Foothill Yellow-legged Frog - Rana boylii

This frog originally ranged from northern Oregon west of the Cascades south along the coast ranges to the San Gabriel Mountains, and south along the foothills of the western side of the Sierra Nevada Mountains to the edge of the Tehachapi Mountains, with an isolated population (now possibly extinct) in the San Pedro Martir Mountains of Baja California. According to Stebbins & McGinnis (2012) "There are isolated populations in Southern California in Elizabeth Lake Canyon and the drainage of the San Gabriel River."

Populations on the north coast and in the northern Sierra Nevada are the healthiest. Several apparently healthy populations occur in streams draining the south coast range into the Central Valley. The few remaining populations in the foothills of the southern Sierra Nevada Mountains are nearly extinct. This frog is no longer found along the coast south of Monterey County or in the San Gabriel Mountains, where some previous locations were North Fork San Gabriel River, South Fork San Gabriel River, SW of Crystal Lake Park, Mt. Wilson, Monrovia, and Claremont. There were old museum records from the San Bernardino mountains east of Running Springs, and San Diego County at Jacumba and near Banner, but it seems those specimens were misidentified. 


Baja California Population

In his 2002 field guide, Lee Grismer mentions that two specimens of Rana boylii were collected by Loomis (1965) from the La Grulla Meadow in the Sierra San Pedro Martir of Baja California, a high mountain meadow at 2,100 meters (6,890 ft.) elevation. The specimens were identified by Robert Stebbins and another herpetologist, but then they were lost in shipment. Because the collection site was inaccessible, Loomis believed that the frogs were not introduced there. After an unsuccessful search, Welsh (1988) concluded that Rana boylii may be extirpated there due to an abundance of Rana draytonii.