There's this strange comic about woman entering world where almost all mythical creatures exist in another world. There she meets a bird shapeshifter (which is a really nice process by the way) and dreams of turning into a bird herself.
The main character's friend reveals herself to be a bird shapeshifter to her, after the former assumed she was always a human.
http://www.zoophobiacomic.com/Zoophobia/?p=251
The main character has a strange dream of turning into a bird. Only her body changes though.
http://www.zoophobiacomic.com/Zoophobia/?p=331