Time series analysis of bat ultrasound signals

The general objectives of this study are to develop new methods to analyze ultrasound signals recorded during field observations of bats, and relate these to bat biology. In particular, I investigate methods to determine whether or not sound pulses produced by multiple bats are independent of each other when the bats are searching for food in the same environment. Four models are proposed to explain the time series of recorded signals and it is found that the Poisson model, which assumes pulses are independent, fits the data best. A computer program, BatCount was developed as part of this study, to provide an automated method to count bat pulses and to allow comparisons of signals recorded during different observations. This program also included methods to compare the different models developed to the signals as part of the data analysis.