Friends frequently ask me , “What happens to your bees in the winter?” What happens is an epic struggle to keep the bees alive. Some people say you aren’t a beekeeper until you get your first hive full of bees through the winter. If you buy new bees every year because your bees from the previous year died, then you aren’t really beekeeping. If you are a skilled beekeeper, your bees should have a better chance of survival than “the bees in the trees” also known as feral honey bees.
Consider in the year spanning April 2016 to Aril 2017, US beekeepers lost 33% of their colonies, and about two-thirds of those losses came during the winter months. Amazingly those numbers represent an improvement over the previous year.
A honey bee colony’s main objective in winter is to keep the queen alive because a colony can’t survive without a queen. To keep the queen alive when the weather turns cold, the bees cluster around the queen in a sort of bee ball. The bees vibrate and flap their wings. The motion burns calories and generates heat that keeps the queen warm. The center of cluster is kept at approximately 85 °F, and the temperature becomes cooler as distance from the queen increases. The bees at the outer portion of the cluster become cold, so the bees must rotate positions periodically. You can see the bee cluster in the hive using infrared cameras. My favorite bee blog, the Honey Bee Suite, has posted numerous thermal images of bee hives you can see by clicking this link.
A large amount of energy is needed to keep the cluster warm when the weather is cold, so bees need large amounts of honey to eat during the winter. The amount of honey needed depends upon the quantity of bees in the hive, the duration of winter in your part of the world, and the winter temperatures in your area. Recently I heard a talk by the retired Kentucky state apiarist, Phil Craft. He said in our area each colony needs at least 30,000 bees going into winter and 55-60 pounds of stored honey. A standard 10-frame Langstroth hive box full of bees is approximately 30,000 bees. One full frame of honey is about six pounds. Thus, if you have a full hive box (also referred to as a deep box or hive body) with all the frames filled with honey, your bees have a good chance of making it through the winter. You can boost the bees’ food stores in the fall by feeding them with a syrup made of 2:1 cane sugar to water. You can see the types of feeders we use in my post about feeding our bees in year one.
The bees also do their part to conserve honey supplies through the winter. In the late fall, they start to kick the drones out of the hives. Drones don’t do much to contribute to the day-to-day working of the hive. Their job is mate with the queen. The rest of the time the drones just consume resources. No mating takes place in winter, so the worker bees banish the drones to die.
Starvation is one of the big threats to bees in the winter, and beekeepers must be careful not to harvest too much honey in the spring and fall so the bees have enough for winter. Many beekeepers also feed their bees during the winter months with sugar patties containing supplements. These patties can be purchased or made at home. Here are some of the other big threats to bees during winter:
Varroa mites – You need healthy bees in fall to make healthy winter bees that can survive until spring. Varroa mite levels typically rise in the fall, so it is important to monitor and treat for mites to ensure a healthy colony during winter.
Moisture – Condensation can form in the bee hive due to the thermal gradients. Hives need small vents at the top to let out warm, moist air so water doesn’t start dripping on the bee cluster. Some people use a popsicle stick to prop open the top cover and allow ventilation. We added a shallow top box that had a pre-drilled vent hole. We filled the box with burlap and pine shavings to absorb moisture. These burlap filled boxes are called quilt boxes.
Mice – Mice don’t like cold temperatures, and a warm, dry beehive can be an inviting location for mice to spend the winter. The entrance to the hive needs to be covered in such a way so that there is a very small opening suitable for bees but too small to allow mice to enter. Most hives have entrance reducers that will prevent mice from entering.
Most hobby beekeepers keep their hives in one place all year long, but commercial beekeepers frequently move their hives at the onset of winter. Many hives are trucked to warmer locations in the southern US where they can begin to pollinate crops early in the calendar year. In late fall, you will begin to see trucks of beehives on the move. My friend took this picture on a local expressway. (She was the passenger. Safety first.)
This is our first year of beekeeping, so I can’t tell you that we have successfully taken our bees through winter. We grew our two nucs into three colonies that we felt were ready for winter. If our bees follow the national statistics, we will lose at least 1 of the 3 colonies. Because of the cold temperatures, we can’t open the hives and perform regular hive checks. My husband gave me a pep talk recently and told me we have to have confidence in all the steps we made to prepare our bees. If people at the restaurant overheard us, they might have thought that we were talking about sending children off to college. For now, we have done what we can do. All that is left is to wait for spring.