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Soil Investigations for Data Collection in the Delta Initial Study/Proposed Mitigated Negative Declaration 49 occurrences. There are several reported occurrences of California red-legged frog less than 0.5 mile from multiple Impact Areas in the southern portion of the Study Area, east and southeast of the Clifton Court Forebay, within Contra Costa and Alameda Counties. Implementation of the following mitigation measures to avoid impacts to all suitable aquatic habitat, upland refugia habitat, and individuals that could be moving through the Study Area: MM-AES-1, MM-AES-2, MM BIO-1, and MM BIO-2, would reduce potential project impacts to California red-legged frog to: Less than Significant with Mitigation Incorporated. Western spadefoot (Spea hammondii) Western spadefoot is identified as a CDFW Priority One Species of Special Concern (CDFW 2019b, Thompson et al 2016). It is an olive toad, ranging from 1.5 to 2.5 inches SVL, with orange tipped skin tubercles, vertical pupils, and a single black spade on each hind foot (Stebbins and McGinnis 2012, Thompson et al 2016). Western spadefoot is found throughout the Central Valley and coastal lowlands from the Shasta County in Northern California to Baja California in Mexico, at elevations ranging from sea level to 4,500 feet (Jennings and Hayes 1994, Stebbins and McGinnis 2012). This species occurs in grasslands, mixed woodland, open chaparral, and pine oak woodlands, with shallow temporary pools or washes. Breeding coincides with the rainy season and usually occurs from January to May, peaking in February and March, in temporary pools and drainages, although breeding can also occur in man-made water sources such as cattle ponds (Thompson et al 2016). Adults remain in underground burrows for most of the year and will travel up to several meters on rainy nights (CDFW 2000a). Eggs are laid in cylindrical clusters and usually hatch in three to four days, with tadpoles metamorphing in 4 to 11 weeks (Nafis 2019). Juveniles will leave the pool a few days after metamorphosis. On land movement is generally thought to be nocturnal, with juveniles and adults able to dig burrows up to eight inches deep (Thompson et al 2016). They will also make use of existing mammal burrows. Western spadefoot has a moderate potential to occur within the Study Area based upon presence of suitable habitat and proximity to reported occurrences. Although there are no reported occurrences within 8 miles of the Study Area displayed in the CNDDB GIS layer, there are several recent research grade occurrences reported on iNaturalist (2019) that are within established with 2 or 5 miles of the southernmost portion of the Study Area, south of Clifton Court Forebay, in Alameda County.