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isolation and security (Shenk and Armbruster 1986; FWS 1987b). Water width is defined by whooping crane authorities as being the sum of all wetted widths (water -filled subchannels) within the unobstructed channel width. LX 1975' 4t, � ti Forage Habitat -Wet Meadows .,&, LWA FV-, U, 7 During migration, whooping cranes forage in small -grain croplands, upland grasslands, and wetland habitat areas where they have been observed feeding on frogs, fish, crayfish, insects, plant tubers, and waste grains (FWS 1981). A major part of the whooping crane's energy requirements during migration across the Great Plains probably comes from waste agricultural crops. Although the proportions of plant and animal food in the diet are not known, whooping cranes, like sandhill cranes, require animal matter to satisfy their nutritional needs. In general, the foraging strategies of whooping cranes are more closely associated with wetland feeding habitats than are those of sandhill cranes (Johnsgard 1996). Foods used by migrating whooping cranes and that are available in wetlands and bottomland grasslands along the Platte River include small fish, snakes, frogs, frog egg masses, crayfish, grasshoppers, crickets, and other insects (FWS 1981, 1994; Currier et al. 1985; Ballinger 1980; Cochnar and Jenson 1981; Ratcliffe 1981; Davis and Vohs 1993). Many of these organisms depend on aquatic moisture regimes, or seasonally moist or saturated soils for all or part of their life cycle. Interior Least Tern and Piping Plover River Channel Habitat + aph >> of the cen ral P1affP _ ��Pr mr��srn+ v__egetated sandbars and sandbars only slightly exposed above water (not suitable nesting habitat)e common (Ziewitz et al. 1992). Areas that could clearly be interpreted as potentially suitable nesting substrate were rare. River discharge at Grand Island ranged from 25 cfs to 2,570 cfs on the eight sampling dates of aerial videography. With one exception, sandbar areas greater than 2 acres were measured only on the two lowest flow dates (June 15 and 24). The mean sandbar area of nest sites was 1.2 acres for the eight dates examined. This was significantly greater than the mean of 0.6 acre for systematic sample sites. The mean channel width of nest sites was 975 feet, significantly greater than the mean of 660 feet for the systematic sample sites. Most. nests (90.3 percent) had less than 50 percent vegetative cover in the surrounding 3 -foot square area, and all had average vegetation heights less than 2 feet (Ziewitz et al. 1992). On the central Platte River, the mean elevation above the 400 cfs stage at nest sites ranged from 0.2 to 2.0 feet, with a mean of 1.0 foot. The mean elevation at the systematic sample of sites ranged from 0.1 to 1.8 feet, with a mean of 0.4 foot. These means were not significantly different. The maximum elevation above the 400 cfs stage at nest sites ranged from 0.4 to 4.4 feet, with a mean of 2.7 feet. The maximum elevation at the systematic sample of sites 4