15 min read

Informed decisions

Beekeeping is all about making informed decisions, some of which involve calculated risks. Are there ways to improve the decision-making process?
Graph analysis
Big data? Not when I'm involved. Photo by Lukas

One of the attractions of beekeeping is the seasonal variation, both within a single season and between one year and the next.

Early colony expansion enables the spring nectar flow to be exploited, and leads simultaneously - almost inevitably and so reasonably predictably - to swarming. Colonies are re-queened (or re-queen themselves) and settle down for the summer, nucs are prepared, queens are reared - though it makes sense to do those two in the reverse order 😉 - and the summer honey is harvested. Things start to slow down, colonies contract, you finally feel in control of things, miticides and winter feeding are applied, and it's all over for another year.


Some years all that happens in an apparently seamless progression, with one phase segueing into the next ... calmly, smoothly and - ever-so-rewardingly - predictably.

You know what's happening, you understand what's coming next, you're prepared in advance and quietly confident.

Life feels good.

And in other years it's a bit of a shambles.

Things start OK, look promising, take a turn for the worse, look poor, look truly awful, pick up a bit, finally look promising again etc.

A sort of beekeeping 'snakes and ladders' effect, in which the seasonal progression is of the two-steps-forward-one-step-back variety.

Sometimes with more backward steps ...

... or longer snakes.

And the start of the 2024 season, feels a bit like that.

I've seen almost no flying drones and have done most inspections in miserably cold and wet conditions.

I've also found sealed queen cells and booming colonies.

Remember, I live in Scotland ... but there are beekeepers from all over the country complaining about the weather on social media.

And they're off!

April started warm and wet. In fact, it continued exactly as March had ended. The last few months have been very wet.

I checked some of my hives - really little more than a "how are you getting on?" peek - early in April, standing ankle-deep in water from the adjacent burn which had overspilled its banks.

I commented on these inspections in All change, the title reflecting an ongoing move to a new apiary. All my Fife colonies looked good, with 100% winter survival. I saw no drones or drone brood, but had skipped the brood nest periphery where I would have expected it to be. Colonies were reassuringly strong and there was a bit of fresh nectar stored ... possibly willow.

The apiary move is now just about complete. All that's left are a few overwintered nucs which I hope to sell in the next fortnight.

Hive and hivebarrow in a flooded field
Buster to the rescue again

It was another fortnight until I looked in the boxes again, the first 'proper' inspection of the season.

Weak colonies had at least 5-6 frames of brood in all stages, most were on 7-8, and a few were on 9+. Although not every frame was necessarily filled to the corners with brood, these were surprisingly strong colonies - in my experience - for this time of the season in my part of Scotland.

One even had queen cells - I'll return to this shortly.

Super start

Supers were added, usually two.

I store the majority of my supers 'wet', simply piled up in a wasp- and mouse-proof stack in the shed. Although the bees probably find these more attractive and move up into them from the brood box faster, I mainly store them wet because I'm lazy.

Since my beekeeping is largely 'remote' {{1}}, storing the supers 'wet' saves me extra visits to the apiary to remove them if I had let the bees clean them out after extraction, and it allows me to get the late-summer miticides on earlier (so helping protect my winter bees).

Remember ... those {{squiggly brackets}} are footnotes and are listed at the bottom of the page if you are reading this newsletter on email. If you view the post online, you get clever little pop-up footnotes instead.

Once the supers are on the season has definitely started 😄.

One step back

And then it turned cold. Really cold. The wind shifted round to the north, and most of the second half of April was unpleasantly cool for the bees ... and the beekeeper. We had lots of overnight frosts and only 3 days when temperatures reached the low teens.

Not exactly the shirtsleeves weather we are supposed to need to inspect colonies.

I checked one apiary again on the 29th. It was a little below 11°C and drizzling. I looked like the 'Michelin man' wearing a fleece, a beanie, a beesuit and a Gore-tex jacket.

The bees were remarkably tolerant of my intrusion ... but the colonies had not progressed at all in the intervening week or so. If anything, they'd gone backwards. Stores were very low, but at least the queens were still laying.

The feeding dilemma

The forecast was predicting much better weather 'soonish'.

There were flowering (albeit still a bit patchily) oil seed rape fields within range. If the weather did pick up, it would be a 'nectarfest', and I'd be kicking myself for not adding another super.

Oil seed rape (canola) starting to flower
Patchy oil seed rape (in a previous - drier - season)

Alternatively, if warmer weather was delayed there was a real chance that the colonies would starve. Probably not to the point of losing them, but certainly enough to stop the queen from laying and potentially triggering them to cannibalise brood.

Unsurprisingly, eating your own young does not help colony expansion, and it would probably clobber any chance of a good spring honey harvest ... if it ever warmed up enough.

Decisions, decisions

Should I remove the supers and give them all a block of fondant to be on the safe side, or should I risk it and hope things improve?

After a few minutes of dithering in the deluge, scrolling through the Met Office forecast on my phone with wet, gloved hands, I concluded the weather was likely to improve.

In addition, I realised that most of the hives had an additional wet super stacked on top of the crownboard.

Rather than driving everywhere with a car-full of supers I often just leave them stacked up in the apiary out of reach of the bees; either over the crownboard, or in a separate stack with a sealed floor and spare roof.

I'd brought 3 supers per hive from storage to the apiary on the day I added the first supers.

I placed the wet super over the queen excluder, added a clearer above it under the two other - now completely cleaned out - supers. The bees get the benefit of the dregs in the wet super without having a huge echoing void above them should the weather stay poor.

But it didn't ... the following day was the warmest of the month and reached a balmy 20°C.

However, by then I was 150 miles away.

Knowing when to retreat

Having re-arranged the supers on the hives, I trudged back to the car, stopped off briefly to deliver some honey in the increasingly heavy rain, and arrived at the second apiary in a monsoon.

I gave up in disgust.

It was likely that the colonies were in a broadly similar state to those in the first apiary. However, the local forage available, at least early in the season, is a bit better (more willow, lots of gorse and ample OSR), so I was hopeful they'd be OK.

It would have really distressed the colonies (and so probably distressed me 😉) to have opened them under those conditions. I've done it when it's absolutely necessary, but it wasn't ... so I 'abandoned ship' and went home.

Early queen cells

Let's briefly revisit those early queen cells.

I found these in a very strong hive on the 22nd of April. There were several open and 'charged' cells (i.e. with a larva sitting on a bed of Royal jelly) together with a couple of sealed cells.

Charged, unsealed, queen cell
Charged, unsealed, queen cell

Had this been the 22nd of May - with correspondingly better weather - I'd have expected a colony with queen cells like that to have already swarmed {{2}}.

However, there were loads of eggs and, although I didn't see the queen {{3}}, the colony gave every appearance of being queenright.

For new beekeepers reading this ... you can tell.

The colony was beautifully steady on the comb, their temper was excellent (remember the conditions were cool and damp), there were lots of eggs ... no agitation, no welcoming 'roar' when removing the crownboard, no aggression.

If it wasn't for the queen cells there would have been nothing to be concerned about (and a lot to be very satisfied with).

However, sealed queen cells ... surely the colony was about to swarm?

The expectation would be that they would be 'up, up and away' on the first good day. Typically, it would be time to apply some swarm control; a Pagden artificial swarm perhaps, or isolate the queen and a frame or two of emerging brood in a nucleus.

But, all I did was squidge the queen cells - open and sealed - and remove a couple of frames packed with brood which I used to boost a neighbouring hive.

I replaced the removed frames with drawn comb, but would have used foundation (or foundationless) if I'd had any with me as this would have held the colony back a bit more.

To be explicit, the 'all I did' included going through every frame and tearing down anything that looked like a queen cell.

No drone brood

The sealed queen cells contained pupae in the early stages of pupation, no melanisation, no purple eyes ... all peely-wally {{4}}. They were at least a week away from emergence.

I don't doubt that they would have emerged ... and the colony might have swarmed (though I'd seen the forecast and I suspect this was unlikely). However, my records showed that the queen in the box was clipped; I might lose the queen, but I would not lose the bees.

But the notable thing missing from the hive were drones, or much drone brood.

Drones take a long time to develop (24 days compared with just 16 for the queen) and yet more time to reach sexual maturity. It takes ~5 weeks from the time an unfertilised egg is laid for a sexually mature drone to be produced.

Like those developing queens, the drone brood in the colony was a long way from emergence. How do you determine this? Scrape back the cappings on a few cells and look at the eyes. If they are very dark, or the pupae are melanised, then emergence is imminent.

And no adult drones

But, not only was there no near-to-emergence drone brood, there were also no adult drones.

Reeking of testerone and Lynx

Drones have a very Marvin Gaye or Paul Young attitude to life ... "Wherever I lay my hat (That's my home)". They move freely between hives.

Not only did the colony with the queen cells have no mature drones, but it looked like none of the nearby hives - there were several - had any either. If they had been present, they'd have drifted into the hive with the queen cells.

And, if those neighbouring hives had no drones, what (or is it who?) was the virgin queen going to mate with?

What were they thinking?

Yes, you're right, there could have been an apiary a mile down the road bulging with drones - all reeking of a heady combination of testosterone and Lynx - raring to go {{5}}.

But I doubt it.

They'd have shared the same environment, they'd have been exposed to the same weather, accessed the same forage. A betting beekeeper would expect them to be broadly at the same stage of colony development.

And, it was a bet I was willing to take.

Informed decisions

These two scenarios - "should I feed?" or "should I apply swarm control?" - are both examples of informed decision-making.

Beekeeping is all about informed decision-making ... and calculated risks.

The weather forecast informed the first decision, and played a part in the second. Although the precise details may be incorrect - rain between 9 and 10 am, 18°C at midday - the broad generalities are rarely very wrong.

Seeing that forecast I'd be expecting rain in the morning and temperatures in the mid- to high-teens around the middle of the day.

Even relatively long range forecasts are pretty reliable. It was pretty clear that the cold weather in mid- to late-April was to be replaced with something much more to the bees' (and my) liking by the very end of the month.

Synoptic chart
Surface pressure charts for Monday 6th May

The weather forecast is available to everyone. The decision to not apply swarm control was based on information of my own.

Firstly, my records showed that the queen - from June 2023 - was clipped. At least, she was in late July 2023 when I'd last fully inspected the colony. There was a possibility (well below 10% I reckon) that she'd been superseded late in the season, but that seemed unlikely for a 2023 queen ... so, again, informed by my records of her age.

Knowing she was clipped gave me confidence I'd not lose the bees, even if I lost the queen (had they attempted to swarm).

Secondly, I knew enough about the development cycle of bees - and specifically drones - to realise that there were few, if any, sexually mature drones in the area.

Why apply swarm control - splitting up the colony and creating the need to get the resulting virgin queen mated - if there was a probability (not possibility) it would be unsuccessful?

There were other things I could have done with the colony, but I was restricted by time (the worsening weather) and the equipment available.

Why make swarm preparations in the first place?

Arguably, the production of queen cells by the colony was also an example of informed decision-making (by the bees), albeit based upon incomplete information.

The triggers for swarming - including the production of swarm cells - are complex. They include external (i.e. environmental) and internal (the state of the colony) causes, not all of which are understood {{6}}.

Presumably, enough of these triggers (known or suspected) - queen mandibular and footprint pheromone levels and distribution, colony size, open/closed brood ratios, age ratios of bees etc. - had occurred in the strong colony that produced queen cells.

However, they lacked - or ignored - the information that there were no mature drones about for the new queens produced.

Any swarming was likely to be a futile exercise ... it probably would not end well for the colony.

Just because the bees do something does not mean that they know what or why they're doing it ... and it certainly does not demonstrate that 'the bees know best'.

Cross channel migrants {{7}}

Despite the near-Baltic conditions in late April, colonies this season are probably stronger at this time than they've been for the last couple of seasons.

Is there a way that could have been predicted?

Could some of my decision-making have been better informed? {{8}}

I've previously discussed phenology; this is the timing of seasonally variant natural events, like the arrival of cuckoos from Africa.

Cuckoo (photo by Chris Romeiks), via Wikimedia Commons

I'm pretty good with the migrant arrival dates; willow warblers, swallows, house martins, cuckoos and grasshopper warblers are all here now, but all are a little bit later than the last few seasons (at least in my part of the world).

How can that be if the bees are more advanced?

The conditions experienced en route may have slowed their journey ... strong winds, rain or cold weather (which April had in abundance) would all be expected to delay these insectivorous birds.

Flowering of shrubs and trees might be a better guide, but many of these don't flower until well into the beekeeping season (i.e. too late to be of much benefit for the beekeeper) and many are influenced by micro-geography (frost-pockets, exposed or sheltered sites etc.).

But there's an alternative, and it's one I've briefly mentioned in the past, and that is growing degree days.

Growing degree days

Penn State University explain what these are used for:

Growing degree days (GDD) ... are used to estimate the growth and development of certain crops and pests during the growing season. They can be used retrospectively to calculate the current growth stage of a crop, or to help forecast the date that a crop will reach a predetermined growth stage {{9}}.

The calculation is relatively straightforward. You need just two pieces of information:

  • the mean temperature on a particular day and,
  • a reference - or base - temperature below which the particular crop you are interested in does not grow

If the mean temperature (often approximated by adding together the daily high and low temperatures and dividing by two) is lower or equal to the base temperature then GDD equals zero.

If the mean temperature is higher than the base temperature then GDD equals the mean minus base.

Even my atrophied mathematical abilities can cope with that.

Summing up the GDD over weeks or months indicates how warm or cold the season has been, using a relevant basal temperature for the crop.

So, I've started {{10}} looking at how GDD's could be applied - or if they could usefully be applied - to beekeeping. And, if they could, how they might best be calculated.

Graph of growing degree days
Growing degree days (January to April) 2020 to 2024

Here's some basic data for the first four months of 2020-2024. I've added verticals for the month start/end dates (ignoring the leap years).

Yes, they all look similar. They would ... it would be a weird spring that did not - overall - warm up from January to April. But look at the variation ... by the end of January, there was almost double the accumulated GDD in 2020 than 2021. By the end of April, the totals were ~30% different.

So were colonies much better developed in 2020 than 2021?

Hold on, not so fast ...

Base temperatures and rainfall

This topic will be getting a post of its own. However, before I wrap up, here are a couple of points to think about that are relevant to bees, but irrelevant to sweetcorn or golf greens.

Depending upon the crop, the base temperature is varied. There is no point in having a base temperature much different from that at which the crop starts growing. In the US, 10°C is often used, elsewhere it's often 6°C or 0°C. In fact, if you look at online GDD calculators, these are usually the presets available.

But for bees, what's important is whether they can exploit the forage that's available in the environment.

I think it makes sense to set the base temperature for bees at the lowest temperature for foraging. I usually reckon this is 8-9°C. 6°C is too low, and 10°C is too high.

A month at 7°C (GDD of 30 using a base of 6°C) is of less use to the bees than a week at 12°C (GDD of 42 using a base of 6°C).

But, if it's 14°C and raining hard, sweetcorn and golf greens continue to grow, but the bees remain 'indoors'. Therefore, I've been introducing a 'fiddle factor' to take into account the amount of rainfall per day - as far as an expanding colony is concerned, cooler and dry conditions are better than a warm downpour.

I'll discuss this further once my spreadsheet-fu has improved a bit

Retrospective vs prospective information

Phenological observation is largely retrospective. It's a warm spring if the cuckoos arrive before the 19th of April, or the willow flowers before the third week in March. But you could not predict it was a warm spring (from these observations) until the cuckoos arrived, or the willow flowered.

And willow hybridisation means that the onset of flowering is hugely variable and of almost no predictive value anyway 😦.

Furthermore, phenological differences may reflect events in geographically distant locations - the weather in the Intertropical Convergence Zone is of little direct relevance to my colonies in central Fife, but has a big impact on migration of cuckoos that overwintered in the Congo rainforest.

In contrast, GDD's are cumulative and local. Loads of weather data are available for past seasons, with a good degree {{11}} of geographic granularity. You can therefore look how this year compares with past years, cross-referenced to your hive records of colony development, frames of brood, dates you added supers, the appearance of queen cells etc.

Hopefully, you should be better informed about what might next happen in the apiary ... and when it might happen.

You do keep those sorts of hive records, don't you? 😉


In proofreading this I started to wonder how hive-haven.con's AI-powered scalping algorithms (see All change) would plagiarise the text.

How will they cope with peely-wally, spreadsheet-fu, the cultural references to Paul Young, or Lynx aftershave?

I really don't care, do you?

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{{1}}: I live on the other side of the country ... it's a small country, but there's a ferry to catch, the roads are narrow, and they're clogged with rubbernecking tourists. The journey takes hours.

{{2}}: I've not needed to use swarm control before the first week of May since 2015.

{{3}}: Are Posca pens waterproof?

{{4}}: Pale and colourless.

{{5}}: Writing this has made me question whether we know if drones move between apiaries? I'll have to check.

{{6}}: And that's putting it mildly ...

{{7}}: A blatant attempt to get a Google news ranking.

{{8}}: I'm certain some of my decisions could have been better.

{{9}}: My added emphasis.

{{10}}: Again, as I've dabbled with this before, but given it a bit more thought this time.

{{11}}: A bad pun is worse than no pun at all.

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