At the very end of Forest Entrance just before Thieves' Forest, there will be a large bush beside the level exit that will emit musical notes behind it. Going behind there will get you Owlet.
Owlet will find fruit in trees and bring it to you. A very vague description for Owlet's ability. Especially when and only when you decide to bring Owlet through a good majority of the game. Owlet will only find fruit in set locations.