Animals have a variety of methods for coping with cold weather: some grow thicker coats of fur or feathers, while others hibernate in underground dens. Honeybees, as eusocial creatures, depend on each other, and work cooperatively to keep their colonies alive through cold weather.
What do bees do in winter?
During the course of the spring and summer, honeybees amass stores of honey to provide nourishment during the winter. In early fall their queens stop egg laying, and older bees are allowed to die off to limit the demand on their food supplies. When daytime temperatures fall below 57 degrees Fahrenheit, they retreat to their hives and huddle together next to their honey supplies to stay warm and protect their queen. When outside temperatures fall to 23 degrees, the bees on the inside of the cluster begin to vibrate their wings, generating heat to maintain an optimal temperature of 95 degrees within the cluster centers, where their queens are housed. During the course of the winter honey bees cycle between inner and outer layers, allowing near-frozen outer bees to rewarm, while their replacements take up position as living insulation on the clusters’ exteriors.
It’s a highly efficient survival strategy that, under natural conditions, assures most colonies will survive until warm weather, when new supplies of pollen and nectar reappear. There are a number of manmade and natural threats, though, that can impact hives’ ability to survive:
- Limited sources of pollen and nectar in late summer and fall can leave hives with stores of honey that are too small to feed them through the winter.
- A weak queen who produces small broods can mean there aren’t enough bees to generate the heat needed to survive extreme cold. Exposure to pesticides can have the same effect.
- Any unwanted moisture hives can bring hive temperatures down to dangerous levels.
- Parasite infestations—such as varroa mites—can weaken and kill enough bees to compromise their ability to stay warm.
Today, more than 40% of northern colonies are compromised and don’t make it through the winter; without the help of professional beekeepers, the mortality rate would be much higher. Here are some tips and tricks from our expert beekeepers on preparing a beehive for the winter:
- Adjust the position: assess the positioning of the hive; while it’s not essential that it be perfectly level, there should be no discernable tilt, or moisture will build up in pockets. The bottom board must be tilted approximately 1-2 degrees downward, to allow moisture to drain away.
- Check the weight: Hives are weighed to determine the volume of honey available for the winter, and to determine the frequency and volume of supplemental feeding required. You don’t need a scale for this— a simple lift will do.
- Feed your bees: Be sure that your beehives have enough honey to survive the winter. If not, supplement with fondant.
- Treat your hives: Dribble the cluster with Oxalic Acid. This is the final treatment to prevent varroa mite infestation for the year. With no capped brood left in the hive, varroa mites have nowhere to hide, and are easier to knock out. Beekeepers apply it in between the frames beginning with the bottom-most boxes that contain bees.
- Ventilate: check to make sure there’s a large-notch inner cover in place, and that top ventilation is opposite from the bottom entrance to the hive. This will assure cross-ventilation, reducing the chance of deadly moisture build-up.
These steps are a bit complicated, and doing them right can be tricky, especially at this critical time of year. That’s one reason why our residential and corporate clients hire us to tend bees for them. If you’re new to beekeeping, you can learn more about what our professional beekeepers do to prepare hives for winter in our blog “Tucking Our Bees in for the Winter.”
Want more information? Here’s some good advice from friends in the beekeeping community:
- Asheville Bee Charmer: “Fall Beekeeping Tips”
- Bee & Bloom: “Winter is Coming: How to Winterize Your Hive”
- Honest Beekeeper: “How to Winterize a Beehive”
- Honey Bee Suite: “How to Prepare Your Hive for Winter: A Checklist”
- Hyper Hive: “Winterizing Beehives”
- Keeping Backyard Bees: “Preparing Northern Hives for Winter”
- Perfect Bee Company: “An Introduction to Overwintering Honey Bees”
Whatever happens to your bees this winter, don’t give up. Successful beekeeping takes many years of practice. You’ll face new challenges every year, and through them you’ll grow smarter and your bees will grow stronger and healthier!