One of the things I love about Riverdale Park is that everybody there seems to be having a good time.
This young dog was hunting a squirrel, with a great deal more determination and enthusiasm than success. His owner kept calling him, and Dog would run a few steps towards him and then turn and go back to the foot of the tree, apparently hoping that the squirrel would come back down. This happened more than once.
He had a big silly grin on his face the whole time.