I've tracked some wounded deer in my days. Some mine, some others. Believe me I'm no expert, but I've seen deer do some crazy things. Once I loose blood I go to following his tracks. I always make note of his size prints, so can pick them out better. You can also make note of way he's walking if favoring certain leg, or slipping often on one. Lose of blood doesn't mean Lose of tracking. I also circle the area of last blood found. I've seen deer jump off a easy run path, and into thick stuff or up hills, reach the peak, and turn back down. They do crazy things for no apparent reason. Especially wounded deer capable of going long distances. Rarely do they run easy, and straight lines the whole time. I don't give up until I've exhausted all means I can think of. I hate nothing more then loosing a deer! Sorry I couldn't get on earlier to help you out. But never give up because you lose the blood.