Central Pacific Chorus Frog
Pseudacris sierra
![[Central Pacific Chorus Frog]](/images/36ds.jpg)
Description
Physical
One of 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 Central Pacific Chorus Frog is typically found at all elevations up to 2268m (7439ft). Maximum elevation we have a record for is 2417m (7928ft).
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 Central Pacific Chorus Frog 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.
Taxonomy
The Central Pacific Chorus Frog (Pseudacris sierra) was originally described in 1966 by Jameson, Mackey and Richmond as Hyla regilla sierra. See Amphibian Species of the World.
There are no currently recognized subspecies.
The Hyla regilla species complex was originally described in 1852 by Baird and Girard as Hyla regilla. See Amphibian Species of the World.
Pronunciation
The assumed IPA pronunciation of this species: /sud ˈeɪ krɪs/ /si ˈɛər ɑ/
Taxonomic Etymology
Pseudacris is a combination of two Greek words. Acris is the Cricket Frog genus, the Greek Ακρις (Akris) referred to a type of locust (see Strongs Lexicon). It probably is in reference to the mating chorus somewhat resembling a chorus of crickets. The prefix Pseuda is from the Greek ψευδής (Pseudes) and indicates “false, fraudulent, or pretending to be something it is not” (see http://en.wikipedia.org/wiki/Pseudo-). Chorus frogs are a very similar group to cricket frogs but are taxonomically different.
sierra references the Sierra Nevada mountains, where the type specimen for this species was collected.
Taxonomy Notes
This frog has gone through a lot of taxonomy changes. It was originally classified in the Treefrog genus Hyla as the Pacific Treefrog (Hyla regilla). Many currently available field guides use that name to describe our population.
In 1966, several subspecies were defined (Jameson, Mackey and Richmond 1966). Using that taxonomy, I believe much of our population would be classified as the Cascade Mountain Treefrog (Hyla regilla cascadae) though some parts of Shasta County may have been considered to be Sierran Treefrogs (Hyla regilla sierra) or possibly intergrade forms. Not all herpetologists accepted the subspecies level taxonomy proposed in that paper and they are not often seen in non academic level field guides.
In 1997 it was suggested that Hyla regilla actually belonged to genus Pseudacris opposed to Hyla (da Silva 1997). This proposal was accepted in the 5th edition CNAH list (Collins and Taggart 2002 pg. 15).
The Jameson et al. 1966 paper was before the dawn of DNA. A more recent study builds upon it and demonstrates that Pseudacris regilla is actually a Cryptic Species Complex (Recuero, Martínez-Solano, Parra-Olea and García-París 2006). This study lumps our population of this complex together roughly with what Jameson et al. 1966 originally described as Hyla regilla sierra based on genetic evidence and elevates them to species status resulting in the taxon Pseudacris sierra. This is the taxonomy used by SSAR 6th edition and thus used here.
I do however slightly deviate from SSAR. SSAR uses the common name “Sierran Treefrog”. I prefer the name “Central Pacific Chorus Frog” as suggested by William Flaxington. I believe it causes less confusion.
The species is not a strictly montane species nor is it primarily found in and around the Sierra Nevada mountains. It is found throughout most of central and northern California including the Coast Range mountains, Cascade Mountains, and the valley floor.
Additional Information
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.
![[Central Pacific Chorus Frog]](/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
![[Central Pacific Chorus Frog]](/images/41sm.jpg)
![[Central Pacific Chorus Frog]](/images/57sm.jpg)
![[Central Pacific Chorus Frog]](/images/61sm.jpg)
©Michael A. Peters
Recently transformed brown phase. Hornbeck Trail, Keswwick recreation area. Shasta County, CA
![[Central Pacific Chorus Frog]](/images/96sm.jpg)
©Michael A. Peters
Adult male. Notice the dark underside of throat indicating specimen is a male. Shasta Lake City, CA
![[Central Pacific Chorus Frog]](/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
![[Central Pacific Chorus Frog]](/images/116sm.jpg)
©Michael A. Peters
You can often see the unfertilized embryos inside a female Central Pacific Chorus Frog 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.
![[Central Pacific Chorus Frog 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
![[Central Pacific Chorus Frog 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.
![[Central Pacific Chorus Frog habitat]](/images/54sm.jpg)
©Michael A. Peters
Breeding Ditch. This is a small temporary pool that will probably be completely dry by mid summer. Central Pacific Chorus Frogs frequently use such pools for breeding. Whether the tadpoles mature or not then becomes a race against time. Sulfur Creek Drainage. Redding, CA.
![[Central Pacific Chorus Frog habitat]](/images/113sm.jpg)
©Michael A. Peters
Central Pacific Chorus Frog 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
![[Sponsor ShastaHerps.org]](/images/SherpBanner2.png)
