What do honeybees do in the winter? Do they hibernate like bears? Do they head south for the winter and then return north in the spring?
Unlike most of their insect cousins who hibernate, honeybees remain active during winter and live in the same abode they did during warmer months. They survive the Winter Wonderland by generating their own heat and storing their food close at hand.
Click here for a short video clip of my hives during a Christmas snowfall.
Heating the Hive
As ambient temperatures dip below 57°F, honeybees huddle closely in the hive to form a cluster, with the queen in the center. Bees on the outside of the cluster are compressed tightly together as a means of insulating the colony. Bees in the center shiver to generate heat. By vibrating their wing muscles, they can raise their body temperature to 111°F and maintain the core of the cluster at a cozy 90-93°F.
Survival of the colony is a communal effort. When workers on the outside of the cluster get chilled, they push to the center and switch positions with their sisters, who then take their turn shielding the group from the cold. During warmer spells, the entire cluster will move within the hive, positioning themselves around unused supplies of stored food.
A thermal camera image shows the hive (orange) is significantly warmer than the outside air. Photo courtesy Greg Burns, Nature’s Image Farm.
Another thermal camera image showing heat radiating from the core (bright yellow) of the cluster during winter. Photo courtesy Edward Del Grosso.
Pre-eminent Planners
Much of the honeybee success is attributed to her ability to prepare for winter. Long before we humans are even thinking about long johns and fuzzy socks, bees are preparing for the cold.
With the last hurrah of summer in August and September, they are in full swing collecting the pollen and nectar that will be their sustenance over the next 4-6 months. Pollen is used to create bread (a mix of saliva and honey), the main source of protein in the bee diet. Nectar is used to make honey, the major source of carbohydrates.
Because the bees need it for survival, beekeepers do not harvest all the honey their bees have produced in the fall. Generally, beekeepers in cooler, northern climates leave about 60 pounds of honey in a hive, an amount that should suffice a typical colony. Many beekeepers also supplement this with sugar cakes or patties. They may also feed dry granulated sugar in the “mountain camp” method, whereby it is spread on top of newspaper above the cluster and consumed by the bees if necessary.
In late fall, the colony will begin to downsize as well so there are fewer mouths to feed in winter. The queen will lay fewer eggs and may even stop laying altogether by November. Now too, the colony is comprised of “fat bees” that can survive the entire winter. These bees are longer-lived and have more body reserves than their summer sisters, who have an average lifespan of just six weeks.
Drones (male bees) will disappear from the hive too as female worker bees kick them out in order to conserve resources. There simply is no reason for their sole existence — mating of virgin queens — in a winter colony.
Though a typical summer colony may number 60,000 bees, a winter colony shrinks to about 10,000 bees. Come early winter, the colony is a lean, mean fighting machine of ladies whose primary job is to warm the queen and ensure her survival through the winter.
Winter Challenges
One might think battening down the hatches and wrapping the hive in a blanket would help the colony survive the cold. But, for beekeepers like me, in central Ohio, this might make a bad situation worse.
Wood shavings are added to quilt boxes like these and placed in the hive over the cluster and under the inner cover. The shavings absorb condensation that drips from the inner cover and prevent it from chilling the bees.
Often, it is not cold weather that kills colonies. Rather, poor hive ventilation and the destructive varroa mite lead to their demise.
Without adequate ventilation, warm air from the cluster rises and hits the cold inner cover, causing condensation. This drips down onto the bees as ice-cold water. The bees become chilled and die.
One means some beekeepers use to manage this is a special hive box called a quilt box. This box with a screen on the bottom is filled with wood shavings and placed above the bees and below the inner cover in the late fall. Condensation that drips from the cover is absorbed by the shavings rather than falling on the bees.
Beekeepers may also prop the lid of the hive slightly to allow for better ventilation in the hive.
Another challenge for honeybees comes from wildly fluctuating temperatures in early to mid-spring. If the weather warms too quickly, the queen may gear up massive egg laying too quickly. If the warmth is followed by a cold snap, there may be too few worker bees to care for a large brood of young eggs and larvae.
There is nothing beekeepers can do but pray in these scenarios. Mother Nature decides the fate of the colony. This is one reason hive health, especially regarding varroa mites, is paramount heading into the winter. Healthier colonies are more likely to survive than weak ones.
Late Winter, Early Spring
Just as winter prep comes early for honeybees, so does spring prep. The queen may begin to lay eggs for spring bees in December and January if conditions permit. Sources of pollen and nectar become available long before the crocus bloom and humans take notice.
Here in Ohio, trees and shrubs provide a great deal of pollen and nectar for foraging bees in late winter and early spring. Valuable sources include silver and red maples, willow, wild cherry, apple and crab apple, and other native trees like serviceberry, catalpa, hawthorn, and red bud.
When temperatures are consistently above 50°F, the hive is abuzz with activity and beekeepers have their hands full with apiary tasks.
For everyone else, the once-again sighting of a honeybee hovering over a bright yellow dandelion signals the passing of winter and the birth of spring.
Michele with one of her hives after a Christmas Day snowfall in 2020.