ORIGINAL: usmc1978
It can be done quietly, although a guy told me once that bucks can be 'called in' by the climber. I'ver personally had numerous instances where a buck showed up while I was still climbing or had just gotten up the tree. Curiosity, maybe? Could just be coincidence (i.e. the number of trees I've climbed in the dark compared to the number of times the buck showed up while climbing or very shortly after).
Has happened to me twice this year! I was getting down from a morning sit and all of a sudden a little 1.5 year old ran directly at my tree. I had no idea he was behind me and it scared the crap out of me. He then milled around and finally went back where he came. The other time I just got up in my tree and again another little 1.5 came charging through the brush to look what was making the noise. I have found a tree in the morning cut limbs as I went in the complete darkness and had does and bucks under me as the sun came up. I wouldn't worry too much about noise just scout out the trees you want and take your time and be quiet climbing. I prefer big ol walnut trees, very quiet to climb.