This amazing flight is more than evidence of the stork's resilience.

This astonishing flight wasn’t just evidence of the stork’s resilience. It was an essential clue in a mystery that plagued scientists for centuries: the seasonal disappearance of birds. Ancient naturalists had various theories to explain the annual vanishing act we now know as migration. Aristotle himself proposed three particularly popular ideas. One theory was that birds transformed into different bodies that suited the season. For example, summer time garden warblers were believed to transform into black caps every winter.