Tuesday, 5 February 2008

What's in a bat box?

Well, hopefully...bats.

When the first bat-box schemes were launched, in the 1970s, using sponsorship from viewers of BBC TV's "Nationwide" programme, there was one design: the standard wooden bat-box. They're not unlike a blue-tit nest-box, but instead of a hole on the front, the bats access by climbing a roughened board and entering through a narrow slit at the base. Easy and cheap to make from a single plank of rough timber, there must be many thousands of them around the country and they're as effective as ever.

Bat boxes do a great job of supporting bat conservation by raising awareness, providing an easy way of monitoring local bat populations, and by providing bats with roosting opportunities in places where alternatives are limited. Annual bat box occupancy checks carried out by local Bat Groups also give a great opportunity for novice bat-workers to see bats close up (strictly supervised by someone with an appropriate licence).

Today, many designs are available, to the extent that choosing bat-boxes is almost as hard as choosing a new car! Do we want it to emulate narrow crevices, to suit Pipistrelles, or bigger tree-holes, to suit Noctules? Do we want cheap and cheerful wooden construction, or shall we push out the boat and use deluxe woodcrete bat-boxes? How about a wedge shape? Should the door be on the top or at the front? Should it be painted black? And so on...

Here in the Lothians, a bat box containing anything other than Pipistrelles is sadly a rarity, though a box full of Pips is still a welcome sight. Whilst the traditional boxes are well-used, they seem to prefer slimmer, more crevice-like designs. However, the most popular design seems to be the dome-shaped woodcrete (a cement and sawdust mix) boxes, made by Schwegler. They're not cheap, but the occupancy rates are definitely higher.

Anyone thinking of putting up bat boxes would be well-advised to take advice from their local Bat Group. A little experience and foresight in choosing the right boxes and positioning them correctly will make a big difference to their success...or otherwise.

No comments: