We've also found bat roosts in houses and derelict buildings. On one walk, we were intrigued to see dozens of bats flying out of a house late at night. Different types of bat can be distinguished by their flight patterns, and by using a 'bat detector'. Each species has a slightly different sound pattern and calls at a slightly different frequency. Of course, not everyone likes bats, but they are certainly not the leathery vampires of legend.
British bats are small furry creatures - some people say they're like flying hamsters.
They only eat insects. A pipistrelle can eat as many as 3,500 small flies and gnats in a night. Contrary to myth, bats don't get caught in your hair - if they can find a midge in the dark, they can certainly avoid a human being. Some people just hate the thought of bats flying around them. This turned out to be a young bat which had somehow got lost and injured a leg.