|Foothill yellow-legged frog (Rana boylii, FYLF), currently a Candidate for Threatened Status under the California Endangered Species Act, reside in numerous Sierra Nevada foothill streams. Many foothill streams, such as Greenhorn Creek located in Nevada County, contain mine tailings due to California's hydraulic mining days from the 1800s.
Greenhorn Creek has been mined for gravel for the past 50 years, and also happens to be home to a breeding population of FYLF. In a typical year the annual harvesting of gravel coincides with FYLF breeding season, and therefore, for the last few years local biologists have conducted capture and relocation of the frogs where the gravel harvesting takes place.
FYLF typically attach their egg masses to the downstream side of cobble-sized rocks to ensure stability within the current, but may also attach them to bedrock, boulders, or substrates too large to move safely. With the newly issued Incidental Take Permit for the project, in 2018 biologists negotiated with CDFW to test a novel egg mass relocation method. This innovative approach involved biologists detaching egg masses from their original substrate and relocating them into a "rock corral" within the stream current. Herein we present the methods and results of the relocation of over 1,000 adults, juveniles, and FYLF egg masses.