Time to deploy!

It’s early April. The weather is finally warming up and the crocus and snowdrops are long gone. Depending where you are in the UK the OSR may start flowering in the next fortnight or so.

All of which means that colonies should be expanding well and will probably start thinking of swarming in the next few weeks.

So … just like any normal season really.

Except that the Covid-19 pandemic means that this season is anything but normal.

Keep on keeping on

The clearest guidelines for good beekeeping practice during the Covid-19 pandemic are on the National Bee Unit website. Essentially it is business as usual with the caveats that good hygiene (personal and apiary) and social distancing must be maintained.

Specifically this excludes inspections with more than one person at the hive. Mentoring, at least the really useful “hands-on” mentoring, cannot continue.

A veil is no protection against aerosolised SARS-CoV-2. Don’t even think about risking it.

This means that there will be a lot of new beekeepers (those that acquired bees this year or late last season) inspecting colonies without the benefit of help and advice immediately to hand.

Mistakes will be made.

Queen cells will be missed.

Colonies will swarm 1.

Queen cells

Queen cells …

It’s too early to say whether the current restrictions on society are going to be sufficient to reduce coronavirus spread in the community. It’s clear that some are still flouting the rules. More stringent measures may be needed. For beekeepers who keep their bees in out apiaries, the most concerning would be a very restrictive movement ban. In China and (probably) Italy these measures proved to be effective, although damaging to beekeeping, so the precedent is established.

Many hives and apiaries are already poorly managed 2. I would expect that additional coronavirus-related restrictions would only increase the numbers of colonies allowed to “fend for themselves” over the coming season.

Which brings me back to swarming.


The final point of advice on the NBU website is specifically about swarms and swarm management:

You should use husbandry techniques to minimise swarming. If you have to respond to collect a swarm you need to ensure that you use the guidelines on social distancing when collecting the swarm. If that is not possible, then the swarm then should not be collected. Therefore trying to prevent swarms is the best approach. 

Collecting swarms can be difficult enough at the best of times 3. And cutouts of established colonies are even worse.

In normal years I always prefer to reduce the swarms I might be called to 4 by setting out bait hives.

Swarm recently arrived in a bait hive with a planting tray roof …

Let the bees do the work.

Then all you need do is collect them once they’re all neatly tucked away in a hive busy drawing comb.

This year, with who-knows-what happening next, I’ll be setting out more bait hives than usual with the expectation that there may well be additional swarms.

If they’re successful I’ll have more bees to deal with when the ‘old normal’ finally returns. If they remain unused then all I’ve lost is the tiny investment of time made in April to set them out.

Not just any dark box

I’ve discussed the well-established ‘design features’ of a good bait hive several times in the past. Fortunately the requirements are easy to meet.

  • A dark empty void with a volume of about 40 litres.
  • A solid floor.
  • A small entrance of about 10cm2, at the bottom of the void, ideally south facing.
  • Something that ‘smells’ of bees.
  • Ideally located well above the ground.

I ignore the last of these. I’d prefer to have an easy-to-reach bait hive to collect rather than struggle at the top of a ladder. If I wanted to do some vertically-challenging beekeeping I’d go out and collect more swarms 😉

So, ignoring the final point, what I’ve described is the nearly perfect bait hive.

Those paying attention at the back will realise that it’s also a nearly perfect description of a single brood National hive.

How convenient 🙂

All of my bait hives are either single National brood boxes or two stacked National supers. The box does need a solid floor and a crownboard and roof. If you haven’t got a spare solid floor you can easily build them from Correx 5 for a few pence.

Inside ...

Bait hive floor

Alternatively, simply tape down a piece of cardboard or Correx over the mesh of an open mesh floor 6. In some ways this is preferable as it’s convenient to be able to monitor Varroa levels after a swarm arrives.

Do not be tempted to use a nuc box as a bait hive. You can easily fit a small swarm into a brood box, but a really big prime swarm will not fit in a 5 frame nuc box.

Big swarms are better 🙂 7

More to the point, bees are genetically programmed to search for a void of about 40 litres, so many swarms will simply overlook your nuc box for a more spacious nest site.

What’s in the box?

No, this has nothing to do with Gwyneth Paltrow in Se7en.

How do you make your bait hive even more desirable to the scout bees that search out nest sites? How do you encourage those scouts to advertise the bait hive to their sister scouts? Remember, that it’s only once the scouts have reached a democratic consensus on the best local nest site that the bivouacked swarm will move in.

The brood box ideally smells of bees. If it has previously held a colony that might be sufficient.

Bait hive ...

Bait hive …

However, a single old, dark brood frame pushed up against one sidewall not only provides the necessary ‘bee smell’, but also gives the incoming queen space to immediately start laying 8.

You can increase the attractiveness by adding a couple of drops of lemongrass oil to the top bar of this dark brood frame. Lemongrass oil mimics the pheromone produced from the Nasonov gland. There’s no need to Splash it all over … just a drop or two, replenished every couple of weeks. I usually soak the end of a cotton bud, and lay it along the frame top bar.

Lemongrass oil and cotton bud

The old brood frame must not contain stores – you’re trying to attract scouts, not robbers.

The incoming swarm will be keen to draw fresh comb for the queen to lay up with eggs. Whilst you can simply provide some frames and foundation, this has two disadvantages:

  • the vertical sheets of foundation effectively make the void appear smaller than it really is. The scout bees estimate the volume by walking around the perimeter and taking short internal flights. If they crash into a sheet of foundation during the flight the box will seem smaller than it really is.
  • foundation costs money. Quite significant amounts of money if you are setting out half a dozen bait hives. Sure, they’ll use it but – like putting a new carpet into a house you’re trying to sell – it’s certainly not the deal-clincher.

No foundation for that

Rather than filling the box with about £10 worth of premium foundation, a far better idea is to use foundationless frames. Importantly these provide the bees somewhere to draw new comb whilst not reducing the apparent volume of the brood box.

If you’ve not used foundationless frames before, a bait hive is an ideal time to give them a try.

There are two things you should be on the lookout for. The first is that the bait hive is horizontal 9. Bees draw comb vertically down, so if the hive slopes there’s a good chance the comb will be drawn at an angle to the top bar.

And that’s just plain irritating … because it’s avoidable with a bit of care.

Bamboo foundationless frames

Bamboo foundationless frames

The second thing is that the colony needs checking as it starts to draw comb. Sometimes the bees ignore your helpful lollipop stick ‘starter strips’ and decide to go their own way, filling the box with cross comb.

Beautiful … but equally irritating 🙂

Final touches

For real convenience I leave my bait hives ready to move from wherever they’re sited to my quarantine apiary (I’ll deal with both these points in a second).

Wedge the frames together with a small block of expanded cell foam so that they cannot shift about when the hive is moved.

Foam block ...

Foam block …

And then strap the whole lot up tight so you can move them easily and quickly when you need to.

Bait hive location and relocation

Swarms tend to move relatively modest distances from the hives they, er, swarmed from. The initial bivouac is usually just a few metres away. The scout bees survey a wide area, certainly well over a mile in all directions. However, several studies have shown that bees generally choose to move a few hundred yards or less.

It’s therefore a good idea to have a bait hive that sort of distance from your own apiaries.

Or even tucked away in the corner of the apiary itself.

I’ve had bees move out of one box, bivouac a short distance away and then occupy a bait hive on a hive stand adjacent to the original hive.

It’s probably definitely poor form to position a bait hive a short distance from someone else’s apiary 😉

But there’s nothing stopping you putting a bait hive at the bottom of your garden or – whilst maintaining social distancing of course – in the gardens of friends and family.

If you want to move a swarm that has occupied a bait hive the usual “less than 3 feet or more than 3 miles” rule applies unless you move them within the first couple of days of arrival. Swarms have an interesting plasticity of spatial memory (which deserves a post of its own) but will have fully reorientated to the bait hive location within a few days.

So, if the bait hive is in grandma’s garden, but grandma doesn’t want bees permanently, you need to move them promptly … or move them over three miles.

Or move grandma 😉

Lucky dip

Swarms, whether dropped into a skep or attracted to a bait hive, are a bit of a lucky dip. Now and again you get a fantastic prize, but often it’s of rather low value.

The good ones are great, but even the poor ones can be used.

But there’s an additional benefit … every one that arrives self-propelled in your bait hive is one less reported to the BBKA “swarm line” or that becomes an unwelcome tenant in the eaves of a house 10.

As long as they’re healthy, even a bad tempered colony headed by a queen with a poor laying pattern, can usefully be united to create a stronger colony to exploit late season nectar.

Varroa treatment of a new swarm in a bait hive…

But they must be healthy.

Swarms will potentially have a reasonably high mite count and will probably need treating within a week of arrival in the bait hive 11. Dribbled or vaporised oxalic acid/Api-Bioxal would be my choice; it’s effective when the colony has no sealed brood 12 and requires a single treatment.

But swarms can bring even more unwelcome payloads than Varroa mites. If you keep bees in an area where foulbroods are established be extremely careful to confirm that the arriving swarm isn’t affected. This requires letting the colony rear brood while isolated in a quarantine apiary.

How do you know whether there are problems with foulbroods in your area? Register your apiary on Beebase and talk to your local bee inspector.

My bait hives go out in the second or third week of April … but I’m on the cool east coast of Scotland. When I lived in the Midlands they used to be deployed in early April. If you’re in the balmy south they should probably be out already 13.

What are you waiting for 😉 ?



  1. Although colonies in their first year with a new queen may not swarm, some do.
  2. Not yours obviously! Or mine. But a surprising number of hives are not looked after properly, or rarely inspected. BBKA and local association swarm lines take hundreds of calls every year about lost swarms. And bumble bees, solitary bees, wasps etc. …
  3. Not all are hanging in a football-sized clump on a waist-high branch with good access.
  4. Or that might bother others.
  5. The stuff they make For Sale signs from.
  6. It does need to be taped down … if you don’t it will lift and move when there is a strong breeze. The inside of the bait hive should be dark and welcoming.
  7. Many small swarms are casts or after-swarms, headed by a virgin queen.
  8. Assuming it’s a prime swarm with a mated queen.
  9. At least in the plane perpendicular to the top bars.
  10. And every one captured is one less that will otherwise probably perish … 75% of swarms do not survive their first winter.
  11. Remember, they’ve almost certainly originated from a managed colony where swarm prevention management was unsuccessful. It’s therefore quite likely that disease management was also sub-optimal.
  12. Which, within a week of arrival, it won’t have.
  13. I’m pretty sure scout bees start scouting even before queen cells are developed.

16 thoughts on “Time to deploy!

  1. Jonny

    Another excellent and informative article. This will be my second full year and I’m still very raw. Last year I put s bait hive out to try my luck and sure enough it worked, unfortunately though it was wasps that took up residence. Is there anything I can do to prevent this happening again or us simply bad luck? TIA

  2. Alan Cooper

    Great web site and blog around which I lurk regularly. Your deployment alert prompts my first reply.
    My apiary is quite isolated here and I have good local bees which seem well behaved and productive. I worry that by capturing swarms I risk introducing genetic traits and diseases that I would rather not have. Fellow bees less rural than my apiary tell of cross bees claimed to be down to drones from elsewhere. Do you have guidance on this?

    1. David Post author

      Hello Alan

      I make the point about diseases at the end. It’s a case of caveat emptor (except you’re not buying them). There’s always a risk of bringing in bad genetics. However, as I said, if the bees are poorly behaved or otherwise undesirable, you can always cull the queen and unite them with a pre-existing colony. They won’t have reared any drones, so will not spoil what you’ve already got.

      The other thing to bear in mind is that queens can travel a long distance to drone congregation areas … you may not be as isolated as you think. And if you are the other concern would be inbreeding if you only have a small number of colonies.

      If you are really isolated the only swarms you’ll pick up are your own and any feral ones.


  3. Trudy

    Hello David,
    Recently I read about “Russian Scion” to catch a swarm. Are you familiar with this concept? Love your blog and appreciate all your info

    1. David Post author

      Hello Trudy

      There’s more information on Beesource. I think it’s not a dissimilar idea to the beekeepers who always sacrifice unwanted queens on the same branch or fencepost at their apiaries.

      It’s worth noting that the Russian Scion is designed to attract the swarm immediately after it leaves the hive i.e. when it sets up a temporary bivouac, rather than attract the swarm to a new nest site. It will therefore only work when very close to (or in) your own apiary and will not attract swarms from elsewhere.


  4. max

    In Australia we are not allowed to leave anything which smells like bees – eg old comb in a trap hive

    1. David Post author

      Hi max
      Interesting. If you exclude everything that smells of bees – propolis, commercial swarm lure or lemongrass oil – they must be significantly less effective. I presume the rule is to exclude transmission of pests and pathogens between colonies.
      Thanks for the comment. It’s always interesting to find how others keep bees.

  5. Jon Meredith

    I just use dadant shallows or Langstroth mediums and intend to put out a two tier bait hive. Should I put my or comb in the top or bottom tier?
    Also what do you think of the rose one size box, with no queen excluder?

    1. David Post author

      Hello Jon

      I’m not entirely familiar with the volumes of Dadant or Langstroths. You want to aim for 40 litres, not a huge amount more or less. In a two-tier box I’d always put the old comb in the top box, next to the side wall. That’s where the bees will go.

      If the question about a Rose box with no QE was ‘as a bait hive’ I expect it would be fine. Any box of about the right size, with the other features listed, will work. Shape is irrelevant. Tom Seeley showed that tall, thin boxes of 40 litres were as attractive (but not more attractive) than short, fat boxes of 40 litres. My calculations suggest that a Rose OSB (46x46x19) is almost exactly 40 litres …

      If the question about Rose box’s was ‘for beekeeping’ then I don’t have a view as I’ve not used them. Fundamentally, all hive designs should work reasonably well. I ended up with Nationals because that’s what my mentor used. I now cannot afford to change 😉


  6. Jon Meredith

    Thanks for your response David, I have slowly worked my way through all your blogs and greatly enjoyed them. I was thinking of using the Langstroth mediums instead of rose OSB for beekeeping, but using his methods, without using a queen excluder most of the time. Just wondered if you had read his book? Thanks again.

    1. David Post author

      Hello Jon

      I’ve not read the book I’m afraid. I can see the benefits of a single size box, but prefer to use a single brood box for my colonies. This suits my bees and my beekeeping better. A single brood box that is big enough for the colony is too heavy for me to comfortably lift if full of honey. I’m willing to put up with the deeps and shallows of broods and supers as it avoids me having to use brood and a half (which I’ve always found a pain). If it’s a really strong colony they go into a double brood box. The reality is that I’m now too heavily invested in standard Nationals to switch to another box. At some point all the boxes are a compromise of some sort.

      I do use queen excluders. Always have … again, suits my beekeeping. I know some don’t but that’s one of the nice things about this hobby … there are a variety of ways of achieving broadly the same endpoint (which should be strong, healthy colonies and a bit of spare honey 😉 ).


  7. Matt Harris

    Good stuff, thanks. I am trying a few double-brood nucs as swarm traps this year, as well as the usual national brood boxes. Will be interesting to see which (if any) gets more traffic. Though the result will be too random to draw any conclusions from I guess. I just have a gut feeling that a double brood nuc with a small round entrance is a bit more like a tree trunk than a national box. But Prof Seeley’s research says not, so fair enough.

    1. David Post author

      Hello again Matt

      Apologies for only just getting to this … lockdown has seemingly quadrupled my workload.

      Ignore the gut feeling. Seeley’s study is pretty conclusive. Bees aren’t interested in whether it’s shaped like a tree, or a dustbin or a brood box. They just want 40 litres. If you’re really going to try it, set out about 50 of each with everything else standardised and you might get some statistically relevant results. Don’t set out two, with no controls and – when they’re both occupied – claim that bees ‘prefer’ double-height nucs. Every year I see people claiming that they caught a swarm in a single nuc box last year so that ‘proves’ that’s all that’s needed. It doesn’t … all it proves is that one swarm decided it was good enough. Honeybee Democracy (in particular) or The Lives of Bees has all the details.

      Gut feelings are irrelevant. Statistically significant results are not 😉


Comments are closed.