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Winter weight

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Synopsis: With colonies now rearing brood there is a risk of them starving. Here are a couple of ways of checking the winter hive weight to determine if you need to add fondant. These checks should be conducted every 2-3 weeks until the bees are foraging in the warmer spring weather. 

Introduction

Last week I described how to determine what was happening inside the hive in winter.

By carefully inspecting the debris that falls through the open mesh floor (OMF) you can tell:

  • the size and position of the cluster,
  • whether they are rearing brood (or, more precisely, whether there is brood being uncapped … I don’t think you can tell if there is open brood simply by inspecting the debris),
  • if frames of stores distant from the cluster are being used.

In addition, I explained the importance of checking that the hive entrance was clear of corpses. These accumulate during long periods of cold or inclement weather. If the hive entrance is small enough to prevent mice from getting in – and it should be – then there’s a chance these corpses will build up sufficiently to stop bees getting out.

Entering the ‘danger zone’ – rearing brood, too cold to forage – don’t let them starve

These two checks take no more than a few minutes and should be conducted at least monthly. There’s no harm in doing them more frequently because – performed correctly – the colony isn’t disturbed at all.

Last week I described these as ”The bees don’t even know they’re being checked” checks.

The final important winter check is to determine the weight of the colony.

Avoirdupois 1

If the bees are rearing brood they will be using their winter stores. Of course, they will have been using these stores throughout the late autumn and winter, but critically, the rate at which they use their stores will increase once brood rearing starts.

I’ve illustrated this before schematically, but have attempted to improve the diagram a little this year.

Once they have reared some brood, they’ll have more bees to help them rear some more brood, meaning that the rate at which the stores are used will increase.

Schematic diagram of winter hive weights

The solid black line is the weight of the colony. In the late autumn the colony almost certainly goes through a broodless period 2. During this broodless period the colony is simply using stores to maintain the adult bees in the cluster. I’ve drawn this as a straight line (i.e. a constant rate of stores usage), but I bet it varies with the ambient temperature as more or less stores are required for essential metabolic processes.

But at some point the queen starts laying again and the colony have some larvae to feed.

I’ve indicated the start of brood rearing by a dashed vertical line. Typically I usually guesstimate this occurs around the winter solstice 3, but for our purposes the precise timing is irrelevant.

Twenty one days later these bees emerge, by which time the queen has already laid some more eggs.

Things start to pick up.

What started as a small palm-sized patch of brood now covers almost the side of a frame, in a month it will be double that.

Or more.

And all of those hungry mouths mean more stores are needed, so the rate at which the stores are consumed will increase, meaning that the colony weight will decrease … and it will continue to get lighter faster 4.

Silent spring

A few crocus and snowdrops are out, but the weather is too poor for foraging.

The weather gradually improves and more spring flowers become available.

There’s gorse available, of course. There always is.

Late December gorse ...

Late December gorse …

The bees can now forage a little more. On unseasonably warm days the bees take cleansing flights and might collect a little pollen and nectar.

I’ve imaginatively and artistically illustrated this in the graph with some little yellow flowers 🙂

But, all the time, more brood is being reared.

If the nectar coming in is insufficient to feed the brood – and early in the season it will be – then the bees will continue to make inroads into their precious stores.

And the colony will get lighter.

And lighter.

Until it drops below some critical threshold and enters the ‘danger zone’ – the absolute weight doesn’t matter 5 – at which point the colony must go into self-preservation mode.

Brood will be abandoned, cannibalised and/or ejected from the hive. The queen will stop laying. The colony will be forced back into a ‘maintenance’ state.

A protracted cold period, or a fortnight of rain, and there’s a very real danger the colony will starve to death.

At the very best the early spring expansion of the colony will be severely retarded and it is unlikely to recover until mid-season.

All of which is easily avoided by carefully monitoring the amount of stores the colony has.

A brood frame full of stores

However, remember you’re supposed to be conducting ”The bees don’t even know they’re being checked” checks, not pulling open the brood box and rummaging through to count frames of sealed stores.

But since the number of bees in the colony is steady (or likely decreasing slowly) and there’s effectively no nectar being collected, the weight of the hive is a good surrogate measure to determine the level of stores available.

Winter weight

There are all sorts of ingenious solutions to determine the weight of a full hive.

Probably the most complicated and expensive is to purchase (or build) a set of electronic hive scales that automagically communicate with an app on your smartphone to give you a real-time readout of the hive weight in kilograms. You can record the weight of a few thousand foragers leaving the hive in the morning 6, and see them return by nightfall together with the 1500 g of nectar they’ve collected.

Arnia hive data

Arnia hive data

At the other end of the spectrum – in terms of both cost and information – is hefting the hive. Using nothing more than than a gentle lift and good judgement you can readily tell whether the hive contains sufficient stores for the bees to continue to rear brood. You won’t be able to tell the exact weight of the hive, but you will be able to determine whether it weighs enough.

I’ve used both methods.

However, I routinely only do the latter.

I’ll leave a discussion of automated hive monitoring to another day 7 and will instead briefly discuss two methods that are quick, cheap and easy (choose any three).

One method – hefting the hive – costs nothing, but requires a bit of experience and judgement. The second method involves – inaccurately, but reproducibly – weighing the hive. This costs about £10 to implement and provides a good way to build up your confidence that your hive hefting is probably good enough to ensure colony survival.

And good enough is probably all you need …

Hefting the hive

This is easier to show than describe:

The general idea is that you judge how much effort is required to lift one edge of the hive – typically the back – a couple of centimetres off the hive stand. As you can see from the video, other than slackening off the strap that secures the hive to the stand 8 there’s nothing else involved.

Comparisons help here.

It helps to have the ‘muscle memory’ of how much the hive weighed last time you checked, or – even better – how heavy it should feel like at this stage of the winter.

Both come with experience, and improve with lots of experience.

If you have several hives in the apiary, all with the same hardware, then hefting one after the other makes this comparison relatively easy. If – like in my apiaries – you have a range of different roofs, it can help to remove the roof to get a better ‘feel’ for the hive weight.

The hive should feel heavy.

If the hive feels light it probably is light.

Too light.

Weighing the hive

This second method is a little bit more involved.

I’ve previously recommended using a set of luggage scales to weigh the hive. You attach them to one edge of the hive floor, pull up gently, let the weight stabilise and then record the value on the digital display.

Don’t try this using luggage scales with an analogue display, or ones that don’t emit a helpful ‘beep’ and freeze the display when the weight stabilises.

Just don’t 🙁

Suitable luggage scale cost about a tenner. Mine are very friendly but cannot spell.

Friendly scales ...

Friendly scales …

However, those of you who have tried this method will be aware of the world of grief that is encapsulated in the words ”let the weight stabilise”, particularly if you do not have a lot of upper body/arm strength.

Here’s the problem … you are trying to hold half the weight of a full hive stationary. Probably 9 your arms will be bent at the elbow.

The hive will probably weigh 30+ kg.

Even half that is a lot to hold steady while you wait for the tinny electronic ‘beep’ to tell you to relax and lower the hive gently back onto the hive stand.

I struggle to do this (more now than I used to) and I’m tall and relatively strong.

Before I explain an easier way to achieve the same thing I ought to say a couple of words about determining the total hive weight.

Physics … Ewwww!

If everything – frames, bees, stores – in the hive are evenly distributed, then opposite sides of the hive (weighed as described above) will be a fraction less than half the total weight 10.

Weighing hives

Since the ‘stuff’ in the hive is probably not evenly distributed the weight you record will either be less than or more than half the weight of the hive, depending on whether you have picked the heavy (C in the figure above) or light (D) side of the hive.

However, the sum of the two sides (C + D) will – with the exception of the fraction lost due to vectors as described in the last footnote – still equal the total weight of the hive and contents.

So, if you want to know the total weight either measure the weight of opposing sides and add them together.

Or, measure one side, double it, assume everything is about even and enjoy being a beekeeping free spirit.

You radical 😉

Let the weight stabilise

The solution to the arm-wrenching, patience-draining, interminably-wobbling, weight stabilising problem is to use a lever.

You need two pieces of stout wood, a strong nut and bolt and a few suitably sized washers. One piece of wood forms a vertical support. The second piece of wood is a lever. It is attached near the top of the support using the bolts/washers/nut.

Hive scales

The digital luggage scales are tied to one end of the lever.

You need a way of attaching the hive to the scales. I use a 6 mm roofing bolt.

Now you see it …

All my hive floors are drilled with a 6-7 mm hole through the middle of each side of the floor 11. This is in the side runner of my kewl floors, underneath the OMF and the Varroa tray.

The roofing bolt is pushed fully into this hole and holds everything very securely.

Now you don’t … when pushed fully home the hive is securely attached to the scales

Using this ‘Heath Robinson’ contraption is simplicity itself.

Place the support vertical and adjacent to the hive, attach the scales to the hive floor, gently press down on the other end of the lever and lift the hive no more than 1-2 cm from the hive stand.

Wait a few seconds for the ‘beep’ from the scales, lower the hive gently onto the stand and record double the weight in your hive records.

Or for those of you who are not free spirits but wear a belt and braces with your beesuit, weigh the opposite side of the hive as well, add the weights together and write up your notes 😉

How reproducible is this?

Actually, pretty good 🙂

I did a bunch of measurements on a range of dummy hives of known weights 12.

By measuring both sides and adding the recorded weights together I determined that the underestimate of the true hive weight was about 8%. With care, the variation in weight of repeated independent measurements of one side of the hive was in the range 0.3 – 1.7%.

That’s more than close enough for me.

You do need to take care to standardise the method you use:

  • make sure the upright support is vertical
  • ensure that the pull exerted by the scales is as vertical as possible.
  • lift the hive by the same distance off the stand. The smaller the distance the more accurately you will determine the total weight 13.
  • push down on the lever gently and smoothly. Don’t jerk the hive. It takes relatively little effort to hold the hive stable for the weight to be recorded 14

All of which is pretty easy to achieve.

Remember – and this is the last time I’ll write this – these inspections are ”The bees don’t even know they’re being checked” checks 15. All of the above can be achieved in 1 minute with no disturbance to the colony if you are reasonably careful.

Then what??

Remember, the weight of the hive is not important, it’s whether they have enough stores to rear brood. However, regularly recording the weight as I describe here will allow you to judge how fast the colony is getting through the stores.

Ideally weigh the hive and heft the hive.

You will then more quickly learn to make a judgement based upon hefting along.

Will the colony be underweight – based upon the hive hardware, the weight of the bees, frames and stores – in a week or two when you next visit?

Bees can use their stores fast when they’re unable to forage and rearing brood. Studies by Tom Seeley have demonstrated colony weight reduction in ‘maintenance’ mode was perhaps 1 kg per week, but that this level increased significantly once brood rearing started in earnest.

If you consider that the colony is already too light, or will be too light before your next visit, you must add some stores.

And, at this time of the year you should use fondant, not syrup, to feed bees.

Feeding fondant

I’ve written extensively about feeding fondant to bees, both in midwinter and at the end of the summer. I only use commercial baker’s fondant, not the overpriced stuff sold to gullible wealthy beekeepers.

The priority is to add the fondant as close as possible to the cluster. You want the bees to have immediate access to it. You don’t want them to have to crawl half way across the hive, up through a hole in the crownboard and into that cold empty void under the roof.

Which bees are better able to access the fondant?

Brrrr.

I add fondant in 1 – 5 kg blocks. The amount depends upon the size of the colony, the likely time of my next visit and the probability of their being nectar readily available before then.

I always err on the side of generosity 16.

You can easily remove unused fondant …

… or you can guiltily remove pathetic handfuls of starved bees.

Your choice 🙁

Pack the fondant into clear plastic food trays 17 rescued from the recycling bin. Once filled, wrap them with a couple of layers of clingfilm, or place them in a securely sealed plastic bags. The fondant will absorb moisture from the environment, particularly if it’s warm. I just keep a pile of them in the car for my winter visits to the apiary.

Spot the blocks of fondant and the scales

Remove all the clingfilm. Bees have a horrible habit of dragging it down into the brood nest, chewing it up and incorporating it into brace comb.

I place the fondant on top of the frame bars, directly over the cluster. My crownboards are reversible and have a deep upper (i.e lower when reversed!) rim which accommodates the tray of fondant.

Fondant block under an inverted perspex crownboard

I add the insulation block back over the crownboard and replace the roof, secure in the knowledge that the colony has sufficient food for the next 2-3 weeks.

If your crownboards aren’t reversible with a deep rim make some that are use an eke or an empty super.

 

Winter wait

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Synopsis: In the winter bees are low maintenance, but they’re not no maintenance. You need to carry out a few regular winter checks to help them overwinter successfully. Here are the first two things to check … I’ll deal with the third and final check next week.

Introduction

The ‘beekeeping season’ runs from spring until autumn. Quite when it starts and stops depends upon your latitude and enthusiasm 1.

More of each have opposing effects in the spring.

More latitude and the season starts later, more enthusiasm and you might be tempted to start colony inspections (the first ‘proper’ beekeeping of the year) in early spring.

I’m certainly enthusiastic but I live in Scotland. I therefore rarely open a hive before mid/late April. In some seasons it might even be mid-May.

But that doesn’t mean that there’s nothing to do between the end of the preceding season and the start of the next.

The winter wait (for the start of the season) doesn’t meant that there’s nothing to do.

During the winter months of the year bees are really low maintenance, but they’re not no maintenance.

You need to check the hives at about monthly intervals. More frequent checks will do no harm – these are ”The bees don’t even know they’re being checked” checks – but probably aren’t necessary. These checks are important to ensure the bees overwinter successfully.

Spring is on the way … Fife snowdrops, mid-February 2022

Of course, you should also check after high winds or heavy rain (very timely as I’m writing this as Storm Eunice bears down on the south west) as an overturned hive or a badly flooded apiary aren’t conducive to colony survival.

So, what do these checks entail?

What are you actually looking for?

How can you tell much of anything from an inanimate cedar or poly box on a miserable, cold, wet February afternoon?

Essentially it comes down to three things … the state of the colony, access to the hive and weight.

What’s happening in the box?

Mid-February, it’s 5°C, there’s a squally northerly blowing intermittent sharp hail showers down from the hills. No self-respecting bee would venture out in conditions like these.

Most self-preserving beekeepers would probably prefer to be sat in front of the fire reading Gilles Fert’s Raising honeybee queens 2.

However, there’s work to be done.

What on earth can you judge about what’s happening inside the box on a day like this?

If you’re a relatively new beekeeper (and this applies to some of us who have been keeping bees for many years) you would probably like to know if there are any live bees in the box.

After all, you’ve not see a flying bee for months.

Perhaps they all froze to death in those heavy frosts over the previous week?

Don’t rap sharply on the outside of the box and listen for an answering angry buzz. Yes, it’s a way of detecting whether there’s ‘life in the old box yet’, but it’s an unnecessary disturbance for the bees.

How would you like it?

There are two relatively simply methods, one much more useful than the other.

The first is to use a clear perspex crownboard on the hive 3. It’s then a simple matter to lift the roof and observe the state of the colony.

Colony viewed through a perspex crownboard – mid-February 2022

Here’s one of my colonies from last weekend. I can tell from the size of the cluster that the colony is reasonably strong.

That’s a good start.

The bees are moving on the periphery of the cluster, so they’re alive 4.

In addition, though it’s not entirely clear from this photograph, there are at least 2-3 frames of capped stores at the opposite side of the hive to the cluster.

Condensation

One of the things missing from the picture above is any significant amount of condensation on the underside of the perspex crownboard. This is because the deep inner rim of the crownboard is usually filled with a 50 mm thick block of insulation.

Perspex crownboard with integrated insulation

This is essential unless the roof is very well insulated. Without insulation immediately above the perspex the high level of humidity within the hive will lead to large amounts of condensation on the underside of the perspex.

This condensation – or at least some of it – will then drip down onto the cluster, making it a pretty unpleasant environment for the bees.

So, by simply building a ‘window’ into the top of the hive you can determine the size of the colony, whether it’s alive and possibly judge something about the level of stores in the hive.

All of which, and more, you can achieve another (better) way … read on 😉

I quite like the perspex crownboards I use on some of my colonies. However, I consider them far from essential and can judge the state of the colony much better by ‘observing’ them from below rather than from above.

Open mesh floors

When I say ‘observing’ them from below, I don’t mean a glass bottomed hive and I don’t mean directly observing them from below 5.

If you use open mesh floors (hereafter OMFs) you can collect and inspect what falls through the floor and get a very good idea of the size, state, health and activity of the colony.

Wow 🙂

An OMF should have a white (or pale yellow) coloured plastic tray or sheet that can be slid underneath the floor to catch the debris that falls through.

Not black and definitely not Varroa-coloured 😉

White polystyrene Varroa trays really need painting as they discolour badly after a couple of seasons.

Abelo poly Varroa tray

Abelo poly Varroa tray – draughty and easily discolours. Yuck.

A well designed OMF – and there are many that are not 6 – should have a close-fitting tray so that those gusty February squalls don’t disturb the debris that falls through. The position and type of debris is important and if it has been blown about all over the place – or half-eaten by slugs or ants – then your task will be that much harder.

Or impossible.

Varroa tray – single brood box, busy colony, mid-February 2022

This is a tray from a reasonably strong colony in a single brood box. You can just about make out 10 fuzzy horizontal lines of debris. These lines are made up of stuff that’s fallen through the OMF.

You realise that ‘stuff’ is a highly technical beekeeping term that covers everything from antennae, legs, wax cappings, pollen and Varroa to a range of other unidentifiable crap 7.

Tasseography

Tasseography (or tasseomancy) appears to be an entirely made up word 8 for reading tea leaves.

Deciphering the debris on a Varroa tray is a more exact science than tasseography which – and at the risk of offending any fortune-teller-beekeeping readers – isn’t.

It’s not science and it’s not exact 9. The existence of well-reviewed books on the subject proves nothing other than the gullibility of purchasers I’m afraid 10.

So, let’s look again at the debris in the picture above.

The four rows in the centre/top are darker. These are directly below the cluster and are cappings produced (and dropped) as brood emerges. Brood capping are biscuit-coloured (think a sort of dark digestive, not a pale custard cream), presumably because of the incorporated pollen and associated pupal casings.

In addition, mixed in with these rows is some paler granular debris, and there is a lot more of this in the very obvious rows towards the bottom of the picture.

These are the wax cappings that are produced when the bees uncap stores. If you have a close look at these rows you can also see some white or off-white sugar crystals.

So, we can tell the approximate size of the brood nest, we know they’re rearing brood and that they are busy uncapping stores.

Hive health

The one thing you won’t see on that tray are any Varroa 11. That particular tray was left in situ from 17/1/22 to 13/2/22. I can therefore be reasonably confident that the colony is healthy, with low Varroa levels.

I can see a tall, handsome stranger in your future … and a lot of Varroa

This second tray is from another colony in a single brood box. They are also rearing brood but have yet to venture much beyond the cluster when uncapping stores.

However, looking closely at this tray I can see a disappointingly high Varroa drop … somewhere in the region of 30-50. Again, this tray has been under the colony for a month, so I’ll need to monitor Varroa levels carefully as they build up during the spring.

As an aside, both these colonies have an identical record of miticide treatments 12 and both are in the same apiary. My records show that the colony with the higher Varroa natural drop (i.e. not due to recent treatment, the tray was cleaned in mid-January and they were last treated in November) in winter have consistently had higher mite levels.

All other things being equal – e.g. temper, behaviour, frugality 13 – I would choose to rear queens from a colony with the low mite levels.

The colony that first Varroa tray was from are not ‘mite resistant’.

They will have Varroa.

My post-treatment mite counts showed a modest mite drop and I’m confident that the treatment will have been no more than 95% effective. However, low mites are better than loadsa mites 14 and it will be interesting to see if colonies headed by daughter queens behave similarly.

Entrances

The late summer/early autumn colony reduces in size as the year progresses and as bees die off. At some point in early spring that daily births outnumber daily deaths (Murray McGregor calls this ‘crossover day’) and the colony starts to expand again.

So what happens to all those corpses?

The bees fall down through the cluster to the hive floor. On good flying days the undertaker bees will carry these away and discard them outside the hive.

However, during protracted cold or wet periods when the bees cannot fly the corpses can end up covering the floor and eventually blocking the hive entrance.

Multi-purpose Swiss Army penknife for beekeepers (sort of)

So the second check you need to perform is to ensure that the hive entrance is clear. This might mean removing the mouseguard and gently raking out the accumulated corpses.

In the kewl floors I favour the L-shaped entrance requires a correspondingly L-shaped piece of wire (a repurposed stainless steel spoke from a bicycle wheel) to check it’s clear. The same tool works perfectly well on almost all other hive entrances as well.

Be aware that you might inadvertently disturb workers near the hive entrance … these can fly out and aggressively ‘ask’ you to move away 15.

Tunnel entrances

The only entrances this multipurpose-and-soon-to-be-patented tool 16 is unsuitable for are those on the hives in my bee shed.

Entrance duct and hive floor ...

Entrance duct and hive floor … brood box removed for clarity

These have a 6” tunnel entrance. Even with a torch it’s difficult to see whether the inner hive entrance is blocked or not.

However, since you’ve already removed the Varroa tray it’s easy to look up through the OMF and check it’s clear.

There are two ways to do this:

  1. Prostrate yourself and look though the OMF while at the same time getting a gentle dusting of the stuff raining down from the cluster, or
  2. Use the phone on your camera to take a quick photo (you’ll need to use the flash).

Nothing to see here … other than some clown photobombing the hive checkup

If you do find the floor covered in corpses and the entrances blocked – whether the hives are in a shed or outside) it’s very important to clear them before leaving the apiary.

Blocked Kewl floor

Blocked Kewl floor …

Simply separate the brood box from the floor, no need to remove the crownboard, set it gently aside. Clear the floor and the entrance and replace the brood box.

Fortunately, the floors of my hives were all reassuringly clear of corpses.

In the photo from underneath the floor you can see the bottom bars of the frames and, between them 17 the serried rows of bees on the underside of the cluster. There are a lot of bees in the box.

Winter weight

So, without disturbing the colony you now know:

  • the colony is alive
  • they are rearing brood
  • stores are being consumed
  • something of the strength of the colony (in terms of number of seams of bees present)
  • whether they have low or high Varroa levels
  • if they are free to fly when the weather becomes suitable

Not a bad result for 5 minutes work.

But there’s one more thing to check.

Do they have sufficient stores to survive until your next visit to the apiary?

Actually, not just survive, but do they have sufficient stores to continue to rear brood so that the colony expands to be strong enough to exploit the early season forage when it’s available.

And I’ll deal with that question next week as I’m already fast approaching 2500 words 18 and there’s quite a bit more to cover on hive weights and winter feeding.