April Beekeeping notes by Amanda Millar
I hope you did not lose any colonies in the cold spells we had in March.
If, however, you found one of your colonies has died recently, it is important you inspect them carefully to find out why. The bees may appear to have died of starvation (heads in cells, no stores on that frame) even if there are stores elsewhere in the hive (isolation starvation). If they are only on one or two seams or the cluster is the size of two fists then starvation may just have been the last straw for an already ailing and doomed colony. Often the bees in the dead cluster look normal as they did die of starvation and there may be a queen there. But look on the floor and see what the earlier ones died of which reduced the numbers to this low level. You may see evidence of Deformed Wing Virus, dead deformed pupae pulled out, Paralysis virus (shiny, K-wing etc). That is what really killed them. Did you monitor your mites after treating in the autumn? Did you have a late invasion of mites which might have caused it? This is what happened to two colonies at our Divisional apiary, even though the mites were brought under control within a few weeks in November, the damage was done. Look at the brood frames too; there may be clues there. One of our divisional colonies had a dozen or so chalkbrood mummies on each frame, more than were recorded during the summer in this colony, although Chalkbrood was known to be present since it was collected as a swarm in 2016 and persisted after a shook swarm last May. Chalkbrood is not normally considered a cause of winter losses on its own but last year one or two DWV and sacbrood were also regularly seen. So my view is that it was no great loss losing that disease susceptible colony; Of course, it is a pain having to clean and sterilise all frames (3 shallow boxes worth on this colony) mostly full of stores to wash down the sink as it will not burn with all those stores. (If most had been honey I might have rescued it for cooking but it was largely syrup, and the other colony on two boxes had a bit of dysentery too). If they were a decent size and they had only died of starvation then you only have yourself to blame. But if you lose a colony during the cold weather to disease, think of it as a good weeding out of poor colonies; clean up and start again either splitting your healthy strong colonies or try again with a swarm. I must say though that I don't often get many swarms I am happy with these days as several times in recent years, I have had to cull within weeks when they showed sacbrood or some other nasty. The swarm I collected from the letter box last year though is now my strongest; 9 seams on a brood and a half, whereas most of my others are 5-6 full seams (and a couple struggling!)
Hopefully though, you had a nice strong colony on 5 or more seams at your first inspection, now we must keep an eye on when they start producing drones, an indication that they are strong enough to consider swarming in a few weeks time. I have a feeling the cold weather may have delayed swarming a bit - I hope as it has hardly been warm enough to look in them and more cold is forecast over Easter, unfortunately. I have had a brief look in all mine, assessed size and stores, carried out a varroa assessment and a couple were dusted before the middle of March, and last week I was able to change all their floors for clean ones, (except the letterbox swarm which was spotlessly clean – I shall breed from them this year!). One small one seemed to have lost its queen so I shook the bees into the adjacent colony, also at marginal critical mass but with brood and queen, and hope the extra bodies will help them build up more quickly.
Keep watch on how much space the colonies have to prevent them feeling congested which can encourage swarming, but before adding any supers, remove any frames full of sealed stores. They are reluctant to uncap stores and they could be a barrier to brood nest expansion too. Also, when they do move it, it will be into the new supers, not what you want if you used a chemical treatment in the autumn or if it is mixed with sugar syrup. I label which hive they came off and store covered, indoors in a tray to catch drips or better still, in the deepfreeze and give them back to the appropriate hive in the autumn. I have a feeling I will have quite a bit to store as some colonies feel rather heavy. Although only 25% of mine had Apiguard, they were all topped up with syrup which they have been very economical with. Even the two seeming light when hefted, turned out to have sufficient on closer inspection, or rather just the right amount as it happens.
It is time to sow some nectar/pollen rich plants for your bees and other pollinators.
My cherry plum humming with bees when the sun shines, I counted (with difficulty as they would not keep still) over 8 bumblebees on it last week.
The European Food Standards Agency (EFSA) published their conclusions on 28.2.18 that the three neonics pose a threat to honey bees, solitary and bumblebees. They assessed the three routes; via nectar and pollen, seed treatment dust and via water consumption. So far so good, we must hold our government to any bans agreed, when/if we leave the EU.
Recent research suggests that bees infected with Nosema ceranae will select better quality pollen, (even though the scientists are unsure how they make this selection) which also prolongs their lives. This is a form of self medication. Healthy bees were not so selective. While I have found what little research there is on pollen quality is mostly on overseas crop plants, high quality pollens (ie protein rich) on plants we have apparently include clover, oil seed rape, pear, almond and lupin. Spring pollen tends to be more protein rich than summer, but may vary between regions and times. Fat and vitamin content may vary so it is difficult to generalise on what is most nutritionally beneficial. In another paper it was suggested that sometimes low quality pollen in abundance may be more valuable to a colony than high quality in short supply. Abundance and diversity should be our motto regarding flowers!
I also came across research (from USA) published last month which finds that hedgerows enhance biodiversity, reduce soil erosion, protect water quality and do not introduce food borne pathogens into crops. Well, well, I would never have guessed! Cynicism aside, sadly many of our farmers have already or want to grub up their hedges too. I believe how they are maintained is also important. A very short back and sides at the end of summer is not going to benefit anything. A thicker hedge cut late winter when the birds have had a chance to eat the berries, and alternate years if possible will enable more flowers, berries, nesting opportunities etc etc. As an ecologist I find all this painfully obvious but many of those lucky enough to have hedges don’t see it, sadly.
A bit of good news:
It is great to know that such a worthy cause as the Bumblebee Conservation Trust has benefited from the People's Postcode Lottery to the tune of £3000,000, in March.