Three species of frog have been observed at the Reserve; two of these are native, while the third has been introduced to California. Additionally, foothill yellow-legged frogs (Rana boylii) are known to occur near Quail Ridge, but the lack of suitable habitat (permanent streams) makes it unlikely that this species will be found on the Reserve.

Western toad; Photo by Mike Benard
Western toad, Bufo boreas (Bufonidae Family) – Western toads occasionally are seen around the south end of the Reserve, usually at night or under cover objects. These medium-sized (5-13 cm SVL) brown and tan frogs with bumpy skin are not likely to be confused with the other frogs of the Reserve. Although adult toads have been observed in the drying mud of Decker Pond in May, they have not yet been observed to breed on the Reserve, despite careful monitoring of the ponds since 2000.

 

Pacific Treefrog; Photo by Mike BenardPacific treefrog, Hyla regilla (Hylidae Family) – The most abundant frog of the Reserve. Males can be heard calling any month of the year, although large breeding aggregations begin in late December or early January, and continue through May. These small frogs (2-5 cm SVL) are readily recognized by the toepads and the dark stripe behind the eye. The dorsal coloration and pattern is highly variable, ranging from bright green to a tan or gray coloration, and can change within a few minutes. Males have multiple types of calls that they use to attract females and communicate with other males. The most common advertisement call is a loud ‘kreeck-eckk’. They breed at all four ponds on the Reserve, but they do not appear to breed in the ephemeral streams. Tadpoles metamorphose into little froglets between May and July, and they usually reach maturity in one (males) or one to two (females) years. Some adults will live to breed for several years. Despite their small size, these frogs are very mobile, and can be found far from the breeding ponds. The Quail Ridge Reserve is currently the site of an ongoing study on demography, movement, and local adaptation in Pacific treefrogs. For more information see Mike Benard's research.

Bullfrog; Photo courtresy of Alan Resetar © 1980 Alan ResetarBullfrog, Rana catesbeiana (Ranidae Family) – Bullfrogs are nonative and breed in the reservoir surrounding the Reserve. They can be recognized from their large size (9-20 cm SVL), large tympanum (eardrum), strongly webbed feet, smooth, olive to green dorsal color, and often a mottled brown and white belly. Every year a few subadult bullfrogs move into Decker Pond. In 2004, an adult male was able to make it into Fordyce Pond – a mile away from the reservoir. Diet analysis has found bullfrogs will eat nearly any animal small enough to swallow, from a host of insects, to other frogs, to snakes, small mammals, and birds. They are an important threat to red-legged frogs (Rana aurora) in the foothills of the Sierra Nevada. Bullfrogs are potentially so damaging that they should be eliminated on sight!

Photo Credits: Title, Treefrog, Toad, and other Treefrog (Mike Benard), Bullfrog (Alan Resetar). For more pictures see: http://elib.cs.berkeley.edu/photos/fauna/

This page last updated: June 24, 2005  


Contact: Dr. Virginia Boucher
John Muir Institute of the Environment
109 The Barn, University of California, Davis, CA 95616
Phone: 530-752-6949; email: vlboucher@ucdavis.edu

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