Among many tribes, the owl is to be both feared and embraced. Traditionally, many tribes believed, (and some individuals still hold these beliefs), that certain medicine people (both male and female) could be drawn to that part of spiritual power that would do harm to other people.
Some tribes called them “witches” or the equivalent of a witch in their particular language. These “witches” or medicine people that practiced “bad medicine” were believed to have the ability to shape-shift or transform themselves into an animal or bird. Many of these witches, it was believed, would change into the form of an owl so that they could fly silently through the night to cast spells on people while they were asleep and vulnerable to spiritual forces, or at the very least, spy on people and learn their weaknesses.
https://www.powwows.com/concerning-owls/