Grant: Discovery Grants Program - Individual

The songs and calls of birds are remarkably diverse, with some species producing simple chirps and others singing elaborate songs that rival a symphony. Vocalizations are critical to survival and reproduction, and their diversity is thought to reflect multiple selective pressures, including the need to communicate with diverse audiences (eg, parents, offspring, mates, and rivals) over short and long distances without being overheard and exploited by unintended receivers such as predators. Understanding the function and evolution of avian vocalizations begins with detailed descriptions of their structure, which can be decomposed into frequency, temporal, and amplitude dimensions. Frequency and temporal characteristics have been described for many species, but amplitude characteristics for very few species. This is a problem because amplitude strongly affects the space over which signals can be heard by intended and unintended receivers. My research team will measure the amplitude of avian vocalizations in taxonomically diverse species distributed across Canada and other global biodiversity hotspots. Using information about body size, vocal tract morphology, habitat characteristics, mating and social system, and environmental noise (including noise pollution created by humans), we will determine the factors that best explain amplitude variation within and among species. We will also investigate the function of amplitude variation by testing how it affects other animals as they respond to vocalizations. Birds are ideal for this research because they are diverse (~10,000 species), their phylogenetic relationships are known, and they rely heavily upon structurally diverse acoustic signals. Yet, the general patterns revealed by our research will also be relevant to all animal communication systems and will thus provide insight into one of the fundamental processes governing interactions among animals. Our research will provide the first comprehensive analysis of the ecology and evolution of amplitude in animal signalling systems, thereby making a Canadian contribution to the international fields of behavioural ecology and animal communication. The research program will provide a stimulating environment in which to train the next generation of Canadian scientists, while at the same time strengthening ties to international collaborators who will help expand the focus of the research from Canadian to global biodiversity. Students will gain experience with ornithological field research, cutting-edge bioacoustic techniques, and statistical approaches for revealing behavioural and evolutionary patterns. Amplitude-calibrated audio recordings will be archived in public sound repositories, and results will be communicated through international journals, conference presentations, social media, and science documentaries. This broad dissemination will maximize the impact of our research and my ability to attract a diverse group of people to careers in science.