Animal communication networks: social, environmental, and anthropogenic drivers of behaviour

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Communication plays a vital role in mediating the social and mating behaviour of animals. Most of our understanding of the ecology and evolution of vocal communication in birds comes from studies of daytime singing behaviour of songbirds. However, species that are diurnally active often sing intensely just before the sun rises each day in an impressive display known as the dawn chorus. A number of daytime singing species also sing at night. The social (e.g. territory boundaries, relative quality of neighbours) and environmental (e.g. weather, ambient light) factors influencing both the dawn chorus and nocturnal singing are not well understood. However, both displays likely play at least equally important roles as daytime signalling does in determining fitness. The studies that my students and I will conduct are designed to test hypotheses for why birds sing in these contexts. We use a combined observational and experimental approach and multiple hypotheses testing to assess the factors influencing vocal displays in three songbird species: black-capped chickadees, white-throated sparrows, and ovenbirds. We focus on vocal signalling in the context of communication networks (where multiple signallers and receivers exchanging information simultaneously). To do so, we use powerful new recording and song playback techniques to record networks of territory holders, such that the social environment and the abiotic factors that influence displays can be considered in concert. By analyzing vocal behaviours in this way, we can provide new insights into animal communication and study emergent properties of networks. In addition to understanding how these vocal displays function in natural conditions, I propose experiments to test how vocal displays are influenced by light and noise. Anthropogenic noise and light are increasingly understood to alter behaviour and fitness of wild-animal populations. However, many studies are confounded by the co-occurrence patterns of these features in the landscape or their influence on settlement patterns of territory holders. The experiments I propose will involve manipulating noise and light levels independently and together using a ski-trail in an otherwise undisturbed natural population. Together with the observational and experimental studies of dawn and nocturnal song, the experimental manipulation will provide insight into ecological effects of the increasing anthropogenic pressures animals face in the landscape. It is imperative to understand how animals communicate and how different displays influence fitness in natural systems. In addition, insights into how altering the system can influence behaviour and ecology of animals can inform conservation and damage mitigation strategies in the longer term.