From roughly mid November to early December — during Rut Phase IV, The Recovery Phase — bucks that had been battling each other during Rut Phases II & III are now OK with being around each other. They are tired, need some rest, and like to be with other bucks for added protection from predators.
(Get your own set of Sign Guides, with Doc’s famous Rut Phase Calendar, at: Doc’s website, or from John Nordberg on ebay.)