SU0004092 - Laserfiche WebLink

Home Browse Search

trees and forage in nearby open fields. It should be noted that the well-maintained orchard does not represent suitable nesting or foraging habitat for either of these ~ sensitive birds. However, due to the potential for on-site construction to result in disturbance to any Swainson's hawks or burrowing owls nesting nearby, these species are discussed below. SWAINSON'S HAWK: The Swainson's hawk is listed as Threatened by the CDFG and is a Federal Species of Special Concern. In the Central Valley, this hawk typically nests in oak or cottonwood trees in or near riparian habitats. Swainson's hawks prefer nesting sites that provide sweeping views of nearby foraging grounds consisting of grasslands, irrigated pasture, alfalfa, hay, and wheat crops. Most Swainson's hawks are migratory, wintering in Mexico and breeding in California and elsewhere in the western United States. The raptor generally arrives in the Central Valley in mid-March, and begins courtship and nest construction immediately upon arrival at the breeding sites. The young fledge in early July, and most Swainson's hawks leave their breeding territories by late August to early September. Trees surrounding the project site provide suitable Swainson's hawk nesting habitat and cropland areas are suitable for foraging. The CNDDB contains ten records of Swainson's hawks in the Lathrop topographic quadrangle (CNDDB, 1999). One record from 1999 indicates a pair of nesting Swainson's hawks approximately 0.5 miles west of the project site. No Swainson's hawks were observed in the project site or surrounding areas during the recent survey; however, Swainson's hawks would not be expected to occur in January as most migrate south in the winter. Cottonwood and oak trees in the project vicinity provide high quality nesting habitat for this species, particularly along the San Joaquin River. Although no active territories are listed in the CNDDB in the immediate project vicinity, the likelihood of Swainson's hawks nesting in this area in the future can not be precluded. BURROWING OWL: Burrowing owls are a year-long resident in a variety of grasslands as well as scrublands that have a low density of trees and shrubs with low growing vegetation; burrowing owls which nest in the Central Valley may winter elsewhere. The main habitat requirement of the burrowing owl is burrows for nesting. The owl usually nests in old ground squirrel burrows, although they have been known to dig their own Landmark Lathrop: Biology 7 January 19, 2000