Sierran Treefrog
Pseudacris sierra
![[Sierran Treefrog]](/images/36ds.jpg)
Description
Physical
Our smallest frog, adults are typically smaller than 5cm (2in) in length (Stebbins 2003 pg 222). Toe pads are present at end of toes. Toe pads allow the species to readily climb most surfaces, including glass. Lacks dorsolateral fold. Eardrum not prominent.
Color and Pattern
Highly variable in color. Yellow, green, tan, brown and red variations exist in various degrees. Some specimens exhibit one color phase on their back and a different color phase along their sides. Contrary to popular belief, this species can not change color between the different color phases. They do however change how light or dark the color appears and can do so quite rapidly.
All specimens have a thick dark stripe on each side of the face that extend from the nose through the eye generally to the top of the front limb. The eye stripe may be difficult to see in dark individuals. Dark banding is often but not always present on the limbs, especially the hind limbs. Irregular spotting is often but not always present on the back.
Sexual Dimorphism
During the breeding season, sexually mature males have a very wrinkly brownish underside to their throat. Females that have not yet laid their eggs often appear bloated at the sides.
Diet
Feeds primarily on invertebrates. If you leave your porch light on during the summer, you can sometimes find this frog on your wall near the porch light feeding on the insects the porch light attracts.
Distribution Range
General range map taken from CWHR.
Museum records taken from following institutions: CAS Herps, MVZ Herps, LSUMZ Herps.
Found throughout Shasta County.
Typical Elevation
Based on records in our database, in Shasta County the Sierran Treefrog is typically found at all elevations up to 2268m (7439ft).
Voice
Despite being our smallest frog, this is our loudest frog and most frequently heard. The call of this frog is also commonly used by Hollywood when a film or television show requires audio of a frog croaking.
Lone individuals often call with a slow lower pitched raspy Kr-e-e-e-e-e-ck while away from breeding sites, even from inside holes where they are hiding. Multiple males will often call in chorus in response to each other with a faster higher pitched one or two syllable Krik-krik.
Reproduction and Young
Most reproduction in our area occurs between January and early Summer, but they also are known to breed in the fall.
Eggs are laid in several small clusters usually attached to aquatic vegetation in temporary or permanent pools or in slow moving streams, the clusters have typically have 20 to 25 eggs per cluster (Stebbins 2003 pg 443). Egg sacs are a clear gelatin ball around a stick or plant branch with dark centers at the center of individual eggs that make up the ball.
Tadpoles are a mottled olive green and can be distinguished from other tadpoles by the position of their eyes and the shape of their tail. When looking straight down at a Sierran Treefrog tadpole, the eyes will appear at the very edge of the outline. The tail fin starts at the top their head.
Recently transformed frogs usually start appearing in Late April to May at lower elevations (IE Redding), may appear later at higher elevations. Recently transformed frogs are about the size of a watch battery.
Additional Information
Notes
Until recently, the Sierran Treefrog was known as the Pacific Treefrog (Pseudacris regilla).
While there is still some controversy, that species has recently been split up into 3 distinct species, including our Sierran Treefrog (Recuero, Martínez-Solano, Parra-Olea and García-París 2006).
An older look at the taxonomy wants to keep them as one species but split the complex into multiple subspecies (Jameson, Mackey and Richmond 1966). By that groups taxonomy, our frogs would be the Cascade Mountain Treefrog (Pseudacris regilla cascadae). That taxonomy, however, does not currently have much support.
Images
Unless otherwise noted, all images are of wild specimens in Shasta County.
Please be kind, do not hotlink images and do not use images without permission of the copyright owner.
![[Sierran Treefrog]](/images/36sm.jpg)
©Michael A. Peters
Example of specimen expressing two different color phases. In situ under water on creek bottom. Sulfur Creek. Redding, CA
![[Sierran Treefrog]](/images/41sm.jpg)
![[Sierran Treefrog]](/images/57sm.jpg)
![[Sierran Treefrog]](/images/61sm.jpg)
©Michael A. Peters
Recently transformed brown phase. Hornbeck Trail, Keswwick recreation area. Shasta County, CA
![[Sierran Treefrog]](/images/96sm.jpg)
©Michael A. Peters
Adult male. Notice the dark underside of throat indicating specimen is a male. Shasta Lake City, CA
![[Sierran Treefrog]](/images/97sm.jpg)
©Michael A. Peters
Adult male. Notice the prominent toepads that distinguish this species from all our other frogs. Shasta Lake City, CA
![[Sierran Treefrog]](/images/116sm.jpg)
©Michael A. Peters
You can often see the unfertilized embryos inside a female treefrog when she is ready to mate. Redding, CA.
Habitat Shots
Unless otherwise noted, these habitat shots are from within Shasta County where this species is known to occur.
![[Sierran Treefrog habitat]](/images/52sm.jpg)
©Michael A. Peters
Breeding Pool. This pool also serves as a nursery to trout fingerlings, which prey upon tadpoles. As a result, the tadpoles are not often seen. However, as you move rocks on the bottom of the pool, you often find tadpoles hiding under them. Sulfur Creek. Redding, CA
![[Sierran Treefrog habitat]](/images/53sm.jpg)
©Michael A. Peters
Breeding Pool. No trout fingerlings were present in this pool. As a result, the tadpoles were seen freely swimming at all depths of the pool. Sulfur Creek. Redding, CA.
![[Sierran Treefrog habitat]](/images/54sm.jpg)
©Michael A. Peters
Breeding Ditch. This is a small temporary pool that will probably be completely dry by mid summer. Treefrogs frequently use such pools for breeding. Whether the tadpoles mature or not then becomes a race against time. Sulfur Creek Drainage. Redding, CA.
![[Sierran Treefrog habitat]](/images/113sm.jpg)
©Michael A. Peters
Sierran Treefrog tadpoles were found in both vernal pools on the right side of the meadow. Redding, CA.
Multimedia
Fall Chorus. A few egg sacs were found, they hatched into tadpoles, but it appears that the tadpoles perished in the followimng cold weather. Redding, CA
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