Sierran Tree Frog

Even though it has the word ‘tree’ in its name, the Sierran Tree Frog is mostly found close to the ground, in bushes and grass. It has large toe pads that allow it to walk on vertical surfaces better than Spider-Man. The toe pads are also useful for clinging to sticks and twigs.

To avoid being eaten, the Sierran Tree Frog is fast! It can jump long distances and swim quickly to hide in vegetation.  It also remains perfectly still and changes color to stay camouflaged. Sierran Tree Frogs can change from green and gray to brown.

Worms, small invertebrates, and flying insects are the frog’s dietary staples. Tadpoles feed on algae, bacteria and organic debris. Their feeding activities help keep streams and waterways clear of slippery plant material.

The Sierran Tree Frog is more often heard than it is seen. Males call to advertise availability and attract mates. Breeding and egg-laying occur from November through July. During this time, males establish a territory that they defend with encounter calls, butting, or wrestling with rivals.

photo credit: Siyavula Education


Global Amphibian Issues

Scientists say that we are living in the Anthropocene epoch, a time when human activity is the dominant influence on climate and the environment. Unfortunately, the consequences of this are that many habitats and species will disappear.

Frogs and newts are indicator species because they have thin skin that easily absorbs pollutants. Since they live both in water and on land, they absorb toxins from both environments. Like the miners who used canaries to warn when toxic gas was present, amphibian health determines the quality of the environment.

There are a number of factors that affect amphibian populations. Not unique to Nevada County, these conditions are happening globally.

Contributing Factors to Amphibian Decline:

Loss of habitat (housing development)

“We’re running out of places where frogs are healthy,” Amphibian Study Volunteer

“It doesn’t matter how many frogs we save if there is no place to put them back in the wild,” Edgardo Griffith, El Valle Amphibian Conservation Center

Chytridiomycosis (Batrachochytrium dendrobatidis – Bd) skin fungus (global epidemic)

Pesticide runoff & flushed prescription medications

California Pesticide Use:

California agriculture is the number one consumer of pesticides in the United States.

The state produces half of the US agricultural produce.

  • 99 percent of artichokes
  • 99 percent of walnuts
  • 97 percent of kiwis
  • 95 percent of garlic
  • 89 percent of cauliflower
  • 85% of the lettuce
  • 71 percent of spinach, and
  • 69 percent of carrots

Contaminated agricultural water runoff affects the entire ecosystem.

“Atrazine (an herbicide) is the most common contaminant in our drinking water. It causes male frogs to turn into females.” – Tyrone Hayes, UC Berkeley Biologist

Invasive bullfrogs

“Bullfrogs pose several threats to the native amphibians of California, many of which are endangered. When bullfrogs—the largest frogs in North America—escape or are released into the wild, they have a tendency to eat other amphibians and any other wildlife that will fit in their mouths. Their size also allows them to outcompete native species for food. Even worse, a large portion of the bullfrogs imported into this country—62 percent according to one study—are infected with the deadly chytrid fungus (Batrachochytrium dendrobatidis), a lethal skin disease which has already been blamed for extinctions of about 100 amphibian species around the globe.” – Should California Ban American Bullfrogs? Scientific American Blog

 How to Help

Be a Lorax (speak up) for Nevada County frogs, toads, and salamanders




Discovering Sierra Reptiles and Amphibians, Basey, H. E.

The Audubon Society Field Guide to North American Reptiles & Amphibians, Behler, J. L., King

Peterson Field Guide to Western Reptiles and Amphibians, Third Edition, Stebbins, R. C.


AmphibianWeb – Overview of Chytridiomycosis

California Tree Frog identification

Chytrid in Nevada County – Sierra Streams Institute

El Valle Amphibian Conservation Center

Frogs Need Our Help –

Hazards of Atrazine herbicide – Clear Health Centers video

Indicator Species –

Nevada County Resource Conservation District – Amphibians

Reproductive problems linked to atrazine – Tyrone Hayes, UC Berkeley Biologist– Sierran Tree Frog

Service Working to Combat Killer Chytrid in California Frog Populations – Sacramento Fish & Wildlife Office

State of Sierra Frogs (2008) PDF – Sierra Nevada Alliance– Sierran Tree Frog

What if there is no happy ending? – Scientific American, 2013

Worldwide Amphibian Declines 2017



Life on the Creek Art


$5 from every sale of ‘Life on the Creek’ art goes to support the website/film production project. Upon completion, the proceeds will be donated to Deer Creek watershed stewardship organizations.

6 thoughts on “Sierran Tree Frog

  1. I have a pond, irregular border ~10’x20′ plus large waterfall, in Campbell CA. I’d like to establish a Sierran Tree Frog colony. Is that feasible? Suggestions for getting the stock?


      1. Thanks Lisa, I’ll check out the website. The pond has been around for years. There was bullfrog we put in which might have kept colonizers away/eaten, but I haven’t seen/heard it for years. Developed area, lots of houses/fences; might be difficult for the frogs to find the pond.


      2. Ohhh… bullfrogs are considered invasive and would surely have eliminated its native competitors. Once the coast is clear for the survival of the Sierran Tree Frog, I’d recommend visiting a friend on the outskirts of town. At dusk, go searching in damp areas, under rocks, at the edges of fountains, drainage pipes, or under hot tub covers. You’ll probably need to collect a few. (I don’t know how you tell males from females!) Best of luck creating an urban habitat for our native amphibians!


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