Bats are extraordinary mammals. If being able to fly wasn't enough, they do it in the dark using an echo-location system.

There are 17 species of bat in the UK, all of which eat insects and all of which have declined due to habitat destruction, disturbance and persecution.

Where do bats live?

Bats frequently roost in lofts and roof spaces and other parts of buildings as their natural roosting sites in trees and caves become more rare or disturbed.

They may be found under tiles, hanging from the roofing felt or timbers, and in joints and splits in beams and timbers. However, they are rarely seen in lofts; most roost in cracks and crevices and are usually only present in the roof void for part of the year.

Even expert bat workers have to content themselves with signs of bat presence, especially their droppings. These are dark brown or black, 4-8mm long and easily crumble into a powder, unlike rodent droppings which are hard. Be sure to wash your hands after conducting this 'twixt finger and thumb' test.

Other signs include discarded moth wings, urine stains and dark 'polished' surfaces around access holes.

Bats and the law

Bats and their roost sites are protected from disturbance by law. Examples of disturbance include:

• entering a loft which is a roost site
• timber treatment
• fitting of loft insulation
• attending to wiring or piping
• storage use
• pest control
• other building work in a bat roost

When bats are hibernating, the presence of a person or their lights can cause them to wake up. This wastes energy which cannot be replenished in the depths of winter when feeding is impossible.

Roosts are protected whether bats are present at the time or not. If you need to enter or work in an area known to be used by bats, or find them after work has begun, stop immediately and contact either Natural England, Countryside Council for Wales, Scottish Natural Heritage, or the Environment and Heritage Service in Northern Ireland.