It means ther major breeding is over. Groups of bucks are called bachelor groups. As the rut approaches, the group breaks up. The senior or dominant buck is the first to leave. However, it is not uncommon, even during the heat of the rut to see two or three young bucks together. Also, now and then you will see a young buck with a mature buck. Usually neither of those situations last very long. As the rut winds down, you begin to see bucks returning to the group...at least the ones still alive.
Naturally, due to attrition, the composition of the group changes. Bachelor groups vary in size from three to as many as nine. The age strata also avries depending on what bucks have survived. However, there is seldom more than one dominant buck.
The largest antlered bucks are usually the first to shed their their antlers. When this happens, they become extremely reclusive until a group is formed.
The study of bachelor groups is interesting as all get out and tremendously educational in termsw of deer behavior.