Build A Scarecrow Day is observed on July 02, 2017. A scarecrow or hay-man is a decoy or mannequin in the shape of a human which is dressed in old clothes and placed in fields to discourage birds such as crows or sparrows from disturbing and feeding on recently cast seed and growing crops.
Modern scarecrows, though still essentially decoys, seldom take a human shape. On California farmland, highly reflective aluminized PET film ribbons are tied to the plants to create shimmers from the sun. Another approach is automatic noise guns powered by propane gas. (With material from: Wikipedia)