Put up a bat box

Why it matters

Bat populations are declining across the world. The primary cause is loss of roost sites. The crevices, hollow trees, and roof spaces that bats have used for millennia are disappearing as old buildings are renovated and mature trees are felled. Bat boxes directly address this by providing artificial roost sites in landscapes that would otherwise offer none.

Bats are also keystone species in their own right. A single pipistrelle bat, the most common bat in Europe and North America, eats up to 3,000 insects per night, including mosquitoes, midges, and agricultural pests. Tropical fruit bats are critical pollinators and seed dispersers. The ecological value of a healthy bat population is enormous and largely invisible.

How to do it

1. 1Choose the right box: rough-textured wooden boxes designed for bats (not birds) with a narrow entrance slot. Avoid boxes with perches, as bats don't need them and they attract predators.
2. 2Position at height: mount at least 3–5 metres (10–16 feet) above ground on a south or south-west facing wall or tree, away from obstructions.
3. 3Avoid artificial light: bats avoid lit areas. Site the box away from security lights or street lighting.
4. 4Install near water or trees: proximity to a water source or mature trees significantly increases the chance of occupation.
5. 5Be patient: it can take 2–3 years for bats to find and adopt a new roost box. Once adopted, they often return for decades.