With the UK currently in “lock-down” and most of us unable to leave our homes, except under 4 conditions, things are uncertain just now. However, one thing for certain is that our bees will swarm. We are awaiting advice from Scottish Government about caring for out-apiaries, but, meanwhile, it is best to plan ahead and assume that there will be more swarms than usual if folks cannot get out to do swarm control procedures.
What can we do? Well, we can all set up bait hives in our apiaries and this will be really useful in towns and places where there may be new beekeepers unable to access mentoring to help them through their first swarm season. We know that swarms hanging from a tree in our gardens will be our own swarms because they initially cluster not far from the parent hive. This is because the scout bees need to advertise the possible new home sites and they do this by dancing on the swarm until the bees decide where to go based on consensus. When they agree, they will depart within an hour or more unless the weather changes for the worse and they cannot fly for a few rainy days. Scout bees start looking for new homes several days before the swarm departs and if we can provide what they seek in real estate, we can usually effortlessly catch a swarm. Sometimes they decide on the new home before they leave the hive and, instead of clustering nearby, head straight for the new nest. So, you may be able to catch your own swarms in the bait hive. The following article by Professor Seeley and Dr Visscher explains the decision-making process.
What Makes an Attractive Bait Hive?
What Can Go Wrong?
Bearing in mind the risks involved with bringing down a bait hive heavy with bees, and the need to stay clear of hospitals at this time, it might be wiser to leave bait hives at ground level this year. They will still attract swarms there.
The first season I put up a bait hive I got excited when I saw a lot of bees going in and out. I called the friend who was to have the swarm and he took the box home to discover that it was empty. The bees may have been scout bees, but more likely they were excited robbers going for traces of honey on the combs. The lessons learned were to only put strips of foundation and perhaps one drawn comb (with no honey) in a bait hive. Also, wait till you see bees going in with pollen to be sure that you have the swarm bagged.
Filling a bait hive with drawn combs will not work because the scout bees need to pace round an empty cavity to assess the capacity and volume. Filling it with empty frames will not do either because they will start drawing comb out diagonally across the top bars. What to do is have one old drawn comb to give off a nice attractive odour (but not such an old comb that might harbour disease) and fix 20mm strips of foundation to 10 deep frames. You could try stabilising the foundation strips by inserting one or two bamboo barbeque skewers vertically between the top and bottom bars.
I use lemon grass essential oil as an attractant, as explained in a previous blog, but you may not have access to it just now. Swarm lures mimicking nasonov pheromones are available from beekeeping equipment suppliers. However, these are not essential if your bait hive has been made from an old brood box, or you have a used an empty brood comb.
Your captured swarm may have a heavy varroa infestation so is it advisable to treat the colony while it is broodless and oxalic acid is a good choice.