Your Wildlife Garden. Jackie Bennett
practical project MAKING A BAT BOX
THE BAT’S YEARLY CYCLE
WHY ENCOURAGE BATS?
Many species of bats are becoming rare and in some cases nearing extinction because of disturbance and loss of natural roost sites. In cities and intensively farmed areas, their food supply of insects is also becoming depleted. A healthy garden with a wide range of insects will provide a rich night-time hunting ground. By eating a large proportion of pests like midges, the bats will help to maintain the garden’s natural balance.
By understanding bats’ natural cycle we can choose the best ways to encourage them to use our gardens and houses. Bats traditionally roost in hollow trees or in caves, but have increasingly become adapted to buildings. For winter hibernation they will seek out a well-insulated spot with a constant temperature, such as a cave or cellar, but it is quite difficult to provide these conditions artificially. During the rest of the year, bats are less particular and will use a number of different sites. In spring they will seek out a safe place to give birth and rear their young. In summer they may choose a cooler spot to roost and in autumn a slightly warmer one. If your garden has any old trees they may well be inhabited by bats. If not, it is even more important to put up bat boxes.
SITING THE BOX
Position bat boxes at 3–5m (10–15ft) above ground (or higher), on a tree, post or on the house wall. Make sure the bats have a clear fight path by removing overhanging branches or other obstructions. If possible site three boxes facing south, south-west and south-east. This will enable bats to select the most suitable roost for the time of year.
CONSTRUCTING A SIMPLE BOX
A bat box works on the same principle as a bird box except that instead of a hole at the front for access, there is a small gap underneath which needs to be wide enough for the bats to enter, but small enough to keep out predators such as cats.
Use a rough sawn plank of untreated softwood, approximately 2.5cm (1in) thick and at least 20cm (8in) wide and 120cm (4ft) long. If the wood is too smooth, you will need to roughen it with saw cuts to enable the bats to cling properly.
FIXING THE BOX
The box can be nailed onto a wooden post or tree, using the holes drilled earlier. If attaching to brickwork, use rawlplugs and screws.
AFTERCARE
Once in situ, leave the box undisturbed. A special licence is required to disturb or handle bats. If you need advice on any aspect of bat behaviour contact the Bat Conservation Trust www.bats.org.uk. It is also possible to buy ready-made bat boxes from various suppliers — your local wildlife group should be able to recommend suitable types.
BAT SPECIES
COMMONLY SEEN IN GARDENS AND AROUND HOUSES: Brown long-eared Daubenton’s (especially near ponds and canals) Natterer’s Noctule Pipistrelle Serotine (especially in the south of England)
RARELY SEEN: Barbastelle Bechstein’s Brandt’s Greater and lesser horseshoe Grey long-eared Leisler’s Whiskered
Extinction In 1990 the Greater mouse-eared bat was officially declared extinct — the first mammal to become extinct in the British isles for 250 years. Although there have been reports of this bat making a return to the South of England, the plight of many bats continues to be precarious.
THE LAW AND BATS Bats and their roosts are protected by law and it is an offence to disturb roosting bats. If you have bats in your roof space, cellar or any part of your property, you should contact the Bat conservation trust.
FEBRUARY
Typically, this is a wet and bitterly cold month with more than its fair share of snow and ice. Fortunately, the weather does not make all wildlife inactive and in the early morning it is quite possible to see fox and badger