An important tool used in surevying bats is a bat detector; basically a box of electronic trickery that translates the near inaudible sounds bats use to "see" in the dark into sounds that we humans can hear. Different species make different sounds and/or use different frequencies so you can tell them apart from their echolocation.
Dean has been carrying out similar work on various of the Trust properties as part of the Trust's bat conservation work. We own all sorts of properties many of which we know to be home to bats, and have the only Bat Reserve in Scotland at Threave, but there are also many properties where we know there are bats, but we don't know what species, and where they are roosting. So Dean has been taken on to fill this gap in our knowledge. He has gone away to analyse all his recordings and data from his work at St Abbs, but initial findings show that we have definitely got roosts of both pipistrelle and brown long-eared bats which is fantastic news. We will keep you posted, and hopefully be able to post some infra-red video too!
If you would like to learn more about bats, check out the Bat Conservation Trust website at http://www.bats.org.uk/.