Absconding swarms leave an empty hive
When all of the bees—including the queen—leave the hive in search of a new home we say they are “absconding.” This is very different from swarming. Swarming is a reproductive process in which one colony splits and becomes two. From 40 to 70% of the original colony leaves with the old queen to start a new colony elsewhere. The remaining bees are left with a soon-to-emerge virgin queen who will head what’s left of the original colony. If a colony is robust, it may swarm more than one time in a season.
Absconding is not a reproductive process because all the bees leave—the entire colony just moves somewhere else. While absconding does not occur very frequently in European honey bees, it happens enough to be annoying.
The primary reasons for absconding are overheating, lack of food, and frequent disturbance. However, it can also be caused by bad odors, parasites in the hive, or disease. It seems that newly installed packages have a greater tendency to abscond than well-established colonies.
I have had two colonies abscond. The first time was after I installed a package of bees in a brand new top bar hive. I had wired some comb onto a few of the bars to give them a start and fed them with sugar syrup. About three days after the queen was released, I found the entire colony in a nearby bush. I re-hived the swarm and re-caged the queen. Instead of letting the bees release her, I kept her caged until comb building was well underway. By the end of the summer it turned into a huge colony—so it all worked out in the end.
The second time was about two weeks after I split an overly-populous hive. Everything seemed fine, the new queen was laying and the workers were storing pollen and nectar. But we were in the beginning of a long, hot, rainless period with very little forage available. Of course I didn’t know it was coming when I made the split. One day I went out to find the entire colony hanging from the supports underneath the hive stand.
As before, I knocked the swarm into a box, returned it to the hive, caged the queen, and fed sugar syrup like crazy. It turned into a good colony as well. Once again, everything worked out.
I was lucky to find both these absconding swarms and get a second chance at tending them. In the first case, I think the new top bar just didn’t feel “homey” until more comb was built. In the second case, I think it was the extreme heat and lack of forage that drove them away. If you have a colony abscond try to figure out why it happened, but don’t get discouraged—it’s just another part of a strange hobby.