Nautiterm: (Nautical Terms Explained) – “As the crow flies”

(Shortest travelling distance between two points) - It was a custom to carry crows on board ships. Vessels out of sight of land would release a crow, which would naturally fly towards land, taking the most direct route. Ships would follow the path of the crow, and the lookout platform at the top of the tallest mast became known as the crow’s nest.