Saturday, 19 July 2014

Bees on the balcony

Bees are getting a lot of press at the moment, much of it focused on the decline of the honeybee and the various reasons behind it.  But there's a lot more to bees than the honeybee - around 270 species are recorded in Britain, 1 honeybee, 27 bumblebees (3 of them extinct, although one is currently being reintroduced), and the rest are all solitary bees (currently 225 surviving species).

Recently (yesterday as I type this, in fact), Defra, guided by several wildlife organisations, have launched a 'Call to Action' highlighting ways for the general public to help bees as part of the National Pollinator Strategy. While several of these suggestions (particularly 'leave patches of land to grow wild', 'think carefully about whether to use pesticides', and 'cut grass less often') should perhaps be aimed more at national and local government as per my last blog, they're aimed at the rest of us and the entire call to action can be boiled down to one sentence: bees need food and a home.

I work for the Bumblebee Conservation Trust (BBCT), one of the main organisations guiding Defra on the NPS, so I'd known the content of the Call to Action for quite a while. It was evident that several of the suggestions were aimed at people with land to spare (particularly 'leave patches of land to grow wild' and 'grow more trees'!), but there are plenty of us for whom owning any land is just a distant dream. My garden is actually my landlady's garden: I can get away with rummaging in the plants for interesting invertebrates but tree-planting would see me out on my ear in short order!  My girlfriend lives in a first-floor flat with no garden, in an urban area of Bath - what could we do there to make things bee-friendly?
The Bath 'garden': before...
Well, as the picture shows, you get to the flat up some exterior stairs with a small landing at the top - space for a few pot-plants and a windowbox! Helpfully, BBCT have an advice tool called BeeKind which gives your garden a bee-friendliness score, and suggests extra flower species based on what you've already got, to fill in the gaps of flowering times and flower shapes (bees need nectar throughout their March-October flight season & different species visit some different flowers). We knew that lavender would be one of the plants - it's Kate's favourite flower as well as being brilliant for bees - and were guided by the BeeKind tool for (most!) of the rest.  We ended up with a French lavender in a pot, along with red clover, coriander, and an ox-eye daisy, recently replaced by a flowering thistle, while the windowbox was stocked with a strawberry, meadow clary, sweet pea and an Osteospermum, topped off with a scattering of 'seeds for bees' which have germinated but remain as yet unidentified.
...and after! Windowbox as first planted
Pot plants, directly beneath the windowbox (note photobombing strawberry!)
That little lot gave us a BeeKind score of 457 - not far off the 500 given as 'excellent' on the website, even without laying claim to the great swathes of yellow corydalis growing from the base of the house wall, or the poppies, hedge mustard, dandelion and buddleia (since cut down - grrr!) growing from the concrete just outside. That was the food sorted - what about the home?  Well, there's no room for a hive of honeybees, or mouse burrows for bumblebees, but solitary bees are a lot easier! We hung a 'bee hotel' (basically a bundle of canes stuffed into a tube) beneath the windowbox, and left it for the bees to find.

And find it they did! Less than 24 hours later a bumblebee had arrived: within a week three species of bumblebee had been seen on the flowers (common carder Bombus pascuorum, buff-tailed B. terrestris, white-tailed B. lucorum), as well as a tiny Lasioglossum solitary bee and several hoverflies (the marmalade hoverfly Episyrphus balteatus and a couple of Syrphus species).  More recently a tree bumblebee (B. hypnorum) had circled without settling and a couple of spiders (the garden spider Araneus diadematus and the jumping spider Salticus scenicus) had made the windowbox home, while an tortrix micro-moth caterpillar of some sort had munched its way through several of the lavender flowerheads (just this weekend Kate found the hatched pupa sticking out of the stitched-together flowerheads so it will remain, alas, unidentified). Sadly none of June's impressive hatch of scarlet tiger moths could be persuaded to land on the flowers!

Most exciting of all, the 'bee hotel' was colonised almost instantaneously by red mason bees (Osmia bicornis (=O. rufa)), so next spring the garden will be able to supply its own home-grown wildlife.  Food and a home - it's really not that hard to help the bees...
The bee hotel in position
Tree bumblebee on Osteospermum. After several flypasts, this one finally settled!
The female red mason bee constructing her nest
The completed mud nest of the red mason bee, ready to sit out the winter

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