Continuity mistake: After they talk about the apartment Melanie wants to use the phone. As she walks through the door Annie looks up at the birds flying and we see the top of her porch and a bare tree. This is wrong, as earlier in this scene when Melanie walks up to the door there are a lot of plants hanging down from the roof of the porch. (00:32:00)
Continuity mistake: As she carries the birthday cake out from the house, the position of Lydia's necklace changes between shots. (00:51:50)
Continuity mistake: In her room Melanie has the green dress hanging to the left of the mirror over the sink. When she returns to that spot after looking out the window, the dress has been moved. (00:58:20)
Continuity mistake: In the scene when Melanie is taking tea to Lydia, Lydia's hair changes between shots. When she is resting on her back you can see sections of hair are down by her neck. When she leans forward, her hair is all up on her head. This changes back when she's lying down again. Lydia's hair changes in consecutive shots, during other scenes as well. (01:07:05)
Continuity mistake: In one shot, a boy hides under a table, when the birds attack at Cathy's party. In the wide shot you can see the table is quite far onto the grass, away from the patio. But a few shots later, the table is right beside the patio. (00:50:20)
Continuity mistake: When the birds attack the town, two horses gallop down the street, dropping crates of vegetables. In a later shot the crates are more broken and the vegetables are more spread out and are in a much different position than when they were in the earlier shot of when they were dropped. (01:23:45)
Continuity mistake: Two gulls attack a man by his car and he falls to the floor, knocking a red bucket and metal can to the floor near him. But in the next shot of Mitch running to help him, the red bucket has now moved further away from the man. (01:21:15)
Continuity mistake: At the children's party, when the birds attack, you can see a child roll under the table with the cake and other party snacks on it. The birthday cake swaps ends with the bowl of drink a few shots later, with nobody re-arranging it. (00:50:20)
Deliberate mistake: The closing scene contains one of the most famous deliberate omissions. As Mitch, his mother, and Melanie approach the front door to leave the house, there is no front door; it was removed so the camera can see them. Mitch mimes reaching for the door and pulling the handle. As he does this, a light is panned onto the actors' faces to help sell the illusion that a real door was opened. Victoria Cartwright later reported that she asked Hitchcock why people wouldn't see there was no door there. He replied that it was the magic of movies - no one would notice. And no one ever does! Read more in the transcript of the documentary "All About the Birds."
Deliberate mistake: Mitch carries Annie's body into her house through the front door, which he doesn't close behind him. In the next shot as he leaves the house it's been closed and he has to open it before he walks out. (01:32:20)
Continuity mistake: As Mitch throws logs onto the fire we see the couch behind him and no one is there. In the next shot Melanie appears sitting on the pillows on the edge of the couch. (01:41:05)
Continuity mistake: The aerial shot of the fire is wrong. The two cars parked across from the exploding orange car are green on the left and white on the right. In the aerial shot they're both black. (01:25:45)
Continuity mistake: The top of the bird cage that Melanie brings to Mitch's apartment has 24 rungs but when we see it again on the floorboard of Melanie's car it has only 12 rungs. (00:11:10)
Continuity mistake: As Melanie runs into the phone booth from the restaurant the four poles that were around it when Mitch walks her to the restaurant after the gull attack have disappeared. (01:26:10)
Continuity mistake: The lamp over the dining room table, when Melanie brings Cathy back from the bathroom, is not this same lamp that was there as they were listening to the television report. Before it had a glass bottom and now the entire bottom is made of metal. (01:40:15)
Continuity mistake: As Melanie runs to Annie in the classroom and says, "Close that door quickly," all the children's jackets and sweaters and everything on the bench below changes between shots. (01:12:00)
Continuity mistake: As Melanie walks into Annie's apartment we see the front door behind here to the left. Before the door had a shade on top of it, this door is different and doesn't have a shade or a space for it between the curtain and the window. (00:41:10)
Continuity mistake: When we first see the table with the food on it the sandwiches in the middle are piled up in interlocking stacks of three with one more pile of three or four sandwiches rising in the center. When we see the sandwiches again up close as Mitch brings the little girl into the house, they are neatly stacked above each other though not interlocking as before and the middle pile is not there. (00:52:25)
Continuity mistake: When Mrs. Bundy tells Melanie that there is a difference between crows and black birds Deke's right arm is leaning on the recessed edge of the bar close to his body. In the next shot his right arm is moved closer to Melanie, placed in the middle of the bar. (01:16:30)
Revealing mistake: When Melanie is brought downstairs and onto the couch, she starts flapping her arms out going 'No! No!' You can see Cathy turn her head and laugh to herself a little, then pretend to cry. (01:45:50)
Answer: The movie takes place in the 1960s, so presumably gas pumps worked a bit differently back then. This is also a small town and probably the gas station had not modernized. There may not have been automatic shut-offs, or if there was, it was faulty.
raywest ★
The automatic shut off is in the handle of the hose. When a person grips the handle they have to lift a levered switch to allow gas flow; the lever is spring loaded so that if it is released the gas will stop flowing. I have looked at older antique gas pumps and they are all the same; even the visible glass gravity flow ones. If that hose was dropped the the gas should have stopped flowing.
michael g