Humans have used scarecrows around the world for over 3000 years; the first historically recorded use of scarecrows was by the Egyptians to protect their wheat fields along the Nile River. Other notable pre-medieval cultures known to use scarecrows were the Greeks, Romans and Japanese, according to Redlands Daily Facts.
Scarecrows tend to reflect an aspect of the culture that uses them. The Greeks carved and decorated their scarecrows to look like one of their deities, and the Germans built theirs to look like witches. Many scarecrows are meant to be frightening to humans as well as animals, reflecting fear based in superstition. According to Modern Farmer, the word "bogeyman" comes from what German farmers used to call their scarecrows.
The immigrant German farmers of the 1800s brought their scarecrow ideas to North America when European settlers were still mostly using live patrols, and the scarecrow concept gained enormous popularity during the period of westward expansion. Larger farms in sparsely populated areas needed to be protected from birds that would eat the crops, so Midwest farmers continued using scarecrows all the way through the Great Depression and World War II.
Chemical farming of post-war industrialization brought an end to the functionality of the scarecrow for modern farms, but smaller farms and hobbyists continue using scarecrows for their functional, decorative and historic value.