ACCURACY OF A PASSIVE ACOUSTIC LOCATION SYSTEM - EMPIRICAL-STUDIES INTERRESTRIAL HABITATS

The accuracy with which an acoustic location system (ALS) could locate a sound source was studied in open meadow and woodland habitats for a number of types of sound. The ALS used differences in the arrival tim es of sound at a fixed, four-microphone array and was based on the Can ary sound analysis package. Location error increased with distance of the sound source from the centre of the array and was smallest in mead ow habitats which induced little reverberation and which had low level s of biological background noise. The physical characteristics of soun d elements could be used to predict the accuracy of the ALS in locatin g them. In general, frequency modulated sounds were located more accur ately than constant frequency sounds, as were sounds containing a numb er of different elements when compared with shorter single-element sou nds. It proved to be possible to locate sounds routinely to within a f ew tens of centimetres, and therefore song perch changes of a few metr es could be detected by the ALS. Thus this system has the potential to become an essential tool with which to study animals generating sound s, in particular acoustic signalling and communication networks.