Heart rate measurement of nesting birds using a microphone in a plastic egg

Abstract

The responses of birds to overflying remotely piloted aircraft (or drones) are poorly understood. While direct ob-servations of behaviour can provide an understanding of wildlife response, this approach is unable to quantify the potential physiological responses of individuals. To do this, a dummy bird egg containing a microphone was sub-stituted into the nests of incubating adult seabirds. Audio recordings were made to capture the sounds of the birds’ heart-beat. The recordings were used to calculate a resting heart rate, which was to be compared with the heart rate when a remotely piloted aircraft flew overhead. The focus of this paper is the signal processing methods that were evaluated to process the audio signals to extract the instantaneous heart rate of the animal.