There is a really interesting discussion going on under a thread called ‘No bumblebees’ under the Bumblebee discussion forum.
I have reproduced here a post I have just made to that thread, but thought it would of relevance to people surveying at this time of year.
I know it has been very disappointing for you to go to all the trouble of surveying and then finding hardly any bumblebees to report. But it is vital you continue your usual routine of monthly surveys so when we compare this year’s results to previous years we can see the full impact of this year’s late spring….
The late spring definitely affected when the queen bumblebees emerged from hibernation.
Activity seemed to pick towards the second half of April and the first half of May.
But like you, since then I haven’t seen many bees at all!
Like some of you I hoped that this could be down to the fact that queen bumblebees were stuck indoors rearing the first brood.
I do hope this is still the case but I’m still not seeing bumblebees in any significant numbers. They are doing better in gardens generally than in the wider countryside but this isn’t the case this year in central Edinburgh!
Had some interesting feedback from a very experienced beewalker (dated 29th May) and he has allowed me to reproduce some of his thoughts here
‘Anyway, with regard to your question below. I attribute the low count on the transect to a lack of suitable flowering plants along the transect at present. There are plenty of thistles, brambles and bird foot trefoil along the route but none of it is in flower yet. The spring has been much later this year than for many years. However up to the early 1980s, springs this late were not unusual. I’m old enough to remember them, and a look at the statistics of first blooming of fruit trees etc confirm it.. So a late spring should not in itself be disastrous for wild bees, in fact I think that the very mild winters and early springs of many the last 25 years were more of a problem for them.
In fact there have been lots of bumblebees around for about 6 weeks in my garden (Queens and workers of B. hortorum, terrestris and pascuorum plus a few pratorum). And there seemed to be just as many nest-searching queens around this year as in any year. I also know from experience that after they find nest sites there can be a quiet period with not many bees around when presumably they are in the nest incubating the first brood.
So we must see what happens. I think that the very cold and wet ‘summer’ we had last year here in the south could have had more of a bad effect, by flooding underground nests.
It is invariably the case that I see far more bumblebees in my garden than in the open countryside, simply because my garden is densely and purposefully planted with flowers for bumblebees. And this planting strategy really works, although of course they could be from a small number of local colonies.
It is also noteworthy that I am rarely seeing any honeybees at all in the garden now, and that local beekeepers are all complaining how their colonies have barely survived the cold winter and late spring. I think that honeybee stocks have been greatly weakened by Varroa and this has made them more vulnerable to viruses and/or amoebic parasites, and also less able to stand up to bad weather. I am told that honeybee decline is quite acute in this area. Apparently cherry and soft fruit growers north of here up in Herefordshire are now paying lots of money to buy in Koppert bumblebee colonies to pollinate their fruit crops (in the open or in open-ended polytunnels) because there are so few honeybees, and because their crops are so valuable. They are also experimenting, apparently, with Red Mason bees in electrically heated boxes designed to persuade them to emerge earlier than normal.
Meanwhile my Red Mason Bees in the garden are just romping away. Hundreds of them in the garden and what looks like a swarm of them around their large (unheated!) bee house, but of course they do not sting.
Interestingly I saw a number of butterflies along my bumblebee transect when I did the last walk. About five species, all adults which would have overwintered in hibernation. I suspect that they the cold late spring has kept them in hibernation longer. Unfortunately hardly any nectar plants for them in bloom either at present.’