After the disastrous 2013-2014 winter with its -20F
temperatures I resolved to do better in the 2014-2015 winter season. While performing the clean up of the many
2013-2014 deadouts I tried to isolate the root cause for each hive failure,
whether it be starvation, moisture issues, mites, or air leaks. The vast majority were simple cases of
starvation; insufficient food stores to carry the hive through the nectar
drought that lasts the 7 months from late September until mid April. In the
summer of 2013 I had started a number of new hives in late June. These hives were especially hard hit, because
of the simple reason they did not get to store honey during the June honey
flow. In this area the honey flow is
primarily in the June through mid July time frame. I saw no cases of mite infestation or
moisture issues. In all my hives I have
a one inch diameter air exchange hole on the downwind side of the upper brood
chamber.
To address the starvation situation I decided on two
actions. On newly started hives I put
them on a 1:1 syrup supplemental feeding at the beginning of August. Then after the late August honey harvest I
put almost all other hives on a 2:1 syrup supplement to ensure they had the
chance to fill the brood areas with winter stores. Sugar was running about $20 per 50 lb
bag. I figured it was better to feed
each hive 25 lb of sugar ($10 worth) than having to buy a $85 package. Little did I know package prices would increase
to about $100 this spring. Nine hives received
no supplemental feeding as a control or comparison point.
There was also the question of hive wrapping. Previously I had never wrapped any of my
hives. Many club members are proponents
of hive wrapping. Articles in American
Bee Journal and Bee Culture are evenly split between proponents and
detractors. At the last minute I decided
to wrap 50% of my hives with BeeCozies.
The Bee Cozy is an easy to install insulation blanket/wind break.
In September I culled three (3) weak hives and combined the
bees and brood with other hives. I had
not done this the previous year. I was
left with 30 hives. Almost immediately
one of the weaker hives was robbed out.
Down to 29. I then did a quick
and dirty analysis of each hive; grading them based on the number of frames
covered in bees. I classed the 29 as:
Strong-2
Normal-20
Weak-8
Six hives were sheltered in an unheated building. I wrapped 12 hives with Bee Cozies in
November when flying had declined to a minimum.
All hives are in somewhat sheltered areas; either trees to the north or
inside the building.
Four (4) of the hives were topbar hives and twentyfive (25)
Langstroth hives. Of the Langstroth
sixteen (16) had 2 brood chambers and 9 had 3 brood chambers.
All hives were treated with formic acid (MAQS). Italian and Carniolan hives were given a full
dose. I applied a half dose to Russian
based hives as a precaution based on the recommendation of two Russian queen
suppliers. I did not analyze any of the
hives for the presence of mites prior to the treatment. Mites tend to be a bigger factor in the
second year of a hive; not the first. This would be the first winter for 28 of the
hives.
As a final precaution, in December I provided each hive with
“emergency” rations; either in the form of 2 pound sugar patties laid across
the upper chamber frames or a sugar board with about 10 pounds of solid
sugar.
Beginning in January I started monitoring the hives using a
stethoscope. This was done on the 1st
and 15th of the month.
Sometimes do to curiosity I did extra monitoring; such as after a -10F
night. By placing the stethoscope over
the air vent in the upper brood chamber you can easily hear either a comforting
buzz or dead silence.
The winter of 2014-2015 was gentle on the bees. The coldest temperature was only -14F instead
of -20F. Also the extreme cold spells
were shorter; usually only a few days in length versus a week or more in length
in 2013-2014. We also had a January
thaw allowing the bees to take voiding flights.
RESULTS
To date my winter survival has been an encouraging 86% (25
out of 29) versus a dismal 35% survival last year at this time. There is still another month to go before
being out of the woods. Also, I have not
yet verified the queens have survived.
Three of the four lost hives had been classed as weak during
the fall inspection. I should consider
tightening my criteria for culling weak hives in the fall. I made the classic error of hoping for the
best. I should have combined two of
these into one hive with sufficient winter stores and population. It’s probably better to sacrifice one queen
than lose 20,000 worker bees.
One of the four lost hives was due to beekeeper error. I placed the sugar board above the inner
cover by mistake essentially blocking the bee’s access to the sugar.
The fourth lost hive had appeared normal during fall
inspection. It had been a good honey
producer, but had failed to store much honey in the brood chambers. I did not detect this during my quick
inspection. Based on its honey
production I had decided to skip its fall feeding. Interestingly, many of the unfilled frames in
the brood chambers were plastic based.
I saw no mites on the bottom boards of the four lost
hives. Do I credit this to the use of
formic acid (MAQS) or the fact that these were first year hives? Mites tend to reach toxic levels in the
second year.
Again this year I saw no “moisture” related failures. Therefore, I believe my system of an open one
(1) inch diameter hole in the upper brood box and leaving the small (one inch
wide) hole of the entrance reducer provides adequate ventilation to prevent
moisture problems.
All hive losses occurred immediately following one of the
-10F nights.
Other observations:
A)
Based on fall hive strength: 100% of the strong hives survived, 95% of the
normal hives, survived, and 4 of 8 weak hives survived.
B)
100% of the top bar hives survived, 89% of the 3
brood chamber hives survived, and 81% of the 2 brood chamber hives survived.
C)
By hive origin type: Carryover from 2013-100% survived; April/May packages-92% survived; June or
later startups/requeens-78% survived; Swarm-100% survived
D)
By queen type: Carniolan-100% survived.
Italian-89% survived. Russian-77%
survived*
*All Russian losses were due to beekeeper
error or related to low population due to late September requeening of a
queenless Carniolan hive
E) Wrapped hives-Three
of the four lost hives had been wrapped.
However, other factors were probably the reason for these hive
failures. Conversely, hive survival of
unwrapped hives did not seem to suffer.
In my small test I would say the wrapping did little, if anything, to
improve hive survival. I will monitor
this again next winter.
F) Unfed hives-8 of 9 hives that did not receive the fall
2:1 feeding survived. This shows the
bees do have the capability of surviving without supplemental feeding if they
go into winter strong enough.
G) The bees in every hive accessed the “emergency” sugar
provided above the frames with the exception of the top bar hives. In the top bar hive the bees congregate at
the top of the comb, but the sugar patty is on the floor.
THOUGHTS
1)
As a beekeeper I feel I did everything I could
to help my bees survive the winter.
2)
Fall feeding should be done on June or later
start up hives.
3)
The price of fall feeding is good
insurance. Whether fall feeding or
spring honey harvesting is a better beekeeping approach can be settled another
day.
4)
I continue to lean in the direction that hive
wrapping is of little benefit other than making the beekeeper feel he is doing
everything possible to help survival.
5)
I didn’t see any disadvantage in overwintering
by top bar hives other than it is harder to provide the bees with “emergency”
feeding.
6)
I don’t know how much of the greater hive
survival was due to the more benign weather or my added precautions.
I will continue tracking my hives through next winter to try
to learn more.
1 comment:
Good stuff Fred. Thanks for sharing your data. And I especially appreciate your notes on bloom times. I plan to start doing that.
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