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137: It should be noted again on the onset that a mixed flock of greater and lesser sandhill cranes were observed once on the site in late November 1991. No additional surveys were conducted at that time due to the EIR processing schedule. The one flock of cranes observed at that time were feeding on the new shoots of annual grass which was just appearing above the dried grass mat of the previous growing season. Wintering cranes appear to target such new growth fields and move their feeding sites as more early stage growth plots appear in the area. The sprouting of the new grass crop in non-irrigated grassland pastures is usually the first in the sequence of such events. By early spring these grass stands are well on their way to maturity and are no longer considered palatable for this species. At this time, however, agricultural fields of winter oats and barley are usually just beginning to sprout, and it appears that cranes now shift their feeding sites accordingly. It is the consulting biologist's opinion that this accounts for the fact that when biological field work was resumed at the site in early March 1992,cranes were no longer observed,not only on the project site but also on the numerous pasture areas located to the north. The northern migration of sandhill cranes was well underway, thus negating any possibility of further observation that season. The two potential habitats for the greater sandhill crane on the project site are those alluded to in the revised biological study: • a foraging habitat, especially during the weeks after the first substantial rains of fall when the new annual grass crop is sprouting; and • a potential roosting area, since the shallow finger bay areas of both North and South Tracy Lakes fit a "textbook description" of such sites, which is shallow water with low- growing vegetation. BS: The Swainson's hawk survey was conducted by Dr. Samuel M. McGinnis,professor of Biology, California State University, Hayward, and Ms. Nancy Allen, a graduate student in Zoology at CSUH,who will be pursuing her doctorate thesis work at UC Berkeley. Ms. Allen also has over a decade of Audubon Society survey experience. Together the two biologists bring to this survey over 40 years of field biology experience. The survey methods were twofold: (a) All buteos soaring over or alighting on or near the project site were identified. The flight paths of any Swainson's hawks were carefully followed to determine if they perched and remained on a specific tree or woodland area. When a Swainson's hawk alighted in a tree or perch, the site was located on an aerial photograph and then cautiously inspected with binoculars and a spotting scope at a distance of approximately 100 meters. It was this technique which led to the detection of the two Swainson's hawk nests on the site. (b) The biologists walked the several trails through and along the edge of Brovelli Woods and scanned the upper tree canopy with binoculars, at approximately 100-foot intervals, for large stick aggregations which may constitute an old or active nest. In addition to the two active Swainson's hawk nests, two other potential nest sites were observed. These were inspected during most visits in late May and June, however, neither were ever occupied. VI-152