Vocal learning and cultural evolution in temperate and tropical animals

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In eight groups of animals on Earth, including humans and songbirds, juveniles learn to communicate by listening to adults. Vocal learning has important consequences for behavioural ecology – for example, learned vocalizations are critical for defending territories and attracting mates – and for evolutionary biology – for example, learning promotes geographic variation and thereby influences population divergence and speciation. Birds provide an outstanding model system for studying vocal learning because they produce diverse vocal signals, because they have short generation times, and because they respond strongly to experimental playback, making it possible to manipulate the learning process. Whereas traditional studies have focused on learning in males, temperate animals, and captive individuals, I propose highly innovative studies on both male and female vocalizations, on both temperate and tropical animals, and on wild animals in their natural environment. With a team of students and postdocs, I will conduct research on two model systems: a population of temperate sparrows where an unusually high return-rate allows us to track birds from birth to adulthood; and a population of tropical wrens where both sexes sing solo songs and coordinated vocal duets. We will teach songs to young birds using arrays of custom-designed loudspeakers that simulate tutors engaged in realistic vocal interactions. In part A of this investigation, we will experimentally investigate new ideas about vocal learning. We will test hypotheses that young animals preferentially learn songs overheard during interactions rather than solo broadcasts; that both an animal’s early acoustic environment and their pre-breeding social environment modifies vocal learning; that young animals preferentially learn high performance songs that are difficult to perform; and that tropical birds learn to perform duets by listening to adults. In part B, we will conduct longitudinal analyses to study vocal learning in tropical wrens. We will test hypotheses that tropical birds exhibit sex-specific vocal lineages, and that tropical birds learn to combine particular songs from their complex vocal repertoires by following “duet codes”. In part C, we will study cultural evolution in both temperate and tropical birds, documenting patterns of acoustic changes through time and space to better understand imitation, innovation, selection, and drift. Uniquely, we will test and refine theoretical models of cultural evolution by quantifying the evolution of songs we introduce using simulated vocal tutors. This body of research will provide groundbreaking insight into the behaviour, ecology, and evolutionary biology of animals, and answer novel questions about vocal learning and cultural evolution. This research will allow me to train many young Canadian scientists, and develop innovative technologies for studying wild animals.