With Paul Johnsgard, we follow the annual migration of the sandhill cranes from the American Southwest to their Alaskan mating grounds and then home again. It is a flight unaltered in nearly ten million years. By presenting various cycles of the migration in four time periods from 1860 to 1980, Johnsgard, a prominent naturalist, is able to show how man's encroachments have imperiled the flocks. In each section there is interaction between a child...