Winter bees are amazing. How do honey bees survive the winter? Many beekeepers lose their bees in the winter. Depending on how cold it gets where you live, bees form a tight cluster to survive the winter. Here in Illinois it gets very cold and windy. And in the winter it is too cold to inspect our colonies. We can open them just for a minute to replace candy boards but for the most part the bees are on their own until April.
Cold does not kill a healthy, populous colony. Usually beekeepers lose colonies during the winter from viruses that are spread by varroa mites. Other winter problems can be tracheal mites, nosema, pesticide build up in stored pollen, starvation or a failed queen.
So many beekeepers ask me what they can do to help their bees survive the winter. I've worked up an easy to remember acronym WINTERS:
Watch for pest & diseases
Initiate protection against extreme climate conditions
Excluders and empty combs off
Restrict Opening to keep out mice
Sufficient Pollen & Honey
We invented the Winter-Bee-Kind Feeding System. Take a look at how much bees love it in our video below, and hurry and order yours while they are still available.
I teach classes specifically designed to help beekeepers get their bees through the winter and now this is available as an ebook.
How does the typical colony overwinter? Bees do not hibernate like bears. Instead, they stay active inside the hive all winter. Bees make no effort to heat the inside of their hive like we heat our homes. We like every room to be warm. Bees, however, only produce heat within the cluster. The cluster consumes honey and shivers to produce heat.
Bees begin to cluster when the outside temperature reaches 57 (f). Temperature of the outer surface of the winter cluster is just over 40 (f). Within the center of the winter cluster the temperature is around 93 (f). Never inspect a frame outside the hive until the temperature reaches 65 (f). Colonies in the Midwest and north need around 4 frames of pollen for the winter, along with 60 pounds of honey. Typically in northern climates the queen will stop laying in November through December but will start laying small amounts of brood shortly after winter solstice (December 21 or 22).
Winter bees have larger hypopharyngeal glands and more fat body reserves. Bees can die in the winter if they become too filled with waste and cannot fly out and defecate. Bees keep their humidity level at 40-50% in the summer hive and in the winter cluster. The diameter of the winter cluster is around 14 inches at 57 (f) degrees, but 10 inches at -14 (f) An outside temperature of 45 (f) degrees is most optimal for efficient use of stored resources. A winter cluster is made up of an outside shell of bees around 3 inches thick that is very compressed. The bees heads are facing inward. Within the center of the winter cluster, bees are less compressed and move around caring for brood. Bees vibrate their wing muscles to generate heat for the winter cluster.
Normally a colony forms a winter cluster below their stored honey and gradually move up near the available honey as winter progresses. Smaller winter clusters consume more resources per bee than larger clusters. Bees can identify temperature differences as small as 0.45 (f). Very small clusters cannot survive temperatures 45 (f) and below. The winter cluster prefers dark comb and usually avoids new comb. Varroa mites, small hive beetles and trachea mites also survive within the warmth of the winter cluster.
Here's some winter tips:
Never remove frames for inspection unless the temperature is at least 65 degrees. Aster is not a good overwintering honey because it crystallizes fast and the bees rarely ripen it prior to winter. Crystallized honey in the winter can give the bees dysentery because it produces liquid as it separates and the bees are unable to take the cleansing flights they need.
Never give bees molasses, brown sugar or corn syrup as these contain complex carbohydrates and other compounds which the bees are unable to digest. Bees prefer to overwinter on foundation that has been used in brood rearing and will rarely move onto new comb. Here in the Midwest colonies need between 60-80 pounds of stored honey. Here are the weights of frames filled with honey:
DEEP FRAME 6 lbs
MEDIUM FRAME 3 lbs
SHALLOW FRAME 2.5 lbs
We always recommend using our Winter-Bee-Kind pollen/candy and ventilation board on top of your hive during the winter. These go online for sale in August. Click here for more info on our Winter-Bee-Kind.
Consider becoming part of our Online Beekeeping Academy and take some of our courses from the convenience of your home, on your own schedule. Select your classes below: