There was a great scurrying sound as I walked down the trail and then I saw this groundhog peering down at me from a maple tree. I guess I'd spooked him and the only place to go to get away was up. Groundhogs can climb well enough (they are, after all, squirrels, albeit ground squirrels) though I don't think they like to unless forced. After a few seconds this one scrambled down and ran off.