What do the birds in the movie Psycho represent in Norman's life?

I believe the birds are symbolic of Norman's split personality. Docile birds represent Norman's sweet side; birds of prey represent Norman's homocidal tendencies. If you have any further questions, please repost. Aslan will be on late tonight or tomorrow morning, and movies are one of his specialties.

There is the scene where Norman is talking to Marion in his parlor. Norman is trying to impress Marion but not doing a very good job. In the midst of discussing his taxidermy hobby, Hitchcock has a large stuffed owl filling the background of the frame. It seems to be looming over Marion: a symbolic reflection of how Norman, and ultimately Norman's mother, will swoop down on Marion a few frames later.