LocustHoney,
Confusing... Perhaps?
When one checks the top entrance, one feels the heat escaping, right?
Well, bees usually successfully survive winters by consuming honey and collectivly producing some heat.
All this is done by them forming a cluster in a form of elongated ball. This cluster varies in size/density according to the outside temperature. Moderate weather, cluster is in all parts of the box. Colder it gets, smaller/denser the cluster becomes. Roughly speaking. . . .
The center of the cluster will be around 85 to 92 degrees - (upper limit of 92 to 95 is reached, when there is some brood - many people mistakenly assume that the whole hive is at that temp? IT IS NOT!)
This heat escapes slowly from the top of cluster and accumulates under the inner cover. There we now have all the vapour from burned food and heat. Also gases from bee-breath. Also "outgassing" from various man-made parts of the hive accumulate there.
When this vapour gets in contact with cold surface it there condenses and forms watter droplets. If we have no upper entrance, this than either freezes and forms ice - this process is than even faster forming - or it escapes out through the upper entrance - if luckily we have one.
When weather outside gets a bit warmer, this "inside" ice begins to melt and usually drips on the bees.
This is what kills your bees!
They can not handle water/moisture on themselves! Such wet bees are lost, cause, no amount of eaten honey/burned energy can produce enough heat to dry/save those bees!
(They are cold-blooded and need sun/heat!)
(That is why we were told, or we read somewhere, that when preparing for winter - we should place under the back of the hive, a wedge, a piece of wood, to tilt the hive forward. This will hopefully cause this water to flow to the front and out!? Or perhaps, down the front wall and out the bottom entrance?)
If one measures the temperature of the interior of hive, one inch away from the cluster, on the sides, any side - this temperature will be, most often, almost that of the outside temperature.
Logically, at the bottom, under the cluster, the temperature will be often that of the bottom super - therefore it will be the coldest and often colder than that of the outside air. . . .
In such conditions, the outer layer of bee-cluster will in such very low temperature - freeze !
( When outside weather has a warming trend - hive inside is colder than outside! Wrap, insulation, slows considerably the infiltration of outside coldness - in warming trend this is of course - reversed!)
Bees in the cluster share in their duty/guard to the outside. They rotate! So that those bees too, have a chance to warm up and eat. If temperature outside don't let up, over two to tree day period, or the sun don't shine, such outside layer of clustering bees will die from starvation - NOT FROM COLD!
I should here mention, that bees can bring up the temperature of their surrounding space (in the hive) by about 13 degrees, maximum!
It is good to keep this in mind....
So, when the temperature outside is in the thirties - in the hive is in the forties and bees have probably a patch of brood going and can even fly....
The colder the hive space gets, the tighter the cluster. At certain point in time, this 13 degrees is no longer detected and/or even possible to achieve, much less to maintain.
So, in my hive - when the outside is minus 30, or -40, or even -50, this cluster is almost "rock hard," so to speak and bees are in overdrive creating barely enough heat and burning a lot of honey, just to keep as many a bee they can - from freezing. . . . on such a day a strong buzzing/grinding sound is heard with a free-ear, even by an old man such as I! No need for stethoscopes and such.
(A simple plastic tube can be slowly inserted in the hive through the entrance and other end stuck in the ear - if one is really that eager to her them buzzing?)
So, the cluster could be encompassing the whole upper box when temperature is right for them to do so. In such a loose cluster occasional interference has no ill affect on the bees.
But, when the hive is in the freeze and the cluster is tight and working in overdrive - ANY DISTURBANCE WILL KILL THEM!
This could be as innocent as a small bird picking up a few dead bees from the front - for a snack? Or a mouse scurrying about and looking for a way to get in. . . ?
The balance between life and death of bees in extreme cold is very delicate and most often it's something totally insignificant to us, that can tilt the scale against them.
author=LocustHoney link=topic=12779.msg88300#msg88300 date=1200763030]
I am a little confused....Trot said.....One has to remember that bees DO NOT HEAT THE HIVE!!! ------Opening hives is usually detrimental to bees in cold climates. (one lets out all the heat from the cluster and if cold nights follow, the bees are goners!)......maybe I am just not understanding your explanation.
The above misunderstood portion has actually more factors involved than just: (one lets out all the heat from the cluster and if cold nights follow, the bees are goners!)
Most are already laid out above. . . .
Surely, I will also miss some. . . . Cause, most knowledge about bees is after 53 years a part of me and is almost embarrassing to be bringing it out to light. It is for me natural like breathing and I for one seldom think about it. It only becomes sort of bothersome when I read/hear about beeks get their bees in trouble - over it. Guess I was not a born-educator/teacher? Sorry for wandering off. . . .
When this occurs, opening of the hive, the rhythm of the cluster is disturbed. They do have a rhythm, if you will? A sort of deep concentration, a collective effort is here gathered and at work. Perhaps a bit awkward explanation, on my part? But this is how I can best put it together?
As previously said: The rhythm is disturbed, the cluster loosens and the heat producing efforts are severed!
The bees do, most often - than not, break cluster and investigate. They are most often, extremely annoyed and will attack/defend their home!
Heat thus escapes and the cluster is at the mercy of deadly infiltration of surrounding (cold) air.
Any brood, that they might or might not have, is in danger of becoming chilled.
If all intrusion is immediately ceased and hive is without any further disturbance - (disturbance: Knocks, scraping, dropping equipment, jolts and jars, etc. . . .) closed, they might have a chance - but I would not bet on it!?
If the weather is in the minus - freezing - bees are already lost! (Even though they are moving about and make your inquisitive heart jump with joy!)
In warmer regions/weather - they MAY get back together and "reform" the cluster. And generate this all important heat, without which the cluster is doomed!
Scientific studies have shown that it takes disturbed cluster a minimum of 3 days to recuperate, reestablish it's rhythm and again starts producing heat to sustain itself.
This same study has also concluded that the upper entrance is ever more important than we gave it credit for.
They concluded that those bees with upper entrance have ready exit to do their thing - if nothing more than just take a look at the sky above?
Those bees without the upper entrance? God help them....
They have no chance to get outside at all! To climb all the way down through cold, often wet and mildewy lower chamber, is all but impossible, if not deadly!
Such bees, if by some miracle survive, will suffer heavyly by dysentery, nosema and myriad of other ills. . . . .
(I feel the need to mention that this study did not involve opening the hive! Just simple disturbance - like knocking, etc. . . .)
Now, for those of you who do not agree?
The above is true for locations where bees, or yards, are isolated from everyday life.
Bees in close relations/locations are a bit differently predisposition-ed to disturbances. Although they can perhaps tolerate walking about? Tolerate cars, animals about, etc....
Some time ago I was in contact with one beekeeper in Europe who did not agree to something similar that I wrote in one of their beekeeping magazines a while back. In times when we did not have Varroa, or TM and such.
That man bragged about how he had been keeping a bee-house some 100 meters from the railroad tracks and bees were doing fine!?
Sure.
He got down right nasty, cause I did not give him an satisfactory answer. So, at the end I did suggest that he move in, to that location, a few hives from a quieter location.
He did and he got his answer.
All newly brought in hives were lost - come Spring. . . .