There is no harm for a Muslim to make a scarecrow to frighten birds and drive away harm from the farm, as the purpose is to obtain a benefit.  Some of the people of knowledge said it is permissible to use some pictures to obtain a benefit. 

Al-Dassuqi said: 'There is an exception to what is forbidden, which is to make a doll for small girls to play with, this is permissible, and it is permissible to sell or buy dolls to teach the girls how to educate children.' 

Allah knows best.