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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Sierran Chorus Frog

Synonyms and Other Names: Central Pacific Chorus Frog, Pseudacris regilla

Taxonomy: available through www.itis.gov

Identification: Pseudacris sierra is a small hylid (treefrog) with a SVL (snout-vent length) of 19-50 mm (0.75-2 in) and small toe pads (disks) (Stebbins, 2003). The dorsal coloration of these color-changing, sometimes mottled, frogs also varies genetically:  green, reddish, tan, gray, brown, or black, but typically green or shades of brown (Stebbins, 1972, 2003; Leonard et al., 1993; Lamar, 1997; Werner et al., 2004).  Unlike Pseudacris cadaverina, the California chorus frog, a black or dark brown eyestripe or mask is more often present, green is the more common dorsal color, and the toe pads are not as large and conspicuous (Powell et al., 1998; Stebbins, 2003). Distinct morphological criteria for distinguishing P. sierra from its sister species the northern Pacific chorus frog, Pseudacris regilla, and the Baja California chorus frog, P. hypochondriaca, have not yet been established. See the species accounts titled “Pseudacris hypochondriaca (Hallowell, 1854)” and “Pseudacris regilla (Baird and Girard, 1852)” on this website. The Sierran chorus frog’s call is a stereotypical, loud, two-part “kreck-ek” or “ribbit” (Stebbins, 2003); it is identical to its sister species P. hypochondriaca, the most commonly used frog call on Hollywood movie soundtracks regardless of the locality depicted in the movie (Davidson, 1995, 1996; Stebbins, 2003; Beltz, 2005). It is shorter, lower-pitched, and less musical than the call made by P. cadaverina (Stebbins, 2003). Recordings of the calls of P. sierra, under the name P. regilla, are available on CDs (Davidson, 1995, 1996; Elliott et a., 2009). The tadpoles of P. sierra are light greenish gray or olive brown, have high tail fins, and the internal viscera can be seen ventrally (Stebbins, 1972, 2003; Werner et al., 2004).

Sierran chorus frogs have been illustrated by a variety of authorities (Test, 1898; Wright and Wright, 1949; Stebbins, 1954, 1959, 1972, 1985, 2003; Basey, 1976; Smith, 1978; Behler and King, 1979; Kricher, 1993; Leonard et al., 1993; Stebbins and Cohen, 1995; Lamar, 1997; Werner et al., 2004; Beltz, 2005; Elliott et al., 2009; Krysko et al., 2011: MorphoBank Project No. p538, www.morphobank.org). Halliday (2002) and Werner et al. (2004) illustrate deformities found in natural populations.

Size: SVL is 19-50 mm.

Native Range: Pseudacris sierra is indigenous to Pacific and western regions of North America, from southeastern Oregon, western Montana, western Idaho, Nevada, through central California (Test, 1898; Stebbins, 1959, 1972, 2003; Jameson et al., 1966; Basey, 1976; Campbell et al., 1982; Nussbaum et al., 1983; Leonard et al., 1993; Lamar, 1997; Duellman and Sweet, 1999; Boundy, 2001; Ripplinger and Wagner, 2004; Werner et al., 2004; Recuero et al., 2006a, b; Elliott et al., 2009).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Pseudacris sierra frequents a variety of habitats and elevations, from sea level to mountains, grasslands, forests, and farmlands (Kricher, 1993; Leonard et al., 1993; Lamar, 1997; Boundy, 2001; Stebbins, 2003). This adaptable little hylid is chiefly a terrestrial, nonclimber, preferring to remain among low plants near or along water (Leonard et al., 1993; Stebbins, 2003; Elliott et al., 2009). Individuals of varying colors will preferentially select microhabitat substrates that most closely match their individual color (Stebbins and Cohen, 1995; Werner et al., 2004). They breed and lay their eggs in a variety of waters including marshes, ponds, lakes, reservoirs, slow streams, and roadside ditches (Nussbaum et al., 1983; Kricher, 1993; Leonard et al., 1993; Stebbins, 2003; Werner et al., 2004; Elliott et al., 2009).

Means of Introduction: It is not entirely known how a nonindigenous species of the P. regilla complex was introduced to Arizona although plant nurseries are involved in a some cases (Brennan and Holycross, 2006). Indigenous populations of P. hypochondriaca exist in the northwestern region of the state (Stebbins, 1985, 2003; Brennan and Holycross, 2006; Recuero et al., 2006a).

The means of introduction for the P. sierra population in Tulare County is unknown, and it is possible it may be an indigenous population (Stebbins, 1985). Perhaps it is a relict population.

All the P. sierra specimens intercepted in Florida arrived from horticultural shipments (Krysko et al., 2011).

Status: Nonindigenous chorus frogs are established in Arizona (Brennan and Holycross, 2006), but it is not clear which species is involved.

Suspected nonindigenous P. sierra are established in Tulare County, California (Stebbins, 2003).  They seem confined to this area.

Nonindigenous P. sierra in Florida were all intercepted (Krysko et al., 2011), and not established. However, its persistent entry into Florida for nearly 25 years through the same horticultural commerce from California is certainly cause for concern (Krysko et al., 2011).

Impact of Introduction: The impact of suspected nonindigenous Pseudacris in Arizona and California will remain unclear as long as their exact species identity or status as nonindigenous or indigenous populations remains uncertain. The P. sierra intercepted in Florida had no impact.

Remarks: The taxonomy of the P. regilla complex has been reviewed or summarized by numerous authors (Test, 1898; Jameson et al., 1966; Case et al., 1975; Frost, 1985, 2000, 2007; Collins and Taggart, 2002, 2009; Crother et al., 2003; Ripplinger and Wagner, 2004; Faivovich et al., 2005; Frost et al., 2006, 2008; Recuero et al., 2006a, b).  Although currently placed in the genus Pseudacris, at one time all species in the Pacific chorus frog complex were in the genus Hyla (reviewed by Frost, 2000); Pacific “treefrogs.” Recuero et al. (2006a) revised the Pacific chorus frog complex, and then corrected the taxonomy (Recuero et al., 2006b), by splitting it into three species: P. hypochondriaca, P. sierra, and P. regilla (Frost et al., 2008). See the species accounts titled “Pseudacris regilla (Baird and Girard, 1852)” and “Pseudacris hypochondriaca (Hallowell, 1854)” on this website. The natural history and biology of P. sierra and its two sister species are summarized by Wright and Wright (1949), Nussbaum et al. (1983), Leonard et al. (1993), Stebbins and Cohen (1995), Stebbins (2003), Werner et al. (2004), and Elliott et al. (2009).

References: (click for full references)

Basey, H. E. 1976. Discovering Sierra Reptiles and Amphibians. Yosemite Natural History Association/Sequoia Natural History Association in cooperation with National Park Service, [place of publication not provided].

Behler, J. L., and F. W. King. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc., New York. 743 pp.

Beltz, E. 2005. Frogs. Inside Their Remarkable World. Firefly Books Ltd, Richmond Hill, Ontario, and Buffalo, New York. 175 pp.

Boundy, J. 2001. Herpetofaunal surveys in the Clark Fork Valley region, Montana. Herpetological Natural History 8(1): 15-26.

Brennan, T. C., and A. T. Holycross. 2006. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix. 150 pp.

Campbell, R. W., M. G. Shepard, B. M. Van Der Raay, and P. T. Gregory. 1982. A bibliography of Pacific Northwest herpetology. British Columbia Provincial Museum Heritage Record (14):i-vi, 1-151.

Case, S. M., P. G. Haneline, and M. F. Smith. 1975. Protein variation in several species of Hyla. Systematic Zoology 24(3): 281-295.

Collins, J. T., and T. W. Taggart. 2002. Standard Common and Current Scientific Names for North American Amphibians, Turtles, Reptiles & Crocodilians. Fifth Edition. The Center for North American Herpetology, Lawrence, Kansas.  44 pp

Collins, J. T., and T. W. Taggart. 2009. Standard Common and Current Scientific Names for North American Amphibians, Turtles, Reptiles & Crocodilians. Sixth Edition. The Center for North American Herpetology, Lawrence, Kansas.  44 pp.

Crother, B. I., J. Boundy, J. A. Campbell, K. de Quieroz, D. Frost, D. M. Green, R. Highton, J. B. Iverson, R. W. McDiarmid, P. A. Meylan, T. W. Reeder, M. E. Seidel, J. W. Sites, Jr., S. G. Tilley, and D. B. Wake. 2003. Scientific and standard English names of amphibians and reptiles of North America north of Mexico: Update. Herpetological Review 34(3): 196-203.

Davidson, C. 1995. Frog and Toad Calls of the Pacific Coast. Vanishing Voices. Library of Natural Sounds, Cornell Laboratory of Ornithology, Ithaca. Audio CD Recording.

Davidson, C. 1996. Frog and Toad Calls of the Rocky Mountains. Vanishing Voices. Library of Natural Sounds, Cornell Laboratory of Ornithology, Ithaca. Audio CD Recording.

Duellman, W. E., and S. S. Sweet. 1999. Distribution patterns of amphibians in the Nearctic Region of North America. Pp. 31-109. In: W. E. Duellman (editor). Patterns of Distribution of Amphibians. A Global Perspective. The Johns Hopkins University Press, Baltimore. 633 pp.

Elliott, L., C. Gerhardt, and C. Davidson. 2009. The Frogs and Toads of North America. Houghton Mifflin Harcourt, New York. 344 pp. + CD-ROM.

Faivovich, J., C. B. F. Haddad, P. C. A. Garcia, D. R. Frost, J. A. Campbell, and W. C. Wheeler. 2005. Systematic review of the frog family Hylidae, with special reference to Hylinae: Phylogenetic analysis and taxonomic revision. Bulletin of the American Museum of Natural History 294:1-240.

Frost, D. R. (editor). 1985. Amphibian Species of the World. A Taxonomic and Geographical Reference. Allen Press, Inc. and The Association of Systematics Collections. Lawrence, Kansas. 732 pp.

Frost, D. [R.] (compiler). 2000 [2001]. Anura¬—frogs. Pp. 6-17. In: B. I. Crother (chair), and Committee on Standard English and Scientific Names (editors). Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Society for the Study of Amphibians and Reptiles Herpetological Circular 29:i-iii, 1-82.

Frost, D. [R.] 2007. Amphibian Species of the World 5.1, an Online Reference. American Museum of Natural History, New York. Available on URL: http://research.amnh.org/herpetology/amphibia/index.php.

Frost, D. R., T. Grant, J. Faivovich, R. H. Bain, A. Haas, C. F. B. Haddad, R. O. De Sá, A. Channing, M. Wilkinson, S. C. Donnellan, C. J. Raxworthy, J. A. Campbell, B. L. Blotto, P. Moler, R. C. Drewes, R. A. Nussbaum, J. D. Lynch, D. M. Green, and W. C. Wheeler. 2006. The amphibian tree of life. Bulletin of the American Museum of Natural History 297:1-370 + Fig. 50 foldout.

Frost, D. R., R. W. McDiarmid, and J. R. Mendelson III. 2008. Anura—frogs. Pp. 2-12. In: B. I. Crother (chair), and Committee on Standard English and Scientific Names (editors). Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth Edition. Society for the Study of Amphibians and Reptiles Herpetological Circular 37:1-84.

Halliday, T. R. 2002. Declining amphibian populations. Pp. 30-33. In: T. [R.] Halliday and K. Adler (editors). Firefly Encyclopedia of Reptiles and Amphibians. [U. S. Edition.] Firefly Books (U. S.) Inc., Buffalo. 240 pp.

Howland, J. M. 1996. Herps of Arizona. The Desert Monitor (Phoenix) 27(1):12-17.

Jameson, D. L., J. P. Mackey, and R. C. Richards. 1966. The systematics of the Pacific tree frog, Hyla regilla. Proceedings of the California Academy of Sciences, Fourth Series 33(19):551-620.

Kricher, J. C. 1993. A Field Guide to the Ecology of Western Forests. Houghton Mifflin Company, Boston. 554 pp.

Krysko, K. L., J. P. Burgess, M. R. Rochford, C. R. Gillette, D. Cueva, K. M. Enge, L. A. Somma, J. L. Stabile, D. C. Smith, J. A. Wasilewski, G. N. Kieckhefer III, M. C. Granatosky, and S. V. Nielsen. 2011. Verified non-indigenous amphibians and reptiles in Florida from 1863 through 2010: Outlining the invasion process and identifying invasion  pathways and status. Zootaxa 3028:1-64 + MorphoBank Project No. p536: URL: http://www.morphobank.org.

Lamar, W. W. 1997. The World’s Most Spectacular Reptiles & Amphibians. World Publications, Tampa. 208 pp.

Leonard, W. P., H. A. Brown, L. C. Jones, K. R. McAllister, and R. M. Storm. 1993. Amphibians of Washington and Oregon. Seattle Audubon Society, Seattle. 168 pp.

Nussbaum, R. A., E. D. Brodie Jr., and R. M. Storm. 1983. Amphibians and Reptiles of the Pacific Northwest. The University Press of Idaho, Moscow, Idaho. 332 pp.

Powell, R., J. T. Collins, and E. D. Hooper, Jr. 1998. A Key to Amphibians & Reptiles of the Continental United States and Canada. University Press of Kansas, Lawrence. 131 pp.

Recuero, E., Í. Marínez-Solano, G. Parra-Olea, and M. García-París. 2006a. Phylogeography of Pseudacris regilla (Anura: Hylidae) in western North America, with a proposal for a new taxonomic rearrangement. Molecular Phylogenetics and Evolution 39(2):293-304.

Recuero, E., Í. Marínez-Solano, G. Parra-Olea, and M. García-París. 2006b. Corrigendum to “Phylogeography of Pseudacris regilla (Anura: Hylidae) in western North America, with a proposal for a new taxonomic rearrangement.” Molecular Phylogenetics and Evolution 41(2):511.

Ripplinger, J. I., and R. S. Wagner. 2004. Phylogeography of northern populations of the Pacific treefrog, Pseudacris regilla. Northwestern Naturalist 85(3):118-125.

Smith, H. M. 1978. A Guide to Field Identification. Amphibians of North America. Golden Press, New York. 160 pp.

Stebbins, R. C. 1954. Amphibians and Reptiles of Western North America. McGraw-Hill Book Company, Inc., New York.537 pp.

Stebbins, R. C. 1959. Reptiles and Amphibians of the San Francisco Bay Region. University of California Press, Berkeley and Los Angeles. 72 pp.

Stebbins, R. C. 1972. California Amphibians and Reptiles. University of California Press, Berkeley, Los Angeles, and London. 152 pp.

Stebbins, R. C. 1985. A Field Guide to Western Reptiles and Amphibians. Second Edition, Revised. Houghton Mifflin Company, Boston. 336 pp.

Stebbins, R. C. 2003. A Field Guide to Western Reptiles and Amphibians. Third Edition. Houghton Mifflin Company, Boston. 533 pp.

Stebbins, R. C., and N. W. Cohen. 1995. A Natural History of Amphibians. Princeton University Press, Princeton. 316 pp

Test, F. C. 1898. A contribution to the knowledge of the variations of the tree frog Hyla regilla. Proceedings of the U. S. National Museum 21 1899(1156):477-492, pl. xxxix.

Werner, J. K., B. A. Maxell, P. Hendricks, and D. L. Flath. 2004. Amphibians and Reptiles of Montana. Mountain Press Publishing Company, Missoula. 262 pp.

Wright, A. H., and A. A. Wright. 1949. Handbook of Frogs and Toads of the United States and Canada. Third Edition. Cornell University Press, Ithaca and London. 640 pp.

Author: Somma, L.A.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.