Continuity mistake: As everyone runs into the house there are four neat stacks of paper cups around the punch bowl. When we saw this spot before there were only two cups around the punch bowl and most of the other paper cups were stacked on trays and knocked over as a bird plowed into them. (00:53:05)
Continuity mistake: After Melanie hangs up the phone she sits and ponders whether to go to Cathy's party, on the desk to the left of the phone is the cigarette lighter that Annie left there before after she lit her cigarette. Next to it is a pack of cigarettes that she didn't leave there before. If you look closely earlier as she takes the cigarette out of the pack in the left pocket of her nightgown the lighter is in her right hand, the cigarette in her left and the pack stays in her pocket. (00:46:35)
Continuity mistake: In an earlier scene as Melanie plays the piano and Cathy stands there look closely at the drapes on her left. In that scene the drapes were right up against the edge of the wall, now as Mitch checks the windows before the last attacks they're pushed back several feet. (00:57:30)
Continuity mistake: As Lydia walks up to Mr. Faucet's room, the hallway is dark except for the light coming through the door. The sunlight on the floor is much wider than the window of the door in front of her and there's no evidence of any light fixture above her or her hair would be lit up. (01:00:10)
Continuity mistake: After finding Mr. Faucet's body, Lydia gets back in her truck through the passenger side door. Notice that the window is rolled up and the side vent window is shut tight. Seconds later we see her inside the truck with the window rolled down and the vent window tilted open. (01:00:55)
Continuity mistake: At the party Melanie grabs a girl from the birds, but when they all run into the house Mitch is now carrying the same girl.