During periods of nectar dearth, especially when removing the fall honey crop and preparing your colonies for winter, be extremely careful to avoid setting up the robbing instinct.
Colonies have little respect for each other when it comes to the possession of honey.
Robbers are quickly recruited and quite suddenly can throw the whole apiary into an uproar. Nucleus, weak, and queenless colonies may be quickly destroyed and robbed of all their honey stores. Strong colonies may lose many workers in robbing or in fighting robbers to protect their own stores. The frenzy reaches its height when the honey supply is exhausted, but it may be some time before the colony returns to routine activities. Robbers are easily recognized as they eventually become smooth, shiny, and almost black.