Increasing use of small wind turbines for domestic and farmland electricity is causing a drop in bat numbers where they are erected, a British study has found. A fall in bat activity of up to 54 percent has been recorded at 20 sites studied across Britain where micro turbines are in use, researchers from Stirling University said. The study recommends micro turbines should not be sited within 65 feet of the animals\' habitats, the BBC reported. The effect of turbine movement on the activity of birds and two species of bat, the common and soprano pipistrelle, was studied at the 20 research sites. While bird activity was not significantly affected, running turbines did reduce bat numbers, the researchers concluded. \"Current planning guidance on the siting and installation of new small wind turbines is very limited so our findings will provide valuable information and help create more sensible and useful guidelines,\" study leader Kirsty Park said. \"This will help us to maximize the benefits of renewable energy generation whilst minimizing potentially adverse effects on wildlife.\"