nest box

Bumblebees are fascinating insects and I have been meaning to learn more about them for a long time. I’m not sure that it doesn’t have something to do with the fact that they looks quite so similar to colourful bats up close… there is something about their furry round bodies which is rather reminiscent!

It is still very early in the season but most of our UK species respond to conditions rather than dates and when the sun is shining and the weather is mild, many hibernating species will come out of torpor and begin their spring routines. I have recorded pipistrelle bats in flight over the last week; the birds are certainly thinking about nesting with the early species such as long-tailed tits gathering nesting materials; and there was quite a gathering of bees on a very early flowering blackthorn on Monday lunchtime.

I managed to get a couple of photographs of this bumblebee and decided that this would be the first ID on my path to learning more about these species. And it looks as though I picked quite a good one – my tentative ID of a tree bumblebee (Bombus hypnorum) was confirmed by helpful tweeters @sbd08simon and @ed_p_wildlife. Apparently there is no other bee which this species can easily be confused with – the colouration is just black and buff-brown with a white tail. No coloured bands! This bee has quite a simple pattern compared with the multitude of variations which other species seem to manage! This guide from Bumblebee Conservation gives a great introduction to identifying bumblebees.

Although I am, as already confessed, no expert, I believe this must be a queen out foraging and potentially searching for a nesting site. The queens emerge in spring (usually March or April) and scope out potential nesting sites before laying their eggs. About six weeks later, the eggs hatch and the entirely female workforce splits into teams, some foraging for the colony, others staying in the nest to do the housework. Later in the year, ‘reproductives’ are produced – these are virgin queens and/or drones. The drones will die after mating with a female but the queens will hibernate through the winter and emerge when the temperatures warm up in the spring and the cycle can begin again. I would therefore suppose that my bumblebee feeding in February is a queen freshly emerged from a relatively short winter’s sleep.

Tree bumblebees are so called because of their habit of nesting in trees – either in woodpecker holes or more frequently, in nest boxes. Like most species, they have adapted to inhabit the world we have created around them and can also be found nesting in houses, in soffit boxes and similar features. Some other species of bumblebee will occupy similar niches but the preference for these tree (or tree-like) nesting sites is most notable in the tree bumblebee. Many other UK species will nest underground and you can often see them bumbling into the undergrowth towards the entrances to their underground homes.

Tree bumblebees are a relatively new additional to the UK’s fauna – they first appeared in Wiltshire in 2001 and have been spreading north every since. It is believed that they are natural colonisers which have established under their own steam, much like the collared dove which was a rare vagrant until the 1950’s when they were first recorded breeding here and now grace most garden bird tables across the UK. The invasion of the tree bumblebee appears, so far, to be benign with no observed impacts upon existing native bee populations and its spread appears to be continuing with the first recording in Scotland last year.

I have recorded my sighting here – the data gathered from recordings around the country can be used to study this species and describe its distribution around the country.

If you want to read more about the tree bumblebee, there is a very informative factsheet available from Bumblebee Conservation.

Last Sunday was such a sunny, beautiful day that it called for outdoor projects to keep me busy in the fresh air. The first thing I noticed when I stepped outside was the sheer volume of bird song, with blue tits, robins, dunnocks and wrens all busy singing and chasing one another in pairs around the garden. I even spotted a long-tailed tit clinging to the side of the house, plucking spiders webs from between the brickwork to build a nest. It seemed a little too early to do much in the way of gardening, but the birds were making it clear that they were making ready to nest. What better project than to build a couple of bird boxes! It is not pure coincidence that this week is National Nestbox Week.

I have to say my choice of design was limited by the tools available – I don’t have a drill bit which can make the large round holes preferred by some species such as blue tits, but fortunately the designs for wrens and robins are open fronted which means that with little more than a plank of wood, a saw and a drill (and an old inner tube for the hinge), you can make a nest box.

I actually used plans I found on the Which? website, adapted a little to suit the wood I had available. I’ve sited the wren box within an area of dense shrubs in the garden – this is the habitat favoured by the species and provides them some cover and protection from predators. I attached the box securely (imagine how bad you would feel if the box blew down when the birds had begun nesting!) using a bungee cord as this will not cause any damage to the tree as it continues to grow. The cord may need to be replaced after a few years but should certainly ensure the box is securely attached until it wears down.

The box has been up for two days and already there has been a great tit investigating. I am hoping that it won’t be long before something takes up residence – watch this space! Just for the avoidance of doubt – it’s the camera which is wonky in the video below rather than the nest box!

Below are some step-by-step photographs which show the progression of the box from planks of wood through to completion.

Why not have a go at making a nest box yourself and see what birds you can attract to breed in your garden as part of National Nestbox Week? Construction is not one of my strengths but you will be amazed at how simple and satisfying it is to make a box of your own. All of the instructions to get involved in National Nestbox Week can be found here, along with some great resources on how to build/buy and site your box. Lincolnshire Wildife Trust also have some fantastic resources for building all kinds of bird boxes including those designed for more unusual species such as kestrel. You can register your box with the National Nest Box scheme and then provide updates on the species which use the box and how they fare – all of this information provides valuable data for monitoring and research into garden birds.