The Importance of Bats in the British Countryside

Small Night-Flyers, Big Job

A common pipistrelle weighs about as much as a two-pence piece and can put away some 3,000 midges, mosquitoes and small moths in a single night. That is the sort of arithmetic that ought to make any of us sit up. Britain has eighteen recorded bat species, seventeen of which breed here, and every one is an insectivore working the same hedgerows, fields and riverbanks we walk in daylight. Noctules patrol high above the canopy; pipistrelles stitch tight lines along hedges; Daubenton's bats skim the millpond and the chalk stream; brown long-eared bats pick moths straight off leaves. Together they are a pest-control service running a shift we rarely watch.

The Countryside's Own Health Check

Bats are indicator species. They live long for their size, breed slowly — usually a single pup a year — and ask a great deal of a landscape: insects in quantity, sheltered feeding corridors, safe roosts in trees and old buildings, and dark routes between the three. Where those things exist, bats thrive, and so do the hedgerow flowers, the ditch invertebrates and the birds that feed on the same insects.

Where they are missing, bats show it first. The decline of the soprano pipistrelle, the lesser horseshoe and the barbastelle tells a story about tidy, brightly lit fields and grubbed-out hedges long before the wider figures catch up. Your own dusk walk is a rough survey in itself: more bats usually means more insects, and more insects usually means a healthier patch of countryside.

What Has Gone Wrong

Numbers have fallen sharply over the past century, and the causes are plain rather than mysterious.

• Roost loss. Old barns, weatherboarded cottages, church towers and hollow veteran trees are converted, repaired or felled, often during the very months bats need them.
• Fewer insects. Pesticides, the loss of rough pasture, sprayed verges and tidied ponds all cut the food supply.
• Broken hedgerows. Bats commute along hedge and woodland edge lines; a gap of twenty or thirty metres can sever a route entirely.
• Artificial light. Floodlights and lit eaves delay emergence, fragment dark corridors, and can leave slower species such as the lesser horseshoe marooned.
• Disturbance. Entering a roost or a hibernation site, even briefly, can cost a colony more energy than it can spare.

All British bats and their roosts are protected by law, whether or not bats happen to be present at the time. If work may affect a roost, take advice from your national conservation body before anything is moved or sealed.

Making Room for Bats at Home

A well-sited bat box is the simplest practical thing most of us can do, and the details matter more than the price.

• Fix boxes three to five metres up, on a wall or a mature tree, clear of the prevailing wind.
• Aim for a south or south-east aspect — warm for the nursery season, but not in all-day blistering sun. Two boxes facing different ways give bats a choice of temperature.
• Use untreated timber or a woodcrete-style composite that holds warmth. Never paint, varnish or treat the interior.
• Keep boxes away from windows, cat routes and outside lights.
• Then leave them alone. An occupied roost needs quiet, warmth and darkness.

Look after the wider patch, too: a pond with soft, unfenced edges, a hedgerow left to flower and fruit, ivy on a sunny wall, a log pile, and a strip of long grass left unmown. A lawn striped like a sports pitch feeds very little.

Think Dark, Not Bright

Light is the quietest threat, because it arrives with the best intentions.

• Choose warm-white, low-output fittings rather than cold floodlights.
• Fit shields and hoods so light points down at the path, not sideways into the hedge.
• Use timers or motion sensors, and switch off what is not needed after about eleven.
• Keep one genuine dark corridor — along a hedge, a brook or a woodland edge — running through the parish.

Joining the Night Shift

Volunteers are the backbone of everything we know about British bats. County bat groups run dusk transects, identification training, hibernation counts in old tunnels and ice houses, and roost checks under licence. You need no equipment to begin: a torch, warm clothes, a notebook, and a bat detector you can usually borrow before buying.

Repeated counts matter far more than clever ones. Walking the same route at the same time each summer, or counting bats leaving a roost, builds a picture no single evening can. Tune a heterodyne detector to around 45 to 55 kHz for the two common pipistrelles, 25 to 30 kHz for noctules and serotines, and listen low over water for the fast, machine-gun rattle of Daubenton's bat.

A Heritage Held in the Dark

There is something quietly fitting about the fact that the buildings we are proudest of — church towers, tithe barns, timber-framed farmhouses, old ice houses and cider cellars — are often the ones bats chose long before us. They damage neither timber nor masonry, and they ask only for a gap, a draught and darkness. Keeping those roosts is not a brake on rural life. It is part of what it means to keep a working countryside genuinely alive, and the night sky over it properly our own.