This is a reply to a personal email that I thought might also interest
this list:
 
> You said in the fall, reduce supers. I have a very large colony that I
> had to put on a 3rd deep super just to contain the bees, waiting to see
> how many will still be around after one more sept honey flow. When it
> comes time to reduce them down to two deep supers for the winter how
> should I go about this.
 
You can winter in three standards too.  I guess I forgot to mention this,
since for running with excluders, a double works better -- unless you plan
to two-queen.  And my comments about space in the original post do not
apply to comb production where bees must be crowded into the sections to
get a good job.
 
Many good beekeepers winter in three boxes.  It has some advantages such as
less worrying about running out of feed in early spring or failing to give
sufficient room when required.
 
Of course, this approach  requires more equipment and the boxes and
frames that are used for wintering are exposed to weather and
deteriorating conditions moreso than boxes stacked in a good honey house.
We've used three broods for wintering, and since our wraps only are
designed for hives that are two high, the bottom boxes were exposed.  Since
the hives were pushed tight together with only inner covers, there was not
too much draft coming up under and we experienced no adverse effects.
 
Now to answer the question: by the time you need to reduce the boxes to
two, the brood rearing should be reduced to the point where it is all
taking place in one or two of the boxes -- in Alberta at least (I'm not
sure where you are).
 
When you inspect the hive, one of three conditions will be found:  all the
brood will be near the bottom with honey packed into the upper box(es), all
the brood will benear the top with empty boxes below, or -- more unlikely
if the season is over -- there will be brood in all three boxes.
 
In the first case, just remove the top brood chamber as you would a
full super and replace the lid.  In the second, remove the bottom box as
you would remove an empty super and proceed to feed heavily until the two
remaining boxes weigh 60 kg or more including lid and floor and bees.  In
the third, you will have to decide which two boxes contain most of the
brood and pollen and feed and move the brood from the least occupied box
into the others, removing the least filled frames from them to make room.
Do not shuffle the combs around any more than necessary, since the bees
have things much the way they want it for good winter survival.
 
Another option is to slip in an excluder and wait the three weeks or so
necessary for all the brood to hatch in the isolated box.
 
While mentioning excluders again, I should mention that once bees are
accustomed to working strongly in a third box, adding an excluder will
cause no impediment whatsoever to the bees -- with the exception of the
queen.  All the difficulties that inexperienced (and experienced
beekeepers) report are related to getting the bees to initially expand
through an excluder during the buildup season.  Once they have become
accustomed to occupying the real estate above an excluder they will pour
through the wires as if they were not there.
 
Bees learn that there are three boxes on a three box hive.  If you remove a
third, they attempt to go where it used to be and they will seem very
crowded until they adjust to having only two.  If you pull a third from a
hive that has never had an excluder then add an excluder and an empty box,
it will fill with bees in moments.
 
Allen