Oxford Bees


All hives upright after Storm Dennis passes through

Hot on the heels of Storm Ciara comes Storm Dennis. The UK experienced strong winds and very heavy localised rain. There has been flooding in some areas, but not in Oxford yet.

Looking at local wind speed and wind gust speed, Storm Ciara looks about the same strength as Storm Dennis. Gusts around Headington up to 30 knots; gusts around RAF Brize Norton around 45 knots. There was steady rain for most of the weekend.

Thankfully my hives have stayed upright. Nothing much to report. I just wish that the rest of the country could say the same.

Storm Ciara blows in. How does it compare to recent storms?

There's a lot of weather around. Last weekend brought Storm Ciara to the UK. Next weekend we'll get Storm Dennis.

There were fence panels down in our garden and a tree has blown down within sight of the house. The forecast was indicating gusts up to 66mph (57kn). It was noisy indoors.

Ciara seemed much stronger than usual, but how does it compare?

I have data for several weather stations going back to the start of 2017 (source: MetOffice WoW). My preferred weather stations are RAF Benson and RAF Brize Norton because they seem most likely to produce reliable results. Air fields tend to be in flatter, more exposed places so the wind gusts are probably as high as they'll be for that region. Urban wind patterns, and those for a valley like Oxford, may be lower. Unfortunately I don't have data for central Oxford and my urban data series (Headington, Bicester) are not continuous for the same period.

Wind speeds in Headington during Storm Ciara, Feb 2020
Wind speed (knots) in Headington during Storm Ciara, Feb 2020
Wind speeds in RAF Brize Norton during Storm Ciara, Feb 202
Wind speed (knots) in RAF Brize Norton during Storm Ciara, Feb 202

For comparison (values > 40 in bold):

month RAF Benson RAF Brize Norton Bicester AF Headington
Jan 2017 32.2 38.2 21.2 NA
Feb 2017 49.5 44.3 32.5 NA
Mar 2017 35.6 32.2 25.1 NA
Apr 2017 29.5 31.3 18.5 NA
May 2017 29.5 28.7 19.2 NA
Jun 2017 37.4 33 28.4 NA
Jul 2017 31.3 28.7 21.8 NA
Aug 2017 26.9 21.7 18.5 NA
Sep 2017 40 35.6 19.2 NA
Oct 2017 39.1 39.1 25.1 NA
Nov 2017 38.2 38.2 23.1 NA
Dec 2017 40.8 34.8 25.1 NA
Jan 2018 53.9 42.6 27 NA
Feb 2018 37.4 33.9 21.8 NA
Mar 2018 35.6 37.4 27 NA
Apr 2018 34.8 29.5 26.4 NA
May 2018 29.5 27.8 42 NA
Jun 2018 28.7 28.7 21.2 NA
Jul 2018 33.9 32.2 19.2 NA
Aug 2018 32.2 26.9 17.9 NA
Sep 2018 40 37.4 23.1 NA
Oct 2018 42.6 38.2 21.2 NA
Nov 2018 48.7 37.4 31.7 NA
Dec 2018 39.1 31.3 22.5 NA
Jan 2019 33.9 38.2 23.1 NA
Feb 2019 40.8 42.6 25.9 NA
Mar 2019 47.8 45.2 31.7 24.3
Apr 2019 40 35.6 25.1 19.1
May 2019 28.7 27.8 49.8 25.2
Jun 2019 33.9 32.2 NA 15.6
Jul 2019 33 25.2 NA 21.7
Aug 2019 40 34.8 NA 20.9
Sep 2019 34.8 33 NA 18.2
Oct 2019 37.4 33.9 NA 22.6
Nov 2019 42.6 37.4 NA 21.7
Dec 2019 37.4 37.4 NA 23.5

In terms of the absolute gust strength storm Ciara doesn't look much bigger than Feb 2017 or March 2019.

All central hives appear to be well

I've been visiting the hives in central Oxford every couple of weeks. There is still evidence of activity on the base board in all 6 hives (chewed cappings; dead Varroa; etc). I believe that they're all still alive and ok.

There are causes for concern though. All the hives have visible numbers of dead bees at their entrances. I don't know whether these were healthy bees which were stranded during cold weather or whether they were virus infected bees which crawled out of the hive. I presume the latter.

Four of the six hives have significant stores. Two are rather light and probably wouldn't last until spring unless I intervene.

Two swarms, but neither for me

Today I caught two swarms. It must be the weather.

Helen from my bee group is on holiday so I caught a very large swarm from one of her hives. It was tricky to catch. The swarm had settled around the trunk of a tree which had lots of stiff little branches. It was a little over 2m up.

Shaking the swarm at all was difficult. I upset the bees so much that I had to walk away for a while. Bees are supposed to lose interest if you walk under a tree. Not these bees. I swatted away with the low hanging branch of an Ash tree but they weren't having it. I was stung and then I found a couple of bees had found their way into my veil. I had to kill them. This was not my best work.

Somehow the shaking got the Queen into the box. From there I propped the box near the tree and let them sort it out. Five hours after the catch the tree had been deserted and most of the bees were in the box. They weren't happy when I sealed them in.

Top tip: use a box which opens on its shortest sides. If you try to seal a cardboard box along its longest side it may open and allow a few bees out. I can see them outside the window now. I hope they find their way home.

The second swarm couldn't have been simpler. I was offered a ladder when I arrived. I banged the swarm into a box from its branch in an apple tree. I let them settle a bit. I could see fanning. I could also see a lot of waggle dancing which I think meant that they were discussing a nest site. I shut the box sooner to end that conversation. Done.

This swarm was from the site in Barton where I've caught several swarms before. They are from a feral colony which lives in a capped chimney. The colony has been there since at least 2016. Sadly my 3 colonies from this source all died in spring 2018 during the very cold spring weather.

One of our bee group took both swarms. I hope they thrive in rural Oxfordshire.

June gap: evidence on the base board

My bee group talks about the 'June gap'. This is is the period where the spring flowers end and forage becomes scarce.

Many of the bee group are in rural areas of Oxfordshire where Oil Seed Rape is the primary crop. There are gardens and some hedgerows left, but their pickings are slim. In the city this is mostly not the case.

In central Oxford there are numerous gardens which are planted to bloom throughout the summer. There are the many rivers where the Elder has been flowering through June and the Iris (Flag) has been blooming. These areas are prone to flooding and so are less likely to be built on or put to single-use agriculture. The city must be beautiful if you're a bee.

All the gardens and green spaces won't completely compensate for the end of the blossom on the big trees like Horse Chestnut. The evidence on the base board of my city hives shows this. The lumps of pollen which drop off the bees' legs are much smaller -- perhaps half the diameter of the lumps which fall in peak time. There is a greater variation in colour at this time -- bright oranges; occasional deep reds; a purple and even blue.

There are lots of flights too. This indicates that there's something to do. I don't know whether they're returning full of nectar or with just enough to make it worth the trip. They might be bringing water or propolis. Whichever it is they're busy.

As June wears on I see that the Blackberry is in flower. This provides good forage for a while. The pale grey pollen is already dominating the base board. The plants grow prolifically around Oxford. Their seeds are distributed by birds and the plants will suffer any soil type. They'll flower during June and some of July and produce fruit during August and into September. With the arrival of the Blackberry flowers I call an end to any June gap.

A swarm, a rainstorm and a complicated start for Colony 18

It has been raining, windy and cold this week. From Monday 10th June to Thursday 13th June the number of flying hours may have only been 12 hours out of a possible 66 hours*. The constrain on flying hours is only hours above a minimum temperature:

date site day length 10C or more 11C or more 12C or more 13C or more 14C or more 15C or more
2019-06-09 Headington 16.6 hours 14.5 hours 14.3 hours 14.0 hours 12.8 hours 11.3 hours 10.0 hours
2019-06-10 Headington 16.6 hours 8.5 hours 6.8 hours 2.8 hours 2.2 hours 1.0 hours 0.0 hours
2019-06-11 Headington 16.6 hours 9.8 hours 0.8 hours 0.0 hours 0.0 hours 0.0 hours 0.0 hours
2019-06-12 Headington 16.6 hours 14.3 hours 12.3 hours 9.0 hours 6.2 hours 3.5 hours 0.0 hours
2019-06-13 Headington 16.6 hours 15.5 hours 12.8 hours 8.8 hours 3.5 hours 0.0 hours 0.0 hours
2019-06-14 Headington 16.6 hours 16.3 hours 16.3 hours 13.8 hours 10.8 hours 10.0 hours 8.3 hours

The rain and wind would have been additional constraints.

On Thursday lunchtime I went to check on the bees. I was concerned that Colony 17 might be starving. While I was there a swarm was pointed out to me. It was clinging to a tree about 6m up.

The weather had been so poor that they must have swarmed on Sunday or early on Monday. There were small mounds of bees on the floor looking very cold and wet. There were very few flying bees.

After some thought I decided to catch them. I reasoned that they had probably used up the honey in their stomachs. In this starved state there was a low probability that they'd be able to find a new nest site, occupy it and forage enough to survive. Stuck on a tree in the rain they might fall and cause a hazard for passing pedestrians.

On Friday morning I called the Oxford University Parks department. They were great. They arranged a team with a cherry-picker to come out. I really appreciate their help.

Once there I went up; shook the branch twice to get the bees into the box; and came down again. The catch couldn't have taken more than 5 minutes once the cherry picker was in place.

I had a hive ready. It had some comb from a previous colony. I also put in a tub of thick (but not fully set) honey. I tipped the bees into the top of the hive. There was no prospect of them walking in. I then did something unusual. I completely shut them in. It was a lock-in.

This morning I checked on them. They had moved up onto the comb. I removed the honey and opened their door. We'll see how they fare.


* Flying hours assume that the minimum temperature for flying bees is at least 13C when measured in Headington. The Headington weather station is a little over 4.5km away from my out-apiary site. The climate in Headington is noticeably warmer than in the valley where my out-apiary is sited. This apparent temperature difference is caused by humidity from the river. I do not have the data to support exact number of flying hours at a particular hive.

Colony 17 building comb

A quick check under the Varroa screen of Colony 17 showed that the bees are building comb. There were shiny wax platelets in a shower where under where they've clustered. There is also evidence that they're cleaning out other parts of the hive. I found 2 dead wax moth larvae and some other detritus.

It's still too soon to see whether they do have a Queen in there. I tried the 'knock test' -- to see whether they remain agitated after a knock on the side of the hive -- but it was inconclusive.


Feeding Colony 17

I don't usually feed my colonies. I'm especially cautious about feeding swarms because they arrive with honey which can contain spores from a variety of diseases including the devastating American Foulbrood. The usual advice is to leave the bees alone for a week. They will build comb and use up the honey which they arrive with.

When I put Colony 17 into their Commercial hive body I had too few full-sized frames. I increased the number by putting in shallow frames from a super. Yesterday I quickly opened the hive to replace the shallow frames with full-sized deep frames.

It was quite cold yesterday, with the temperature only briefly climbing above 13C. The colony was clustered in one corner; there were very few flying bees; there was no sign of comb building. Had they run out of stores? There is still forage around -- the wild roses are in bloom and the Elder -- but we are approaching the 'June Gap'.

I decided to feed them with sugar. They discovered it very quickly. I hope that it will replenish their energy so that they can forage when conditions improve. I don't like feeding because it may disrupt the normal behaviour of the bees. On this occasion I've relented.

Colony 17 arrives

I was called by Mary, a member of my group. She had caught a swarm from her top-bar hive in Headington. She kindly offered me the swarm, knowing how much I value untreated colonies.

The swarm is from a colony which Mary has kept, untreated, for about 2 years in a Top Bar Hive. Before that they came from a feral swarm somewhere near Steeple Aston in Oxfordshire.

I took the swarm down to central Oxford in the early morning and walked them in. They went in very willingly. The swarm was a reasonable size. I didn't see the Queen going in.

They seemed agitated in their box. Every movement causing them to buzz loudly. This might be a sign that they are not Queen-right (ie they have lost their Queen). A knock on the hive wall is the usual way to test whether they have their Queen. They'll buzz but calm down quickly if they do have a queen. I think that they'll need to be left for at least a week before I do that test.

June Harvest

On Sunday I harvested two supers of honey from Colony 1. They had filled three supers during the spring and had started building comb on top of the crown board.

Harvesting is fairly straightforward now. Cut; spin; strain; put into containers. Easy.

At the edge of one of the supers there was some louvred comb. This is where the bees cross-comb at the edge, reorienting their comb in a direction which looks like it's part of a circle. I cut this out. It's one of the downsides of comb without foundation. Over time I'm building up straight comb to put back into the hives so this happens less.

I also successfully extracted the foundationless comb without any damage to the comb: spin slowing on each side. Then a second spin on each side to get the remainder.

The first Wasp

I saw the first worker wasp of the season. She was hovering near Colony 1.

Earlier this season we saw a lot of Queen wasps. This suggests that it may be a waspy year. There have also been lots of aphids for the wasps to feed on. Wasps require mostly protein early in the seasons which they use to feed their brood. They switch increasingly to needing sugar during the season, which is why they try to rob honey bee colonies.

I have annual problems with wasps. These are most noticeable in central Oxford. I've seen wasps trying to rob my hives at dawn (6am), at dusk (10pm) and all through the day. This continual onslaught would destroy a weak colony so I stop down the doorways to a space about 9mm by 25mm. Even so the wasps still get in and may even be attacking the bees through the Varroa screen under the hive. It's brutal.

Three full supers on Colony 1

Colony 1 has been very busy. I opened the top today to find three full supers. The bees were even building above the crown board and would very soon have run out of space.

I lifted off two of the three supers and put two new ones in their place. Then I put a Canadian Clearer Board and replaced the two full ones on top. In a day or two there will be an early harvest.

We had a taste of the fresh honey from on top of the crown board. It had a light colour and subtle aroma which probably indicates Horse Chestnut. The taste had the intensity which only fresh honey can deliver.

Crawling bees and signs of Deformed Wing Virus prevalent across hives

Colony 1 has been continuously occupied for over 6 years. Every spring, except 2018, there have been bees crawling around outside the hive -- stricken with Deformed Wing Virus or some other paralysing virus. These bees became food for Sparrows.

This year seems worse than previous years. There appear to be more bees crawling and for longer. This might not be worse than usual but it feels it. In April it was mostly Drones which were crawling around. Now it is more likely to be workers.

Last season had a very cold spring. Four out of seven colonies died from starvation or isolation starvation (ie there were too few bees to reach the few stores that were left). There was a definite brood break which will have reduced the number of Varroa and may have been the reason that there were very few crawling bees that season. Observing crawling bees is confused by the Sparrows eating them. I think that in 2018 there was very little Sparrow activity.

This season there have been warmer temperature. I can't say for sure whether there was a brood break. There have been higher than expected levels of Varroa this season which suggests that any brood break that did happen had a limited effect on Varroa numbers.

All this points to higher stress in the established hives this season. Conventional wisdom would suggest that there will be colony failures. Perhaps this will happen. I would expect that this would be seen as colonies succumbing to robbing by wasps or other colonies if it does. We'll see what happens.

Honeydew falling from the Lime Trees

The Lime tree (Tilia Cordata, or the Linden tree) is found all around Oxford. As I cycle under the avenue of them on South Parks Road I can feel the slight prickle of honeydew falling.

Honeydew is a sugar-water liquid secreted by the aphids who live on the Lime trees. They suck the sap and excrete the liquid which falls in a light spray from the trees. The leaves quickly get a shine where large amounts of this liquid has dried on them. I've seen this in other places around Oxford.

Honeydew can be forage for bees. They collect it when there are fewer nectar sources. The flavour of the honey is said to be distinctive -- "very dark brown in colour, with a rich fragrance of stewed fruit or fig jam" (source: Wikipedia). Hopefully there will be some to collect from my city hives this season

Colonies 15 and 16 getting settled

I took a quick look at the stuff which has been falling out of Colonies 15 and 16 today.

The removable tray under Colony 15 had lots of new wax platelets, indicating that they're busy building comb. There were also at least 3 Varroa bodies. This shouldn't be a surprise. Varroa are in all the colonies which I've encountered. This period after swarming has no brood so all the Varroa in the hive are clinging to the bees. Every mite which dies now does so before it can infest a brood cell, which is good news.

While Colony 15 had very little comb in their hive, Colony 16 had lots. Much of this was brood comb from a previous colony. It was beginning to suffer from wax moth and was heavily propolised (brood cells are lined with propolis). After only 16 hours were was a thick mess of dropped comb on the removable tray. There were half a dozen wax moth larvae in various stages of development -- a vigorous swarm doesn't tolerate them. The detritus was so thick that I couldn't tell whether there were any Varroa. I'll have another look in a day or two.

One method of detecting Varroa mites amongst a thick layer of muck is to use Methylated Spirits (a mix of Methanoic and Ethanoic alcohol). This separates the mites from the muck, making them easier to see.

edit 25/05/2019: the flight patterns of colony 16 appeared to be the increasing circles which indicate orientation flights. It's hard to be certain. Individual bees are hard to see -- they are small and dark; they move quickly across a patterned background and there are lots of them.

Welcome to Colony 16

I received a call at lunchtime today that there was a swarm settled in Portland Rd, Summertown, Oxford. I went immediately.

The swarm was big. It was in the lower branches of an apple tree where it hung over a fence. I borrowed a ladder and just knocked the bulk of the swarm into the box and waited while they got organised. In went the remainder. Boxed.

Collecting could hardly have been quicker or easier. From phone call to me leaving with a box of bees was only just over an hour. Quick work given that I must have taken 30 minutes just to get there.

I was very grateful for the kind assistance of the neighbour Chris and to the home owner who gave us access. They were superb. This sort of help fantastic -- freely and kindly given -- and much appreciated.

I took the bees back to central Oxford where I left them, boxed, to calm down. At about 8:45pm I tipped them onto a sheet in front of the hive. The movement was immediate. In they started to go.

After a while the door became jammed with bees. More bees climbed up over the entrance and onto the front of the hive. It was a bit chaotic. The evening is still warm though so I hope they'll get organised before it cools down too much.