Why we need more bumble bee nest boxes in gardens

Increasing importance of parks and gardens for wildlife

Parks and gardens can comprise of a large proportion of a town or city, particularly in the suburbs and as in the countryside, parks and garden form a fragmented mosaic of forage habitats for bumblebees and other wildlife. Although gardens may be individually small, collectively they account for around 3% of the total land area of England and Wales, with over 3 million hectares in the UK which is more than all the nature reserves added together. Such areas can be linked to other urban areas that bumblebees forage, including roadside verges, railway lines, disused railway lines, cycle paths, cemeteries, allotment sites, churchyards, disused and used canal paths, all providing habitats for bumblebees to forage. It is becoming increasingly important, that faced with increased hostility to wild bees, bumblebees and other wildlife in the agricultural environment, parks and gardens in urban and suburban areas now play an important, perhaps even decisive roles in the survival of bumblebees.

There is far more to attracting bumblebees than simply putting out a nest box!!

With the opportunity to offer continuous forage from March to September, (and beyond see below) when it is most needed by wild bees and bumblebees. It may be that in some areas some species are entirely dependent on gardens for foraging at critical times of the year and may well have extended their range due to gardens and parks. Indeed it may come that for some species, it may be easier to find and study them in gardens and parks rather than the countryside. In accordance with previous studies which suggest the importance of gardens now provide a stronghold for bumblebees in an otherwise impoverished agricultural environment. Data has suggested that the positive influence on gardens for our bumblebee populations can found that they can spill out from the gardens, to at least 1km into the surrounding farmland. Wild bees pollinate the berries in our parks, gardens and countryside, allowing birdwatchers the opportunity to enjoy their hobby in the winter months. Without the wild bees many birds would suffer.

Bumblebees queens increasingly using gardens

As well as different species of wild solitary bees and solitary wasps taking up residence in our gardens and making use of nest boxes, several species of bumblebee queens are using our gardens to set up and establish their colonies, with workers using our gardens to forage. Gardens can and do provide suitable nest sites for some species of bumblebees. Researchers found that young nests of Bombus Terrestris, placed in suburban gardens grew quicker and larger than those placed in arable farmland and farmland with substantial areas of set aside. They also found within gardens, a higher nest density than a range of rural habitats. The range of different flowers, their density, numbers and flowers available over longer periods, probably provided the bumblebees with more variety of pollen and nectar upon which they feed their young. Gardens offer numerous opportunities for foraging and nest sites for bumblebees with their numerous sheds and out buildings, rockeries, compost heaps, bird boxes and more.

The value and increasing importance of Citizen Science

A recent report, (see below) emphasises the valuable contribution volunteers, citizen scientists, have made to science. This review suggests it is vital, not only do citizen scientists contribute to the professional body of scientific research, they also help to monitor our environment. This has enabled professional scientists to collate indispensable information which they may never have achieved alone. It has been provided by volunteers who by observing, monitoring and recording wildlife have, besides stimulating an environmental education and interest for themselves and others, enjoyed doing it!

Such enthusiastic volunteers may well add to this pool of knowledge by studying wild bees that nest in suitable nest boxes in their own back gardens, without disturbing the bees. For example, note how easy is it to observe the full life cycle of Red Mason Bees (Osmia bicornis) through large observational windows. Imagine the useful data that could be accumulated with the help of citizen scientists with bee boxes like below in their gardens.

Winter bumblebees foraging in parks and gardens

Researchers have also found Bombus terrestris, normally associated with spring and summer, are increasingly being seen in southern England during the winter months using for example, Mahonia spp. for their nectar and pollen requirements. They found there was enough winter food available to keep a healthy bumblebee colony going. Such activity was also found only in urban areas were there were plenty of exotic flowering plants in parks and gardens, highlighting the importance to bumblebees in their fight for survival.

Honey bee hives or wild bee boxes?

Being humans, our interest in wildlife, including insects, is usually primarily selfish. I am regularly asked, “What good is a mosquito, or what good is a wasp?” Unless it has a some value to us, some people think something does not have a right to exist! Even with honey bees, our motives for keeping them is primarily selfish. They provide honey to store over the winter months for themselves and waterproof wax to store it in, which we ‘harvest’ from them. We house them in fields or even transport them many miles to pollinate our crops, which we harvest for cash. They have an enormous economic value to us. Regularly in the press and on TV, we hear about the huge decrease in the numbers of honeybees and the potential effect it could have upon the security of our food supplies. With 35% of of global foods dependent on animal/insect pollination, if this decline continues, we may be looking to our wild bees to compensate for the ever increasing pollination gap left by honey bees. As mentioned, it has been found that bumblebees in gardens spill out for up to 1km into the surrounding countryside.

All the while, our native wild bees are quietly and efficiently pollinating garden and wild flowers, fruit, vegetables, as well as the wild fruits and berries in our hedgerows and trees, providing vital food resources for birds and other wildlife, work undertaken in the main unnoticed. There has also been a huge surge in the numbers of people, particularly living in urban areas, who are thinking of bee keeping and some that actually now keep hives. Sure that will be beneficial for you and worthwhile for your crops, flowers and fruits. Many thousands of people are willing to spend the time, expense and effort in keeping honeybees and reaping the rewards. No doubt a very interesting and rewarding way to spend ones time.

Although having potentially, thousands of honeybees in your garden and those of your neighbours may cause a few problems! Pets, elderly people, children and their parents need to be considered. How will it affect them? Do your neighbours spray their gardens with chemicals? Then practically, if you have a small urban garden, will you be able to share it with thousands of honeybees?  What about a barbecue, playing outside with your kids, or simply sitting outside? These and many more reasons would have to be considered.

You highly likely will have different species of wild bees already visiting your garden, busy pollinating your fruit, flowers, vegetables and yes wild flowers that help to make our gardens and countryside a beautiful place. If you feel that honey bee keeping is simply not for you, then consider looking after the wild bees and other pollinators that, themselves are also declining, by planting appropriate flowers and offering them a home, allowing you to observe the hidden world of wild bees.

Other pollinators contribute more to pollination than honey bees

Red mason bees are increasingly becoming more important pollinators of apples

As mentioned above, many people are aware of honey bees and their role in pollination, but most probably their role in making honey, because we like it! They may not be aware that bumblebees, solitary bees (at least 250 different species in the UK) and hoverflies are key wild pollinators of our crops and flowers. As honey bee numbers are declining to such an extent that they now only pollinate a third of the UK’s pollination needs, whereas it used to be around 70%, it is becoming increasingly important that we work to save our other pollinators, not just honey bees. Paradoxically, the proportion of UK crops dependent upon insect pollination has steadily increased in the UK. Researchers have found the bumblebees, (several of these themselves are declining) solitary bees and other wild pollinating insects are much more important for pollinating UK crops than previously thought. We need to help these other pollinators. Gardens as safe refuges could well help, as they have done with many species of birds. For those people who like sloe gin, it is thanks for our wild bees pollinating the early blackthorn flowers early in the year, when many honey bees find it too cold to forage! So birdwatchers can also add a ‘thank you’ to wild bees for heping to provide berries for such birds as blackcaps, fieldfares,redwings and song thrushes! The fruits and seeds that have been pollinated by wild bees are then consumed by birds that then facilitate the dispersal of seeds away from the parent plants with the potential to germinate and create a new population of those plants.

Duty of care and responsible conservation

In these trials the artificial nest boxes were attacked by the wax moth  (Aphomia sociella), which detects its host by scent, more frequently than those placed in the countryside. This would be for several reasons. I myself have found wild bumblebee nest with three of more entrances, located in over perhaps an area 1.5 sq metres and larger. This would dilute the scent from the nest itself, by however many entrances there were to the nest chamber. The scent from such a nest has to travel along tunnels and could be further diluted by plant roots, stones, worm tunnelling acivity underground etc., and of course rain would dampen the scent inside tunnels further still as it soaked through the soil along the tunnels to the nest chamber. The wax moths themselves would have to navigate along damp dark tunnels, with numerous nooks and crannies along the way, with the potential of they themselves falling victim to a predator or dying whilst making this potentially perilous journey. Wild nest sites are difficult to find and the site entrances more so! Vegetation covers them in some cases further lessening the chances of wax moth detecting the nest entrances. All this makes it much more difficult for the wax moth to detect the scent.

Being artificial, the nest box exposes the bumblebees to attack by wax moths, with most of the scent being concentrated at the nest box entrance, making them easier to detect. The entrance tunnel, also artificial is short, straight and far less dangerous for the wax moth to travel inside. Several nest boxes in a smaller area would further concentrate the scent. As people attract birds to feed and nest in their gardens, then purchase all manners of cat deterrents to protect the birds, if we are attracting bumblebees into our gardens, by default or otherwise, we owe them a responsibility to house them and protect them from pests and predators.

Location of wild bumblebee nests

Even queen bumblebees can make a mistake when finding and establishing a colony for their chosen nest site. At the time she decides the site may be warm and dry. Only later will she find that the site may be damp, cold, windy and may even become waterlogged. This can result in smaller colonies, fewer queens and males produced and even the total collapse and death of the colony in its early stages. Yet just a few yards away there may have been an ideal site.

Chemicals in the countryside

There has been a lot of press covered about the use of chemicals, more recently those called neonicotinoids, a commonly used pesticide, that researchers from Stirling University have found had a negative effect on our bumblebees, in particular inhibited the production of queen bumblebees by an astonishing 85%. Young queens are needed to established new colonies every spring after hibernating. Whilst researchers in France found these chemicals had caused high honey bee mortality due to the effect it had on their homing ability. France, Germany and Slovenia, have already restricted their use because of such worries. As these noxious chemicals are not available to the general public, our parks and garden may well become increasing important to some species of bumblebees as a safe haven.

Purchasing of live bumblebee colonies and live captures

Live captures involves capturing live wild queens and placing them into bumblebee nest boxes. This is an old practice that has gone on for many years. The practice of importing bumblebees from abroad has been going on for a number of years to facilitate the pollination of greenhouse grown tomatoes for example. Researchers are importing live colonies for research purposes. However a recent practice is steadily increasing and like it or not members of the public are purchasing live colonies of bumblebees imported from abroad to place inside bumblebee nest boxes in their gardens. The Bumblebee Conservation Trust offers this advice for prospective customers to consider. I would agree with their advice regarding purchasing such colonies for educational purposes and I feel educating school children would have a huge benefit for all concerned, including bumblebees! With this in mind the Nurturing Nature nest box goes some way in address issues of observing the bumblebees inside the nest box with its simple ‘lift and look’ lid, the red view observation window, the bumblebee cat flap, not only as a defence against wax moths, cuckoo bumblebees and other pests, but as a pleasurable viewing experience as children watch the bumblebees using the cat flap.

Positive features of the Nurturing Nature Bumblebee and wild bee nesting boxes.

Bearing in mind I am an environmental educationalist, I designed them for educational purposes offering unique insights into wild bees, not readily available in many other wild bee nest boxes. They offer numerous educational opportunities within the National Curriculum. For example, the 2 large viewing windows in the wild bee nest box, allows for the study of  complete life cycles to be observed including other organisms, such as predators and parasites of the wild bees. The wild bee box also lets you have the option to attract and study solitary wasps, which use garden pests upon which to feed their young. Solitary wasps are also in decline. With many other features in the bumblebee nest box, sturdy, FSC timbers, easy ‘lift and look ‘lid, its red glass viewing window, bumblebee cat flap defence against pest, easy adaptation for making a ‘false underground’, securing to a site, supply of mouse scented kapok, fine metal mesh ventilation covers, wax moth monitoring box, mouse excluder, bumblebee porch and landing platform.

Refs:

Benton, T. (2006) “Bumblebees” Harper Collins, London

Breeze ,T.D. et al (2011) ” Pollination services in the UK: How impotent are honey bees?”, Agriculture, Ecosystems & Environment doi:10.1016/j.agree.20011.03.020

Goulson, D. (2010) “Bumblebees behaviour, ecology and conservation”, Oxford University Press, Oxford.

Goulson,D. et al (2010) ” Effects of land use at a landscape scale on bumblebee density and survival” Journal of Applied Ecology, Vol 47. issue 6, p1207-1215.

Henry, M. et al (2012) “A Common Pesticide Decreases Foraging Success and Survival in Honey Bees” Science Magazine, Vol 335 No. 6076

Jacobs, J.H ( 2008) ” The birds and the bees: pollination of fruit-bearing hedgerow plants and consequences for birds” PhD thesis University of Stirling

Roy, H.E., et al, (2012) “Understanding Citizen Science & Environmental Monitoring. Final Report on behalf of UK-EOF. NERC Centre for Ecology & Hydrology and National History Museum. http://bit.ly/T0PCC3

Stelzer, R.J. et al (2010) ” Winter active bumblebees (B. terrestris) achieve high foraging rates in urban Britain” PLoS ONE, 2010; 5(3): e9559 DOI; 10.1371/journal.pone.0009559

Wheater, C.P. (1999) “Urban habitats” Routledge, London

Whitethorn, P.R . et al (2012), “Neonicotinoid Pesticide Reduces Bumblebee Colony Growth and Queen Production”, Science Magazine Vol 335. No. 6076.