© Dealing with winter losses is very sad but do not necessarily blame yourself - "where there is livestock, there is dead stock" is an old saying. In nature, more than 50% of colonies would perish in their first winter. Even in professionally managed apiaries where we would expect this figure to be an average of less than 10%, dealing with winter losses is still a fact of beekeeping life.
Some winters are naturally worse for honey bees than others but winter losses can be minimised. Colonies that have been treated for Varroa if necessary and well provisioned with stores well before autumn with a large population and a young queen are the most likely to survive winter. "Take your winter losses in autumn" is another old saying. This refers to the practice of uniting colonies in autumn that would otherwise be too small or have queens past their best to guarantee survival through the winter. These colonies can then be split again in the following season to bring colony numbers back again if required. As a rule of thumb we would advise colonies should have at least 5 combs of bees and queens should not go into their third winter but this naturally depends on the thumb.
Winter losses should be dealt with as early as possible in the year and as soon as possible after they are discovered. A hive with no flying bees whilst bees in other similar hives are flying can be an indication of winter loss (this is just one of many good reasons to maintain a minimum of two hives). Close observation should also be given to the behaviour of the workers at all hive entrances to see if any are being robbed out by others, an obvious sign of winter loss. These signs can be seen as early as January so keep a regular eye on your hives. Mark or record those that are possible winter losses for further investigation.
Choose the first day possible when bees are flying from other hives to check those hives that are possible winter losses. It does not have to be warm enough for normal inspections i.e. 16°C, 60°F, this is just a quick check but be prepared in a bee suit. If you open the crownboard to be greeted by bees then close up again quickly and be pleased with your luck otherwise remove some frames to check there are no bees. There might be a small colony left that are too small to break cluster and fly whilst other hives are flying. The best that can be done in this case is close up and hope for the best for them until the season progresses.
As soon as the hive has been confirmed as a winter loss it should be removed from the apiary to a bee proof place. This is to prevent robbing by other colonies which is a problem in itself when it starts a robbing frenzy with every colony trying to rob every other. It is also a safeguard in case the hive is carrying an infectious disease which can be transmitted by robbing. Although infectious disease is not common it can be very difficult to diagnose when there are no bees left so every winter loss should be treated as if it was infectious just in case. If the hive cannot be removed immediately, securely block the entrance to prevent any other bees robbing the hive until it can be removed.
The hive should be sterilised, disinfected and renovated as soon as possible before the contents are taken over by mould and wax moths which will make the job harder.