Continuity mistake: When Ian films the Chipettes during the sing-off, he says, "If you like what you see then call Ian Hawke." But when someone else plays the video back later, he says, "If you're interested, then call Ian Hawke."
Alvin and the Chipmunks: The Squeakquel (2009)
Ending / spoiler
Starring: Justin Long, Jason Lee, Zachary Levi, David Cross
Alvin and the Chippettes reunite with Simon and Theodore, and Sabe, too, in the concert in a toy helicopter. Returning home, Alvin and the chipmunks go to sleep.
Chosen answer: Because they're more sensitive and weaker.