Numerous birds are shot on the movie set, but they never appear dead on the floor.
An extended driving scene switches back and forth between a green screen and live shots on the street. The driver's sunglasses appear and disappear repeatedly between shots.
While Bill is waiting for Rod, he asks for a pint of beer and two glasses. When Rod appears with Nathalie, Bill stands up to greet them. A full pint and two empty glasses are on the table. When they sit, 3 full glasses and a nearly empty pint are on the table.
In one scene, the main characters talk to the tree-hugger in the woods. In the next shot, they're exiting a building in downtown L.A. and getting into the RV.
On the movie set, the characters fire almost 80 shots from two handguns without reloading.
The film references birds falling from the sky in "Beebe (pronounced BEE-buh), Arkansas-Kentucky." The city, Beebe, Arkansas, is actually pronounced BEE-bee.
During a close-up of the characters driving, the car they're in is also behind them. That means the movie's own tracking shots were used on the green screen.
As the group leave the La Brea museum and run into Dr. Jones, they wave goodbye to him. A group of people in the back and to the left of them wave to Dr. Jones at the same time, for no apparent reason.
When the woman runs out of the ocean, three people standing at the waterline look at her. Their faces are blurred, which means they were actual beach goers who happened to get into the shot.
In the cemetery zombie fight scene, one of the actors points a shotgun at one of the zombies and shoots him in the head, but no shotgun blast is heard.
A boom operator in a purple shirt and faded jeans is reflected in the mirror during Gloria and Bill's sex scene.
In several shots of the RV driving through city streets, the camera vehicle's spare tire and dashboard are visible. At one point, someone's hair blows into the shot.
Toward the end of the movie, a camera operator in a pink hat is reflected in a hotel door after a character is attacked by a bird.
When Bill has lunch and watches the news at Hoy's Wok, a camera operator is reflected in mirror.
The man at the zoo said that the birds didn't attack the zoo because it runs on green energy. In the next scene the birds attack the zoo as the main characters leave.
After the birds attack the movie set, a dead man's eyes move.