Demons are like Doves

 Netziv (Devarim 32:17) They will sacrifice to demons who are not God. All the idolatry of the first generations had a known power that God had allotted to them, and that was true also of the heavenly realm including the sun. But the demons have no power at all, and they are created from the foundation of the spirit, and their place is in the desolate wilderness, and they feed as other creations on what God, their Creator, has determined for them. They also have a food of desire, which is the spirit of animal blood. The demons also have an internal power to fly up and hear behind the veil what will be as is memtioned in Chagiga (16a). In fact they are like a dove which has an internal power to perform a mission as is mentioned in the story of Noah. However not all doves have this ability but only those specifically trained and this is rare and their owners get great benefit. This is also true of demons and they are rewarded by animal sacrifices. The Torah says they have no real power only the information which they hear, The sacrifices made to them motivates them to gather information and is sometimes done solely to anger G-d