What causes swarming?
Swarming has many causes and it is normally the interplay of several of these that causes a hive to swarm;
There is no doubt at all that genetics plays a huge role in both encouraging and discouraging swarming.
The time of year when most hives swarm varies from place to place but in general October and November will be the worst.
Letting hives get to full, especially in late spring is not a good idea.
The type of nectar and pollen they are collecting is heavily implicated with Barbary and Broome the two main offenders.
A dearth period following good spring flows such as willow can lead to a large number of bees in the hive with nothing to do. Hives in this condition even with plenty of room and sometimes low on honey stores often swarm catastrophically and yet even a moderate honey flow normally alleviates this problem.
Old Queens are reputed to swarm more than young Queens and while this may be true for spring Queens I have not found it so for autumn raised Queens with my Queens entering their second year swarming significantly less than first year Queens.
Early beekeepers in New Zealand talked about hives putting out up to 8 swarms. This is not something we should encourage any more. Unless they are hived by a beekeeper, all swarms now die within 12 months from varroa.
Swarms can move into buildings where they are a public nuisance and the only way to remove them is generally using lethal methods. In general members of the public do not like swarms and they can cause bad publicity.
Swarming drastically affects the honey crop especially if it is an early season. After the main swarm some hives continue to put out virgin swarms often to the point of the hive dying. Spring weather is notoriously fickle and not infrequently the new Queen is not properly mated and once again the hive can die.
What can you do to prevent swarming?
If you keep bees they will swarm at some stage, everybody’s hives swarm all you can do is keep it to a minimum.
Never breed from hives with any tendency to swarm.
Never let hives get to full in the spring or two hungry for that matter.
There may be some advantage in trapping pollen in areas where hives are strong and pollen is plentiful in late spring.
Take a split from any strong hives especially from those raising cells.
Remove frames of sealed brood from strong hives and use them to build up weak hives either in the same apiary or in another area.
Swap positions between week hives and strong hives.
How to detect swarming.
Assuming you are running your hives with two brood boxes the simplest method is to split the two boxes and look underneath the top box where you will see swarm cells hanging down. You need to go through every frame that the Queen has access to and look very carefully destroying all cells as you go (or saving them for royal jelly). If the main honey flow has started this may be all you need to do but otherwise you must do something or they will simply swarm again. Removing two frames of sealed brood from the bottom box and three from the second box and replacing them with foundation frames is my preferred option. I normally give these frames are light shake which tends to remove the older bees (young bees hold on tight) and then after a careful check for the Queen, I use them to build up weak hives.
If we are taking them to a different apiary we carry them in ventilated sealed boxes where they are fine for several hours, you can also leave them leaning against the front entrance of the hive as long as there is not much robbing and they will collect returning field bees which is useful if you want to use the brood frames for starting some new hives in a different apiary.
It’s better if you use Queen cells or cage Queen’s but if you really want to it’s very simple to take the existing hive a few meters away and preferably facing it in a different direction, set up a new hive in its old position with three frames of honey and three frames of brood leaving one and only one swarm cell to create a new Queen.
John Berry – June 2012
Our thanks to John for allowing us to share his notes with you.