In April 2009, two wild Whooping cranes migrating from Texas to Canada stopped at the LaCreek National Wildlife Refuge in South Dakota. They fed in the marshes at LaCreek. About five times a day they also flew to a farmhouse where they fed on a pile of corn the people living there put out for pheasants. The corn's starch and calories would provide energy to help the cranes on the final week of their migration to the nesting grounds. But the two cranes stayed one, two, three, days and more yet. Why?

Photo Laura Crawford Williams