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Bats in houses

Like house martins and swallows, bats are usually seasonal visitors to houses and are typically present for only four to five months of the year. They tend to form maternity colonies during May and June and then leave during August and early September once the young bats are independent. The colonies are often most obvious during July, when the young are starting to fly; soon after this the adults will start to leave, followed by the young. Although this seasonal pattern usually applies, there are exceptions and sometimes bats can be found using the same buildings in both winter and summer.

To maximise warmth, maternity roosts are often located on the south and west of houses or close to sources of heat such as chimneys and boilers. Most species prefer to roost in quite small spaces and are not usually found in open draughty areas. The common and soprano pipistrelles are our smallest and most common bat species. They are generally found in the inaccessible parts of the roof structure and around its edges and rarely enter the loft space. Both species colonise new buildings quite readily and frequently roost in houses built since the 1960s. By contrast, the brown long-eared bat prefers older buildings with large roof spaces and is often seen in clusters at the top of the roof ridge inside the loft. Where bats are seen in buildings during the winter, they tend to be alone or in small scattered groups, hidden in crevices or under slates and away from sources of heat.

Bat colonies usually live happily with their human landlords, but occasionally problems or concerns arise. Scottish Natural Heritage is happy to provide advice on how to deal with any problems. See Need help with bats in your house?

Last updated on Monday 19th September 2016 at 15:00 PM. Click here to comment on this page