According to the University of Michigan BioKIDS site, whitetail deer rut between October and December. Most whitetails mate in their second year. Babies are born in the spring following a gestation that lasts approximately seven months.
An article in The Noble Foundation newsletter expands the definition of "rut" to include not only the peak breeding time, but also the behaviors and activities associated with it. Males are more aggressive with other deer, but these scuffles are usually short-lived contests of shoving and pushing. Other typical pre-rut, nocturnal activities, such as rubbing against trees and scraping the ground to establish territory, are initiated by the males as they prepare for the rutting season to begin.