Ever since farmers began to grow grain, they have had to protect their crops from birds. In the 1300's, English farmers hired children to protect their crops. They were called "bird scares". The children chased birds and threw stones at them. Bird scares were replaced in the 1800's by scarecrows. A scarecrow is anything that is set in a field to scare birds away. Often it is a pole dressed like a person. Some farms with small fields still use scarecrows today. Farming became big business in the twentieth century. Scarecrows could no longer protect the huge fields of grain, so farmers used poisonous chemicals on the fields. The poison made the grain bitter. The birds usually would not eat the bitter grain. Although they can prevent crops from being destroyed by insects and birds, some chemicals can be harmful to humans. Therefore, farmers are using fewer chemicals now than they did twenty years ago. Perhaps scarecrows may be seen more often in the fields in the future. Bird scares keep birds away from crops by  _  .
feeding them bitter grain pretending to be scarecrows spreading chemicals in the fields chasing them and throwing stones