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.Habitat Type During a 2-month period, primarily ~larch through April, the cranes utilize three general habitat types within this river reach (Fish and Wildlife Service, 1976): (lJshallow, submerged, unvegetated sandbars in broad stretches of river, (2) wet meadows, particularly those near roosting areas, and (3) corn and milo stubble and alfalfa fields as primary feeding sites. Afforded protection from predators, the cranes use the shallow sandbars almost exclusively for night roosting. Their preferred roosting habitat is water less than 6 inches deep, a. broad channel, and infrequent vegetation on the sandbars and islands (Frith, 1974). Duri ng the.-morning hours, .cranes 1 eave thei r watery roosts for the wet meadows. The Fish and Wildlife Service has j:lrovided this description of wet meadows: "lowland areas which are relatively free of sizeable . trees and where the soil is usually without standing water during most of the growing season, but is periodically waterlogged within a few inches of the surface in scattered spots du~ primarily to a 'high water table. These areas are frequently undulating; therefore; are often basically habitat complexes. Vegetation commonly occurring may include grasses (excluding feed grains, grains, and/or sorghum crops), and/or sedges, and/or rushes, and/or small nonagricultural broad1eaf plants. This wet meadow classification includes ephemeral (lasting only a short time) areas which are a gradation between the lowest areas and the more upland areas." Wet meadows are the cranes' "marshaling areas," where they often group before movin.g.i.nto.the.grainfields to feed. Generally, less than a mile from the river roosts, wet rneadows are used for preening, dancing, resting, feeding, and as secondary roosts. Migratory Habits The "stem of the hourg1 ass" betweenO'iert.on and Chapman, Nebraska, provides some of the most important habitat within the sandhill cranes' top and bottom-heavy migratory route (Fish and Wildlife Service, 1976). There is no habitat of similar quality and quantity within the. United States' portion of the Central Flyway ihNorth America (Fish and Wi1.d1ife Service, 1976). It is here, after a nonstop 600-mi1e migration from wintering areas, that the cranes choose to pause 'and replenish their energy reserves. The birds arrive at the Platte in relatively poor physical condition. Each bird stays on the Platte River for approximately 6 weeks feeding on sprouting vegetation and invertebrates in the wet meadows andwaste grain and sprouts in the croplands. Each one of theset:ypes of foods provicles_es.sentiale.1ements in their diet. (Fish and Wildlife Service, 1976). During this stint, each crane gains .' -~ 26 . ';-"-'-'"..-." ',-:, ' '.~ "'.'- .-' .