Continuity mistake: Once the chipmunks are inside the food cupboards, they begin to devour everything inside. Theodore is seen chewing off a corner of a box of Lucky Charms cereal and eating the cereal that pours from the hole. But a few shots later when the same box of cereal can be seen, the hole that Theodore gnawed from the corner of the box is gone and the corner is fully intact. (00:11:00)
Continuity mistake: When the chipmunks are hiding under bowls and slowly moving across the counter, the bowls keep changing location, whenever the chipmunks stop moving. (00:11:45)
Continuity mistake: When Dave leaves his house for work, there is a skateboard leaning up against the wall by the door and there is an umbrella stand with a lot of umbrellas in it. But when Dave gets back home from work the skateboard is now on the other side of the door in the corner and there are now fewer umbrellas in the stand. (00:03:35 - 00:09:30)
Continuity mistake: On top of the white cabinets / cupboards that run along the kitchen is a whole row of glass jars, vases, pots, etc. During the whole kitchen scene, the actual jars and pots that are on top of these cabinets move around and rearrange in different shots. In the close-up of Alvin pushing over the packet of Cheese Balls for instance; you can see that the jars and pots on the cupboard above are differently arranged than in other wide shots of the whole kitchen. (00:11:15)
Continuity mistake: In the scene inside the house that Uncle Ian gave the chipmunks, Alvin has foam darts on three air-pump launchers. He fires all three of the foam darts from the launchers; and we see him standing on the table with the three launchers and the three attached air-pumps, nothing else. But in the next shot suddenly all three of the launchers have a foam dart readily attached to them! And in addition a large pile of foam darts has appeared on the table, behind Alvin. (01:00:30)
Continuity mistake: When Dave hears the chipmunks singing outside on the tree trunk, he goes and opens the window to hear them better. The window to the viewer's right (from outside) has its slatted blinds down - and they are also closed. But after the chipmunks finish singing 'Funky Town', the same blinds aforementioned are now open. (00:16:10)
Continuity mistake: When Dave is lying on the couch watching television (before he starts hearing the chipmunks rummaging around in his kitchen) the cushions that are behind his back that he is resting on completely rearrange themselves between shots. (00:10:35)
Continuity mistake: When Dave gets back from work and is lying on the couch, on the counter behind him you can see two jars (one with a green lid and the other with a white lid.) But later when Dave notices the bowls moving across the same counter, the glass jar with the white lid has now vanished. Also the magnets and papers on the fridge differ as well. (00:10:35 - 00:11:50)
Continuity mistake: Once Alvin has opened up two of the food cupboards in the kitchen and all three of the chipmunks are rummaging around inside of them, the items that are inside of the cupboards themselves move about and rearrange themselves without the chipmunks touching them; for instance the items of food next to Alvin as he pours out the packet of Cheese Balls. (00:10:55)
Continuity mistake: When Dave throws the muffin basket inside the garbage can there is a clothing item hanging down off of the kitchen seating area, right next to the bin. However a few shots later when we see the bin, the seating is completely clear with nothing on it. But when the chipmunks climb out the bin the item is back on the seat, hanging over the side of it. (00:09:30 - 00:10:25)
Continuity mistake: When Dave arrives at Jett Records and gives Ian his CD, we see Ian putting the disc into a Bose CD player with no speakers; and next to the CD player is a stack of CD cases. However in following shots, the CD player we see now has speakers that are actually attached to the player itself (and this is the same CD player Ian is using.) Additionally the stack of CD cases next to the player is much higher as well. (00:06:05)
Continuity mistake: Dave throws the muffin basket that he stole from Jett Records into his garbage can; and when we see the front of the can there is a handle visible on the side. However when the film goes back to the garbage can (as the chipmunks climb out of it) the handle is no longer visible on the front part of the can that we see, meaning the can itself has somehow rotated. (00:09:30 - 00:10:25)
Continuity mistake: When Dave gets back home from Jett Records, he throws the muffin basket that he stole into his garbage can. When he does this, as he throws it into the can it causes the clear plastic bin liner inside to come off from around the edge of the bin. But in the next shot the bin liner is perfectly sitting around the whole edge of the bin again. (00:09:35)
Answer: No it isn't his voice.