Thousands of sandhill cranes gather each fall on the banks of the Wisconsin River before they head south for the winter. Anne and Steve visited the Aldo Leopold Foundation in Baraboo, Wisconsin to witness this migration firsthand, along with their guide: wildlife ecologist Stan Temple.

David Barrie is fascinated by how animals find their way. How do they travel thousands of miles across oceans or continents, to a place they've never been, without any other creature to show them the way?