In 1822, Count von Bothmer shot down a stork in Germany. However, the bird had already been impaled by a yard-long wooden spear. The stork had been speared in Africa and then flew over 2,500 km. This astonishing flight proved to be an essential clue in a mystery that had plagued scientists for centuries: the seasonal disappearance of birds. Lucy Cooke digs into the discovery of bird migration. [Directed by Visorama, narrated by Addison Anderson, music by Bamm Bamm Wolfgang & Gavin Dodds].