Tag Archives: climate

Convenience or laziness?

It’s cold and dark and all is quiet in the apiary. Hives appear somnolent. Colonies are clustered 1 and, other than the odd corpse or two on the landing board, I’ve not seen a bee for at least a fortnight.

The apiary in winter ...

The apiary in winter …

Based upon previous experience I suspect colonies are – or very soon will be – broodless. I usually reckon that the first extended (2-3 weeks) period of cold weather 2 in the winter is the most likely time for the colony to be broodless.

In 2016/17 this was the first week in December.

In 2017/18 it was just a day or two later.

In both instances, when the hives were checked, they had no brood.

What’s all this about being broodless?

If a colony is broodless there are no capped cells in which the Varroa mite can ‘hide’. As a consequence it’s an ideal time to apply a miticide like a trickled solution of Api-Bioxal 3.

There are very good reasons why a midwinter OA treatment is necessary, particularly if you treated early enough in the autumn to protect the overwintering workers from the ravages of Deformed Wing Virus (DWV). High DWV levels reduce the lifespan of bees and contribute to many (possibly most) winter colony losses. I’ve even suggested here that “isolation starvation” might actually be due to Varroa-transmitted viral disease.

Time of treatment and mite numbers

Time of treatment and mite numbers

Early autumn treatment protects the winter bees but also leaves the long autumn for the residual mites to continue replicating.

And there will be residual mites. No treatment is 100% effective.

So, paradoxically, if you treated early enough in the autumn to really help protect the winter bees, your mite levels will be higher at the end of the year.

Which also means they’ll be higher at the beginning of next year.

Not a good start to the 2019 season 🙁

Convenience or laziness?

Many beekeepers, for convenience, laziness or historical precedent, choose to apply the winter OA treatment between Christmas and New Year. I suspect that this is often too late. If the queen starts laying again around the winter solstice there will be sealed brood – and therefore unreachable Varroa – by the end of the month.

I’d prefer to have a cold and damp afternoon in the apiary slaughtering Varroa now than the convenience of treating them less effectively during the Christmas holiday period.

The latter might be more convenient … the office will be closed, I’ll be replete with turkey and sprouts and it will be a good excuse to ‘escape’ visiting relatives and yet more mince pies 4.

But is it the best time for your bees?

We have the technology

We have a couple of hives with Arnia hive monitors fitted 5. These have a temperature probe inserted into the brood nest. Brood rearing temperature is around 34°C. Here is a trace of one colony over the last month.

Arnia hive monitor temperature

Arnia hive monitor temperature

The colony temperature was pretty stable (around 33-35°C) until about the 19th of November and has dropped about 10°C since then. Although I’ve not opened the colony I think that this is additional evidence that the colony is broodless 6.

Beekeeping by numbers

Keeping bees properly involves being aware of the seasons, the available forage and the state of the colony. This varies from month to month and year to year 7.

You can’t mechanically (‘by the numbers’) add supers on the 5th of May and harvest honey on the 15th of June. Sure, it might work some years, but is it the best time to do it?

Similarly, you can’t optimally treat a colony for Varroa on the 30th of December unless the climatic conditions and state of the colony coincide to make that the best time to treat.

It might be, but I suspect that generally it’s a bit late if there is a brood break.

If you’re going to the trouble of preparing the OA treatment, donning the beesuit and disturbing the colony you might as well do it at the right time for the bees.

I’ll be treating in between the predicted sleet showers and sunny periods this weekend.

Time to treat

Time to treat

Isn’t evolution a wonderful thing? This post started with a working title of Know your enemy” and was on a different topic altogether. I’ll save that for next week.


STOP PRESS

The above was written at the beginning of the week. Now the weekend is closer it’s clear the weather is going to be cold with heavy snow predicted. Unless the forecast is wrong (and how often does that happen?!) I’ll hold off treating until a) it’s over 5°C, and b) the roads are safe.

Waving not drowning

Marooned ...

Marooned …

It’s been a miserable wet winter in Fife … but the days are now noticeably longer (and drier), though I’m still usually driving to and from the office with headlights and wipers on. However, finally there are signs that spring is on the way. I heard my first skylark yesterday and there are drifts of snowdrops in the hedgerows …

Snowdrops

Snowdrops

Having moved here last summer with the expectation that the east coast would be dry but cold (remember, these things are all relative) the winter has delivered almost the complete opposite. It’s been spectacularly damp. Not only here in Fife of course. Most of the northern half of the UK has enjoyed some terrible weather, with significant levels of flooding in major cities like York. For the last three months the rain has been ~200% of the 30 year average:

The graphs above (from the excellent Met Office website) are the rainfall anomaly from the 1981-2010 average, with the darkest blue indicating at least 200% of the average. In contrast, the temperature has been at or above the average, with December being very much warmer (more than 2.5°C above the average, which is 2-4°C).

It’s not clear to me whether warm and wet winters benefit either bees or beekeepers. In inclement weather the bees can’t get out to forage – not that there’s much for them to forage on – and the warm temperatures prevent them from clustering tightly. They probably get through their stores more quickly and may continue to raise brood – inevitably this makes midwinter Varroa treatments by trickling or sublimation less effective. On the other hand, there are probably fewer losses of weaker colonies through isolation starvation when it’s too cold for them to move across the frames to the sealed stores.

However, my preference would always be for short and cold winters. It might sound heartless but I’d prefer weak colonies didn’t survive the winter as they are usually slow starting in the spring and remain unproductive – if they survive at all – through the year. Far better is to realistically assess all colonies in the autumn and unite weak ones with strong ones, boosting the latter and increasing their chances of overwintering successfully. There is no point in uniting weak colonies with other weak colonies, unless you’re stuffing three into one (and the ‘one’ is a strong colony). It shouldn’t be necessary to say it – but I will anyway – if a colony is weak because of overt disease it should not be used to ‘boost’ a strong colony … it’ll do nothing of the sort.

Colonies that went into the winter apparently strong, but dwindle rapidly and get significantly weaker may well have dangerously high levels of pathogenic viruses such as deformed wing virus. This might occur if Varroa control was left too late in the season.

Winter cluster ...

Winter cluster …

Anyway, enough discussing stuff that should have been sorted out months ago … the weather is belatedly showing signs of winter, with temperatures below freezing for several nights in a row, a bit of snow here and there, interspersed with some cold, clear days. I’ve not seen a bee venturing out on a cleansing flight for days and the colonies visible under the perspex crownboards are tightly clustered. Nevertheless, there are some very obvious signs of spring, with daffodils, snowdrops and celandines flowering, the leaves unfurling on the hawthorn bushes and the willow buds just about breaking.

I realise that this is mostly another ‘not beekeeping‘ post, but I thought something slightly easier than the graphs and chemistry of Varroa treatments might be welcome. With the season proper fast approaching, now is the time to make plans and to ensure everything is ready for those early season hive inspections.

Yet more snowdrops ...

Yet more snowdrops …


The title of this post is a play on the title of a poem by Stevie SmithNot waving but drowning, in which she describes the thrashing of a drowning man being mistaken for waving. It might not have been wet enough this winter to drown, but it sometimes felt like it …