This baby/juvenile turtle was hanging out in Nevada Creek, which drains a landscape dominated by arid oak woodland and chaparral in northeast Napa County. I was surprised to find a turtle here, and was especially excited to find a young one - I've never seen one before. It was only about 2.5 inches long and had a noticeable tail (I think it's tucked around and sticking out from the left side in the picture). Although there is not much in the way of riparian habitat along this creek, I'd guess that at least portions remain wet year-round, as there were lots of small fish and a Belted Kingfisher flew through the area.

I'm assuming this was a western pond turtle, since the location was pretty remote. I can't imagine that an introduced species would be hanging out here. However, I'm no expert in turtle identification, so confirmation of the species would be much appreciated. The last picture that I've added shows the habitat. The turtle is circled in red.