Chipmunks Eating Serviceberries

I have been watching the berries ripen on the serviceberry shrub to see if the rust will coat all of them. So far, many of them are untouched. Some are starting to turn red, and a few are turning blue. I first tuned into this with the help of a chipmunk. I heard it nervously chirping, and when I went over to investigate, I saw it running around a serviceberry eating the fruit. I am not sure why it was alarming, but it seems to feel vulnerable in the shrub for some reason. I have noticed it doing this a few times. Another mystery is that it is eating the green berries. Is it richer in a certain nutrient that it craves at the moment? Is it more interested in eating the flesh of the berry, the seeds inside, or both? Anyways, I love watching this little creature scurrying around and investigating the world.