Lovebirds in a Cage
Hitchcock effectively uses the imagery of birds in a cage to carry two distinct and equally important meanings. On one level, the imagery works to advance the narrative thread of romantic pursuit and, by extension, the continued propagation of the species when Mitch and Melanie inevitably pair and reproduce. This imagery also works to foreshadow the eventual insurrection of the birds against man, who holds dominion of their own propagation. It may also indicate that the romantic pursuit the cage symbolizes will inevitably lead to Mitch and Melanie being trapped in their own domestic prison of expectations and conventions.
The "Jungle" Gym
Arguably the most famous image from The Birds is that of the slow accumulation of birds on the jungle gym behind Melanie as she sits outside the school. Melanie's obliviousness to the ominous scene taking place behind her reflects mankind's ignorance of the effect we are having on the natural world around us. More subtly, Hitchcock’s use of the jungle gym holds an important meaning: the birds perch on a man-made structure that, for its complex system of interlocking parts, we termed a jungle. Without a single line of dialogue, Hitchcock gives the audience a contextual clue that the birds may be revolting against man’s intrusion into their territory, or destruction of their habitat.
The Scapegoat
When Mitch and Melanie make their way back into the diner after the attack at the center of town, the chaos and disorder have died down somewhat. The diners are quietly huddled in a hallway, trying to escape the attack. As soon as Melanie re-enters, their accusatory stares seem to indict her as an interloper, troublemaker, or on a more basic level, a stranger—someone who doesn't belong. The accusatory glares are chilling, and made more chilling and even violent, when the frightened mother yells at Melanie and calls her "evil." This imagery draws out the way that an insulated society might respond with paranoia when they feel threatened, and it draws out how wrong it is to scapegoat someone. Further, it allows viewers who might have been tempted to blame Melanie for the attacks to feel guilt when they see such glares from her perspective, which is how they are shown.
The stages of the school building
The imagery of the school building is used to show the progression of the birds' attacks and takeover of the town. When we first see the school from down the street that leads to the bottom of the hill, it is a bright day and the scene is calm. We are then shown the school from the same exact angle on two more occasions over the course of the film: first, during the attacks on the children as they flee the school, and next, after the attack at the center of town, at which point the birds seem to have taken over the school. These three images are frightening when compared with each other—they show a gradual transition from normal, to the chaotic attack, to the battle already won by the birds, who perch victoriously on the school and surrounding landscape. This sequence itself also foreshadows the inevitable plight of our heroes on a larger scale: just as the birds seem to have 'conquered' the school, they will eventually conquer the entire town, forcing the family and Melanie to flee Bodega Bay just as the children fled the school.
