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is located on the Cosumnes River Preserve where the birds prefer the restored seasonal marsh units south of Desmond Road. This roost is comprised of between 800- 1,500 cranes with over 400 greater sandhill cranes, 200 more than was found by Pogson and Lindstedt (1991). Thus, the preserve winters 10% of the Pacific Flyway's greater sandhill cranes. Over 3,000 cranes can be found on the preserve after mid-January as delta farmlands are drained. During this period the preserve may winter up to 25% of the flyway population of greater sandhill cranes. The birds utilizing fields around Buckeye are probably from the Cosumnes flock. The overall importance of the Cosumnes River bottom lands and fallow agricultural lands and irrigated pasture of the Delta are the main reasons these birds continue to winter in the region. For roosting, they require shallow (less than 6") water in flat uninterrupted wetlands, with low relief shorelines (Pogson and Lindstedt 1988). These conditions probably allow birds to readily locate potential predators. In the Delta, sandhill cranes forage in open pastures,flooded croplands, and fallow fields, with the majority feeding on waste grain in fallow corn fields. Cranes also feed in winter wheat fields that are "greening." Here they feed mostly upon tubers, sprouts, shoots and invertebrates (Pogson and Lindstedt 1988). Grinnell and Miller(1944) indicate that both subspecies frequent open grasslands and fields near freshwater marshes, and frequent unwooded rivers and lakes. Cranes rarely feed in the open savanna of the Cosumnes Preserve and more than likely do not regularly utilize the savannah on Buckeye Ranch. Their size, flocking behavior, and poor maneuverability while landing and taking off, would make foraging among trees risky. The main cause of mortality in the wintering grounds are collisions with powerlines (Pogson and Lindstedt (1991). The steep banks (average 20 foot embankment) of Tracy Lakes do not provide loafing habitat this open country species requires. Cranes have not been observed by the study team on the ranch, Buckeye Ranch Resource Plan (November, 1993) 57