I do beleive there is plenty of confusion in the northern areas on the cause of high winter losses. 

IMO its hard for some beekeepers to do an autopsy without being biased when constantly 
bombarded by the hype and massive misinformation being spewed daily by the media on the 
"deathly silence of the spring of 2007."

Here is a report from Ontario which may explain some of the losses in north eastern Canada and 
the USA. 

What Happened to the Honey Bees in Ontario During the Winter of
2006-2007 in Ontario?

By 

Doug McRory

Provincial Apiarist

 

Let us consider a short biology lesson on honey bees on how the
population of a colony develops during the season.  In spring a colony
normally comes out of winter with about 15,000 honey bees. These bees
need to be quickly replaced with young workers and that occurs if there
is a good influx of pollen and nectar into the colony in early spring.
If this does not happen we have what is termed "spring dwindling". The
colony population normally builds up to about 60,000 bees in the summer.
The last week of August through to the third week of September, if the
colony has access to adequate pollen and honey resources it will develop
a flush of brood that will give it about 15,000 - 20,000 physiologically
young bees to form the winter cluster. This is the most critical segment
of the yearly population for the survival of the colony through the
winter.  Honey bees naturally die off at 2% of the population per day
during the active season.  In about 50 days all of the old bees will die
out of the fall population leaving a cluster of young bees that have
neither raised brood nor burned themselves out collecting pollen or
honey.  This cluster does not normally raise much brood during October,
November and December when they let the temperature of the cluster drop
down to 70 degrees F. These bees are much longer lived than the bees of
summer.  About January 15 the bees respond to the lengenthing day length
and if they have pollen and honey available from that stored in the
brood chambers, the bees raise the temperature to raise brood and they
normally replace the bees that were produced in the fall by the end of
March. Thus the cycle of the colony can carry on into the next season.

 

 In Haldimand-Norfolk and Niagara Regions the weather in August and
September was wet and cool.  The plants remained in a vegetative state.
They did not produce nectar and pollen and the bees were not stimulated
to produce the fall flush of brood.  We had "fall dwindling" as the old
bees died off.  It was warm enough that old adult bees could fly out and
die away from the colonies, as it stayed warm right across Ontario until
mid January. Bees normally leave the colony to die if it is at all
possible.  Normally in October and December the bees die in the colonies
as the temperatures do not allow them to leave.  Beekeepers in the area
south of a line from St.Thomas to Hamilton lost on average 70% of their
colonies. Three beekeepers lost close to 100% of their colonies.  

There were beekeepers with bees inside the area and also outside that
area and their losses were signifantly less outside the affected area.
Everyone lost their bees in that area and they all had different mite
management regimes, genetics and management. There were many colonies
with no adult bees left in them with lots of feed in the combs.  There
were no significant amounts of brood as the combs were dry. Beekeepers
with all of the publicity about Colony Collapse Disorder (CCD) in United
States jumped to the conclusion that they had CCD.  After much
discussion with many of them they do not feel that their colonies were
alright one week and then two weeks later all of the adult bees had
disappeared leaving three to four frames of brood with a queen such as
is described with CCD in the United States.  CCD hits when bees are in
their active brood rearing stage. Beekeepers in Ontario are reusing the
dead equipment and they are not seeing reoccurring losses like
beekeepers in United States where it is recommended to not reuse the
equipment.  Ontario beekeepers are convinced that the two winter loss
scenarios explained in this article represent what has happened in
Ontario this past winter.

 

 I am aware of only one beekeeper in the region that lost so many
colonies that recognized that the bees were not getting anything in
August and pulled off his supers the last week of August and treated and
fed his bees early with both pollen subitute and sugar syrup. He had
bees to sell to those beekeepers around him that lost this spring. 

 

A complicating factor in Haldimand-Norfolk and Niagara was that the
Varroa mites were building up quickly last fall.  Samples from
beekeepers who had mite scouting done by the Tech-Transfer Team were
made aware of this and began treatments.  Most beekeepers saw all of the
great plant growth and waited to take off the honey supers and did not
start treatment until later in September. Most beekeepers in the region
felt that the bees did not look right even in August. Some beekeepers in
the region do not know their resistance status to the various treatments
and were undoubtly using very ineffective treatments.   Virus built up
in the bees due to the Varroa levels and the fall clusters were
noticeably smaller than normal. Because these colonies had no young bees
coming into the population they simply dwindled away in late fall.  One
beekeeper at the Simcoe beekeepers meeting told me that he had all of
his dead hives cleaned up and stored before Christmas of 2006.

 

In the rest of Ontario, another coincidence happened that is very hard
to defend against in early 2007.  The weather across Ontario was very
mild until about January 15, 2007 which encouraged early brood rearing.
The weather turned extremely cold for a period of over six weeks.  The
bees normally start to rear brood in January and it is usually the best
colonies that have a supply of pollen and feed that get the most brood
going.  The bees once they get brood started will not leave it in cold
weather but will pull into a very tight cluster on the brood to keep it
warm and they loose contact with the feed.  Honey or feed is the honey
bees' source of energy to produce heat. They starve to death with lots
of feed very close to the cluster.  Occasionally bees are found in
little clusters throughout the colony on the feed as they have warmed up
enough to venture out to get feed from the outside combs and then the
temperature dropped again and caught the groups of bees out from the
cluster.  Bees can move up onto feed if it is cold but cannot move
sideways to get to feed.  The beekeepers that feed at least 60 pounds
plus of sugar syrup in the fall, along with whatever the bees have in
their brood nests in the fall had the advantage over those who feed
less.   The extra feed in the combs directly above the brood nest really
paid off in this type of winter.  Those that normally feed heavy have
not lost significant numbers of colonies. Winter wrapping also helped as
it would offset the quick changes in the cold conditions.  This was the
one winter in 20 when the beekeeper had to do all of the good management
things that in many years do not make a significant difference but every
so often make all of the difference. 

 

The average loss for the province is about 37%.  Loses last year
averaged 11% and for several years before that were 18%.  The mites are
having a pronounced effect.  Before mites if the average was over 10% it
was a bad season.

 

Those beekeepers with no bees in their equipment need to get bees back
in it to protect it from wax moth damage!  Ontario beekeepers have been
very helpful to the beekeepers that have lost their colonies.  The bees
needed for spring pollination are currently in the orchards. Other
beekeepers still have bees available to help if necessary.

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