What chatters and chatters and is a bird?

Many think this is a bird making the repeated chatter and chirps, but Chipmunks, in SE Michigan do. It seems for different reasons. Some I've seen half full checks as if asking for an escort home with the goods and I've seen them with empty cheeks chirping a warning or possibly part of their mating ritual. I have been about 4ft. away and have repeatedly asked the local Chipmunks, but have received no answer as of yet.