Bat "At height" surveys'At height' surveys use bat detectors combined with a microphone mounted on a long cable. This allows recordings to be made on a variety of structures such as meteorological masts and buildings which give an indication of the amount of bat activity at a specified height above the ground.
These surveys are particularly useful in determining bat activity at height in order to predict any collision risk with proposed wind turbines. Anabat bat detectors are used as produced by Titley Electronics in Australia; these are designed to record large numbers of calls over a long period whilst using very little electrical power. The timing of an 'at height' survey should take into account the Spring migration period (February to April), the breeding period (May to August), the mating period (August to September) and the Autumn migration period (September to October). An 'at height' survey by The Wildlife Survey Unit would identify:
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