Differences between the songs of rural and urban Australian magpies (Gymnorhina tibicen) and the potential consequences for territorial interactions

A number of studies have found that birds in urban areas alter singing behaviour, possibly to increase signal transmission and avoid masking by high levels of anthropogenic background noise. However, few studies have focused on how these song differences might be interpreted by receivers. We investigated differences in song between populations of urban and rural Australian magpies (Gymnorhina tibicen), an Australian species abundant in both habitats. First, we compared urban and rural magpie songs to determine if magpies shift the frequency, duration and output of songs in response to anthropogenic noise. Unlike some songbirds, urban magpies did not shift minimum frequencies to avoid masking, however they did sing shorter songs. We then played back unfamiliar urban and rural songs to groups of both urban and rural magpies, and monitored their territorial responses. Results showed that differences in song across both habitats do not affect receiver responses, indicating that magpies from both urban and rural habitats can readily communicate with each other. Interestingly, rural magpies responded with more aggression to rural songs than to either urban songs or to control songs. We propose that the flexibility of Australian magpie songs aids this species in its ability to adapt successfully to urban environments. © The Ornithological Society of New Zealand, Inc