I saw the same experiment tried with a red squirrel with quite opposite results. The boy who had caught the squirrel in his wire trap had a very bright and nimble dog about the size of a fox, that seemed to be very sure he could catch a red squirrel under any circumstances if only the trees were out of the way. So the boy went to the middle of an open field with his caged squirrel, the dog, who seemed to know what was up, dancing and jumping about him. It was in midwinter; the snow had a firm crust that held boy and dog alike. The dog was drawn back a few yards and the squirrel liberated. Then began one of the most exciting races I have witnessed for a long time. It was impossible for the lookers-on not to be convulsed with laughter, though neither dog nor squirrel seemed to regard the matter as much of a joke. The squirrel had all his wits about him, and kept them ready for instant use. He did not show the slightest confusion. He was no match for the dog in fair running, and he discovered this fact in less than three seconds; he must win, if at all, by strategy. Not a straight course for the nearest tree, but a zigzag course; yea, a double or treble zigzag course. Every instant the dog was sure the squirrel was his, and every instant he was disappointed. It was incredible and bewildering to him. The squirrel dodged this way and that. The dog looked astonished and vexed. Then the squirrel issued from between his hind legs and made three jumps toward the woods before he was discovered. Our sides ached with laughter, cruel as it may seem. It was evident the squirrel would win. The dog seemed to redouble his efforts. He would overshoot the game, or shoot by it to the right or left. The squirrel was the smaller craft and could out-tack him easily. One more leap and the squirrel was up a tree, and the dog was overwhelmed with confusion and disgust. He could not believe his senses. "Not catch a squirrel in such a field as that? Go to, I will have him yet!" and he bounds up the tree as high as one's head, and then bites the bark of it in his anger and chagrin. The boy says his dog has never bragged since about catching red squirrels "if only the trees were out of reach!" When any of the winged creatures are engaged in a life and death race in that way, or in any other race, the tactics of the squirrel do not work; the pursuer never overshoots nor shoots by his mark. The flight of the two is timed as if they were parts of one whole. A hawk will pursue a sparrow or a robin through a zigzag course and not lose a stroke or half a stroke of the wing by reason of any darting to the right or left. The clew is held with fatal precision. No matter how quickly nor how often the sparrow or the finch changes its course, its enemy changes, simultaneously, as if every move was known to it from the first.