Fail: this strong colony needs to be divided, plus the winter cover is causing overheating in the colony.
The things that trigger swarming are:
- Having an old queen in the hive. The hive wants a new queen, they achieve this with swarming. Queens cells are made and the hive swarms with the old queen when the queen calls are capped in the hive. The hive gets a young queen to carry on and the bees that swarmed look for a new place to setup shop. The swarm has alot against it to survive period. It needs to get established, grow in strength, an put up enough honey to survive winter.
- Overcrowding, there is nothing that sets swarming off like crowded conditions. Failure to divide a strong colony in May is a swarm ready to happen in June. If your hive swarms there will be no excess honey for the beekeeper on that hive.
- Heat, this is partly with overcrowding. A hive that can't keep itself ventilated will swarm. Keep the grass cut in front of a colony, remove the entrance reducer. Most colonies will not need entrance reducers after June 7. If it is a strong overwintered colony the do not need an entrance reducer anymore until fall.
- All queens cells are not the same. As beekeepers we need to know when a hive is truly in swarm mode. An inspection schedule of every 7 - 10 days to check for swarm cells. Active swarm cells have a larvae in them, peanut shaped, usually on the bottom of a frame, But can really be anywhere. Looking is the key. Bees will make cups on the bottom of frames but these are just for show. It is the larvae filled that is troublesome.
- The easy way to stop a hive that is hell bent on swarming is to do this: Hive A is in full swarm mode, Hive B is a weaker colony chugging along. Switch hives, move Hive A to where Hive B is and move Hive B to where Hive A is. What happens is the field bees fly out to forage. When they comeback they fly to where they used to live. Now Hive A the swarm hive gets weaker and Hive B gets stronger. Swarming impulse will diminish on Hive A and Hive B may turn out to be the honey producer. This method works every time and there is no problem with fighting.