As well as doing the annual butterfly survey at Lauriston Farm, volunteer Huw Pennell also surveys our bumblebee populations as part of the national BeeWalk project. Here he explains how it works, and the results of the 2024 survey…

What is The BeeWalk?

The BeeWalk is part of the standardised national bumblebee monitoring scheme, which has been running since 2008. I set up the BeeWalk at Lauriston Farm at the same time as the Butterfly walk in May last year, creating a set route to walk for my surveys, called a ‘transect’. I do the survey walk monthly (as opposed to the weekly Butterfly walks), to capture the life cycle of the bumblebee population.

What is the Life Cycle of the Bumblebees?

The overwintering/hibernating young queens emerge in the early part of the year. These will tend to be the largest bumblebees you will see. In early spring, they are building their energy by feeding from the early flowers, and flying low overground looking for suitable nesting sites. They usually use abandoned mice or vole holes, or thick expanses of grasses. Bumblebee nests are much smaller than honeybee nests or hives, housing from around 40 to 400 bees (whereas a hive could have 50,000 honeybees).

During the late spring and early summer, once the queen has established her nest, look out for the smaller female worker bees, who fly urgently amongst the flowers looking for nectar and pollen to feed the next generation of workers and, later in the season, the new queens and males. These worker bumblebees are vital pollinators –  and much more effective pollinators than honeybees, thanks to their variety, strength and ‘buzz pollination‘.

In the late summer and early autumn you can see the males and the new queens, who will mate with a male soon after leaving the nest. The queens are the larger bumblebees you see at that time of the year, building up their fat reserves in preparation for hibernation. As the weather cools, the old queen dies, as do the remaining workers and males, and the life cycle starts again.

What Types of Bumblebees Are On the Farm?

In the UK there are 24 resident species of bumblebees. Six are known as ‘cuckoo bees’ who parasite the nest of their host species. There are eight common species which are known as ‘The Big Eight‘. On Lauriston Farm, we are lucky to have recorded six of these common species in 2024 (one less than last year) and one species of cuckoo bee along the transect.

The most recorded was the ‘all ginger’ Common carder bumblebee (see picture). This was also the latest recorded bumblebee flying throughout September and October.

Common Carder on Comfrey, by Huw Pennell

The earliest recorded was the Buff-tailed bumblebee. The Buff-tailed queens, with their classic, black, white and yellow stripes, are one of the largest bumblebees you will see in the Spring and Autumn. The other species recorded were the Garden bumblebee (which has the longest tongue of our native bumblebees, for foraging on long-tubed flowers such as foxgloves and comfrey), the White-tailed bumblebee, the Early bumblebee and the Red-tailed bumblebee. Plus, the Southern cuckoo bumblebee, which takes over the nest of its host, the Buff-tailed bumblebee.

According to The Bumblebee Conservation Trust, this has been the worst year on record for UK bumblebees. The Red-tailed bumblebee, which nests later in the year than many others, was the most affected of the common bumblebees, with their numbers plummeting by 72%. In line with the UK-wide picture, the Red-tailed bumblebee came the lowest of the ‘Big Eight’ in my count on the farm.

Surprisingly, I did not get any sightings of the Tree bumblebee this year at the farm. This is a relatively recent arrival into Scotland, having arrived from the continent in 2001. It is now very common in Edinburgh, so it was a surprise that it was not recorded. It is short-tongued and visits many cultivated and wild plants including wild raspberry (very common on the nearby Corstorphine Hill transect) and brambles.

The recording season starts again next spring. With the continuing development of pollinator-friendly flora on the farm, I hope we will see a growing number of bumblebee sightings and species next year, and a recovery of the Red-tailed bumblebee – my personal favourite.

Key Numbers

(brackets reflect comparison to same recording period last year)

Number of recorded sightings on transect: 90 (-54%)
Highest number of recordings on a single day: 49 (-28%)
Most common recorded species: Common carder bee = 40% of all recordings
Number of recordings of Red-tailed bumblebee: 5 (-81%)
Earliest recorded bumblebee: Buff-tailed bumblebee
Latest recorded bumblebee: Common carder bee

Huw Pennell, October 2024

As with the butterflies, it’s upsetting for us at Edinburgh Agroecology Co-op to see these low numbers compared to last year. We understand it’s connected to the weather this year, rather than being a particular issue at the farm – especially as it’s in line with the UK-wide picture. But we do not see this as a one-off ‘bad year’. The UK has seen decades of declining numbers of bumblebees (and loss of two species) amongst much else.

We believe agroecology can stop this decline, and bring life back to farms. Farms should be biodiverse places: good food comes from healthy living systems, and as the Landworkers’ Alliance says, Agrobiodiversity = Resilience. And when we have biodiverse farms connecting with biodiverse corridors to biodiverse allotments, parks, burns and rivers, gardens and woods, we can have thriving ecosystems again.

As an antidote to distress and despair, we believe in doing what you can, where you are. We welcome volunteers at the farm – click here to see the upcoming sessions. Also, if you have a growing space of your own, join us for a free workshop on Thursday 7th November on wildlife-friendly food growing.