is also a very important species in all of the regions where it is found because it is a keystone species. Many other species, such as garter snakes, depend upon its abundance as a prey item for their survival. References External links Fact sheet, taxonomic details, distribution maps, slideshow, and images of Pseudacris regilla at ZipcodeZoo.com. Californiaherps.com description - Includes detailed description, photos, recordings of calls mister-toad.com Pacific tree frog description - Description of the ecology of Pacific Tree Frogs with photographs, audio and video. https://web.archive.org/web/20081202055931/http://www.npwrc.usgs.gov/resource/herps/amphibid/species/hylareg.htm Pacific Chorus Frog recordings Chorus frogs Fauna of the San Francisco Bay Area Amphibians of Canada Amphibians of the United States Amphibians described in 1852 Taxa named by Spencer Fullerton Baird Endemic fauna of the Pacific Northwest