Try to encourage bats

Bats – protected by law, misunderstood by humans – are vulnerable and declining in numbers with changing in farming methods destroying much of their habitat

Bats are evocative of long summer evenings, flitting above you while you sit and enjoy a peaceful break from work. Do you agree? If you see one would you rush indoors in a panic, afraid that the ugly little creature that looks like a flying mouse may get in your hair?

If you think that, you’d be quite wrong. Bats have an amazing radar and don’t crash into things. While they give some people the shivers and over the centuries have been associated with folklore and witchcraft, to others they are part of summer in the garden and perfectly harmless.

Nor are they a pest. As they flit about they are ridding the garden of many insects, catching them by emitting high squeaks beyond our hearing range and homing in on the tiniest of echoes bouncing off the insects’ bodies.

They are also vulnerable, with greatly declining numbers over the past 100 years, with changes in farming methods destroying much of their habitat, and old buildings demolished or modernised.

Protected by law in this country, the Bat Conservation Trust marks its 20th anniversary this year and the United Nations has marked 2011 as the Year of the Bat, to increase our awareness and understanding of them.

There are 17 species of bat breeding in the British Isles, with another that is a visitor, but more species are found in southern areas. Many species are rare and some are more regularly around gardens than others. The most frequently observed are the Common Pipistrelle, the Soprano Pipistrelle (so called as it has a higher voice than the other Pipistrelle), the Serotine and the Brown Long-eared Bat.

They are difficult to identify and you need a licence to observe them in their roosts (and it is an offence to kill or injure them, to disturb or handle them). They like lowland areas, woods, hedges, orchards, parks, ponds and lakes, sometimes cliffs and meadows – and our gardens.

Coming out at dusk from their roosts, they are creatures of habit, following set routes and working one good food patch before moving on to the next. They may travel as far as four miles from their roost, often resting by clinging to trees or walls as they digest food.

One way to observe different bat species is to watch their flight patterns. Long-eared bats tend to flutter close to trees, Pipistrelles loop and wheel at about head height, and Noctules fly high in straight lines, making steep dives. Or use a bat detector that makes their sounds audible to us, detecting the species by the number of recorded sounds.

Their food consists of midges, lacewings, beetles, moths and other insects, and they need thousands per night to survive. Long-eared bats can snatch caterpillars off leaves, and several species feed off insects above water. Owls and cats are their main enemies but they can live for up to 30 years.

They choose different roosts at different times of year, seeking dark, undisturbed places in winter that are humid and cool but not cold. They hibernate from November until April in caves, cellars, mines, barns and hollow trees but few houses are suitable, although they may like an out-building. Sometimes emerging briefly in mild spells to find insects they will use up precious fat stores and are less likely to survive if in the open for long.

The males court the females in autumn, and in spring the females will gather into a maternity roost to have their young. Usually female bats produce just one, in June or July: the name for a baby bat is a pup, weaned at about six weeks.

To encourage bats

• Dig a pond for them to swoop over and feed on insects
• Grow plants that encourage insects – flowers rich in nectar and pollen
• Put up a bat-box – but get advice as it must be in the right place and it may take a long time to see results
• Bats are protected by law – don't disturb their roosts

To understand more about bats

• Visit the hi-tech bat roost viewing rooms at Hestercombe Gardens, Cheddon Fitzpaine, near Taunton TA2 8LG
• Buy a bat detector to discover species in your garden