It's the "Witch Hunt"
I bet the only difference between witches and magicians is that one is convenience for the church while another is not
Well, the boy sage, also illustrates a difference. He has to practice and learn magic. Whereas the little girl, just awoke to magic. She wasn't taught how to be a bird, by her non-witch parents. So that transformation skill and her "dark magic" are more likely some sort of blood line inheritance. Probably due to some monster/demihuman/spirit parentage in their past, that occasionally reveals itself randomly within a lineage.
And like Earthican witches, the Church and normal humans are probably scared of uncontrolled random magic that shows up in their midst. So, the easiest corollary, is that Witches are X-men. ::Cue theme music:: duh nuh nuh nuh nuh nuh nuh.