Why Bats Are Worth Courting

Britain is home to 18 species of bat, 17 of which breed here, and every one of them is a serious insect-eater. A common pipistrelle — barely the weight of a two-pence piece — can take something like 3,000 small flies and moths in a single night, hoovering up midges, mosquitoes, craneflies and garden moths that would otherwise find you. Encouraging them into your garden is one of the most rewarding things you can do for local wildlife, and it costs remarkably little.

Do bear in mind that all bats and their roosts are legally protected in the UK under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017. The aim is to invite them in, never to move, handle or disturb them once they arrive. With that in mind, here is what actually works.

Turn the Lights Down

If you do only one thing, do this. Bats are nocturnal, and most of our species emerge from their roosts in the half-hour or so after sunset. Bright security lights, floodlights and permanently illuminated paths delay that emergence and cut short the hours available for feeding. A permanently lit garden is also an uncomfortable commute for a bat travelling along a hedge line.

Practical fixes:

• Use warm white bulbs rated 2700K or lower rather than harsh blue-white LEDs.
• Fit hoods or shields so light falls downwards onto the path, not sideways into hedges and trees.
• Run lights on PIR sensors and short timers so they are on for seconds, not all night.
• Keep at least one boundary completely dark, giving bats a corridor between gardens.
• Leave ponds, mature trees and hedgerows unlit altogether.

Plant for the Night Shift

Bats hunt insects, so the real trick is to grow plants that pull in moths and other flying insects after dark. Pale flowers that release their scent at night are the classic answer, because both the colour and the fragrance are designed to attract nocturnal pollinators — and the moths that follow them.

Good choices:

• Evening primrose, night-scented stock and the tobacco plant — all pale and heavily fragrant after dusk.
• Common jasmine, honeysuckle and sweet rocket, whose scent carries on warm evening air.
• Ivy left to flower in autumn, when it becomes a magnet for late-flying moths.
• Flat, open flowers such as ice plant, Michaelmas daisy, knapweed, scabious and teasel.

Don't forget the caterpillars. Moths need larval food plants too, so a patch of nettles, bird's-foot trefoil, cuckooflower or hawthorn will pay dividends. And please be sparing with insecticides and slug pellets: a garden that kills its insects cannot feed its bats.

Add Water, However Small

Bats drink on the wing, skimming low over still water and lapping as they go, so a pond is a genuine draw. Even a small one — a metre or two across — will do the job, and it will also multiply the insects your garden supports.

• Give it gently sloping or planted edges so frogs, hedgehogs and insects can get in and out.
• Leave it unfenced and un-netted, with a few stones and a log pile alongside.
• Avoid fish, which will eat the larvae you are trying to encourage.
• Plant native marginals such as water mint, marsh marigold and lesser spearwort.

A little algae and a bit of untidiness around the edge is exactly what you want. Resist the urge to scrub it clean.

Offer Somewhere to Roost

Bats need somewhere warm, dark and undisturbed to spend the day. A well-sited box is a genuine help, particularly where mature trees are scarce.

• Mount it three to five metres up, facing south, south-east or south-west.
• Keep the approach clear of branches and wires, and shelter it from prevailing wind and driving rain.
• Cluster two or three boxes together — bats prefer choice, and different species like different crevice sizes.
• Use untreated timber or a durable wood-and-concrete mix, and never apply preservative inside.

Bats also roost in gaps under roof tiles, behind fascia boards, in old tree cavities and in wall crevices. If you know of such a gap, the best thing you can do is leave it alone. Renovation work that might affect a roost needs professional advice and, in most cases, a licence.

Watch, Record, and Let Things Get Scruffy

Once the basics are in place, spend a warm, still evening at dusk sitting quietly with the lights off. Common pipistrelles fly fast and jerky, low over the garden; brown long-eared bats are slower and flit about the foliage. Daubenton's bats skim the surface of water. If you want to know exactly who is visiting, a bat detector will tell you, but you don't need one to enjoy them flying.

Above all, don't over-tidy. Long grass, leaf litter, log piles, dead wood and thick, deep hedges are all larder and shelter. A scruffy corner is not neglect — it is habitat. Bats are slow to change their habits, so give it a season or two. A dark, insect-rich, watery garden is very hard for them to resist.