Development of vocal culture in birds – BirdVocalCulture

Understanding the origins of language is a challenge in human sciences and evolutionary biology. It has probably originated when first hominids started cooperating. The use of language has become deeply entrenched in human culture and, apart from being used to communicate and share information, it also has cultural and social uses, such as signifying group identity or social hierarchy. If language is a human attribute, one of its components – vocal learning – is shared with other species including oscine songbirds. Experiments to address central questions about vocal culture that cannot be conducted on humans for ethical reasons can be done with captive populations of birds. For this project, we have chosen two bird species well suited to explore these aspects: a non songbird (galliform), the Japanese quail (Coturnix japonica) and an oscine songbird, the Zebra Finch (Taeniopygia guttata). In both species, we will raise young birds in controlled social environments and we will track their vocal development as well as their vocal interactions, to examine dynamically how their vocalizations are influenced by their social milieu. In particular, we will analyze how vocal learning can enhance group coordination and individual recognition. From earlier works, it is believed that social influences play no role in the development of the vocal repertoire of the Japanese quail. In the first part of this research project, we will revisit these aspects in quails raised in small groups from hatching to adulthood to examine whether subtle changes - that could not be detected with previous technics of sound analysis - occur through vocal imitation. In the Zebra Finch, the song is learned during a sensitive period of the early life, mainly from the father. In normal conditions, each male produces a different song. Using song playback, we succeeded to train young males to produce the same song. We will use these males as founders of a colony to adress the following questions: how would song evolve in a colony where all males sing the same song? Will the offspring sing also the same song or will they invent/improvise new songs to facilitate individuality? This is the aim of the second part of our research project. Vocalizations produced by both species have the potential to be used as individual signatures. In a third part of this research project, we will investigate which acoustic features are salient in individual recognition. The present study will contribute to a better understanding of the social mechanisms of communication and will shed light on the specificity and evolution of vocal learning.