General Wintering Advice
The BeeHolder, Autumn 2012
As the colder weather arrives brood rearing slows down and then ceases, maybe around September or October. The bees that are born towards the end of the season don’t need to feed young emerging bees and it’s these bees that are the long life winter survivors. As the brood rearing actually stops the temperature requirement in the hive drops from 36C to about 12C and as the outside temperature drops the bees begin to cluster together.
This cluster gets tighter and looser as the outside temperature goes up and down (tighter with the cold) and it is this movement that allows the bees to move onto the stores and use them up.
Winter progresses in this way and I was last year interested to look at a hive that a beekeeper had placed onto two sets of bathroom scales which were an Aldi bargain. Weight records were taken throughout the winter and showed a steady drop in weight (about 250 – 350 grams per week) until spring time, then it stopped still for a while and started to go up again. We all knew that was what would happen, really, but it was still interesting to actually see it!
Before your bees start to cluster there are some basics to be aware of;
Feeding – A hive going into the winter should weigh about 25kg and any shortfall in this weight can be made up by feeding sugar syrup. More detailed information on feeding is available in the WAG booklet “Feeding Bees” which is available on the WBKA website. A honey flow from Ivy can leave stores that granulate hard and be useless to the bees. This can be a deceptive situation because when you periodically lift (commonly called “hefting”) the hive to check that it still has enough stores for your bees it feels heavy but there isn’t food that can be used. If you do get an ivy flow then feeding at the same time can help with this.
Varroa – An on-time and effective Varroa treatment is an important part of good wintering. It’s the bees that are born late in the season and haven’t had to feed young bees that make up the winter surviving population. If these bees have not been damaged by the feeding action of these horrible little mites then they are more likely to be healthy. If you need more information about Varroa you can download the bee unit's guide to managing Varroa at https://secure.fera.defra.gov.uk/beebase/ index.cfm?pageid=93 or contact your bee inspector.
Nosema - There are two known Nosema species that can infect honey bees: Nosema apis and Nosema ceranae. N ceranae was first reported in Apis ceranae in China in 1994 and has been present in Europe since at least 1998. N ceranae was first detected in the UK in 2007. Nosema are microsporidia (primitive fungi) transmitted via spore ingestion. Although Nosema can be spread by dysentery it is not the cause of dysentery. It is, however, a major cause of poor over wintering.
The Hive – Bees can stand really cold temperatures but not damp, therefore making sure the hive is in good condition, well ventilated and not being dripped on by overhanging objects is important. Also, check the stands are secure and the hives cant be knocked over by animals and install suitable mouse guards, particularly if the hives are close to the ground or next to hedges.
This list is not exhaustive of course but does cover the “before clustering” basics and then once the bees have clustered you need to occasionally lift (heft) the hive to see that stores aren’t diminishing too quickly, have mouseguards on, occasionally check for animal, weather or vandalism damage and, of course, carry out the oxalic treatment in late December/early January.