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Annual grasslands and irrigated pasture at the project site provide foraging habitat <br /> for Swainson's hawks. The riparian trees and oak woodlands provide potential nest sites. <br /> Osprey <br /> The osprey is designated by the DFG as a species of special concern. Ospreys <br /> formerly bred throughout much of California, but by the 1960s their numbers had declined <br /> substantially because of human persecution and pesticide contamination (Remsen 1978). <br /> Osprey populations are now increasing and their range is expanding south from their major <br /> breeding areas (Jones & Stokes Associates file information). Osprey inhabit areas along <br /> large streams, freshwater lakes, and ocean shores where they forage for fish. Ospreys use <br /> large, dead, broken-top trees for nesting. <br /> Ospreys have been observed regularly near the project site along the Mokelumne <br /> River during winter (Yee, Estey pers. comms.). The riparian trees at the project site <br /> provide suitable perch sites for foraging osprey. <br /> Cooper's Hawk <br /> The Cooper's hawk is a DFG species of special concern. Cooper's hawks nest in <br /> lowland riparian woodlands and foothill and midelevation oak and montane hardwood <br /> forests. This species is more common in these habitats during migration and in winter. <br /> Pesticide contamination and habitat loss are thought to be the primary reasons for the <br /> decline of Cooper's hawks populations (Remsen 1978). <br /> An adult Cooper's hawk was observed in the oak woodlands on the project site <br /> during field surveys on September 6, 1990. Pairs of Cooper's hawks have been seen during <br /> the breeding season in the riparian vegetation along the Mokelumne River near the project <br /> site (Yee pers. comm.). <br /> Burrowing Owl <br /> . The burrowing owl is a state species of special concern. The species was formerly <br /> a permanent resident common throughout California. Burrowing owls prefer open, dry, and <br /> nearly level grassland or prairie habitat. (Grinnell and Miller 1944.) The owl lives and <br /> breeds in burrows, typically in abandoned ground squirrel colonies. Ground squirrel control <br /> measures and conversion of grasslands to agriculture and residential development are the <br /> primary causes for the species' decline (Zarn 1974). <br /> No burrowing owls or their sign (pellets and whitewash) were found during <br /> field surveys. Furthermore, local landowners and Audubon members have not observed <br /> burrowing owls in the area (Baker, Yee pers. comms.). <br /> 21 <br />