After almost two full years of enjoying our healthy hives at TLC's demonstration beeyard, we finally lost one one of them this winter. Winter losses are all too common for beekeepers these days (average winter losses are somewhere the in the neighborhood of 30%), and there are a number of reasons a hive might not make it through this trying season of the year.
Without leaving sufficient stores on the hive (I'd say at least 50 lbs. of honey), a colony could easily starve over the winter months. In our parts, beekeepers usually harvest in the summer, trying to leave enough honey for the bees to get through the summer dearth. We then usually experience a modest nectar flow in the fall, and the beekeeper may or may not do some supplemental feeding at that time to get the hive up to weight.
Also, if there are problems with the queen in late summer or fall, there might be a low population going into the winter, so that they have a hard time forming a sufficient cluster to stay warm and move to where the stores are in the hive. Bees don't exactly die from the cold, but if there is inadequate ventilation in the hive, it can become damp. Cold and wet bees is definitely a deadly combination. Add to the equation stresses from parasitic Varroa mites and their associated viral diseases, and the cluster of bees could already be dwindling throughout the winter due to a really high attrition rate.
The hive we lost was "Hive A", which was previously a superstar, but attempted to swarm last summer and stumbled a bit in requeening itself. It didn't seem to have an especially high Varroa count, but honestly any Varroa mites in the hive are not helping matters. When I found it dead on March 16th, I didn't have time to do a full autopsy, but peeked in and closed up the entrance to prevent the remaining stores from being robbed out. There seemed to be a rather small number of (dead) bees in the hive, which leads me to believe there weren't that many in there going into winter. That may have been related to queen issues from last year, that I didn't pick up on in the fall, or it may have succumbed to a combination of other stress.
The fact of the matter is- hives die; though it's sad, it's the beekeeping world we live in. On the bright side, the hives at TLC's apiary have done better than average. Also, as long as Hive A did not fall to a communicable disease, we can reuse all of the equipment and drawn comb from that hive to give a new colony a real head start this spring. Sounds like a post for the near future!
