Hi, Sherry, and sorry for the delayed reply! This is a golden-mantled ground squirrel (Callospermophilus lateralis), which does look a lot like a chipmunk...but it's roughly twice the size :) The characteristic that's easy to see at a glance: chipmunks have a striped head; this species doesn't. You can read more about them here: https://en.wikipedia.org/wiki/Golden-mantled_ground_squirrel (Love all of these guys, even if they do eat up the birdseed!) -Sally Roth, North Forty News