The other day I witnessed a swarm at my hive. It was very impressive, (see earlier post) ..... but I couldn't understand why. This was a colony I started from a package of bees that I hived April 12th. The girls had two large brood boxes, plus two supers. I placed the supers on the hive a good 5 weeks ago. I rotated the brood boxes in a effort to get some uniform comb in each box. Over the period of the last 5 weeks, the girls were not building of comb in the two supers, that were above a plastic queen excluder. Monitoring the two supers, I only saw a small number of bees above the queen excluder. (Hmmmm.)
Bees will usually not pass through a queen excluder unless baited bt partially drawn frames of comb and honey/necdtar. If you want bees to work the supers leave the excluder off until after they have begun working the frames. You just found out why queen excluders are also called honey excluders.
Too often the excluder works just like an inner top and the bees back fill the brood chamber and swarm.
This afternoon I inspected the hive. Both of the brood boxes were every heavy with honey. I did find a opened queen cell at the bottom of a frame. There was far far more honey than brood in the two brood boxes. Luckily, I found fresh larva so, it looks like I have a queen that is laying. Part of the problem may be that the brood boxes are so full of honey, there isn't much comb available for brood in the two brood boxes.
This condition is called honey bound, it is usually the 1st sign the beekeeper has of potential swarming. When the bees begin to place nectar or pollen in amoungst the brood cells as the brood hatches they are back filling the brood chamber and on their way to becoming honey bound and swarming. At the 1st sign of honey or pollen in brood cells immediate swarm pervention measures need to be taken.
I rotated the two brood boxes and removed the queen excluder from the top of the upper brood box today. I also off-set the two supers in the hope of providing a little more ventilation and encouraging movement to the two supers. (No more excluder)
Having said all this .................... was the swarm caused by the brood boxes being full of honey and there being little space for new brood
My original queen seemed to be a real work horse and perhaps the lack of available comb made her leave. Or something else cause the swarm.
What surprised me is that I still have lots and lots of bees, so this doesn't seem to make sense.
Any ideas ?
The queen leaves with mostly young nurse age bees and some foragers, the younger bees are necessary to insure the swarm population survives long enough to build enough comb for the queen to begin rearing brood in the new location asap and have them begin hatching asap. The foragers out of the hive remain with the original colony and will backfill the brood cells as the brood hatches because the new queen isn't going to be laying right away and as long as a small area on 1-3 frames are saved for the new queen to begin laying everything works because the bees will begin using the honey and pollen stored in the brood area to feed to new larvae and the brood chamber is gradually returned to full size after a month or so.
It was a good move to remove the excluder, now if the super is the same size as the brood chambers move up some of the frames of honey to bait the bees up into the super. Wait until they get to working thesuper well before replacing the excluder (if you find it necessary to use 1).