Ben hit the nail right on the head. Concetrate on the food sources. Mature bucks do very little feeding during the rut, and thats why they lose so much weight.If you can stand the bitter cold temps that come with the late season it is not uncommon to see a mature buck feeding in an open food source well before sunset,but like he said you will have to hunt higher because they will be more alert. TO put in a more simple way, they are not as STUPID during the late season.