The recurrence of birds, specifically “deathbirds,” is a classic horror convention. In “Visual Style,” Richard Allen says, “In Psycho, the main character, Norman Bates, a psychotic murderer, is not simply likened to birds of prey, but to stuffed birds of prey. … he articulates the key significance of the death bird as the figuration of a nature that is emotionally dead—that is, inhuman, and destructive of the human.” This is clear in the scene when Norman invites Marion to dine with him in the parlor. When she begins eating, he says that she eats like a bird. He goes on to tell her how he uses his hobby of taxidermy to pass the time but not fill it. “I guess I’d just rather stuff birds because I hate the look of beasts when they’re stuffed. You know, foxes and chimps. Some people even stuff dogs and cats, but, oh, I can’t do that. I think only birds look well stuffed, well, because they’re kind of passive to begin with.” He tells Marion.
One of the most forefront themes of Psycho, though it is never explicitly stated or filmed, is sex (Heller, 100). Sexual tension weaves its way through most scenes in the movie, and it is almost always centered around Norman. From Norman’s peeping Tom scene to the implied incest between him and his mother to the ever-phallic imagery of the knife stabbing and penetrating Marion, Hitchcock made sure that the audience noticed the sexual themes.
A final classic Hitchcock and horror convention utilized in Psycho is the concept of the double. After Marion is murdered in the shower and we watch the water and her blood wash down the drain, the camera slowly pulls back from an intimately close frame of her eye to her entire face smashed on the bathroom floor, frozen by death. This alludes back to Norman’s peeping Tom moment and gives us a grim look into the other side. Her eye in the close-up appears to peer out of the drain; the hole-within-a-hole of this eye is the double of Norman’s peephole (Rothman, 317).