California Reptiles & Amphibians

Rana boylii - Foothill Yellow-legged Frog, Pg. 1

Click on a picture for a larger view

Historical Range in California: Red

Listen to this frog:

A short example

More sounds of
Rana boylii

More pictures and information
from this web site:

Page 2: Eggs and Tadpoles

Oregon frogs and habitat

Watch short movies of this frog at
Endangered Species International
(www.endangeredspeciesinternational.org)

Adult, Mendocino County

Adult, Santa Clara County

Juvenile, Del Norte County

Adult, Butte County
© 2005 Jackson Shedd

Juvenile, Santa Clara County

Adult, Del Norte County
© Alan Barron

Red-backed forms, Humboldt County © Steven Krause

Juvenile, Del Norte County

Adult, Shasta County
© Michael A. Peters

Sub-adult, Shasta County © Michael A. Peters

Small paired vocal sacs on a calling adult male, Linn County, Oregon

Egg mass, Linn County, Oregon

Tadpole, Santa Clara County

More pictures of eggs and tadpoles and breeding habitat.

Habitat, Mendocino County

Habitat, Del Norte County

Habitat, Santa Clara County

Habitat, Shasta County
© Michael A. Peters

Habitat, Santa Clara County

Habitat, 1600 ft., Del Norte County
© Alan Barron

Short Video

Scenes from a Foothill Yellow-legged Frog breeding site along a river in Oregon, including air and underwater calls. (The underwater calls were not recorded along with the video, they were added later, however, the frogs depicted underwater are male frogs who had been calling.)

A Foothill Yellow-legged frog calls at the edge of a small pool at the edge of a river with its head out of the water, producing a call that can be heard in the air and underwater. The sound is recorded with a hydrophone (an underwater microphone) placed about 3 feet behind the frog.

Description

Size

Adults are 1 1/2 - 3 1/5 inches long from snout to vent ( 3.8 - 8.1 cm).

Appearance

Coloring is gray, brownish, or olive, tending to match the background of its habitat. Can be plain or mottled with dark spotting. There is no mask through the eyes. Light-colored band across top of head. Underneath rear legs and lower abdomen are yellow. Underneath is whitish with dark spotting on throat and chest. Skin is grainy. Dorsolateral folds are not distinct.

Voice (Listen)

Rarely heard. A faint one-note low-pitched, raspy series of 4 - 6 notes per second. Grunts and oinks may also be heard. Calls at night and during the day from the air and underwater. Paired vocal sacs are small.

Behavior

Little is known about the life history of this frog. It is usually found near water and mostly active during daylight. It dives to the bottom and hides in rocks or litter when threatened.

Diet

Diet probably consists of a wide variety of invertebrates. Typical of most frogs, the prey is located by vision, then a large sticky tongue is used to catch the prey and bring it into the mouth to eat.

Reproduction

Mating and egg-laying occurs in water from mid March until June after streams have slowed from winter runoff. Clusters of eggs are attached to the downstream side of submerged rocks. Tadpoles transform in about 15 weeks, from July to September.

Range

Ranges from northern Oregon west of the Cascades south along the coast to the San Gabriel Mountains, and south along the western side of the Sierra Nevada Mountains to Kern county, with an isolated population (now possibly extinct) in the San Pedro Martir Mountains of Baja California.

Habitat

Frequents shallow, slow, gravelly streams and rivers with sunny banks, in forests, chaparral, woodlands. Sea level to 6,700 ft. (2,040 m.)

Conservation Issues (Conservation Status)

This frog has disappeared from much of its range in California (possibly up to 45 percent.) Populations south of southern Monterey County are now apparently extinct. Extremely high water levels in 1969 may have been a cause. Gone from 66 percent of its range in the Sierra Nevada Mountains, especially south of highway 80, possibly due to water released from reservoirs that washes away eggs and forces adult frogs away from the streams where they are more vulnerable to predators.

Taxonomy
Family	Ranidae	True Frogs
Genus	Rana	True Frogs
Species	boylii	Foothill Yellow-legged Frog
Original Description
Baird, 1854 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 7, p. 62 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Rana - Frog - "Rana" probably mimics how the Romans heard their call. boylii - honors Boyle, C.C. from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
None
Related or Similar California Frogs
Rana yavapaiensis Rana catesbeiana Rana draytonii Rana cascadae Rana aurora Rana pretiosa Rana pipiens Rana sierrae
More Information and References
Natureserve Explorer California Dept. of Fish and Game AmphibiaWeb Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Corkran, Charlotte & Chris Thoms. Amphibians of Oregon, Washington, and British Columbia. Lone Pine Publishing, 1996. Jones, Lawrence L. C. , William P. Leonard, Deanna H. Olson, editors. Amphibians of the Pacific Northwest. Seattle Audubon Society, 2005. Leonard et. al. Amphibians of Washington and Oregon. Seattle Audubon Society, 1993. Nussbaum, R. A., E. D. Brodie Jr., and R. M. Storm. Amphibians and Reptiles of the Pacific Northwest. Moscow, Idaho: University Press of Idaho, 1983. Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Game	DFG:SSC	California Species of Special Concern
Bureau of Land Management	BLM:S	Sensitive
USDA Forest Service	USFS:S	Sensitive
Natureserve Global Conservation Status Ranks	G3	Vulnerable
World Conservation Union - IUCN Red List	IUCN:NT	Near Threatened