Thousands of sandhill cranes (Grus canadensis) roost on the Platte River, forming living sandbars, during their annual migratory stopover at the Rowe Audubon Sanctuary near Gibbon, NE. With water in the river fully appropriated for urban areas and agriculture, many wonder how long it will be until the river runs dry. Some 600,000 to 800,000 cranes use just a few miles of the river in central Nebraska--areas that have been been mechanically cleared of the woody vegetation that the birds can't tolerate.