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Soil Investigations for Data Collection in the Delta Initial Study/Proposed Mitigated Negative Declaration 55 rookeries (colonial nest sites) that often include interspecies nesting and roosting with other species in this group. These species are widely distributed across North America. Nesting habitat includes mature riparian trees and snags adjacent to water, and the species forage by stalking in aquatic habitats for fish, small birds, mammals, reptiles, and amphibians. Tree-nesting waterbirds tend to exhibit high fidelity to rookery sites. While most species need mature, riparian trees, rookeries for Black-crowned Night Heron have also been located in riparian scrub (CDWR 2011). Breeding occurs between February and August at these rookeries (CDFW 2018). All of these species have a high potential to occur within the Study area based upon the known ranges, availability of suitable habitat and the presence of known roosts in the vicinity of the Study Area. Implementation of Mitigation Measures MM AES-1, MM BIO-1 and MM BIO-5 would reduce potential project impacts to these five species by avoiding and reducing impacts to the roosting habitat in the Study Area to: Less than Significant with Mitigation Incorporated. MM BIO-5: Rookery Birds To minimize the potential impacts to special-status rookery birds that may occur within the Study Area the following general measures will be implemented: a. A pre-activity survey for active rookeries will be conducted (during nesting season between February 1 – August 31) a maximum of 72 hours prior to the onset of soil investigation field activities. The qualified biologist(s) must, at a minimum, have experience conducting surveys to identify the specific rookery bird species and associated habitat that could occur on site. b. If any active rookeries are identified within or adjacent to an Impact Area, a buffer will be put in place to ensure that the birds are not disturbed during work activities. This buffer will be up to 50 feet, but can be smaller, dependent on-site conditions and at the discretion of the qualified biologist. Cooper’s Hawk (Accipiter cooperii) Cooper’s Hawk is included on the CDFW Watch List. Cooper’s Hawk is a crow- sized woodland raptor with orange-red eyes, blue-gray mantle feathers, barred underparts, and a dark crown. The species is found across North America from Southern Canada to Northern Mexico (Rosenfield et al 2019) and occurs throughout most of California where appropriate habitat exists. Habitat includes riparian and oak woodland, and trees in rural and suburban areas adjacent to foraging habitat. Cooper’s Hawk forages and nests in live oak, riparian deciduous, or other forests where it hunts primarily for small birds and mammals (CDFW 1990a). Nests are built in mature trees, usually near streams. Breeding