Acoustic correlates of body size and individual identity in banded penguins

<div><p>Animal vocalisations play a role in individual recognition and mate choice. In nesting penguins, acoustic variation in vocalisations originates from distinctiveness in the morphology of the vocal apparatus. Using the source-filter theory approach, we investigated vocal individuality cues and correlates of body size and mass in the ecstatic display songs the Humboldt and Magellanic penguins. We demonstrate that both fundamental frequency (<i>f</i>₀) and formants (<i>F</i>₁-<i>F</i>₄) are essential vocal features to discriminate among individuals. However, we show that only duration and <i>f</i>₀ are honest indicators of the body size and mass, respectively. We did not find any effect of body dimension on formants, formant dispersion nor estimated vocal tract length of the emitters. Overall, our findings provide the first evidence that the resonant frequencies of the vocal tract do not correlate with body size in penguins. Our results add important information to a growing body of literature on the role of the different vocal parameters in conveying biologically meaningful information in bird vocalisations.</p></div

Name, sex and values of the vocal parameters (mean ± SD) of each Humboldt (a) and Magellanic (b) penguin.

<p>Name, sex and values of the vocal parameters (mean ± SD) of each Humboldt (a) and Magellanic (b) penguin.</p

Spectrographic representation of ecstatic display songs uttered by adult Humboldt (A) and Magellanic (B) penguins during the breeding period.

<p>Asterisks indicate the syllables type 2. Spectrograms were generated in Praat using a Gaussian window shape, window length = 0.03 s, number of time steps = 1000, number of frequency steps = 250, dynamic range = 50 dB.</p

Vocalisations of Humboldt and Magellanic penguins plotted in the two-dimensional space defined by DF1-DF2.

<p>The calls of the different individuals made distinctive clusters within the range of variation of their species.</p

Abbreviations and descriptions for the acoustic parameters measured.

<p>Abbreviations and descriptions for the acoustic parameters measured.</p

Average values for the bill length (a) and body weight (b) of each penguin plotted against duration of the type 2 syllables.

<p>Error bars show 95% confidence Interval.</p

Standardised coefficients for the canonical discriminant functions generated by the stepwise procedure to classify vocalisations of Humboldt (a) and Magellanic (b) penguins.

<p>Standardised coefficients for the canonical discriminant functions generated by the stepwise procedure to classify vocalisations of Humboldt (a) and Magellanic (b) penguins.</p

sj-pdf-1-lan-10.1177_00236772221111261 - Supplemental material for General and species-specific recommendations for minimal requirements for the use of cephalopods in scientific research

Supplemental material, sj-pdf-1-lan-10.1177_00236772221111261 for General and species-specific recommendations for minimal requirements for the use of cephalopods in scientific research by Giovanna Ponte, Katina Roumbedakis, COST Action FA1301, Viola Galligioni, Ludovic Dickel, Cécile Bellanger, Joao Pereira, Erica AG Vidal, Panos Grigoriou, Enrico Alleva, Daniela Santucci, Claudia Gili, Giovanni Botta, Pamela Imperadore, Andrea Tarallo, Lars Juergens, Emily Northrup, David Anderson, Arianna Aricò, Marianna De Luca, Eleonora Maria Pieroni, Graziano Fiorito in Laboratory Animals</p