Inspired by going on an organised bat walk, members of the Hurst Water Meadow Trust started the bat project in 2012.
The aim of the project is to learn more about the current bat population of Hurst Water Meadows (two water meadows alongside the River Thame on the edge of Dorchester-on-Thames in Oxfordshire), to involve local people and to use what we learn to inspire the community to appreciate these shy mammals and to help maintain and enhance the area as a bat-friendly environment.
What we’ve done so far
The equipment: Thanks to a grant from the Trust for Oxfordshire’s Environment (TOE), we set up some bat boxes and acquired a bat detector and a small recording unit. We could hear and record the bats’ echo-location calls but we could not tell which species they were; no bats occupied the boxes. We obviously had a lot to learn before we could provide useful information about the species present and how abundant they were. But The Hurst, lying between the Thame and the Overy mill race, and the Old Bridge Meadow are good places to start.
Bat workshop: Identifying bat calls by ear requires long experience. On the detector, calls sound like rapid slaps, smacks, chips, chops or plops – difficult to describe any other way. One call may last from 0.2 to 100msec, according to species and the type of call. We got to grips with some of these distinctions in a workshop run for us by Dr Danielle Linton (Wiltshire Wildlife Trust) where she showed us how to distinguish echo-location calls, feeding calls, the buzz of a successful catch, and territory calls. We then went on a bat walk in the Hurst where she identified four species by ear: common pipistrelle, soprano pipistrelle,Daubenton’s bat, and noctule.
Further training: Bats are protected by law. We are not allowed to look in roosts or handle bats unless with a licensed handler. So we joined Dani Linton and Dr Tom August on a daytime survey in Wytham Woods where we could see the bats as they were taken from their roosts, and handle them (provided we had had the obligatory rabies injection). We helped to record the details of the bats in nearly 100 bat boxes: species, sex, age, whether or not lactating, and weight. One box held more than 30 bats, all clustered together in a tight ball. Note: the handlers are very gentle and all the bats are returned to their bat boxes, unharmed.
It is going to take a long time to gain all the necessary skills, but we hope to enthuse others further upstream to take an interest in these fascinating creatures. Ideally, one or more groups could be established; between us we could assess the status of the bat population, another indication of the health of the River Thame.