Note that there are three individuals in the photo above, two in the foreground and one in the background near the overturned wheelbarrow.
Here's a close-up of the left-hand animal:
Although I don't have any resources with me tonight, and I have very little experience identifying ground squirrels, I think this is a California Ground Squirrel, also known as a Beechey Ground Squirrel (Spermophilus beecheyi).
Here are two additional views of the other individuals:
And one more of the left-hand squirrel, splayed out like a sphinx in the warm sun.