Traditionally, scarecrows take to the fields during the spring, but they have largely disappeared with the advent of high-tech farming in the U.S. Yet Japan and Europe retain a rich tradition of scarecrow use, with farmers using the figures not only to scare off birds but also as symbols of fertility. With a history that stretches back at least 500 years, the scarecrow has been through many incarnations, including his famous appearance in the Wizard of Oz. Perhaps the straw man could offset his American decline if he only had a brain.
Source: Modern Farmer