Editor’s Note: This story accompanies the May 2016 issue of National Geographic magazine ... In the lower 48, where migration routes were unrecognized and fragmented by human settlement ...

This story appears in the August 2019 issue of National Geographic magazine. Five years ago I spent a few days with National Geographic Fellow Paul Salopek, a writer who is walking around the ...

This story appears in the November 2010 issue of National Geographic magazine. Animal migration is a phenomenon far grander and more patterned than animal movement. It represents collective travel ...

This story appears in the September 2019 issue of National Geographic magazine ... However, tracking migration through surveys, like an official census, is costly and can take years to complete.

This story appears in the January 2018 issue of National Geographic magazine. If birds left tracks in the sky, what would they look like? For years Barcelona-based photographer Xavi Bou has been ...