Our farm bee yard (apiary) is only a few yards from our door. We over-winter our bees and hope that our efforts to keep them alive result in healthy, vigorous bees by the time spring arrives. In the years past, when we have had consistent, season-long cold days, we have been successful with an average of 80% survival rate (i.e. 8 out of 10 hives live to the next spring). To help the bees survive, we insulate each hive with hay held in place with chicken wire. A hole drilled in the top super (the top wooden box that the bees live in) allows them to keep their hive ventilated, and a funnel placed through the insulation into their ventilation hole allows them an exit way for a short cleansing flight.
Because we take a portion of their honey in late August or early September, we need to feed them in order to help them have enough stores to make it through the long Alaskan winter. The Italian species of honey-bee we have evolved in Europe and can tolerate the depth of the Alaskan cold winter, but have not evolved to survive the length of winter that we have in Alaska. They need the extra stores to survive. So part of our regimen in the fall is to keep their top-feeder full of sugar water for them to eat and to store until they are able to forage again in the spring. Our efforts worked in the past until last year’s winter, when we lost all of our hives. The loss was devastating, both emotionally and economically.
The general pattern that I have seen when a hive dies in the past is due to starvation. This can happen even when they have frames full of honey. What normally happens is that when the hive becomes cold, the bees move into a cluster around the queen and help to regulate her temperature. The workers flex their wings and keep their queen and each other warm (their summer and winter hive/cluster temperature is about 98 Fahrenheit). The bees on the periphery of the cluster become comatose and then are moved into the cluster by the interior bees. And then the interior bees take a turn on the outside of the cluster. A few of the bees are what I would call “roaming” bees. They are warmed from the interior and then go to outside of the cluster to locate the cells with food and help with the slow migration of the entire cluster to move over the full cells.
Sometimes the cluster of bees stop their migration to full cells in their hive. My guess is that the movement is somewhat chaotic given the outside bees are comatose. If the cluster is big enough and the stores sufficient, then the cluster manages to migrate to where the the honeycomb cells are full. But if the cluster is rather small, as can happen when some of the older bees begin to die off, then the cluster may have more difficulty in the migration process in the hive and may stop moving altogether. If that happens, eventually all of the cells that the cluster is on will become depleted. Even when there are full cells just inches away from the cluster, they end up staying in place and dying when they have eaten everything in the cells underneath them. The pattern of death in this case is detectable by the formation of the dead bees in the cells. The bees are in a small cluster and each bee is in an empty cell where they died, and are facing toward the back of the cell as though they were trying to reach the very last residues of food in the cells. Meanwhile cells full of food are about two-three inches from the dead cluster.
I’m always saddened by a hive that doesn’t survive. Luckily we usually lose only 2 hives in a winter, but the experience of last year was the hardest to take. The circumstances were different. The winter was mild. We insulated and fed the hives the way we normally do in preparation for the winter months. All of the hives were very active into the last weeks of November. By “very active” I mean that they were flying outside of the hive in a little cloud as though it was an early day in spring, and then landing on the edge of the funnel to walk back into the hive. This was actually unusual behavior but understandable given the variability of those November days that were warm (high 40’s to low 50’s on mild days). But proved to be deadly on the day that was so warm and then dropped to an unprecedented low in the night after such a warm day. That was the last night I heard and saw my bees alive.
When I opened their hives in spring, all but two did not die in a cluster. All had stores. My interpretation of this phenomena was that the majority didn’t have time to form a cluster as the temperature fell so fast. Without a cluster, the queen can become exposed and if she dies the whole hive dies.
This winter, we have snow and for several weeks we have had consistently low temperatures. And I rejoice. So far 8 of 10 hives have survived. But the winter isn’t over yet. And we have at least three more months for them to endure before they come out and find forage.