Please be wary of categorical and oversimplified statements about
wintering, even if they sound convincing in theory or are  vastly
popular.

Wintering is a complex topic that is very interrelated with
other management practices and requirements are strongly dependant on
locale.  Wintering and spring issues have been covered in depth in the
past on BEE-L and from many perspectives. Members in search of a wider
range of ideas are advised to dig a little at
http://www.internode.net/HoneyBee/BEE-L/ and to consult web sites (1) and
texts.

Although BEE-L can provide some ideas and understanding,
the only way to be sure what will actually work in any given region is to
meet neighbouring beekeepers and analyse their successes -- and failures.

Remember that speculation, dogma, fads and partial truths
tend to dominate discussion lists.  This is part of the development and
discussion of ideas, but while such development is underway, a lot of
half baked ideas get chewed over.   Wintering is a practical, rather than
theoretical process, and although theory can give some guidance to
practice, empirical success is much more meaningful than all the
calculating and theorizing in the world.

Also, it pays to keep in mind that repetition of a statement does not
make it more true, any more than capitalizing it does.  Often the truth
is repeated less frequently than popular simplifications because the
truth is often complex and not easily reduced to simple saws.  It
takes a lot more effort to state truths rigorously than to generalize
and sloganize.

For this and other reasons (2) those who really know the
answers often can't be bothered to get involved in discussion, and
although they may make occasional attempts to set things straight, are
normally content to just ignore untruths, half truths and out right
fantasy.  If experts do bother to read the list, they often do so just to
keep a finger on the pulse, for companionship, or for entertainment.
There are, thankfully, exceptions on this list, but 9 times out of 10,
experts just lurk and let others speculate and pontificate. (2)
Therefore be sure to research the archives.  Some gems exist.

On the matter of wintering:

The simple truth is that, even with all the research that has been done
to date, we humans know very little about bees.  Our understanding is at
a very gross and macro level.  A wise reader should doubt the
pronouncements of anyone who declares, without reservation or respect for
opposing views, that any specific thing is always so in regard to bees.

In particular, I would like to say here -- once again -- that there can
be absolutely no doubt in the mind of anyone who has much experience
wintering bees outdoors on locations in Western Canada that wrapping in
some form is normally essential to reliable success.   Enough people have
been taken in by naive pronouncements of southern 'experts'  -- and lost
most or all of their hives -- to prove this point conclusively.  Over and
over.   Moreover, good things have been said about insulation used wisely,
even in what many of us consider to be the south.

As for whether bees are killed by cold, take a handful of bees and put
them in the freezer for a while and see if they are dead.  Then
reconsider what has been said here recently.  Moreover, beekeepers know
that nucs and small hives are vulnerable to chilling of brood, serious
set back, and even total loss due to even brief exposure to cold weather.
There is definitely a colony size below which cold is deadly.  Small
hives do nicely, though, if protected from the cold.

Larger colonies are better able to withstand (manage) cold, but all
beekeepers know that colonies do best in sheltered locations compared to
windy places or low spots where frost collects.   Beekeepers know
sudden temperature drops often result in bees being isolated from the
cluster and perishing to the detriment of the colony, or in clusters
becoming divided and perishing.  Cold is a stress that
consumes the bees resources, both individually and collectively and
reduces their ability to deal with other stresses.  Cold kills.  It is
just not as quick, certain or obvious as the result of a sudden
drenching, starving or suffocation.

Do bees heat the interior of their hives?   Recent posts say 'no', with
no reservation expressed.  Well, this has been covered thoroughly in the
past. I'll recap a bit here.  Again.

Bees do heat the hive interior, but not necessarily as
the result of a deliberate attempt to do so.  A cluster of bees releases
heat.  Some say it is equivalent to the heat given off by an average
chicken.  The interior of a tighter, smaller hive will naturally warm up
faster than a larger draftier hive as a result of the cluster's
cumulative body heat, due to lower comparative heat loss.

At some point, the
bees will break cluster and hive metabolism will drastically increase as
result of this activity, resulting in further warming.  This results in
better access to food, possibly more brood rearing, foraging, etc. .   In a
larger, draftier hive, a similar cluster may
never break in similar weather.  This can be good or it can be bad, but
it is true.  This knowledge helps us manage splits and nucs -- as well as
designing our wintering system.

Studies have shown that steady temperatures around the freezing mark with
controlled humidity and good air circulation are the best for successful
and economical wintering of bees.  Any method that can assist in
moderating temperature swings and in managing cluster heat without
eliminating the ability of bees to exit the hive when appropriate -- and
without upsetting the moisture balance -- is bound to be beneficial.
Hives wraps are used to this purpose in some management systems.
Styrofoam hives apparently can be much warmer than wood hives and most
who have used them have raved about how well the bees do. (1)

Can you have too much ventilation?  Of course you can.  If a lid blows
off a hive here in winter or spring -- even if there is no precipitation
during that time -- it is pretty well a goner or, at minimum, badly
damaged unless the lid is replaced within days.

As for moisture being the killer, well, too much of anything can be bad,
whether it be heat, air flow, food -- whatever...  Studies show that bees
regulate the humidity inside the cluster within narrow limits if they are
able.  Moisture is an
essential supply for bees.  Like us, bees are made up principally of
water and need to maintain the balance in their bodies within fairly close
limits.  They need liquid water and they need some humidity.  Without the
correct amounts of vapour and liquid, winter or summer, they suffer, are
weakened and ultimately may die.  In Western Canada, bees starve in
winter when on granulated stores, if they cannot find enough moisture to
liquefy them.  In extreme dry cold, on windy days excessive air flow air
may suck the moisture from the hive and the individual bees in the
cluster.

Under such a scenario, any water
from respiration that is not expelled by ventilation is immediately
unavailable as it turns to ice on contact with cold surfaces and the bees
may be in a dehydrated condition and lose any open brood.  The challenge
reverses a few days later when there may be excess moisture in the same
hive as conditions change and ice melts.

While the bees are in free air at the beginning of winter before they eat
their way up through the hive, and wrapping is less essential, wrapping,
particularly the insulation at the top of a hive, allows the top board
and frames to be warmed by contact with the bees once they eat their way
to the top.  This allows the bees to spread out and to also to collect
condensed water just outside the cluster as they begin brood rearing.
Bees need water to raise brood. (3)

Make no mistake.  Air, water, and heat are all essential factors that
must be *managed*, winter and summer, spring and fall, for bees to be
successful. Bees can manage these things quite well by themselves under
most conditions, and, indeed, their ability to mitigate conditions and to
thrive under a wide range of environmental conditions makes it difficult
to assess exactly what the limits of their abilities are and what optimal
parameters might be.  The goal of any successful wintering system is to
ensure that the bees are housed in conditions that cause the least stress
possible on the bees and the colony, by requiring little effort on their
part to maintain acceptable airflow, moisture and temperature levels.

No matter whether the bees are indoors or outdoor, wrapped or not,
strongly ventilated or relatively closed, the goal is to ensure each bee
maintains maximum lifespan and health so that the colony will be ready
for spring.   Adjusting hive volume, wrapping hives, and adjusting
ventilation are some of the techniques that an observant and
understanding beekeeper can use to help the bees survive and thrive.

Spring brings on its own environmental challenges...

allen
http://www.internode.net/HoneyBee/

(1) Some web sites
http://www.hunajainensam.fi/english/bees.html#a6-c
http://reineschapleau.wd1.net/articles/hivernage.fr.html
http://entomology.unl.edu/beekpg/tidings/btid2001/btdapr01.htm
http://www.internode.net/HoneyBee/Spring/unwrap.htm
http://www.ncf.carleton.ca/Apiculture/Wintering.htm

(2) A few reasons why experts lurk and don't correct obvious lies and
half truths

There are too many lies and half truths: they never end
Experts are experts because they use their time wisely
Experts are usually pretty busy
Experts have valuable reputations and often get attacked  and abused if
they reveal themselves
Experts are often in sensitive positions and if they casually express
personal opinions may find complaints are made to their employers and
find they are subject to discipline for public conjecture
There are more reasons...

(3) Henry Pirker published a paper some time back entitled "Steering
Factor Humidity" that showed how he could control brood rearing in
wintered colonies at will by adjusting humidity.

http://www.internode.net/HoneyBee/Diary/