In the very early days the crows nest was sometimes made from a barrel or a basket. Have you ever wondered where they came up with the name crows nest?
The crow was an essential part of the early sailors' navigation equipment. These land-lubbing fowl were carried on board to help the navigator determine where the closest land lay when the weather prevented sighting the shore visually. In cases of poor visibility, a crow was released and the navigator plotted a course that corresponded with the bird's because it invariably headed straight toward land, "as the crow flies".
The crow's cage was situated high in the main mast where the look-out stood his watch. Often, he shared this lofty perch with a crow or two since the crows' cages were kept there: hence the "crow's nest."
As quoted by Wikipedia regarding the ships crow's nest, you now officially know where the term crows nest originated. Have fun as you go sailing from the crows nest! You might want to take a bungee cord to strap yourself in!