Stability and change in short songs of yellow-rumped and red-rumped caciques (Cacicus cela and Cacicus haemorrhous)
Résumé
Functional analysis of bird song dialects have been the object of extensive researches. Several hypotheses emerged from these investigations, among which the social adaptation hypothesis : using the same dialectal variant as social partners would facilitate the integration of newcomers into a social group. The social dialect could also constitute a local population or group marker. The social adaptation model predicts changes in bird vocalizations in response to social changes. In a previous study, we found local dialectical variants in French Guyanian populations of yellow-rumped and red-rumped caciques, two congeneric species of Icterid birds, both living in large multi-males / multi- females groups. We found dialects characterized by time and frequency parameters in male short songs involved in social communication. The social adaptation hypothesis predicts a progressive change in local dialectal vocalization types. In the present study, we analyze the temporal evolution of timing and frequency parameters of male short songs in these two species, over five years at the same localities.
Domaines
Acoustique [physics.class-ph]
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