Winter Loss – What happened to my bees?

If you are reading this the chances are you have lost your bees over winter, you are feeling upset and saddened and you want to know why they have died and most beekeepers think “What did I do wrong?”

There are always winter losses and there are many reasons why colonies don’t make it through winter. It stands to reason that the more colonies of honeybees you have the more likely you are to suffer with winter losses and it may not be anything you have done so before you go blaming yourself see if you can see why the colony has died. It may be that you can’t work out what has happened, below I have given some examples of winter losses.

Starvation – there are two types of starvation, one is beekeeper error, you took too much honey off your bees and didn’t bother to check them through the winter and they have starved. The bees will be found with the heads in the cells because they are desperate for food. This is your fault entirely and yes you should blame yourself, this was completely avoidable and its because you were greedy – sorry but that is exactly what this is. The early spring is often when we see this, the bees become active, the beekeeper sees the bees flying and assumes they are collecting nectar. Well have a look around you, how much flower is there and is it warm enough for the nectar to flow. Yes they are bringing in pollen, but they need nectar and now they are active and the queen is laying they need more and more of it. They will be eating more than they can forage and so they starve.

The other starvation is “Isolation Starvation“. This happens when the winter cluster of bees moves away from food instead of with it. The result is the same, dead bees with heads in cells but you will also have frames of food in the brood box and even more sadder is that the food may only be a couple of inches away from the dead cluster. This is not your fault, do not blame yourself, there is nothing at all that you could have done to help these bees. Sadly nature has a weird way of working at times.

Queen issue – If your colony was queen-less going into winter they are not going to survive, even if there are still some alive in early spring they are not going to live long enough to support the colony until you can get a new mated queen to go in with them. If you are lucky enough to find mated queen early the bees will be too old to support her. It could be that you had a late supercedure happen and she didn’t manage to mate. A colony with a drone layer is not going to make it, again this may make it through winter but, sad as it is, the colony is doomed.

Varroa / Unhealthy colony – An unhealthy or stressed colony is unlikely to make it through winter. Varroa causes much stress on a honeybee colony, to avoid high varroa levels going into winter make sure you treat your bees at the end of the season. I have a post on Varroa which will give you much more information on this topic. Make sure you look at the brood throughout the season to see that it looks healthy. Also look at your bees, do they look healthy? Varroa damage can be seen at larvae stage and also at capped stage, your bees will detect infected cells, they will uncap them and remove the infected larvae, so look for chewed cell capping’s. You could take some blame for this if you didn’t treat your bees.

Unusual winter with temperature changes – With climate change we are seeing winters with more and more temperature fluctuations. The bees cluster in winter during the cold weather, if we have warm days they will break this cluster and maybe even go out to forage in the warmth of the sun. The winter days are short and the temperatures drop quickly, this can have a big affect on the bees, some won’t make it home because they get too cold and in the hive they may not make it back to the main cluster and they may die from the cold. A small weak colony will almost certainly die in a big hive as they won’t be able to generate enough heat. You definitely can’t blame yourself for this, no one can control the weather!

Predators – Mice are big winter predators to honeybees, the bees offer a lovely snug warm environment with lots food for them! If they get into the broodbox they will cause lots of stress to your bees. By fitting a mice guard or simply reducing the hive entrance to a single bee space you can stop mice getting into the brood chamber.

Moisture – moisture by way of condensation can cause detrimental effects at any time but especially during the cold winter months. Make sure your hives have appropriate ventilation, many beekeepers make the mistake of covering both holes in the crownboard, this stops the airflow and causes condensation. This may cause the demise of your colony. If you think your bees have died due to excess moisture have a look at the hive ventilation and also look at the location of the hive, does it very wet/damp where the hive is located?

Blocked entrance – Your bees need to be able to get out of the hive, even in winter they will take short cleansing flights if the sun is out. If the entrance is blocked by something they won’t be able to get out. It could be heavy snow fall causing the blockage or it could be early spring, there will have been natural bee deaths over the winter months and if the colony was big going in these numbers will also be big and could block a small entrance.

5 thoughts on “Winter Loss – What happened to my bees?”

    1. Hi. No its not completely avoidable, often we don’t see a definitive reason for the lose. However, if your bees have starved, due to lack of stores, because they have not been checked and offered food as they are getting short, then yes, I would say its beekeeper error and definitely avoidable.

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  1. Thank you, excellent summary. Been keeping bees in 3ā€“4 national hives for about 6ā€“7 years. The point about the crown board holes not being covered to encourage ventilation was one I’d never considered. I do cover the crown board, then pack a few hessian sacks in a super above, then a thick polystyrene sheet, then the roof. Open mesh floor remains open for ventilation and the hives sit on stands with plenty of air movement underneath them. Within the hives underneath the crown board, I put pollen patties/fondant on the top frames with an eke on top for space to accommodate the feed. In one hive, I saw a little condensation at the top, but its bees are otherwise vigorous and numerous. I close the crown board holes on all of the hives otherwise the bees get caught in the hessian sacks. So now ā€“ this weekend in fact ā€“ I’ll put mesh over the crown board holes instead, so the hives get ventilation at the top without bees going up through the holes. Let’s see if that keeps things drier without compromising on the insulation.

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    1. Hi, thank you for your comment. We all do things differently so its good to share how you prepare your bees over the winter months, the extra insulation is not something we do, we are however based down in Hampshire so it doesn’t get cold enough. I hope that adding the mesh to the holes so you have leave them for air works next winter

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