"Large scale bird migrations are breathtaking. In March, I saw sandhill cranes during their spring stopover on the Platte River in central Nebraska. Approximately 500,000 cranes come to a relatively small area on the Platte River. They roost in the river during the night because it is both wide and shallow, an advantage for the cranes in terms of safety from predators. James Michener, in his book 'Centennial', referred to the Platte as '...a mile wide and an inch deep...' At dawn the birds head for various cornfields nearby to feed. In six weeks, they are gone to northern nesting grounds. - Terry Isaac