Quick thinking & second thoughts

I gave my last talk of the winter season on Tuesday to a lovely group at Chalfont Beekeepers Society. The talk 1 was all about nest site selection and how we can exploit it when setting out bait hives to capture swarms.

It’s an enjoyable talk 2 as it includes a mix of science, DIY and practical beekeeping.

Nest sites, bait hives and evolution

The science would be familiar to anyone who has read Honeybee Democracy by Thomas Seeley. This describes his studies of the features considered important by the scout bees in their search for a new nest site 3.

Under offer ...

Under offer …

The most important of these are:

  • a 40 litre cavity (shape unimportant)
  • a small entrance of 10-15cm2
  • south facing
  • shaded but in full view
  • over 5m above ground level
  • smelling of bees

All of which can easily be replicated using a National brood box with a solid floor. Or two stacked supers.

And – before you ask – a spare nuc box is too small to be optimal.

That doesn’t mean it won’t work as a bait hive, just that it won’t work as well as one with a volume of 40 litres 4.

Evolution has shaped the nest site selection process of honey bees. They have evolved to preferentially occupy cavities of about 40 litres.

Presumably, colonies choosing to occupy a smaller space (or those that didn’t choose a larger space 5 ) were restricted in the amount of brood they could raise, the consequent strength of the colony and the weight of stores they could lay down for the winter.

Get these things wrong and it doesn’t end well 🙁

A swarm occupying a nuc box-sized cavity would either outgrow it before the end of the season, potentially triggering another round of swarming, or fail to store sufficient honey.

Or both.

Over thousands of colonies and thousands of years, swarms from colonies with genetics that chose smaller cavities would tend to do less well. In good years they might do OK, but in bad winters they would inevitably perish.

Bait hive compromises

If you set out a nuc box as a bait hive, you’re probably not intending to leave the swarm in that box.

But the bees don’t know that. Their choices have been crafted over millenia to give them the best chance of survival.

All other things being equal they are less likely to occupy a nuc box than a National brood box.

Another day, another bait hive, another swarm …

For this reason I don’t use nuc boxes as bait hives.

However, I don’t recapitulate all the features the scout bees look for in a ‘des res’.

I studiously ignore the fact that bees prefer to occupy nest sites that are more than 5 metres above ground level.

This is a pragmatic compromise I’m prepared to make for reasons of convenience, safety and enjoyment.

Bees have probably evolved to favour nest sites more than 5 metres above ground level to avoid attention from bears. The fact that there are no bears in Britain, and haven’t been since the Middle Ages 6, is irrelevant.

The preference for high altitude nest sites was ‘baked into’ the genetics of honey bees over the millenia before we hunted bears 7 to extinction.

However, I ignore it for the following reasons:

  • convenience – I usually move occupied bait hives within 48 hours of a swarm arriving. It’s easier to do this from a knee height hive stand than from a roof ladder.
  • safety – I often move the bait hive late in the evening. Rather than risk disturbing a virgin queen on her mating or orientation flights (assuming it’s a cast that has occupied the bait hive) I move them late in the day. In the ‘bad old days’ when I often didn’t return from the office until late, this was sometimes in the semi-dark. Easy and safe to do at knee height … appreciably less so at the top of a ladder.
  • enjoyment – I can see the scout bees going about their business at a hive near ground level without having to get the binoculars out. Their behaviour is fascinating. If you’ve not watched them I thoroughly recommend it.

Scout bee activity

The swarming of honey bees is a biphasic process. In the first phase the colony swarms and forms a temporary bivouac nearby to the original nest site.

The two stage process of swarming

The scout bees search an area ~25 km2 around the bivouacked swarm for suitable nest sites. They communicate the quality and location of new nest sites by performing a waggle dance on the surface of the bivouac.

Once sufficient scouts have been convinced of the suitability of one of the identified nest sites the second phase of swarming – the relocation of the swarm – takes place.

Swarm of bees

Swarm of bees

However, logic dictates that the scout bees are likely to have already identified several potential new nest sites, even before the colony swarms and clusters in a bivouac.

There are only a few hundred scout bees in the swarmed colony, perhaps 2-3% of the swarm.

Could just a few hundred scouts both survey the area and reach a quorum decision on the best location within a reasonable length of time?

What’s a reasonable length of time?

The bivouacked swarm contains a significant amount of honey stores (40% by weight) but does not forage. It’s also exposed to the elements. If finding sites and reaching a decision on the best nest site isn’t completed within a few days the swarm may perish.

Which is why I think that scout bees are active well before the colony actually swarms.

Early warning systems

If scout bees are active before a colony swarms they could be expected to find and scrutinize my bait hive(s).

If I see them doing this I’m forewarned that a colony within ~3 km (the radius over which scout bees operate) is potentially making swarm preparations.

Since I’ll always have a bait hive or two within 3 km of my own apiaries I’ll check these hives at the earliest opportunity, looking for recently started queen cells.

Whether they’re my colonies or not, it’s always worth knowing that swarming activity has started. Within a particular geographic area, with similar weather and forage, there’s usually a distinct swarming period.

If it’s not one of my colonies then it soon might be 😉

So, in addition to just having the enjoyment of watching the scout bees at work, a clearly visible – ground level – bait hive provides a useful early warning system that swarming activity has, or soon will, start.

Questions and answers

Although talking about swarms and bait hives is enjoyable, as I’ve written before, the part of the talk I enjoy the most is the question and answer session.

And Tuesday was no exception.

I explained previously that the Q&A sessions are enjoyable and helpful:

Enjoyable, because I’m directly answering a question that was presumably asked because someone wanted or needed to know the answer 8.

Helpful, because over time these will drive the evolution of the talk so that it better explains things for more of the audience.

Actually, there’s another reason in addition to these … it’s a challenge.

A caffeine-fueled Q&A Zoom session

It’s fun to be ‘put on the spot’ and have to come up with a reasonable answer.

Many questions are rather predictable.

That’s not a criticism. It simply reflects the normal range of topics that the audience either feels comfortable asking about, or are interested in. Sometimes even a seemingly ‘left field’ question, when re-phrased, is one for which there is a standard answer. The skill in this instance is deciphering the question and doing the re-phrasing.

But sometimes there are questions that make you think afresh about a topic, or they force you to think about something you’ve never considered before.

And there was one of those on Tuesday which involved biphasic swarming and scout bee activity.

Do all swarms bivouac?

That wasn’t the question, but it’s an abbreviated form of the question.

I think the original wording was something like:

Do all swarms cluster in a bivouac or do some go directly from the original hive/location to the new nest site?

And I didn’t know the answer.

I could have made a trite joke 9 about not observing this because my own colonies swarm so infrequently 🙄

I could have simply answered “I don’t know”.

Brutally honest, 100% accurate and unchallengeable 10.

But it’s an interesting question and it deserved better than that.

So, thinking about it, I gave the following answer.

I didn’t know, but thought it would be unlikely. For a swarm to relocate directly from the original nest site the scout bees would need to have already reached a quorum decision on the best location. To do this they would need to have found the new nest site (which wouldn’t be a problem) and then communicate it to other scout bees, so that they could – in turn – find the site. Since this communication involves the waggle dance it would, by definition, occur within the original hive. Lots of foragers will also be waggle dancing about good patches of pollen and nectar so I thought there would be confusion … perhaps they always need to form a bivouac on which the scout bees can dance? Which explains why I think it’s unlikely.

In a Zoom talk you can’t ponder too long before giving an answer or the audience will assume the internet has crashed and they’ll drift off to make tea 11.

An attentive beekeeping audience … I’d better think fast or look stupid

You therefore tend to mentally throw together a few relevant facts and assemble a reasonable answer quite quickly.

And then you spend the rest of the week thinking about it in more detail …

Second thoughts

I still don’t know the answer to the question Do all swarms bivouac?”, but I now realise my answer made some assumptions which might be wrong.

I’ll come to these in a minute, but first let me address the question again with the help of the people who actually did the work.

I’ve briefly looked back through the relevant literature by Seeley and Lindauer and cannot find any mention of swarms relocating without going via a bivouac. I may well have missed something, it wouldn’t be the first time 12.

However, their studies are a little self-selecting and may have overlooked swarms that behaved like this.

Both were primarily interested in the waggle dance and the decision making process, they therefore needed to be able to observe it … most easily this is on the surface of the bivouac.

Martin Lindauer mainly studied colonies that had naturally swarmed, naming them after the location of the bivouac, and then studied the waggle dancing on the surface of the clustered swarm. In contrast, Tom Seeley created swarms by caging the queen and adding thousands of very well fed bees.

Absence of evidence is not evidence of absence.

So, what were the assumptions I made?

There were two and they both relate to confusion between waggle dancing foragers and scout bees.

  1. Swarming usually occurs during a strong nectar flow. Therefore there are likely to be lots of waggle dancing foragers in the hive at the same time the scouts are trying to persuade each other – using their own fundamentally similar – waggle dances.
  2. Bees ‘watching’ are unable to distinguish between scouts bees and foragers.

So, what’s wrong with these assumptions?

A noisy, smelly dance floor

Foragers perform the waggle dance on the ‘dance floor’. This is an area of vertical comb near the hive entrance. It’s position is not fixed and can move – further into the hive if the weather is cold, or even out onto a landing board (outside the hive) in very hot weather 13.

So, although the dance floor occupied by foragers isn’t immovable, it is defined. There’s lots of other regions of the comb that scouts could use for their communication i.e. there could be spatial separation between the forager and scout bee waggle dances.

Secondly, foragers provide both directional and olfactory clues about the identity and location of good sources of pollen and nectar. In addition to two alkanes and two alkenes produced by dancing foragers 14 they also carry back scents “acquired from the environment at or en route to the floral food source” which are presumed to aid foragers recruited by the waggle dancer to pinpoint the food source.

Importantly, non-dancing returning foragers do not produce these alkanes and alkenes. Perhaps the dancing scouts don’t either?

A dancing scout would also lack specific scents from a food source.

Therefore, at least theoretically, there’s probably a good chance that scout bees could communicate within the hive. Using spatially distant dances and a unique combination of olfactory clues (or their absence) scouts may well be able to recruit other scouts to check likely new nest sites.

All of which would support my view that bait hives provide a useful early warning system for colonies that are in the very earliest stages of swarm preparations … rather than just an indicator that there’s a bivouacked swarm in the vicinity.


All this of course then begs the question … if the scout bees can communicate within the hive, why does the swarm need to bivouac at all?

The bivouac must be a risky stage in the already precarious process of swarming. 80% of wild swarms perish. At the very least it’s subject to the vagaries of the weather. Surely it would be advantageous to stay within the warm, dry hive until a new nest site is identified?

Apple blossom ...

Apple blossom … and signs that a bivouacked swarm perished here

This suggests to me that the bivouac serves additional purposes within the swarming process. A couple of possibilities come to mind:

  • the gravity-independent, sun-orientated waggle dancing 15 on the surface of the bivouac may be a key part of the decision making process, not possible (for reasons that are unclear to me) within the confines of the hive.
  • the bivouac acts to temporally coordinate the swarm. A swarm takes quite a long time to settle at the bivouac. Many bees leave the hive during the excitement of swarming but not all settle in the bivouac. Perhaps it acts as a sorting mechanism to bring together all the bees that are going to relocate, separate from those remaining in the swarmed colony?

Clearly this requires a bit more thought and research.

If your association invites me to discuss swarms and bait hives next winter I might even have an answer.

But, as with so many things to do with bees, knowing that answer will only spawn additional questions 😉



  1. Freebees – bait hives for profit and pleasure.
  2. To deliver at least … you’d need to ask the audience whether it was an enjoyable talk to listen to.
  3. And work from others as well, in particular Martin Lindauer a protégé of Karl von Frisch, but Seeley and his PhD students have probably made the greatest contribution to this area.
  4. Seeley actually has a section in Honeybee Democracy titled Mediocrity in 15 litres which is a bit of a clue!
  5. Not quite the same thing.
  6. More’s the pity …
  7. And wolves, lynx, beaver, boar, bison, moose and wolverine … this really is not a good track record.
  8. Not always … there are certain scientists who, like lawyers, only ask questions to which they already know the answer. This sometimes initiates a petty tit for tat exchange lasting the entire conference. We have name for colleagues like these …
  9. To go with all the others I’d already used.
  10. Nothing to see here … let’s move on.
  11. And during an in person talk if you pause and think for a long time they assume you’re just forgetful, or stumped or stupid … I talk to some very perceptive audiences.
  12. In fact, it’s probably happened a gazillion times before.
  13. Some interesting changes must be involved in switching to a well lit horizontal dance floor outside the darkness of the hive. Do the bees seamlessly re-orientate the directional component of the dance away from gravity and to the sun?
  14. Thom et al., 2007 The scent of the waggle dance. PLoS Biology 5:e228.
  15. Some assumptions there as well … but bivouacked colonies often lack vertically-oriented faces.

36 thoughts on “Quick thinking & second thoughts

    1. David Post author

      Hello Michael … you always need a solid floor in a bait hive. The open mesh floor gives the bees the impression there’s a large entrance to defend. If I’ve got no solid floors I just put a piece of cardboard or Correx over the OMF.


  1. David Jones

    My limited experience suggests the bivouac stage can be very short. I have seen a huge prime swarm emerge from a hive, settle almost immediately into a “perfect” ice-cream cone, textbook bivouac on a hawthorn and, by the time I have driven 20 minutes home and 20 minutes back with swarm collection gear, there was no sign of them.

    Unless, of course, they had gone to a second, more distant bivouac. Hmmm. “I’d just like to ask the speaker…”

    1. David Post author

      Hello David

      A short duration bivi would also suggest they know where they’re going already … interesting.

      I hived a swarm a couple of years ago that had crash-landed in someone’s hedge on the other side of the village. It wasn’t one of mine (it never is 😉 ) and there were no bees within half a mile. I assumed they’d been en route to a new nest site and the queen had got tired and landed, to be joined by the remainder of the swarm.


    1. David Post author

      Thanks Ihor … very interesting. I know some beekeepers think that using the same fence post in the apiary to squidge unwanted queens on results in a ‘magnet’ for bivouacking swarms, but this set up with propolis looks far more attractive.

      Russian scion

      There are loads of variants of the basic design … a T-shaped board wrapped in burlap (hessian or jute to UK readers) soaked in a mix of propolis and some essential oils, hung near the apiary with some sort of shelter over the top to keep the worst of the rain off. The idea is that swarms find it attractive and settle on the russian scion, rather than out of reach at the top of a tall tree. Reading the thread it’s clear that some swear by it, and others fail completely … 😉

      Isn’t it always the way?

      Many thanks again,

      1. David Post author

        Many thanks for the link Paul.
        There’s lots of additional stuff on bait hives dotted around this site as well … the search function should turn most up if I remembered to spell things correctly or tag them properly. Alternatively, the practice page has a long list of swarming and bait hive-related links.

  2. Ray Clayton

    Two questions David , you mention a cavity of 40 litres is preferred by the scout bees, yet my mentor leaves 2 or 3 empty hives in his apiary replete with a full set of old frames/ comb , and they always attract swarms every year without fail, so I am reluctant to place a bait hive in my apiary with only one frame as you suggest.Also I see swarms settle on a convenient hedge near the apiary but they often abscond if I try to pop them into a sleep too soon. is there an optimum length of time to let them settle first ? Thanks in advance.

    1. David Post author

      Hello Ray

      I don’t suggest one frame … I use one drawn frame (old, dark comb) and the rest are foundationless frames. The bees have the impression of space, but all the guides are present for them to draw comb when they arrive. I can assure you it works … 🙂

      Perhaps you’re putting the swarms into a skep too late if they then abscond. If the swarm has decided where to go (and is just waiting for the right conditions) when you drop them into the skep, they might well go there anyway.

      I’ve never had a swarm that has arrived in one of my bait hives abscond. That’s yet another of the advantages of bait hives as far as I’m concerned (aside from how little effort they take … literally fit and forget).


  3. Hans Weijman

    Some years ago a swarm took up residence in a hive in my apiary. It wasn’t a bait hive,I had forgotten to properly put the roof on an empty hive for at least a week. The queen was a yellow Canary, quite distinct. Another beeker nearby told me that their colony had swarmed with their newly acquired, expensive yellow Canary. This happened within some 5 minutes of the swarm arriving in my apiary. That swarm had not bivouacked but came straight to their new abode.
    I guess that strictly spoken this wasn’t a ‘proper’ swarm but escapees with a recently introduced 👑. She didn’t last long, being used to the sunny beaches of Puglia so her genetic material hasn’t interfered with my locally adapted bees.

    1. David Post author

      Hello Hans

      Or did your neighbour tell you s/he’d lost a swarm headed by his expensive queen only after you’d told them that you’d acquired one? 😉

      If a queen and a load of bees arrive in one of my bait hives it’s a swarm … however new, or whatever the provenance, the queen is.

      Your comment made me think about colonies that abscond. Do these also bivouac? If not, how do they know where they’re going unless they’ve already made that decision with scout bees communicating within the hive?

      The more beekeeping I do, the more I realise I don’t understand about bees.


      1. Elaine Robinson

        I’ve only experienced absconding once (except from tiny Apidea mating Nucs). This was a v embarrassing occasion, as a 3 year bee keeper I invited a beginner to my out-apiary, to show how to house a Nuc into a hive. Proudly i opened the 6 frame well populated Nuc and started to move it into a hive. Suddenly the bees took flight into a nearby hedge and absconded with not a queen cell in sight, left behind . To this day I don’t fully understand why they did this. Just felt a bit embarrassed as the newly appointed mentor. I ‘attracted’ / shook the absconded colony into a Nuc to settle and when I returned a couple of hours later, leaving said beginner perplexed, it had absconded again.

        1. David Post author

          Hi Elaine

          Absconding has been studied in tropical strains of bees where it’s associated with a specific form of dance, different from the waggle dance used by scouts and foragers. Bees in temperate climates don’t use ‘migration absconding’ like tropical strains do, but the dance has been observed in temperate strains. I presume they didn’t like your nuc box and had decided to clear off … your attempt to re-hive them clearly didn’t meet with their exacting demands and they decided to go anyway.

          They don’t read the books 😉


    2. Rory Fields

      I too have left a hive of drawn frames out and watched the swarm depart one of my other hives and immediately move without any bivouacking 30 metres into the previously beeless hive. Happened last year during lockdown when we had that lovely spring – utterly magical to observe, cheers, Rory

      1. David Post author

        Hi Rory

        Very interesting … clearly there’s lots more to learn (at least by me) about this topic 😉


  4. Elaine Robinson

    Hi David, I’m not convinced that all swarms bivouac. From experience most do, but I can think of two occasions in my home apiary, when as a beginner, I witnessed both swarms (on different occasions) going straight from the hive and over the hill, not stopping anywhere in sight. Doesn’t mean to say they didn’t bivouac somewhere else, but between me and the next garden it’s several hundred meters away, over a few fields. If they did bivouac elsewhere some distance away first, why would they do this, rather than choosing a handy near-by bush for their fellow bees to first join them and check the queen was flight worthy and there? Only reason I can think of is they’d already found a new home. One of those head scratching moments that I still haven’t solved. Biology isn’t perfect!

    1. David Post author

      Hi Elaine

      Very interesting. In my experience the bivouac is always nearby the originating hive. However, that’s of necessity rather limited … I do my best to try and stop losing swarms.

      Did you not chase after them and try and recover them? I’ve done that, or tried to. A swarm moves surprisingly fast considering the apparently random flight of workers in the swarm.

      I’ve watched mini-nucs abscond and disappear over the fence into the blue-yonder. These might only contain a few hundred bees, so the ‘swarm’ (it’s not a true swarm as it contains almost all the bees in the little colony) is only ~3 feet in diameter in flight and looks like a little dark cloud.


  5. Emily

    Interesting thoughts… this is often something I’ve wondered about… why risk being exposed to the elements for a while, why not swarm directly from the old location to a new chosen home? I assumed it was because the scouts needed to dance on the surface of the bivouac so that a decision could be reached, but you have added another possibility, that the bivouac helps coordinate the bees… I wonder if scientists will come up with a good experiment to test the purpose of the bivouac.

    1. David Post author

      Hi Emily

      It’s clear from some other comments that some people think they do go directly, rather than via a bivouac. It would be interesting to do some of these swarm/nest site types of experiments, but not entirely practical here on the west coast of Scotland. The swarm season is very short and the weather is varied (to put it mildly … snow on the hills this morning).

      I’m going to read up a bit more about swarms and absconding to see if I can make some more sense of it … or at least be better prepared for questions next winter 😉


  6. Bridget Clyde

    Although we have a bait hive (never been successful but we are far enough from other beekeepers that the only occupiers will be our own) we always rush out, do some death defying antics involving ladders, branch cutters, trees and me standing with a poly hive on my head below the swarm. Should we rush about less and see if they will go into the bait hive? I’ve possibly answered my own question as I’ve never seen more than a couple bees investigating.

    1. David Post author

      Hi Bridget

      It might be worth looking at the link Ihor posted about the Russian Scion. It looks very interesting.

      If your bait hive hasn’t been getting any ‘love’ from the scout bees it might be worth relocating it to a different location. One thing I didn’t comment on in the post (or the talk, or previous posts on the subject) is that some sites appear much better than others. I’ve no idea why this is. I’ve had bait hives in my Fife and Midlands gardens that always attracted swarms … every year, without fail. I never kept bees in these gardens. In contrast, I’ve had other bait hives that have failed. I tend to move these the following year (I do the same thing with nestboxes that aren’t occupied for a year or two as well).

      I can’t explain this. Before someone pops up and suggests ley lines I’d remind readers I’m a scientist and need evidence that such things exist before considering them as an explanation 😉

      Try moving your bait hive. My successful ones tend to be in very sheltered locations.

      Or improve your swarm control of course 😉

      Best Wishes

  7. Dorothie Jones

    Hi David
    Thanks for a great talk on Tuesday we have had some good feedback from our members. A bit of science combined with practical advice..perfect!
    I have a question about swarms though.
    Are bivouac swarms attracted to apiaries? Before I kept bees, I never saw a swarm in my garden, and neither did my neighbours! Now we always get at least one (not my bees). Last year I had 5….only 2 of which I’ll admit to!!! I watched one zoom in over the houses only to zoom straight off again!

    1. David Post author

      Hi Dorothie

      Delighted the talk was received well. It’s always a slightly odd feeling delivering a Zoom presentation. You never know how well it was liked. With a live audience (and I know the audience is live on Zoom) everything is ‘one step removed’ and the only two real clues as to how well things went are: a) the duration of the Q&A session (~50 minutes was the longest this winter 🙂 ), and b) any subsequent feedback. So, thank you.

      I think swarms are attracted to bees. They’re certainly attracted to the smell of bees. I’ve seen one or two bivouacked swarms that I was pretty sure weren’t mine in or near my apiaries over the years. However, their arrival wasn’t seen and it was in my earlier days as a beekeeper. If they were from remote hives it doesn’t quite fit with my current understanding of the way swarms behave; a bivi near the original hive and then relocation to the new nest site which may be some distance away. For them to specifically target an apiary the scouts would have had to lead them there, and I’m not aware of any evidence scouts do this. I have seen bees stop en route to somewhere else, presumably when the queen tires mid-journey.

      Apis mellifera scutellata (and other tropical strains) can exhibit seasonal absconding, where the colony migrates up to 100 km. This journey must involve numerous stops for refueling which I presume involves bivouac formation. I’ve been meaning to write about this for a year or two …


      1. Dorothie Jones

        Thanks David.
        As you pointed out, I know there are a number of other members’ apiaries close by, plus prob some others I don’t know about! So they may not have travelled far. My neighbour’s pear tree is a real favourite!
        Have a good season

        1. David Post author

          Hi Dorothie

          Fruit trees appear to be particularly attractive to bivouacking swarms in my experience … or I’ve been in a lot of apiaries near to orchards 😉


          1. David Jones

            My bees are in my orchard, with 20+ heritage apple, 4 or 5 plum, a couple of pear, cherry, almond, quince and mulberry. In 10 years, I have _never_ had a swarm in a fruit tree; always on hawthorn or blackthorn – at anything from shin height to 25 feet up in a blackthorn thicket last year (and I got it!) They don’t do much pollination either – preferring to fly over the apple blossom to the OSR; I don’t know why I keep them. Anecdotal evidence – don’t you love it.

          2. David Post author

            Weird … in a previous association apiary the bees would routinely fly over the Leylandii hedge to bivouac in the fruit trees of the neighbouring orchard. Periodically they might also choose one of the mature trees and would (inevitably) be out of reach.

            The apple vs. OSR choice presumably comes down to sugar content of the nectar … I think it’s about three times more concentrated in OSR.


  8. Maggie

    Hello David I was interested to see the photo of the empty comb in the apple tree. I retrieved a late swarm from a branch on an apple tree last August and was surprised to see that they had started to build comb. Is this common?

    1. David Post author

      Hi Maggie

      I’ve only seen it a couple of times … but I’m not that observant 😉

      To generate that amount of comb the bivouac must have been resident for quite a time. I’ve got some better photos which suggest to me they reared at least one round of brood in the comb. I suspect they got trapped by bad weather and – for whatever reason – then failed to relocate to a new nest site.

      Perhaps the scouts stop scouting after a period? Perhaps the presence of brood stops scouting activity? Yet another thing I don’t know …

      Whatever, the colony got stuck on that branch and probably never moved on, perishing from exposure in the autumn or winter.

      ~80% of natural swarms do not survive. I think these figures are from those that did manage to establish a new nest. A proportion never make it that far. I don’t know the numbers but expect it’s a rather small percentage of colonies that do swarm.


  9. Michael

    I’m wondering, if the scout bees scout potential sites before the bees back at the home colony swarm, how does a scout bee recruit fellow scouts to come and assess the site and not distract the main foraging force from collecting nectar and pollen?

    1. David Post author

      Hello Michael

      I don’t know, but I speculate on a couple of mechanisms in the post … different ‘dance floors’ or different olfactory clues perhaps?


  10. Alistair

    Hi David. I was sorry to miss your recent talk to our association, but I like your discussion above about the need to bivouac. Here is a thought: I am sure that I read somewhere that someone (possibly the University of Cardiff) had made a mechanical waggle dancing bee. My memory is that when they first tried it out the bees attacked it, because it did not give them signs of the forage and they needed to add the scent of a forage plant for it to be accepted. This makes me wonder whether, if scouts tried to recruit within the hive, the other bees would discourage them. My hunch would be that recruiting within the hive would be confusing because of the forage dances and also, many of the bees within the hive will not be joining the swarm.

    1. David Post author

      Hello Alistair

      Martin Lindauer made a mechanical bee back in the 1990’s and investigated the components of the waggle dance (Michelsen, A., Andersen, B.B., Storm, J. et al. How honeybees perceive communication dances, studied by means of a mechanical model. Behav Ecol Sociobiol 30, 143–150 (1992).).

      It’s clear from responses to this post – in both comments and direct emails – that some swarms do not bivouac. That being the case there must be a mechanism for scouts to communicate within the hive without too much confusion. I discuss the potential spatial separation of the dance floor and different olfactory clues (perhaps scouts only listen to dances from bees that do not smell of potential forage, or perhaps foragers only follow dancers that do smell?). It’s also possible that the dancing might be temporally separated … or even be of a different form. I’m going to go back and look at the dances associated with absconding for starters …

      It’s an interesting area … ideal for uninformed speculation by me 😉


  11. Giles K (from Chalfonts Beekeepers’ Society)

    In the May 2021 edition of BeeCraft, Tom Seeley, answers the question of whether a swarm always bivouacs, before heading to the final nest site. He conducted an experiment in 2008 which witnessed one swarming colony skip the bivouac stage.

    Article: The astonishing behavioural versatility of nest-site scouts by Thomas D Seeley

    1. David Post author

      Many thanks Giles … something else to add to my (never ending) list of things to read 😉 I don’t subscribe to BeeCraft – though I think I may have written something for it in the past – so will search it out.



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