The narrative progression in The Birds is pretty straightforward in the sense that it's linear—no flashbacks, flash-forwards, or fantasy sequences. Still, Hitchcock does a 180 on us in terms of narrative point of view.
And not for the first time.
Hitchcock's Psycho, the film he made right before The Birds, is famous for its shifting point of view. The film starts with the story of Marion Crane (Janet Leigh), a secretary who's stolen some money. Thirty minutes into the film, she's brutally killed off in one of the most famous scenes in movie history, and we have to follow someone else's narrative POV.
Likewise, The Birds starts out as a girl-meets-boy, girl-stalks-boy, boy-seems-to-like-it narrative. We're seeing things primarily from Melanie's point of view as she pursues Mitch and decides to stick around Bodega Bay for the weekend. Out of the blue (literally), we're plunked into a horror story filled with bird attacks and grisly deaths. Hitchcock still keeps Melanie's POV front and center as she experiences the bird attacks and tries to help the family, but it's a totally different story.
Unlike poor Marion, Melanie lives until the end of the film, but she is left traumatized and almost senseless after being attacked in the attic in one of the final scenes. Take another look at the attic sequence, and we'll tell your teacher to give you extra credit points for an essay comparing it to the Psycho shower scene.