‘Flight Paths’ Unfurls the Wondrous History of Migration Science

A new book details how amateur birders and bird-loving scientists pieced together the true story of avian migration.
A flock of Sandhill Cranes fly in a line against a blue sky, the moon in the background.
Watching birds like these Sandhill Cranes as they crossed the face of the moon was an early form of migration science. Photo: David Policansky/Audubon Photography Awards

In the 1680s, when philosopher Charles Morton sat down to figure out where birds overwinter, he made a guess so off-base that it’s still the butt of jokes today: the moon. How ornithologists and birders puzzled together the barely less outlandish story of migration is the subject of Flight Paths by Audubon contributor Rebecca Heisman. Its focus is less on the journeys themselves—although Heisman has a knack for capturing the miracles of scale involved—than on the ingenuity it takes to map them.

The book builds toward the cutting-edge tools of migration science, like weather radar, featherweight trackers, and genetics. “I did not realize how many electrical engineers and computer scientists and geochemists I was going to end up talking to,” Heisman says.

But it delights in the homespun practicality of research: a needlepointing scientist who sewed harnesses for warblers; a researcher who watches night fliers cross the full moon from a lawn chair; or a crew who chased a Swainson’s Thrush for seven nights “in a converted Chevy station wagon with a large antenna poking out of a hole in the roof.” In those efforts, both low and high-tech, it becomes clear that you don’t need formal training to be an ornithologist. The history of migration research, as Heisman tells it, often builds on the work of dedicated amateurs, or bird-loving engineers and physicists, who bring new tools to bear on old questions.

“Not a lot of scientific fields have this corresponding hobbyist population,” Heisman says. “I think there’s always been fuzzy lines between ornithologists and birdwatchers.” It’s by marshaling that collective enthusiasm, turning birders around the world into an international bird-monitoring network, that humanity has begun to grasp the immensity of bird migration.

Flight Paths, by Rebecca Heisman, 288 pages, $30.00. Available here on HarperCollins.