Oh dear, it is getting to be that time again!
There are all kinds of winters, but no matter what yours is like, bees the world over handle cold spells and winters in the same way: they cluster.
Like the penguins, bees do not hibernate, they huddle in a group and take turns rotating from the warm interior of the huddle (the cluster) to the outside. The warmth is centred over queen and whatever brood is in the hive.
Shivering their wing muscles, fueled by their honey stores, the bees generate warmth all winter long. The interior of the cluster is 95F, year round. This is what allows us to use infrared imagery to monitor cluster size and location when it is too cold to open the hive.
The big danger to bees (aside from losing access to the calories needed to fuel the cluster) is their own respiration.
Thanks to all that metabolic activity, warm, moist air rises off the cluster, and promptly condenses on the cold inner cover, dripping moisture down onto the bees.
Chilled by the cold shower, the bees lose their ability to move their muscles (they are cold blooded), chill and die. Very sad.
The preventive is….a quilt…a ventilated quilt box!
In cold weather, it is of great benefit to place a quilt box on the hive. The quilt box goes OVER the top box of frames and UNDER the inner cover.
To make a ventilated quilt box:
-take one super, deep or shallow
-drill one or two holes high in the sides of the super, slanting the cuts upward as they go from outside the box to inside the box (this prevents rain dripping in).
-staple 1/8″ screen inside the box to cover the holes (prevents unwelcome lodgers from moving in, ie. mice)
-staple burlap to the bottom of the box
-fill box with absorbent material ie. fine wood shavings (hamster bedding)
These stay remarkably dry as the ventilated holes and the hole in your inner cover allow a flow of air to move off the cluster, through the chips and out. The top inch or two of the chips may be dampish, but I have never found them soaking and mouldy, even in our long, rainy…endlessly rainy…winters.
Store them in a warm, dry space off-season and they should last many years.
Tip: if you place a screened shim between the top box and the quilt box, the bees will not propolize down the burlap layer. You can place winter emergency rations on the top bars, under that screened shim, ie. fondant or Krabby Patties.
(in photo above, this shim would be placed screen side UP onto the top box)
On the coldest days, you can quickly lift the quilt box, peek through that screen, and check to see there are still emergency rations for the bees. In spring you will see bees feeding there and that gives you a rough idea of the strength and health of the cluster well before you get the weather to inspect.
These two measures, providing a ventilated quilt box and leaving emergency rations high in the hive, in the warm air column above the cluster, should help your colonies come through the winter, safe until the first nectar flows.
Bonne chance, mes filles.