The Scarecrow can Read People's Mind

The Scarecrow can Read People's Mind is one of the series The Collection of Works Authored by New Generation Winners of Bingxin Children Literature Prize. It is composed by Hu Ying. When night falls, there are always appearing flocks of crows in the sky above our school test fields. In order to expel the crows, a batch of scarecrows 'settle' in the test fields. Although the crows are expelled, I, as the monitor, still feel that these scarecrows are creepy. My guess is not proved until my friends Bai Yanxin and Lan Xiaodie faint in succession beside the scarecrow. There must be a problem with the scarecrows! Who has done this? What is the purpose? How can I save my friends...