The approach varies according to whether it's a "bottom" or "top" chipmunk. The ones at the top are accustomed to people; most folks stay at the top (and the viewpoints are all beautiful from there too). The top chipmunks approach as directly as a chipmunk can do.

The bottom chipmunks are another story. The approach is accomplished through many zig-zags: "Hey! do you notice me? are you safe?" There are brief intervals when the chipmunk stays still:
 
 
The next phase is the near approach. It can be imagined as a type of jig, as the chipmunk alternates between small steps closer and farther.
 
 
Can anyone doubt that chipmunks possess binocular vision?
 
 
There was also a second chipmunk at the time, but the second one was much shyer and kept out of direct sight.

Photography note: The photos were taken with a Pentax LX and the Voigtlander 125mm macro lens.