It wasn't a noise or movement that tipped me off. I was watching three whitetail does feed casually near my stand when the animals suddenly went on high alert. Their ears flared ahead and their eyeballs probed the forest edge to my right. All thoughts of eating left their minds as they tracked something moving in the undergrowth.
I slowly shifted my bow, made sure the arrow was nocked, and curled my fingers around the string. Two seconds later, a massive 5x5 buck materialized 20 yards away in the only opening below me. Fortunately, I was ready. Before the big deer could vanish, I drew and put an arrow through his chest. He staggered 25 yards and collapsed.
Animals have keener senses than humans. For this reason, you should watch their body language closely. They will almost always smell, see, or hear another creature approaching before you do. They'll tense up and concentrate until they know what's going on. If you pay attention to this "early warning system," you will be prepared when the big boy steps out.