Bats are the species most likely to affect a Northern Ireland planning application, and the one most often misunderstood. They are also, quietly, one of the hardest-working parts of our night-time ecology.
Northern Ireland has eight resident bat species, from the tiny common and soprano pipistrelles to the larger Leisler's bat. Every one of them is insectivorous. A single pipistrelle can take in the region of 3,000 small insects in a night — midges, mosquitoes, moths and crane flies — which makes a local bat population a substantial and entirely free form of pest control over farmland, gardens and watercourses.
Because they feed high up the food chain and need a range of habitats across a single night — a roost, a commuting route, and good foraging ground — bats are a useful indicator species. Where bats are doing well, the hedgerows, treelines, watercourses and insect populations underneath them are usually doing well too. Where they disappear, something further down has usually gone first.
The pressures are familiar ones. Older buildings are converted, re-roofed or demolished, and the roosts inside them go with them. Hedgerows and treelines that bats use to navigate are removed, leaving gaps they will not cross. Lighting spills across foraging areas. And the insect populations they depend on have declined markedly across these islands. None of that is dramatic on any single site — it is cumulative, which is exactly why the planning system looks at it site by site.
All bat species and their roosts are protected under the Wildlife (Northern Ireland) Order 1985 as amended, and as European protected species under the Conservation (Natural Habitats, etc.) Regulations (Northern Ireland) 1995 as amended. A roost is protected whether or not bats are in it at the time — so a barn used only in summer is still a protected roost in December.
Bats come into a planning application whenever the proposal affects a structure or feature that could support a roost: roof voids, slated or stone buildings, cavity walls, bridges, and mature or veteran trees with cavities, splits or lifting bark. Demolition, conversion, re-roofing and tree felling are the usual triggers.
The first step is a preliminary roost assessment, which can be done at any time of year. Where that finds anything above negligible potential, dusk emergence surveys follow — even low suitability normally merits a precautionary visit — and those are limited to roughly May to August.
Eight species are resident here, including the common and soprano pipistrelles, Leisler's bat, brown long-eared bat, Daubenton's bat, Natterer's bat and the whiskered bat.
No. Bats do not gnaw or build nests, they do not bring in bedding material, and they cause no structural damage. A roost in a roof void is generally invisible apart from droppings, which are dry and crumble to dust.
It should not. What it changes is how works to the building are planned and timed. Most schemes proceed with a mitigation strategy, and in many cases replacement roost provision is built into the new structure.
Bats and their roosts are legally protected in Northern Ireland. If your proposal affects a building, a roof void or mature trees, the council will usually want to know whether bats are present before it determines the application.
Other species: Badgers · Otters · Nesting birds · Red squirrels · Pine martens · Irish hare · Barn owls
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