Imagine a superhighway that extends from the Arctic down the eastern coast of the United States, and all the way to South America. This route is real—it’s called the Atlantic Flyway, and its travelers are birds.
Though no two species of birds will follow the exact same migration route along the flyway, each bird’s path is like a lane within this superhighway. Birds weave in and out, sometimes crossing paths, and sometimes diverging. “Honk, honk!”
There are four North American flyways: the Pacific Flyway, the Central Flyway, the Mississippi Flyway, and the Atlantic Flyway. Scientists estimate that five billion birds travel along them in the spring and fall. But this number is
