Below is some information from the National Geographic that might help some of you.
"Sandhills (cranes) are the most common of all the world's cranes. A fossil from the Miocene Epoch, some ten million years ago, was found to be structurally the same as the modern sandhill crane. Today, these large birds are found predominately in North America. They range south to Mexico and Cuba, and as far west as Siberia.
Migratory subspecies of sandhill cranes breed in the Northern U.S., Canada, Alaska, and Siberia. Each winter they undertake long southern journeys to wintering grounds in Florida, Texas, Utah, Mexico, and California. En route, more than three-fourths of all sandhill cranes use migratory staging areas in a single 75-mile (120-kilometer) stretch along Nebraska's Platte River."
Take care and thanks for the lovely pictures.