Migration Facts

Christmas Island has bridges for crabs to stop them getting run over during the mass migration.

Captive-raised whooping crane chicks had no parents to show them the way south, so pilots in white crane costumes did it instead. The chicks heard a recording of an ultralight engine while still in the egg, then followed the tiny plane 1,200 miles from Wisconsin to Florida. In all, 186 cranes learned the route that way, and their flock still migrates every year on its own.

The ruby-throated hummingbird weighs less than a nickel. Every fall it flies about 500 miles nonstop across the Gulf of Mexico. The crossing takes 18 to 20 straight hours, no rest, no food. For decades, people doubted something so small could cross alone. Folklore said they hitched rides on migrating geese. They don't. They fly it solo, on fat they'd doubled. Every September, it happens again.