Communication hétérospécifique et syntaxe dans les cris de harcèlement des Paridés

One strategy for prey facing a predator is to harass it until it flees. Mobbing is a collective behaviour involving many species, especially in birds. In this context, some species of Parids assemble several elements to create a new call, and recent work has shown that the order of these elements is of particular importance. In this thesis, I explore the relative importance of syntax (i.e., the order of the elements in the sequence) in the recognition of heterospecific calls in the great tit. I complete this work with experiments targeting the production and reception of harassment calls in Parids and the impact of the protocol on studies about heterospecific communication. The results of the eight experiments proposed in this thesis support the hypothesis that syntax recognition is an effective recognition system used by the great tit in response to unfamiliar calls. Furthermore, these results demonstrate the importance of the protocol in the interpretation of the results and open new discussions and projects in animal linguistics.Face à un prédateur, les proies peuvent se regrouper et le harceler jusqu’à engendrer sa fuite. Le harcèlement de prédateur est un comportement collectif impliquant de nombreuses espèces, notamment chez les oiseaux. Dans ce contexte, certaines espèces de mésanges assemblent plusieurs éléments afin de créer un nouveau cri, et de récents travaux ont démontré que l’ordre de ces éléments revêt une importance particulière. Dans cette thèse, j'explore l’importance relative de la syntaxe (i.e., l’ordre des éléments dans la séquence) dans la reconnaissance des cris hétérospécifiques chez la mésange charbonnière. Je complète ce travail par des expériences ciblant la production et la réception des cris de harcèlement chez les mésanges ainsi que l’impact du protocole sur les études portant sur la communication hétérospécifique. Les résultats des huit expériences proposées dans cette thèse corroborent l’hypothèse que la reconnaissance de la syntaxe est un système efficace de reconnaissance utilisé par la mésange charbonnière face à des cris inconnus. Par ailleurs, ces résultats permettent de démontrer l’importance du protocole dans l’interprétation des résultats et ouvrent une discussion nouvelle sur des notions de linguistique animale

Great tits ( Parus major ) adequately respond to both allopatric combinatorial mobbing calls and their isolated parts

International audienceWhen mobbing a predator, birds often produce specific mobbing calls that are efficient in recruiting both conspecifics and heterospecifics. Recent studies on Parids have demonstrated that these mobbing calls are in fact a combination of two distinct calls-first, introductory notes eliciting vigilance in the receiver, then broadband frequency notes (D notes) triggering approach. Debates on a parallel between human syntax and this form of combination have emerged. The degree to which this combinatoriality is perceived in heterospecific communication may shed light onto the relative complexity of such combinatoriality. In this study, our aim was to determine whether European great tits (Parus major) appropriately responded to mobbing calls (and their isolated parts) of an allopatric species, the black-capped chickadee (Poecile atricapillus), a North-American species which produces similar combinatorial mobbing calls. In addition, we tested whether the behavioural response to complete mobbing sequences was different than the simple sum of its two constituents. As we hypothesized, great tits behaved differently when hearing the two isolated calls or the complete mobbing sequence: they produced calls and displayed excitement signs only towards the complete mobbing sequence. Moreover, great tits responded to the introductory and D notes by respectively scanning and approaching, and to the complete sequence by mobbing. Our results altogether support the emerging hypothesis of semantic compositionality in Parids, although the present study does not definitively demonstrate the existence of this cognitive process in the great tit

Both learning and syntax recognition are used by great tits when answering to mobbing calls

International audienceMobbing behavior, in addition to its complex cooperative aspects, is particularly suitable to study the mechanisms implicated in heterospecific communication. Indeed, various mechanisms ranging from pure learning to innate recognition have been proposed. One promising yet understudied mechanism could be syntax recognition, especially given the latest works published on syntax comprehension in birds. In this experiment, we test whether great tits use both learning and syntax recognition when responding to heterospecifics. In the first part of the experiment, we demonstrate that great tits show different responses to the same heterospecific calls depending on their sympatric status. In the second part, we explore the impact of reorganizing the notes of the heterospecific mobbing calls to fit the syntax of great tits. Great tits showed an increased mobbing response toward the heterospecific calls when they shared their own call organization. Our results corroborate the recent finding that syntactic rules in bird calls may have a strong impact on their communication systems and enlighten how various mechanisms can be used by the same species to respond to heterospecific calls

Biological conclusions about importance of order in mobbing calls vary with the reproductive context in Great Tits ( Parus major )

International audienceCurrently, there is considerable debate surrounding the presence of some human language-specific characteristics in non-human animals, such as the use of compositional syntax (i.e. meaning of a sequence determined both by meaning of its individual parts and in the way they are combined). Compositional syntax has been investigated in mobbing calls of two closely related tit species, the Japanese Tit Parus minor and the Great Tit Parus major, but with one contrasting result: hearing calls in the reversed order diminished the behavioural responses of Japanese Tits but only partially those of Great Tits. This difference may have been due to an external factor such as the season in which the experiment was undertaken, as the Japanese Tits were tested in winter and Great Tits in spring. Here, we studied the responses of Great Tits towards natural and reversed mobbing sequences during spring and winter by investigating two behaviours: approaching and vigilance behaviours. We found that sensitivity to syntax reversal was impacted by the season. The birds were vigilant but less likely to approach reversed calls in winter. However, the opposite occurred in spring, with the birds scanning less but still approaching. This study suggests that the perception of combinatorial calls in Great Tits is influenced by the season, emphasizing the importance of context in studies investigating complex cognitive processing in animals