Having bumblebees nesting in the garden is a great way to learn about them. If you have a nest, you may at first just see a single queen carrying food to the nest, which she stores for her future offspring. A few weeks later you should see the first worker bees who will be helping the nests get larger, and hopefully they’ll soon be followed by new queens or males, which should mate with males and queens from different nests before the new queens go into hibernation.

Providing nesting sites for bumblebees can be as simple as just leaving a quiet spot somewhere such as a corner or behind a shed, and letting the weeds and grass grow tall. But if you want to go further than that, you could try making a bumblebee nest space yourself. We have teamed with up with the people at Hartley Botanic to produce this guide for making bumblebee nests. It may seem strange to think about nesting bumblebees in late summer, but if you make one now you may find that mice will use it over the autumn and winter. Bumblebee queens searching for nests actually seek the scent of mice when looking for nests. Having the mice in residence now could increase your chances of having your very own bumblebee nest next year.

So go on and have a go, and let us know if you have made any successful bumblebee nests yourself!

What is a winter-active bumblebee?

Since the 1990s, naturalists have noticed that, rather than hibernating, some bumblebees have been active all winter. Queens and workers have been seen foraging for pollen and nectar from a wide range of winter-flowering plants, and mating pairs have been recorded in February. These have almost all been identified as the Buff-tailed bumblebee (Bombus terrestris) and it is clear that a proportion of queens produced over the summer have begun to establish nests in the autumn instead of going into hibernation.

The Trust are working closely with the national recording body BWARS (Bees, Wasps and Ants Recording Society) to understand more about this behaviour – which species are involved, what’s driving the change, and how are they managing it?

To help, if you see a bumblebee between the 1 November – 1 March, please record it at iRecord. Include as much detail as possible – we’re particularly interested in answering these questions:

• Which species are involved? The Buff-tailed bumblebee is by far the most common, but there are winter records of several other species, though these may just be early-emerging queens.
• Which castes are involved? Queens, workers and males all tell us different things about the state of the colony they have come from
• Where in Britain are bumblebees becoming winter-active? How far north and is this just an urban phenomenon?
• Are the bees collecting pollen from the flowers or just feeding on nectar (or both)?
• Which species of flowers are being visited?
• What weather conditions are best for the bees?

If you do see any winter-active bumblebees it is particularly useful to have a series of repeated observations (e.g. weekly or fortnightly visits in suitable conditions, or a series of observations under varied conditions). This lets us better understand the dynamics of winter-active populations and which weather conditions they can best forage in.

What do we know so far?

Traditionally, hibernating queen bumblebees in the UK would emerge in the spring (roughly March-May depending on species and weather conditions), and establish a nest (in some cases with a partial second generation). As summer fades to autumn, the old queen and all of the workers and males would die off, the new queens would enter hibernation, and from October onwards our skies would be bare of bumblebees.

In recent decades however, this has not always been the case. From the 1990s onwards, bumblebees have been recorded actively flying and foraging through the November-February period. Several species have been reported, although most have been queens in February and are likely to represent queens emerging early from hibernation. For the Buff-tailed bumblebee, however, queens and workers have been seen actively foraging from October right through to March, collecting pollen as well as nectar, and males (and mating pairs) have been seen in early spring. Occasionally, the nests themselves have even been found.

These nests are able to survive on the increasing amount of forage resources available throughout the winter (both non-native plantings such as Mahonia and longer flowering seasons of native plants such as White Dead-nettle). Key flower species seem to be Mahonia (several species and hybrids), Winter-flowering Heather Erica carnea, Winter Honeysuckle Lonicera x purpusii, and Strawberry Tree Arbutus unedo, but foraging has been recorded from a wide range of plant species over the course of the winter. In at least some cases these nests are able to produce new reproductive individuals in spring, so the production of winter colonies is not a dead loss to the population, although it is unclear whether enough colonies survive that

Many of the sightings are in towns and cities. This may be because these tend to remain warmer than the surrounding countryside through the Urban Heat Island effect; alternatively there may be more winter flowers in towns than in the countryside (some non-native species such as Mahonia are common in amenity plantings and in gardens but scarce in wilder areas). It may just be that there are more people in towns so more eyes to spot bumblebees!  There are some sightings in the wider countryside, especially along the coast in the south and south-west, but winter-active bumblebees have been recorded as far north as Edinburgh and Dundee.

Wherever you are there’s a chance of seeing a winter-active bumblebee – please do send in any sightings to iRecord.

A scientific article on winter activity and foraging rates of bumblebees was published in 2010 (Stelzer et al) and can be downloaded for free from the journal website. An update is in preparation.

Frequently asked winter bumblebee questions:

• I’ve found a stranded bumblebee in bad weather, how can I help it? 
• I’ve disturbed a hibernating bumblebee, what do I do? 

By Ron Rock, Bumblebee Conservation Trust Volunteer

Don’t worry, to the best of my knowledge we are not about to be invaded, at least not by a belligerent force. However, the forces of good are beginning to stir, nest hunting queen bumblebees are on the move, one of which was recently described to me as the size of a B52. If you own a patch of pulmonaria or early flowering comfrey keep an eye open for a small ginger bee with a distinctive high pitched buzz and whizzing flight for this will be a male hairy footed flower bee. This bee jealously guards his chosen flowers, only allowing females of the species to forage in his patch. This way the all black females gain a protected pollen and nectar resource and he gets to perform the function that male bees are designed for, all in all a rather neat arrangement!

Many more of our 240 plus species of solitary bees will soon be emerging including one of my very favourite creatures, Osmia bicornis, the red mason bee. Red mason bees are a univoltine (single brooded) spring flying solitary bee active from April to mid June and occasionally a little later. They are approachable and docile little bees which are not given to stinging and so are safe around children and pets. Like all bees it is only the females that carry a sting and it has been said that the only way a female red mason will sting you is if catch her and roll her between your fingers! Red mason bees are hugely beneficial to our gardens and crops as they are excellent pollinators of fruit trees, together with a wide range of wildflowers. A single female red mason bee can do the pollination work of 120 honeybees and may in the future be commercially reared to pollinate fruit orchards in the U.K.

Male red mason bees emerge around two weeks before the females. When the females emerge they are mated by the waiting males and immediately set to work establishing a nest. Red mason bees use mud to build a linear row of chambers that they provision with a mixture of pollen and nectar into which an egg is laid and the cell is then sealed and work begins on the next one. This method of feeding their offspring is known as mass provisioning, bumblebees and honeybees employ a technique called progressive feeding, where the larvae are fed by worker bees as they grow. It takes a female red mason bee between 1 -1.5 days to build and provision one cell. The eggs hatch after about a week and the resulting larvae eats the pollen and nectar in the cell.

After around 56 days the larvae spins a cocoon and remains in this state within the cocoon for a further 48 days before metamorphosis into an adult bee takes place. The bees then remain quiescent within their cocoons until emergence time the following spring. The sole function of male is to mate with as many females as possible, drink copious amounts of nectar and eat pollen (well, boys will be boys). The males die off after about 6 weeks and the last females are active until mid June when they too perish. No red mason bee ever lives to see its own offspring and the sight of tattered and sun bleached almost grey females is a sure sign that spring is handing over to summer.

In a completed nest, male (unfertilised) eggs are laid in the cells at the entrance (vestibular) end of the nest and these are the first to hatch out in the spring. The end cell is always left empty and sealed with a thicker wall of mud than used in cells containing the eggs. This is a form of protection from predators and other species of bees and wasps which might otherwise nest in the vestibular cell and make it impossible for the red masons to emerge from the nest, thus causing them to starve to death. The cocoons consist of two layers, an inner silky lining and a surprisingly tough outer layer. The cocoons are white when spun but soon revert to the familiar brown colour shown here. On hatching the bees secrete a substance that softens the outer layer of the cocoons to aid emergence.

Bee nesters (bee hotels)

These are some of my nesters at home, mason bees always look along edges for a nesting site, the linear edge in this case being provided by the hedge beyond.

Red mason bees are our most numerous osmia species and it is surprisingly easy to attract them into our gardens. All you need is a bee nester, I don’t like the term bee hotel as the name gives the impression of a short stay, when in truth the bees once established spend their whole life in and around these structures. They can be bought though I prefer to build my own as a lot of the commercially available ones are not too well made. The nesters are stocked with cardboard tubes and liners, bamboo or routed out wooden trays, 8mm is about right for red masons. Nesting cavities should be at least 160mm long. The boxes with the single holes are release chambers where cleaned and overwintered cocoons are placed each spring. I no longer use drilled out logs and I will expand on these last two statements later in the year.

‘The Red Storm’
The males emerge first, a trickle then a flood. They spend their days jostling and jousting outside the nesters and occasionally nipping off to refuel before rejoining the riot whilst waiting for the emergence of the females. They seem to know when this will be as the activity becomes even more frenetic! Once mated the females start their nesting activity collecting mud in their mandibles and pollen on the underside of the abdomen. The males fade away and the activity becomes more ordered and fascinating to watch. These bees work so hard and by the end of June you are hopefully left with lots of tubes neatly capped off with mud. So sit back and enjoy these lovely little bees, they are like a fine wine served with the main course of bumblebees. A little later in the year, afters are served a la leafcutter bees, but that is another story!

Bliss! You can spend hours watching these cracking little bees!
Part 2 will follow in September/October when I will let you see how I look after the bees over the wintertime.
If anyone has any questions please feel free to e-mail me at ronrock@phonecoop.coop

By Helen Dickinson, Surveys & GIS Officer

There has been a ‘buzz’ around the words citizen science for quite some time and the involvement of members of the public in scientific monitoring and research is increasingly relevant in a world with increasing demands for data around the continued loss of biodiversity. Citizen science is an incredibly important way individuals can contribute to conservation in the UK and across the globe. The large quantity of data required to get a good understanding of what’s happening to our habitats and species is something that we need as many people as possible out recording.

There is an ever growing number of ways that people can get involved in citizen science biological recording: from seaweed searches to ladybird counts, to bat roost monitoring and commitments from one off, to monthly, to annually, means that the range of schemes available provides something for everyone. See detailed list of surveys.

There are many reasons why people choose to become citizen scientists, including to support scientific research, to get fresh air, to develop identification skills, to meet like-minded people and the benefits to people as well as the schemes they contribute to, are becoming increasingly evident.

Volunteer recording links people to their local natural areas, encouraging a greater interest and equipping amateur scientists to monitor their changing environment and play a role in the natural world. Having a better understanding of local species and habitats empowers people to take on guardianship roles and increase awareness in their own communities.

The benefits of being outside and engaging in the natural world are highlighted more and more, with positive impacts on mental as well as physical health. It’s wonderful to have a reason to observe the changes in the season and get better acquainted with the wild world on our doorstep, and doing so whilst contributing to scientific research is a win-win!

You don’t necessarily have to be an official part of a recording scheme either, there are many ways you can now submit all types of wildlife records that you may encounter in your garden of when you’re out and about. If you’re really new to identifying species iSpot is your first port of call. You can upload photos and get help on identification of all types of flora and fauna from the UK, and you can also help identify other photos on the website which is a great way to get involved whilst improving your own identification skills!

If you’re ready to get recording iRecord is an online portal where you can submit all your wildlife records in one place, where they will be collated and checked by experts and made available for research and policy making, all via the National Biodiversity Network (NBN). This data is also shared with National Recording Schemes and Local Environmental Records Centres (LERCs). These LERCs are often a great local resource and you can often submit records directly to them for your local area.

There is a balancing act in play when creating citizen science projects, with a need to ensure schemes are accessible for the amateur scientist whilst also ensuring collected data is accurate and usable from a scientific perspective. This is hugely important, particularly for national monitoring schemes like the Trust’s BeeWalk scheme, and this is why there can seem to be a frustrating set of criteria that need to be met to submit data!

Particularly for people completely new to biological recording, there can be obstacles and the set methods required to be followed can occasionally feel daunting and unnecessary. This is where adequate resources and support comes in: it can be easy for those running schemes to forget how alien things like counting insects and submitting data to an online portal can be to people doing it for the first time!  At the Trust, we have been working hard behind the scenes and we are now able to offer more support than ever for our own BeeWalker citizen scientists. A big part of my role as Surveys and GIS Officer for the Trust is to support BeeWalkers through the process and be on hand to offer advice and assistance when required.  If you think this is you, please do get in touch via beewalk@bumblebeeconservation.org.

BeeWalk is the only standardised national recording scheme for bumblebees, but it’s still a relatively new scheme.  It began as a University of Stirling PhD project, undertaken by Leanne Casey (supervised by Professor Dave Goulson) entitled ‘Using citizen science to monitor bumblebee populations’.  The scheme was opened up to Trust members in 2010 and then to the general public. The early years began with just 1 transect walked in 2008 with 226 individual bumblebees recorded: this has now grown to 373 transects, with over 18,000 records of more than 54,000 individual bumblebees received in 2016.

The aims of the recording scheme are to:

• collect long-term data on bumblebee distribution and abundance
• analyse data to identify population trends
• use findings to inform BBCT projects and policy work
• improve understanding of forage plants preferences
• identify impacts of habitat and climate change
• identify impacts of management
• encourage public understanding of bumblebees and the changes they are facing.

The ability to monitor population trends for bumblebee species enables us to detect population declines over time, meaning the scheme can act as an early warning system to changes in species abundance. Holding up-to-date national population data allows us to better target our conservation activities and ensure that the advice we provide, including to governmental organisations, results in policies such as National Pollinator Strategies, which reflect the current needs of our bumblebee populations.

We have a fantastic group of regular BeeWalkers but we need more, could you help? Bumblebee monitoring involves choosing a set route, generally of around 1-2 miles (although it can be any length!), setting this up on the BeeWalk website, then walking it once a month between March and October and counting and identifying the bumblebees you see. Basic knowledge of how to identify common bumblebees is required, you can find help with this on the Trust website Identification and also keep an eye out on our events page for identification workshops throughout the summer.

Our citizen scientists contribute a massive number of hours to BeeWalk every year, and we really couldn’t run the scheme without them, it’s an incredibly important way you can contribute to bumblebee conservation, if you’d like to find out more please see www.beewalk.org or email beewalk@bumblebeeconservation.org.

By Peter Lawrence, Trust member and keen gardener.

Here, Peter gives us a run-down of his best plants for bumblebees in winter. As Peter points out, bumblebees are becoming increasingly active in the winter months when they would normally be hibernating. If you spot a bumblebee this winter, you can report it to BWARS for their special survey on winter-active bumblebees.

I don’t know about you but every time I see a bumblebee my morale takes a little leap upwards before it starts to sink again. They are wonderful beasts.

We have a large garden and I try to grow nectar-rich flowers all the year round. I thought my information might help others with ideas for flowers that the bumblebees evidently like, particularly during the harsh winter months. I know they are supposed to be underground in the winter, but the winters are getting shorter and I see bumblebees every month of the year in my garden, near Cambridge, on alkaline soil.

One group of plants that can flower from summer and well into autumn are the calaminths (Calamintha). They will provide food for the new queens before they go into hibernation.

But as we move into autumn, November can be a tricky month for flowering plants. The ivy is still flowering in some places well into late November, and that can be a great source of pollen and nectar. Indeed the ivy bee (Colletes hederae) relies on the food from ivy flowers. This species is a recent arrival to England and we have them in our garden well into November.

There are also autumn crocusses (Colchicum autumnale), and plenty of flowers on the wonderfully-scented Viburnum (Viburnum x bodnantense), but I don’t see the bees appreciating it so much. We have some sternbergia (Sternbergia lutea) which would have golden yellow, goblet-shaped flowers if it weren’t for the pheasants which eat them! This November, some of the salvia are in a sheltered site and still undamaged by the frosts so they provided nectar for some busy late queens, particularly the Tree bumblebee (Bombus hypnorum) and Buff-tailed bumblebee (Bombus terrestris).

I have to admit, we don’t have much on offer in December. Between cold snaps there are fresh flowers on the Autumn-flowering cherry ‘autumnalis’ (Prunus x subhirtella) and still some late autumn crocus and that’s about it. November and December do present problems for any bees that are still about, so if anyone has any good ideas please tell us.

January is a most difficult month, but the Autumn-flowering cherry should still be in flower, and the Christmas rose (Helleborus niger) should begin to bloom too. If it’s at all mild, the really essential winter honeysuckle (Lonicera x purpusii) will provide fresh flowers and nectar for all manner of bees well into the spring. In sheltered parts of the garden the first crocusses, snowdrops (Galanthus) and aconites (Eranthis hyemalis) may be flowering and the bees like these, as well as the winter iris (Iris unguicularis).

In February, the various mahonias are favoured, and they sometimes flower in February. After the winter honeysuckle, the most important of all winter-spring flowers for the bumblebees is stinking hellebore (Helleborus foetidus). This wild hellebore is preferred over the Helleborus orientalis, although they like those also.  Every garden should have as many Hellebores as possible; they grow in shade and all the bees, including the Hairy-footed flower bee (Anthophora plumipes), the mason bees (Osmia bicornis) and the queen bumblebees go for it. They usually start to flower in March and various cultivars will keep going well through the spring and early summer.

In March there are now plenty of flowers, the bees will visit the honeysuckle (Lonicera) and the Hellebores while the plum blossom (Prunus mume) may be starting. Norway maple may come into flower this month, and can be very attractive to the first queen bees to emerge from hibernation.”

To find out more about how to make your garden better for bumblebees, visit our Bee the change resources.

By Suzanne Rex, Conservation & Volunteer Assistant

I began working at the Bumblebee Conservation Trust in February 2016, answering a number of enquiries and helping out in the office. Starting this job with little knowledge about bumblebees and other pollinators, I have been required to research a great deal of information for email replies. This opened my eyes to the huge diversity and importance of pollinators. One group of bees which I found particularly interesting were Leaf-cutter bees, which is why I decided to write a blog about them.

As well as the social living bumblebees and honeybees, there are over 225 species of Solitary bees pollinating the UK. They are called solitary bees as they have no social caste and basically fend for themselves and their offspring. Leaf-cutter bees belong to the Megachilidae family, and are a fantastic pollinating group for a variety of fruit, veg and other plants including wildflowers.

Some species, like the Silvery leaf-cutter bee (Megachile leachella) and the Coast leaf-cutter bee (Megachile maritima) can be found nesting in groups called aggregations, although each female tends to their own nest cells. However, most species choose to nest in existing cavities on their own. Leaf-cutters have been found to nest in a variety of places such as dead wood, hollow plant stems, cavities in walls and occasionally in the soil. Commonly found in gardens, these bees are widespread across the UK, though they have a smaller presence in the north.

One of the most common species of Leaf-cutter bee is the Patchwork leaf-cutter (Megachile centuncularis). Patchwork leafcutters look similar to honeybees, though the females have a patch of hair beneath their abdomen called a pollen brush. The pollen brush is used for storing pollen, as opposed to most other bees which store pollen in pollen baskets on their hind legs. Intriguingly, some Leaf-cutter species including Patchwork leaf-cutters lift their abdomen up into the air while feeding; see this video to watch this distinctive foraging behaviour. However, they are probably best known for their trick of cutting neat, semi-circular pieces out of rose and wisteria leaves to take to their nests. These bees will grasp the leaf cutting and carry it underneath their body to their nest. The Patchwork leaf-cutter will glue the overlapping pieces of leaf together with saliva to use as lining, in order to build individual cells for their eggs which are sealed off by more pieces of leaf. Within each cell, the egg is provisioned with pollen to provide the hatched larvae with essentials to grow. This pollen can come from a variety of flowers including legumes like runner beans, as well as berry flowers like brambles. The larvae will then pupate into adults in autumn and hibernate inside their cells over winter.

Make a home for the bees

Like many solitary bees, Leaf-cutters can be limited by the amount of available nesting habitats. The good news is that this is something we can all easily do something about – by creating a bee hotel. Leaf-cutters and other solitary bees are great for pollinating your fruit and veg, so why not help them out and entice those that like to nest in cavities into your garden? Bee hotels are great to watch, provide lots of entertainment and are available to buy in most garden centres.  You can also make one yourself which is cheap and easy. For 5-star accommodation all you need to do is find an untreated block of wood and drill holes of varying diameters into it (2-10mm), but not all the way through the wood. Try and make the holes as smooth and splinter-free as possible, as splinters can damage their wings. It is also important that rain does not get into it so the gaps should be created at a slight incline. The hotel should then be propped up or mounted onto a sunny, south facing wall and at least a metre off the ground. Another option is to find sections of old, hollow bamboo canes (around 20-30cm long). Tie the bamboo sections together, or place them into a plastic drinks bottle with both ends cut, and hang them horizontally in a sunny and sheltered position.

Many bee hotel designs and ideas can be found on the internet to help. It is best to replace the holes in your hotel every two years, as this prevents the build-up of fungus and parasites. Patchwork leaf-cutter can be seen between mid-June to early September, so if you can set up a home for the bees soon, you may find it is used this year. If not, it will be ready for next year’s bee season in spring!