What Can Virtual Vocal Tracts Tell Us About Lemur Communication?

Gamba, Marco; Medard, Jules; Andriamialison, Haingoson; Rakotoarisoa, Gilbert; Giacoma, Cristina

doi:10.1007/978-1-4614-4511-1_36

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…However, before getting into the measurements of filer- related acoustic parameters, we estimated the approximate vocal tract length (VTL) for African penguins, to set a plausible number of formants in a given frequency range. We built computational models of the penguin vocal tract deriving information from silicon casts (for details please refer to Gamba and Giacoma 67 ; Gamba et al 68 ) of two cadavers kept frozen at −20 C°. These individuals (one male and one female) died from natural causes in 2011 and 2012, respectively.…”

Section: Methodsmentioning

confidence: 99%

Vocal individuality cues in the African penguin (Spheniscus demersus): a source-filter theory approach

Favaro

Gamba

Alfieri

et al. 2015

Sci Rep

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The African penguin is a nesting seabird endemic to southern Africa. In penguins of the genus Spheniscus vocalisations are important for social recognition. However, it is not clear which acoustic features of calls can encode individual identity information. We recorded contact calls and ecstatic display songs of 12 adult birds from a captive colony. For each vocalisation, we measured 31 spectral and temporal acoustic parameters related to both source and filter components of calls. For each parameter, we calculated the Potential of Individual Coding (PIC). The acoustic parameters showing PIC ≥ 1.1 were used to perform a stepwise cross-validated discriminant function analysis (DFA). The DFA correctly classified 66.1% of the contact calls and 62.5% of display songs to the correct individual. The DFA also resulted in the further selection of 10 acoustic features for contact calls and 9 for display songs that were important for vocal individuality. Our results suggest that studying the anatomical constraints that influence nesting penguin vocalisations from a source-filter perspective, can lead to a much better understanding of the acoustic cues of individuality contained in their calls. This approach could be further extended to study and understand vocal communication in other bird species.

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Section: Methodsmentioning

confidence: 99%

Vocal individuality cues in the African penguin (Spheniscus demersus): a source-filter theory approach

Favaro

Gamba

Alfieri

et al. 2015

Sci Rep

Self Cite

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“…We generated a virtual population of 1160 penguin vocal tracts using these vocal tract area functions as input for a customized version of VTAR modelling software [53,54]. We calculated the acoustic response of each model and collected formants F 1 , F 2 , F 3 and F 4 , total length and total volume, of the region whose measurements were changed [55,56].…”

Section: Methodsmentioning

confidence: 99%

Vocal tract shape variation contributes to individual vocal identity in African penguins

Favaro,

Zanoli,

Ludynia

et al. 2023

Proc. R. Soc. B.

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Variation in formant frequencies has been shown to affect social interactions and sexual competition in a range of avian species. Yet, the anatomical bases of this variation are poorly understood. Here, we investigated the morphological correlates of formants production in the vocal apparatus of African penguins. We modelled the geometry of the supra-syringeal vocal tract of 20 specimens to generate a population of virtual vocal tracts with varying dimensions. We then estimated the acoustic response of these virtual vocal tracts and extracted the centre frequency of the first four predicted formants. We demonstrate that: (i) variation in length and cross-sectional area of vocal tracts strongly affects the formant pattern, (ii) the tracheal region determines most of this variation, and (iii) the skeletal size of penguins does not correlate with the trachea length and consequently has relatively little effect on formants. We conclude that in African penguins, while the variation in vocal tract geometry generates variation in resonant frequencies supporting the discrimination of conspecifics, such variation does not provide information on the emitter's body size. Overall, our findings advance our understanding of the role of formant frequencies in bird vocal communication.

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What Can Virtual Vocal Tracts Tell Us About Lemur Communication?

Cited by 2 publications

References 9 publications

Vocal individuality cues in the African penguin (Spheniscus demersus): a source-filter theory approach

Vocal individuality cues in the African penguin (Spheniscus demersus): a source-filter theory approach

Vocal tract shape variation contributes to individual vocal identity in African penguins

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