Shouldn't He Be HIBERNATING?

The squirrels amuse me to no end, but the chipmunks really fascinate me.  There are a few that live between the few yards by my house and occasionally I will spot one for a few seconds.  They aren't nearly as bold as the squirrels and quickly dart into hiding.

Around Thanksgiving we saw our last chipmunk and I figured they had started hibernation.  The hole where I had spotted activity over the summer was covered in matted leaves.  Farewell to spring.  Imagine my surprise as I looked out my window while eating breakfast and saw this

He popped up again a few days later

And here is the new hole, smack dab in the middle of my front yard (yeah, please ignore the complete lack of lawn.  We're hoping with the tree trimming a few months ago sunlight may actually reach the ground)