Counting the Sound of Summer
by
Elizabeth Winder (1)
In the summer months, I have found a pleasant way to take gentle exercise - I beewalk. This activity has nothing in common with dogwalking – bees are non-demanding and don’t fuss if I don’t show up at my normal time. In fact, they won’t notice because they take all the exercise they need by themselves, and don’t miss my company. My role is simply to walk the same route once a month from March to September, recording the bees I see. I then report the results to the Bumblebee Conservation Trust (BBCT), an organisation working to prevent the further decline of bumblebees in the UK. The BBCT has data about the distribution of bumblebee species, but needs volunteer beewalkers to maintain good data about numbers and to identify current trends.
Bumblebee populations have declined substantially in the UK during the last 80 years, with 2 species becoming extinct. While honey bees are threatened by viruses carried by verroa mites, bumblebees are affected by food shortages, caused by the dramatic loss of flower-rich grasslands and hedgerows, and huge acreages given to single crops. For this reason bumblebees are probably more common now in suburban gardens than they are in the countryside.
Like honey bees, bumblebees are social bees, with a queen building a nest, raising worker bees and then the next generation of male and queen bees. Unlike honey bees, the nests will house only two to three hundred bees at most rather than several thousand, and unlike honey bees, only the new queens who have mated will hibernate over the winter to start a new nest entirely on their own.
The new queens need to build up their energy reserves at the end of the summer for hibernating, and when they emerge from hibernation they must find a good supply of pollen and nectar-rich flowers. Bees flying low over the ground early in the season are prospecting for a nest site, and may use a hole in the ground, a cavity in a building, or even a birdbox. Queen bees seen carrying pollen on their hind legs have already established a nest and are building up a food supply inside to support them while incubating eggs, or to feed the first hatched larvae. When the first worker bees emerge they take on the task of supplying the nest with food. Thus it is critical for bees to have access to suitable flowering plants throughout the season.
My interest in bees was sparked when I moved to a house with a small garden almost entirely covered in concrete. I built and planted raised beds in a sunny position and in no time there was a gentle buzz from the bees attracted by the flowers. I realised for the first time that there is more than one type of bumblebee. When some of them – white-tailed bumblebees – set up residence under an outbuilding, my interest was hooked, though only recently have I had time to follow up this interest.
According to the Bumblebee Conservation Trust, there is one species of honeybee in the UK, 24 bumblebee species, and around 225 species of solitary bee – bees which create a nest in which they seal their eggs in solitary cells with a food supply, then leave the next generation to develop without any further input from the parent bee. The bumblebee species include cuckoo bees, whose females (there are no workers) invade the nests of other bumblebees, often killing the queen, and leaving their own eggs to be raised by the workers of the host nest.
Southern Cuckoo (click to enlarge)
The number of species does not remain stable. A newcomer from France, the tree bee, arrived in the UK in 2001, spread north very rapidly and was first sighted in Scotland this summer. The short-haired bumblebee is currently being reintroduced to the UK, using Swedish queens, after becoming extinct here in 1988.
This is the third summer I have kept records over the same route (transect), and even in that time I have seen changes. The transect includes suburban gardens, road verges, a nature reserve, and streams. There are many large trees on or near the route, one of which houses a honey bee colony. The route is close to allotments and also to arable land where cereal crops and rapeseed are grown in rotation. There has been an almost complete absence of bees when the rapeseed has been in flower, though this may be a coincidence rather than cause and effect.
My first recording year was a dry summer following a dry winter, and undergrowth in the unmanaged areas was sparse, with plants producing few flowers that quickly went to seed. I saw very few bees and began to wonder whether I had chosen a poor route providing insufficient foraging.
The second year was very warm at the end of February, and from a bedroom window I had a grandstand view of a neighbour’s plum tree in full flower well before any other local flowers were out. The tree was visited by a large number of bees emerging from hibernation, some of whom obliging basked in the sun low on the house wall, so I could get close enough to identify them. Unfortunately the weather was very wet later in the spring, and some areas where queens had been nest-prospecting earlier in the year became waterlogged, so that any nests established there would have been flooded. Nevertheless there was a greater variety of plants in the unmanaged areas, they flowered for longer, and there were more bees.
This year the weather was exceptionally cold in the spring and the neighbour’s plum tree had finished flowering well before I saw any bees. In consequence there are no plums this year, clearly showing the vital role of bees in maintaining our supplies of fruit and vegetables. Anyone who tries to grow their own will already understand this! I saw queens of five species during my walk late April, then the weather became not only cold but exceptionally windy, and parts of the transect were flooded rather than just waterlogged. The tree bees seemed to do well during the cold spell but to my dismay I saw no workers from three of the species for several weeks. When the weather warmed again there was a sudden explosion of bees, including workers from the missing species and others I had not observed in the area before.
Tree Bee (click to enlarge)
The tall trees in my transect present some frustrations. If the tree is isolated, one can see bee traffic high up without being able to identify the bees. It is reassuring to know the bees are visiting a plentiful food supply, however for identification and recording purposes they need to be not more than 2 metres from the ground. If the tree is in a clump, bees can move around in the canopy unseen from the ground. As the trees gain their leaves and the smaller workers appear, it is impossible to spot them when the blossom is high up, let alone distinguish them from other insects. When the cherry trees were in flower, I could see bee traffic to one solitary tree, however a very heavy crop of cherries in nearby large tree clumps is evidence of how many I didn’t see! The many large willows, hazels, hollies, oaks, elders, ashes, and fruit trees flowering in or near the transect may be a superior attraction to the smaller plants at ground level, and explain why on some walks I see very few bees.
The cherries made tasty jam!
Here I should note that bees practice what is called ‘flower constancy’. For any type of flower, the bee needs to work out how to access the nectar and pollen. This exploration process takes energy, so it makes sense for the bee to move on to another flower of the same type rather than starting again with a different type of flower. This is why bees are attracted to large spreads of the same flowering plant. Bees also have smelly feet, leaving a chemical message to other bees not to waste their energy exploring an empty flower.
Not all flowers produce enough nectar or pollen to attract bees, and some popular bedding plants have shapes too complicated for bees to access. The BBCT website at http://bumblebeeconservation.org provides a wealth of information about how to encourage bees in gardens and also how to manage other types of land, such as brownfield sites, hedges, and field margins in a beefriendly way. There is even a Bee Kind tool to help you assess and improve your current planting scheme. Simple actions, such as not raking up all the autumn leaves, can improve the chances for overwintering bees. If they emerge from hibernation inside a compost heap they are unlikely to escape.
The website also offers forums on bee topics, identification information, the opportunity to upload your own photographs to contribute mapping the rarer bumblebee species or to obtain or confirm an identification. Most importantly, there are details of the many diverse volunteering opportunities with varying time demands, for individuals with an interest in bumblebees who want to support BBCT work. Raising public awareness is a key task to which volunteers contribute.
So far I have written about bees and not about people. As a controversial planning application may affect part of my transect, I was met with suspicion when I first walked slowly along my route with a clipboard! Rather puzzling – do I look like a council official? But not as puzzling as the dogwalker who thought I was afraid and insisted on reassuring me I was safe. I was pressing slowly into brambles at the time, trying to get close enough to identify a bee without startling it into flying away. If I had been trying to escape a dog, how would getting stuck in a bramble thicket – with my back to the dog - be a helpful strategy? Of course, by the time I had explained and dutifully admired the beautifully behaved, totally nonthreatening dog which was totally under its owner’s control on a lead, the bee had indeed flown away.
When I explain what I am doing people are usually interested, talk of their own bee experiences, and sometimes invite me into their gardens to see what is visiting their plants. Once I was invited to photograph some bees mating, though my photos didn’t turn out too well as I didn’t want to trample their flowerbed. Through doing a beewalk I have got to know my neighbours better, as well as watching how the cycle of the seasons plays out in my local area.
This year I attended a training session run by the BBCT at Harcourt Arboretum, a wonderful opportunity not only to develop my knowledge, but also to meet others who share the same interest and to practice bee identification as a group activity – a first for me. We used photographs and specimens, including some brought along by other participants, before walking through the Arboretum and catching some live bees. I had wanted to know more about some of the insects I had seen on my walks which were clearly not bumblebees, but looked a bit like them. This topic was also covered in the training.
One more beewalk before the winter, then next year all the UK beewalkers will receive the BBCT summary report of our activities this year. We’ll find out how far north the tree bees have travelled, and we will hear whether the short-haired bumblebees have taken to life in the UK. I will find out whether the same species will visit my garden, and most importantly – whether my neighbour and I can make plum jam!
Elizabeth Winder has worked in mental health in the UK for several years, earlier managing a mental health advocacy service in Oxfordshire, England. She worked on the European project Value +, led by the European Patients’ Forum, and wrote the Value+ Toolkit for Patient Organisations on Meaningful Patient Involvement – Patients Adding Value to Policy, Projects, and Services, with the input of patients and their organisations from around Europe. She keeps trying to be retired, but is currently advising on a project to support Romanian mental health service users to set up advocacy services