for the first time. But, the team experienced an unforeseeable challenge.

VIDEO: Biologists Bring Red-Legged Frog Back To San Diego, Days Before Virus Could Have Derailed Plans

COVID-19 shuts down the border

"The COVID-19 pandemic was beginning to shut down the border, in the middle of the project the museum closed its doors to the public, that was right at the time and I’m down in Baja California seeing everything unfold," Hollingsworth said.

Hollingsworth says two days before the border shut down, the team was scrambling to come up with a game plan, because federal biologists could no longer travel across the border.

Biologist Robert Fisher with the U.S. Geological Services says those two days were intense, especially with a mid-March storm sweeping through San Diego County.

"We had a scenario set up [to move the eggs earlier], and then we got rain, and then that pushed us behind. And then there were those mandates for social distancing and shut down of the border, and rules for essential and non-essential workers," Fisher said.

USGS biologists were barred from crossing over the border. But, with some shuffling in travel plans and duties, Hollingsworth and the museum staff were ultimately able to transport the eggs.

If they had missed that small window of opportunity, Hollingsworth said, "well, we would have had to wait a whole 'nother year."

A binational border collaboration with years of planning

The frog made it back to Southern California, but some cross-border environmental work has become more difficult. In an email statement, the U.S. Fish and Wildlife Services wrote that “some field research and wildlife management activities have been temporarily halted or restricted for the safety of the public and Service staff.”

For the red-legged frog, American biologists had partnered with the Mexican nonprofit group, Conservación de Fauna del Noroeste. Anny Peralta-García is the co-founder, and she said she has heard some concerns from other people in the field in Mexico.

"You’re missing all this fieldwork and all this information. Maybe [other conservationists] were working for 10 years collecting data and now may not be able to do it," she said.

Peralta-García says they were lucky to get the first frog egg masses across the border.

"Like me, I cannot go to the U.S. anymore. If I want to take some egg masses, I can’t. Somebody from the U.S. has to come."

But, Fisher said, it wasn't just luck. They succeeded because were prepared, he says.

"Yeah (laughs), we got really lucky, and a lot of it was we really prepared, because we had done work previously in Mexico to prepare for this with the Mexican team … we did experimental translocations," Fisher said.

Fisher said they want to try to move frogs again next year to build up the population.

"I think this really built enough momentum that we’ll be able to show we can do it and we can get more partners on board," Fisher said.

And even if they can’t, the work will still go on.

"We’ll use these two ponds as source populations for other sites in the U.S. hopefully over time," Fisher said.

And as red-legged tadpoles grow into adult frogs, Fisher says he’s excited to start hearing them singing their songs throughout San Diego.

This story is part of #CoveringClimateNow, an effort by news organizations worldwide to bring about a greater understanding of the real-time impacts of climate change. For more head to