Who is the Yellow-breasted Barbet?

The Yellow-breasted Barbet (Trachyphonus margaritatus) is an Africa Barbet species, member of the Lybiidae family which includes several duetting, chorusing and non-duetting species through the African continent (Hall 2009). This bird lives in pair or small social group and is described as a group breeding species (Soma & Brumm 2020). It defends its territory throughout the year, mainly by producing loud tonal duets and choruses.

Cooperative behavior is a prominent feature among group-living species and continues to pose challenges to our understanding about the evolution of social relationships and task coordination between members of a same social group. Individuals who are willing to cooperate to achieve a joined action need to communicate their intentions and somehow make a common agreement. The first part of my research project is to investigate how barbets initiate their communal vocal displays. It is known that the the Yellow-breasted barbet initiates its duet and chorus songs with "pre-duet notes" (also described as "chewp" notes) during a kind of "greeting ceremony" (Short and Horn 1983). However, the nature of these vocalizations and their functions remain unknown. I recorded with video camera several group displays of barbets, in order to describe in details the way they use such chewp notes. I also investigate the possible existence of a multimodal signal that could be similar to what is observed with the D'Arnaud's barbet (Trachyphonus darnaudii). The pre-duet notes could be a specific signal that serves either as recruitment signal or as mutual agreement between individuals to start a duet or chorus song.

The second part of the project focus more on the song features. I study the between-group vocal interactions to understand how and why birds sing in group. These group vocal displays could transmit different information such as the group identity, the number of individuals present as well as the level of cohesiveness of the group members (Baker 2004, 2009 ; Radford 2003 ; Seddon and Tobias 2003 ; Wu 2013). These information could be useful for neighbors to determine the intention and evaluate the level of threat represented by a given group of barbets. To do so,  I used Song Meter Micro (autonomous recorders) to monitor the daily vocal activity of different groups simultaneously within a same area. I collected hundred hours of recordings from which I extracted the different vocalizations emitted by barbets. I analyze in details the acoustic features and the context of each emission of a duet or a chorus, whether it was a spontaneous one or in reaction to a neighbor's group vocal display.