These factors combine to make this day the start of the "seeking" phase of the rut. At no time since summer are big bucks easier to spot moving between doe family groups. They'll use scent, sound, and body-posture clues (such as a doe holding her tail to one side) to determine which female is closest to estrus. Also, mature bucks are often highly aggressive toward other bucks right now, especially strangers that have wandered into their home range. Today marks the day when some of the true buck battles will begin. Like a playground fight, these confrontations attract onlookers of all sizes.