Bees dying in the snow

[Mellifera Crofter]

We had some sun yesterday and today, and some bees came out and promptly died in the snow. I coaxed some back to life (after having recently killed over 30 in the freezer!) but whether they actually made it back into the hive I'm not so sure.

I know that people suggest that you should cover the entrance with a plank so that the bees don't see the bright sunshine and get lured out - but I worry that if I do that, some may still leave the hive and are then less likely to find their way back.

I have been told about a large Canadian apiary where the hives are completely covered by snow for most of the winter with no ill effect. So, if we are trying to dissuade them from leaving the hive (with a plank in front of the entrance), why don't we just stop them from leaving by turning the entrance block around (provided we have an open mesh floor) until the snow has disappeared?

[gavin]

Interesting questions again ... and I promise not to divert the conversation towards exotic cuisine (but then again, what *are* you going to do with those corpses?!).

I visited my seven yesterday (also have one in the garden) and could see only one bee out on the snow. Probably it is best to leave them well alone at the moment, as any disturbance might induce more flying. I don't usually use boards but just leave them to their own devices. Is blocking the entrance wise? I'd have thought not. Locked-in colonies often sense this (at least in summer) and quickly start chewing their way out, and you wouldn't want to increase stress. Also, there could be a reason for the flights. It is possible that the bees being lost are diseased for example.

If they are healthy bees getting confused by the snow, then the losses you see probably do not represent a significant portion of the colony. In any case, the number of bees in colonies plumments in autumn and early winter and it may be that the colony needs to lose some bees to come down to a healthy size. (I'm blethering now I suspect!)

Why not have a look at the lost bees. Are they carrying Varroa? Do their trachea show darkened areas? Are there any signs of Nosema?

best wishes

Gavin

[ian]

Today I had dead bees in the snow and had to clear the mouseguard of more,but it was only one hive the other four were fine.It has become warmer today but no sun.
Ian.

[lindsay s]

We’ve had snow here for the last week although there’s a slight thaw today, more snow is forecast for the weekend. I made a quick visit to my apiary today and yes I also found dead bees on the landing boards and in the snow. This happens most winters especially when the sun warms the front of my hives and the bees come out and get chilled by the cold air. As Gavin says we probably all lose bees in the winter but it's more obvious in the snow. One of the main reasons not to block the hive entrances is to allow the bees out for cleansing flights on mild days. The Canadian bees must have learned to keep their legs crossed until the spring. Now it looks like we’re in for a long hard winter I wish I hadn’t changed most of my hives to open mesh floors but that’s another story.

[Mellifera Crofter]

Thank you, all. I won't block my hives' entrances, but I may continue with the occasional rescue mission (even though they may just fly away again to crash-land somewhere else). I'll check for Varroa or other illnesses, Gavin.

Lindsay, I thought one of the advantages of the dark bee is their ability to keep their legs crossed for a long time while being snowed in - but do I have full-blooded dark bees ... Well, for morphology's sake, Gavin - the wings of the bees in the freezer are going to measured. Jimbo is sending me some slides. I'll let you know the results.

Nice seeing photos of your apiary, Lindsay.

Kitta

[chris]

Hi M.C. Although most people think of "sunny Provence", where I live is a mountain climate.Fifty cm. of snow is par for the winter. Last night the minimum was -12°c, rather tropical for December:cool:
So, let me assure you. Dead bees are normal, all the time. It's the snow that lets you see them right now. Also, a lot of the *nasties* that feed on the dead bees are not around to clear them up. I suggest that you just put something slanting towards the hive, across the entrance, to stop them being lured outside by a false idea of weather conditions.Those that need to get out will still be able to. The bees can manage fine in these conditions providing they have enough stores.And that we don't interfere unnecessarily.

[Mellifera Crofter]

Thanks Chris. I'll remember that the dead ones are more visible in the snow than in the summer. I imagine I can even see the dead ones in the snow in front of one of Lindsay's hives (the middle picture) - that visible.

[gavin]

How many bees are there in a colony going into winter? Let's try 7,500. Maybe more, not sure. Between October and March (inclusive) there are 180 days and you might imagine that by the end of March the population has turned over. OK, maybe November to April inclusive is more realistic for that turn-over as the spring brood raising will finish more off.

7500/180 means 42 bees will die every day on average. Or 290 per week. OK, they may die in batches or at a higher rate (in some colonies) as spring approaches, but it does give you an idea of the numbers of corpses which may need carried out (or which remove themselves voluntarily from the colony before they become corpses!) during the winter months.

That late-season burst of brood raising before winter closes in is very important as it skews the population towards survivors to raise spring brood and see the colony through into the next season with some vigour.

Maybe that helps beginners not worry so much about some corpses in the snow? Of course a sudden surge might be a cause for concern - or it might simply represent a burst of activity from the undertakers.

all the best

Gavin

[Jon]

That late-season burst of brood raising before winter closes in is very important as it skews the population towards survivors to raise spring brood and see the colony through into the next season with some vigour.


...which is why late varroa treatment or no varroa treatment at all can lead to be problems as the last batch of brood will be severely damaged and virus laden.
Lucky for some in Orkney with no varroa yet.

Dead bees in front of the hive doesn't bother me unless there are hundreds like the poisoning incident I reported in another thread.

The worst thing to see is dozens of live but crawling bees as it means you have something bad like nosema, trachael mite, deformed wing virus or other varroa vectored viral problems.

Gavin I would say 7,500 is on the small side for a full colony at this time of year. As a rule of thumb I reckon a frame densely covered with bees right out to the corners in summer has about 3000 bees on it. I have a few that size but also a few I hope are at least double that.

If the temperature ever reaches 8c again the undertakers will be working overtime.
In the summer I have watched corpses being carried dozens of yards away from the colony.
I have also noticed two bees flying with one corpse carried between them.

[Trog]

In some ways, dead bees outside the entrance can be seen as a good sign. A colony that is too weak to survive will not have the energy to do the housework, n'est-ce pas?

[gavin]

Salut Trog

Peut-être!



If the temperature ever reaches 8c again the undertakers will be working overtime.
In the summer I have watched corpses being carried dozens of yards away from the colony.
I have also noticed two bees flying with one corpse carried between them.

I'll bet that Private Frazer worked below 8C.

I'd like to see cooperative carrying by bees.

G.

[Alvearium]

There is probably an inclination for bees which are not well adapted to local weather patterns to leave the hive during the winter as you describe in sunny conditions when there is snow lying. Bees that more readily stay at home and are not enticed out can winter better. I would expect the native bee to be like this provided that all other factors are OK with the hive eg no nosema etc. Work has been done at Craibstone in the 1940s (Edward Jefree) and later by Bernhard Mobus that suggest that bees going into a winter cluster at an optimum size fare best. Also there is the question of winter water balance within the cluster according to Bernhard Mobus. If this is upset bees may fly to relieve themselves (dysentery) or to seek water (dehydration) if they cannot redress this balance themselves within the closed winter cluster. This flying at inopportune times may lead to a heavy loss of bees on snow. If you think of it there are colonies more prone to do this than others. Bernhard Mobus presented a paper to Apimondia in 1977 or thereabouts on this very subject.
Alvearium

[Mellifera Crofter]

...Also there is the question of winter water balance within the cluster according to Bernhard Mobus. If this is upset bees may fly to relieve themselves (dysentery) or to seek water (dehydration) if they cannot redress this balance themselves within the closed winter cluster. ... Alvearium
Can we do anything to ensure a good 'water balance' in a hive entering winter? Would feeding them candy or fondant (are they the same?) cause a possible water imbalance? If they only ate honey, would that be better?

[gavin]

Yes.
No (but it depends).
Maybe.
No!

Burning sugar creates moisture. They will not be doing a lot of that at this time of year (hive weight remains fairly stable) but it increases steadily from New Year when they start raising brood. If your hive is airy and well insulated then the moist air may be vented before it condenses. So there is an optimum for these things. Another factor is the absorbancy of whatever is over the frame tops. In some places with continental winters (is that us now?!) some beekeepers put in a frame feeder with water to help them when brood raising starts, but perhaps restricting ventilation is enough. If the moisture doesn't condense above the brood area it may do so on the walls.

Queen candy and fondant are different, but in some places people use the terms fondant and candy interchangeably.

Fondant has a water content which is not very different from honey. I think.

In most winters in Scotland none of this would matter, but in this kind of winter maybe it does.

cheers

Gavin

[Mellifera Crofter]

Thanks Gavin.
Kitta