A Hop In The Right Direction: Oakland Zoo’s Conservation Collaboration Marks The First Ever Release Of Foothill Yellow-legged Frogs

Oakland Zoo
July 2, 2020

Oakland Zoo continues to be a leader in conservation efforts during Zoo closure with history making collaboration of first ever Foothill yellow-legged frogs release into the wild.

Samantha Sammons, Conservation Biologist at Oakland Zoo releasing Foothill Yellow-legged Frogs into Plumas National Forest

Oakland, CA – July 2,2020… During the longest Zoo closure in the history of the organization, Oakland Zoo continues its efforts in Taking Action for Wildlife with its most recent Foothill Yellow-legged frog (FYLF) release into the wild. This marks the first release of FYLF back into the wild.  The Zoo participates in a captive rearing-program in partnership with U.S Fish and Wildlife Services (USFW), Pacific Gas and Electric (PG&E), U.S Forest Service, California Department of Fish and Wildlife (CDFW), and Garcia and Associates.

“The lessons these tiny frogs have taught us about captive rearing will set the stage for this species’ conservation,” says Service Biologist, Kat Powelson.

On June 30th, 115 Foothill Yellow-legged frogs were successfully released into Plumas National Forest in Cresta, CA after a year long stay at Oakland Zoo. Last summer, Oakland Zoo was able to expand its conservation collaborations by treating and raising this group of FYLF at the Zoo’s Biodiversity Lab.  The Zoo has had success in captive-breeding programs in the past with the Mountain Yellow-legged Frog (MYLF) species programs.

Historical release of Foothill Yellow-legged frogs marks the first ever release of this species back into the wild

Recently, Foothill Yellow-legged frogs were listed as threatened in the California Endangered Species Act (ESA) and petitions are in the works to expand its listing to the federal level.  To expand conservation and recovery efforts, the Zoo is developing a Husbandry Manual to provide a step-by-step guide for other organizations or biologists to use to protect these frogs.

The US Forest Service has a fantastic relationship with the Oakland Zoo and U.S. Fish and Wildlife Service, and we’ve shown tremendous success rearing Foothill Yellow-legged frogs for the first time in captivity”, says Collin Dillingham, District Wildlife Biologist for the Mt Hough Ranger District, Plumas National Forest.

With this massive collaboration, the frogs can be continually cared for and studied for further protection in the future.

We are hoping that when we come back next year, we will see happy healthy frogs that are breeding and producing more Yellow-legged frogs” says Margaret Rousser, Conservation Manager at Oakland Zoo

Margaret Rousser, Conservation Manager at Oakland Zoo, sees project full circle from raising at the Zoo to release into the wild

Each Foothill Yellow-legged frog was transported in their own container that labeled their PIT tag number and sex. Safety measures were ensured to prevent overheating

Oakland Zoo takes pride in the around the clock care of the animals at the Zoo as well keeping to their tagline Taking Action for Wildlife. The Zoo relies on community support during these times to continue these efforts during and after COVID-19 closure. To donate to the Zoo, please visit: https://bit.ly/31w22zr  


Isabella Linares

Oakland Zoo


Office: 510-632-9525 ext. 239

Cell: 650 – 776 -9589

Erin Harrison

Oakland Zoo


Office: 510-632-9525 ext. 120

Cell: 415-601-1619



Oakland Zoo, home to more than 850+ native and exotic animals, is managed by the Conservation Society of California (CSC); a non-profit organization leading an informed and inspired community to take action for wildlife locally and globally. With over 25 conservation partners and projects worldwide, the CSC is committed to conservation-based education and saving species and their habitats in the wild. Oakland Zoo is dedicated to the humane treatment of animals and is accredited by the Association of Zoos and Aquariums (AZA), the national organization that sets the highest standards for animal welfare for zoos and aquariums.


With support from the US Fish and Wildlife Service, the endangered Foothill Yellow-Legged frogs are reared at the Conservation Society of California’s Oakland Zoo which are the last remaining population surrounding the area effected by the Camp Fire, with field biologists having to add water to the pools as they scooped up the tadpoles with a teaspoon literally an hour or so before the isolated pools they were in dried up. Like many frogs worldwide, Foothill yellow legged frogs also come from lakes that have been infected with the deadly fungus, chytridiomycosis. This is a type of fungus that lives in water or moist environments and is causing mass amphibian extinctions worldwide. Foothill yellow legged frogs must be treated for the fungus in the tadpole stage, or they will die of the disease shortly after completing their metamorphosis.  Oakland Zoo inoculates the juvenile frogs against the deadly disease, and cares for the froglets as they grow and develop in a safe environment at the zoo.  The inoculated frogs are then returned to their lakes, protected from chytridiomycosis.  Researchers monitor the frogs each summer to track their progress and manage any new outbreaks of the fungus.