We do a lot when we work with our bees. We disassemble our hives, we examine the brood combs, we scrape and rearrange things, we get a few stings, and we harvest some honey. For most successful beekeepers, keeping bees is a very hands-on activity. That's a big part of why winter beekeeping is so hard for us. All of a sudden, we have to be very hands-off and hope that our bees will fare well without our constant meddling.
Our bees spend the winter clustered together for warmth. The special population of long-lived winter bees that our colonies made in the late fall are happily eating honey and buzzing their flight muscles to generate heat. They eat honey (or another sugar-based winter feed) as fuel for those muscles. In cool weather, the bees will form a rather loose cluster, with bees walking around near the edges. As the weather outside gets colder and colder, the cluster will tighten up, taking up less space and protecting more heat in its core.
When bees consume sugar to generate heat, they're also manufacturing water, which leaves their bodies as water vapor when they breathe out carbon dioxide. The water they exhale can be either a blessing or a curse for the colony, depending on the set-up of your hive. Moisture that condenses on the walls or bottom of the hive can be slurped up by the bees and reused to help dissolve honey on the verge of crystallization. Some of that moisture can be fed to new larvae in the spring when it's still too cold to go out and collect water from elsewhere. But if that moisture condenses directly above the cluster and then drips down on them, it can quickly chill and kill the bees.
Some beekeepers focus on ventilating their hives in the winter with upper entrances (as seen in this article on ventilating winter hive tops) or quilt boxes. These strategies are based on removing moisture before it can cause any trouble. Other beekeepers focus on insulating their hive's roof (and sometimes walls) to prevent the moist air from condensing in the wrong locations. This strategy keeps the moisture in the hive, where the bees can use it if they want (or else the excess drips out of the hive's entrance). Both strategies can work, but each comes with a tradeoff. A ventilated hive loses moisture but also loses more heat (meaning more honey is needed each winter). A hive with no ventilation will retain more heat, but it may retain too much moisture, which needs a way out of the hive so it doesn't pool on the bottom board and start to rot it.
If only we could check on our bees in the middle of winter, to see how they're doing…
Just because we can't pull out our brood frames and check on the queen, that doesn't mean we can't do winter inspections. The simplest winter inspection is just walking past the hives to make sure that the hive covers haven't been blown off in a windstorm, and the hives aren't buried under snow drifts. Flecks of yellow-brown bee poop or a few dead bees tossed out on the snow in front of a hive tell you that the cluster inside is alive and doing periodic housekeeping.
A better kind of winter inspection provides direct knowledge of how your bees are doing at that moment. Pressing an ear against your hive and giving one or two knocks against the side should reveal a telltale buzz from any clustered bees inside. Moving your ear and knocking a few times can even tell you which box the cluster is in. Just make sure to do this when it's cold, or else a cloud of annoyed bees may come out to see what the disturbance is.
If crouching down with an ear to your hive doesn't appeal to you, you can also quickly crack open the outer cover and peek through the inner cover hole. You should be able to see the bees and get a sense of whether they're up near the top of the hive or deep down within it. A cluster typically works their way upwards through their honey stores during the winter, so bees deep in the hive likely have some honey left, while bees up near the inner cover may be running out, and need supplemental winter feeding. Just be sure to wear a veil, because the sunlight through the open cover may cause a few bees to fly up out of their warm cluster to tell you to buzz off.
If you get really excited about winter inspections, you can also use technology to find out what your bees are up to. A sensitive enough thermal camera can show whether your bees are alive, and even where in the hive they are. If you don't have a thermal camera lying around, you might consider a hive temperature monitor like the BroodMinder system. You'll get temperature readings from your hives, and it's pretty clear whether there's a little space heater of bee bodies running near the temperature probe or not.
Inspecting your hives every month or two during the winter lets you know that your colonies are still alive, and also lets you know when a colony died. Winter is the season when most colonies die. However, what month they die can be a crucial clue to the mystery of WHY they died. A colony that dies in October or November may suggest mites were involved, while a colony that dies in March could point toward starvation. Check out this video on analyzing your "deadouts," to try to diagnose what went wrong.
If you haven't already, many beekeepers perform an oxalic acid vaporization or oxalic acid dribble treatment during the broodless (or low-brood) winter to knock mites back to square one before spring begins.
Check out this past article to learn more about when to feed different feeds to your bees in winter and spring.
This article is based on a lecture prepared by Betterbee's Education department. If your bee club is interested in having a Zoom or in-person talk by one of our staff, check out Betterbee's speaker biography page to learn more!