WINTERING HONEY BEES

by George Brezina, West Québec, Canada

OBJECTIVES:

Survival

Spring development

Cost and labour

EVALUATION OF WINTERING METHODS:

Average winter loss (include queenless & weak colonies to be united):

0 to 5% very good

10% expected (Québec)

Wintering cannot be taken out of context of year round management
Wintering method must have the capacity to withstand extreme weather conditions in exceptional years

WINTER CLUSTER = ball of bees keeping in the heat

outer layers - insulation (temp. above 10 ⁰C / ⁰F)

inner cluster - heat production (by shivering flight muscles; energy of 20 40W light bulb; temp. 20-36⁰C / 68-96⁰F)

Open cluster will form at outside temp. 5-10⁰C / 4O-5O⁰F; it will close from the top and tighten with dropping temperatures.

Input: honey and oxygen

Output: heat, water, and carbon dioxide

CLUSTER SIZE

large: smaller surface relative to volume (favorable to withstand extreme weather conditions) – colony may eat all the stores and die of starvation

small: may not be able to generate the heat to move to the stores – colony may die of starvation with honey left

Weaker colony - sometimes better chances to survive long winter but less likely to produce honey - do not winter it.

NUC - winter on top of another colony

CLEANSING FLIGHT

late winter, sunny days
ashes or shavings may be spread on snow to reduce losses

With no disturbance and cool temperatures bees may go over 5 months without flight.

If fecal material in rectum reaches about 1/2 weight of the bee - it will defecate inside the hive.

STORES

quantity - determined by strength of the colony, location, wintering method
- count min. 18kg / 4Olbs of sugar per hive or leave more honey and feed less

quality - indigestible matter will cause dysentery
- feed only proven mixtures e.g.
white sugar : water = 2 : 1 (or 3 : 2) by weight
(1/2l of vinegar per 10 kg of sugar against nosema)

timing - feed early (start by September 10)
- supplement if needed (in October) or leave sugar candy in top feeder

Compare other methods of local beekeepers.

STARVATION

major cause of winter losses
dead bees with heads inside the cells

(almost no bees and left-over honey - likely a varroa mite kill)

Two critical periods:

late fall (October, November)

some years colonies may consume a substantial part of winter stores

early spring (late February, March)

loss of the best (strongest) hives
feed (honey comb or creamed honey) if out of stores (heft the hive to check)

do not open hive in full sun
open for less than 1 min . (-5⁰C / 23⁰F is OK)

QUEEN

strain: best is a proven local queen or a queen from harsher environment

age: young— less risk of loss (new queen or from last year)

Important: laying queen in July, August (eggs for winter bee population)

requeen
feed wet sugar during inclement weather

TEMPERATURE:

low temp.:

not a problem

(e.g. On December 21/1993 temp. dropped to -30⁰C (-22⁰F) and stayed in -20⁰C to -30⁰C (-4⁰F to -22⁰F) range, often dropping to -40⁰C (-40⁰F ) with an extreme of -48⁰C (-55⁰F). This lasted till February 15/1994. A strong colony would survive this with no protection but run out of stores at the end of February. )

heat loss:

increased consumption
bees falling off the cluster
danger of starvation

high temp.:

cluster may break
high consumption
temperature drop may catch bees away from the cluster

HUMIDITY:

condensation and ice formation
molded frames
heat loss (increased conductivity of air)

Prevention:

ventilation

full width of lower entrance
(clean if plugged with ice, dead bees – snow is OK) or
upper entrance (notch in the rim of inner cover)

winter sun

dark color of the hive

insulation (reduces condensation)

permeable packing material (metal cover is a major source of condensation)

protection from ground moisture (tar paper)

overhang (tar paper under top cover)

absorbent materials (shavings in top feeder, newspaper)

WIND

heat loss
increased condensation

Protection:

protected location
wind fence
packing

DISTURBANCE

(rodents, hive inspections, ice removal, branches hitting the hive …)

cluster looses temperature (at 18⁰C / 64⁰F it looses ability to generate heat)

increased consumption, loss of bees

MEDICATION

provincial /state apiarist may provide guidelines

CONFIGURATION OF THE HIVE

single box:

larger honey crop (honey super above the brood chamber is extracted)
less room relative to hive population (favorable environmental conditions)
possibility of insufficient empty comb space to form a tight cluster
higher risk of insufficient stores
potentially a superior configuration (with adequate wintering methods)

two boxes:

top box full with capped honey and pollen
bottom box partly empty
common configuration for outside wintering (Ontario / Quebec)

three boxes:

space for larger stores
larger clean up job of a dead colony in spring

Organize hive before fall feeding:

remove queen excluder
remove frames that are not built
move some pollen comb up

WINTERING INSIDE

cellars (ventilation essential!)
refrigerated /ventilated buildings (e.g. a converted hot room)

conditions: 3⁰C/38⁰F, 25ft³per hive, darkness

feeding: 30 — 40 lbs of sugar per hive

well researched and tested – Quebec Ministry of Agriculture

cold spell in spring (after the hives have been moved out) may set them back

used by some large beekeepers in Montreal area

WINTERING OUTSIDE

stronger colonies in spring

lower cost

commonly used in Eastern Ontario / West Quebec

WRAPPING

Requirements:

Adequate protection
Ease of access to the hive/replacement (spring inspection, feeding, medication)

Grouping:

pairs
pallet of 4
stacking on top

added protection at no cost
more work
may not provide for easy access

Examples of Wrapping Methods:

BLACK CARTON (bottom waxed)

standard method in Eastern Ontario, West Québec
quick and easy installation
air space between the hive and the carton reduces heat loss by conduction
allows for the hive to be reheated by sun
may be marginal in exposed locations
preferably use with additional top insulation (e.g. 3" of polystyrene on inner cover)
tar paper on top of the carton box (under the outer cover) may provide overhang
supplier: Benson Bee Supplies Ltd.( 613-821-2797 / 1-800-214-7366 / fax: 613-821-2621)

WINTERING CASE

traditionally wood (or particle board), plywood platform and cover
filled with shavings, fiberglass etc.
pipe for top ventilation or not insulated front side
mouse screen
lightweight case may be constructed from an insulation board and used in a similar way as slip-over carton
good results

TAR PAPER WRAP

by itself may not be sufficient
may be used over fiberglass or straw insulation
benefits of over-insulating are questionable
may accumulate moisture
southern side may be left uninsulated (only wrapped)
may not provide for easy access to the hive

BURIED UNDER THE SNOW

best in combination with some wrapping
permeable insulation, total draft protection
will even temperature fluctuations
low honey consumption
possible delayed spring build up

NO PROTECTION

may work on occasion

BEE-HOUSE / PERMANENTLY INSULATED HIVES

used in parts of Europe

non-standard equipment

QUESTIONS and ANSWERS:

When to remove the winter packing?

The hive protection is more important in spring than in winter. A cold spell will chill the brood and set the hive back. In our climate wait till the middle of May or later - not before the tomatoes are planted out.

When to wrap the hives for winter?

Not too early. Cool hive will cease rearing brood and decrease consumption. In West Quebec it may be done in the first week of November (before the deep frost or heavy snowfall).

Is the upper entrance essential in winter?

It depends on the wintering method. Personally, I had better experience with full width of bottom entrance and no upper entrance.

Is it necessary to reduce the bottom entrance?

No. The primary reason for entrance reduction is the defense against robbing. Reduction of the bottom entrance may help to reduce the heat loss if the upper entrance is used.

How to protect the hive in winter against rodents?

Several methods exist. For example the height of the bottom entrance may be lowered to the size of the bee space using a metal strip. Metal screen (1/4") can be used. Care must be taken that the entrance will not get blocked by dead bees / ice.

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