By Ruth D'Alessandro, The Wildlife Gardener

For the Wildlife Gardener, one of the pleasures of summer evenings is watching bats zoom and wheel around at dusk:

A bit blurry, but not easy to photograph bats in the dark with a compact camera!

Bats are enchanting creatures, and are the only mammals that can truly fly. I like them as much as I like birds. My birds have nest boxes put up for them, so in the interests of equality, I decide that the bats should have bat boxes. Little did I realise that there are lots of different boxes out there to choose from...or we could make one ourselves. Up to our eyes in DIY projects, I chose not to burden Mr WG with another carpentry task, so I took a look at the items on offer.

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A local craft fair had a simple box for £12.50, which my friend bought:

Hmm. The correct design: a gap at the bottom and a little wooden ‘ladder’ for the bats to use to crawl into the box. So far so good. However, the box had been painted with wood preservative. Oh dear. Bats, very sensitive creatures, steer well clear of any kind of chemical treatments. So, the well-meaning maker, no doubt intending to produce a lasting product may be inadvertently excluding the very tenants he/she hoped to house for many years. Added to this, why the bat logo? Was the intention to make bats, social creatures that they are, think they had an automatic friend and come on in? Or would it scare them away, especially as it probably smells of gloss paint chemicals? This box would look good in a pretty, magaziney garden manicured to within an inch of its life – saying all the right things to the wildlife, but not noticing that it has nipped over the hedge into Mrs Wiggins’s messy brambly garden and her rotting trees where it is having a lovely time, thank you very much.

I didn’t want a bat box like this, and in an astonishingly timely bit of serendipity, we were approached by Nick Mann of Habitat Aid to try out his range of products. Habitat Aid’s mission statement is as follows:

Habitat Aid sells high quality products which enhance or regenerate our vanishing native habitats. Half of the profits we make go to specialist charities working to protect and promote biodiversity in Britain.

I could have chosen, among other things, pond plants, wildflower meadow seed and hedging plants, but the thing I most wanted was a bat box. Nick generously allowed me to try out a pair of bat boxes. These are usually priced at £29.00 each, although you have to buy a pair because:

Products are carefully chosen from selected specialist suppliers, with whom we have negotiated advantageous prices; to keep them low there is a minimum order size of £50.

This does make them expensive, but they are very well-made boxes, reminiscent of proper batcaves, and built to last. Habitat Aid’s customer service and delivery was excellent: I had a convoluted post-holiday delivery request, and the boxes arrived exactly when they should have done. You can order them here.

So what were Habitat Aid’s bat boxes like? The first thing I noticed was how large and heavy they were: 4kgs each as they are made of a concrete-like material. How easy would it be to get them 3-6 metres up a ladder and fix securely to a tree?

Then, the multilingual label sent me off on an amused linguistic tangent about the various EU names for Chiropteran residences:

German: Fledermaushöhle (a hole for a flying mouse)

French: Gite à chauves-souris (a smart holiday rental for a bald-headed mouse)

Italian: Cassettina-nido per Chirotteri (typically Italian - long curly-wurly words)

English: Bat box (Wot it sez on the tin)

I had worried that the painted bat on my friend’s wooden box would frighten away its intended inhabitants. Would the Habitat Aid boxes be less scary?

The boxes do look like a cross between an Easter Island statue and the Sutton Hoo helmet. If the bats shied away from Paint-on Batman, how would they feel about crawling into the mouth of one of the Knights of Ni? I am assured by Nick that he has bats resident in his own boxes, so we’ll see.

Next, where to site them? Bat boxes should be sited in a warm South or South-East facing direction. This is in contrast to bird nest boxes that should face a northerly direction. I was slightly surprised by this – wouldn’t the sleeping bats cook in strong daytime summer sunshine? Apparently not, and Habitat Aid’s boxes are well-made and thick so, like a smuggler’s cottage in Cornwall, they should resist extremes of temperature.

Boxes should be hung between 3-6m high, ideally near water. In the Wildlife Garden the 170-year old oak tree stands next to the pond, part of it faces South, so this is where we decided to put them. I had my misgivings about banging nails into such a noble tree so I consulted The Ranger who helpfully chirruped as follows:

Strictly, any invasive attachment is a bad idea. This is for several reasons - firstly it could introduce infection, but this is unlikely. More significant is the possibility that the metal fittings will be engulfed by the wood as it grows back to repair the wound. This could eventually result in the box being forced off, and the fittings being lost, in due course. If metal becomes enclosed in the wood, one day in the far future a tree surgeon or sawmill will curse you when they break a chain/blade - this can be dangerous.

You can reduce the risk by using aluminium nails (a job to bang in and very hard to find) which are chainsaw-friendly; and by putting a bloody great galvanised washer or two that fit closely to the shank of the nail to go between the back of the box and the tree.

However best practice for trees is a non-invasive system of webbing or belts - nylon rope probably would do fine, and no it shouldn't injure the tree as you would just slacken it off every couple of years. If you can easily get a ladder up to your box site this would be the simplest solution.

So, sometime soon, when we find our ladder, Habitat Aid’s bat boxes will be placed on the oak tree. It will be very interesting to see which style of box attracts bats sooner: The Knights of Ni or Paint-on Batman. I know which one my money’s on. Watch this space.