Counting bumblebees for the ‘Volunteer Monitoring of Farm Wildlife’ project

This year, the RSPB is piloting the Volunteer Monitoring of Farm Wildlife (VMFW) project.  Below is a diary account from one of our volunteer surveyors, Lynne Roberts.

We are told that our farmland ecosystems are in crisis and that farms these days offer little to the wildlife which depends on the special habitats that can exist in the farmed landscape. And while the crisis message is true, I have seen at first-hand how farms can provide places for wildlife to feed and breed.

The opportunity to see how this can happen was provided by the Volunteer Monitoring of Farm Wildlife (VMFW) project, which is piloting in Cambridgeshire and Wiltshire. I was keen to help and put my name down to do some invertebrate surveying in Wiltshire, not knowing at that time what was involved and how rewarding (and tiring!) it would be. It is an ambitious project, aiming to provide a wildlife surveying and monitoring service to farmers through a large volunteer workforce, many of whom will be the boots on the ground throughout the breeding season, recording birds, bees, butterflies and pollinators.

It was early June, and I was itching to get started on the first BeeWalk, so I donned my boots, stepped out of my car and looked around over a sweep of huge fields of wheat and linseed, with woodland in the distance. It was a breezy day, slightly overcast, and I really wasn’t that hopeful of seeing very much. However, as I hiked up a chalky track to the start of the survey route I had agreed with the farmer, one or two queen bumblebees crossed my path and my spirits lifted.

Wiltshire is a county of wide-open spaces. Undulating chalk downland abounds, broken up by woodlands, river valleys and clay vales, with farmland that is characterised by large fields and small isolated tree clumps. My allocated farm certainly had very large arable fields, but I became aware as I walked that there were significant strips of land which looked ‘different’. I remembered my farmer pointing out the areas where he had sown wild bird seed mixes, both for Grey Partridge and Corn Bunting. He also highlighted on my map where there were long established grassy field margins, and where there were areas of arable reversion which had been in place since 2000, of which he seemed especially proud.

As I stepped through the gate at the top of the path, I could see why the farmer was so enthusiastic about the arable reversion. A spectacle of colour lay before me, carpeted pink and white, alive with the buzzing of bees. I was stunned at the beauty of it, and slightly nostalgic for a time when this would have been a much more common sight. However, I was there to do a job and the challenge of now trying to count the constantly moving dumbledores was not an easy one! (Dumbledore is a rather lovely archaic word for bumblebee.)

Image: (c) Lynne Roberts. Arable reversion area – a magnificent sweep of species-rich grassland

Armed with a clipboard, butterfly net and ID sheets I set off, looking to one side of the path and the other, constantly tallying Red-tailed, White-tailed, Buff-tailed, Common Carder, all busy foraging on the Sainfoin. As I looked closer, I could see that the pink Sainfoin was definitely the flower of choice for the bumblebees, although other insects were frequenting the Ox-Eye daisies and a variety of other flowering species nestled lower down. Tortoiseshell, Red Admiral and Common Blue butterflies, Burnet moths, flower beetles and spiders – a microcosm of activity!

Image: (c) Lynne Roberts. Two different species of bumblebee on Sainfoin

My BeeWalk survey route was divided into three sections: through the arable reversion, across an area of semi-natural grazing land, and then alongside a wide field margin backed by a scrubby hedgerow. The survey methodology required three walks at monthly intervals, and it was interesting to see how the distribution of bumblebees across the three sections changed over the season.

The glorious arable reversion meadow was cut for hay in early July (how wonderful and aromatic that hay must have been!) and the next time I visited the farm, the bees had all but vanished from that area. However, by then the field margins were coming into their own, with flowering species such as Wild Marjoram and Bird’s Foot Trefoil lighting up the long grass. In these margins, combined with the flowering of the linseed crop, there was plenty of foraging to sustain the bees.

Image: (c) Lynne Roberts. Field margin in June, not yet in flower

Image: (c) Lynne Roberts. Field margin in July, showing Wild Marjoram in flower, taking over from the Knapweed which has nearly finished

As I walk the grass margin section of the BeeWalk route I see the bundles of black fluff buzzing in and out of the delicate blue flowerheads of the linseed, weighing each one down as it lands, before springing back up again. I also note a few butterflies alighting on the linseed flowers, and it occurs to me that I hadn’t really thought of butterflies as pollinators. I suspect they are not quite as good at it as the hairy bumbles, but useful all the same, and of course beautiful too! I will spend the afternoon doing a few Flower Insect Timed (FIT) Counts to look at the pollinator groups in more detail, but for now it’s all about the bees.

Image: (c) Lynne Roberts. Bumblebee working the linseed crop

I count a total of seven out of the ‘Big 8’ bumblebee species that I am looking out for, with over 300 individuals recorded. An amazing result that I am excited to tell my farmer about.

The farmer tells me he cuts the first 3m of the margins in late July, leaving the remaining 3m or so as permanent refuge areas to become part of the hedgerow ecosystem, which seems a good idea to me since that means there is always somewhere to provide a home for the wildlife that makes a living in those environments. And by removing the arisings from the cut area he will be keeping the sward open and nutrient-poor, allowing the flowering species to thrive. He certainly seems to be doing a good job for the bees, since each of the queen bumblebees that I observed would have needed somewhere safe to nest, either underground in a sheltered spot, in a hole in some deadwood, or low down in the undergrowth. This aspect can often be overlooked, since the requirements for breeding are not as visible and obvious as the feeding requirements.

As the summer hots up (and it got SO hot out there this year!), there will be more butterflies around as the seasonal flights of the different species coincide, and I will see the later-emerging male bumblebees and cuckoo bees join the throng, working the flowers in the margins and in the bird seed mix areas which I have seen developing through the summer.

Image: (c) Lynne Roberts. Bumblebee on Bristly Oxtongue in an area of wild bird seed mix

When I reflect on this season’s surveying, I realise that my views on the amount of wildlife on farmland have changed considerably. I had thought that our countryside was a barren wasteland for wildlife, but when you look closely, as long as there are areas for nesting, shelter and foraging, there can be a healthy patchwork of habitats that all can benefit from, human and wildlife alike. 

I see the farmer as I make my way back to the car from that first survey day, tired, but in a good way. We chat, and he smiles as I recount some of the things I have seen. ‘Good day then’, he says. ‘Amazing!’ I reply. And it was!

The project is still under development and we anticipate continuing with trials in just Cambridgeshire and Wiltshire into 2023. But if you would like further information, please contact farmsurveys@rspb.org.uk.