Anthropogenic noise affects vocalisation properties of the territorial song of Western Australian magpies

Abstract

Anthropogenic noise is considered one of the most serious forms of pollution globally and has been shown to have negative effects on the distribution, behaviour, cognition and reproductive success of animal species worldwide. One of the most well researched impacts of anthropogenic noise is its effect on acoustic communication. Animals may adjust the rate, amplitude, duration, and/or frequency of their acoustic signals to better maintain communication when anthropogenic noise is present. In this study, we combine behavioural focals, amplitude measurements and audio recordings to investigate how female Western Australian magpies (Gymnorhina tibicen dorsalis) alter the acoustic features of their territorial song (known as a carol) when anthropogenic noise is present. Magpies reduced the rate at which they carolled when loud anthropogenic noise was present, and increased their peak frequency during anthropogenic noise, but, contrary to our hypotheses did not alter the amplitude, duration, or other frequency parameters of their carols. Results from this study add to the growing body of literature documenting changes to the vocal behaviour of wildlife in the presence of anthropogenic noise and highlights the importance of investigating multiple acoustic parameters to understand how species adjust their vocalisations in response to this pollutant.