A small vocal repertoire during the breeding season expresses complex behavioral motivations and individual signature in the common coot

Xiang Li,Xiaoying Xing,Changjian Fu,Feng Li,Guangyi Lu,Atul Kathait

doi:10.1186/s40850-021-00088-4

Xiang Li, Xiaoying Xing + Show 4 more

Open Access

https://doi.org/10.1186/s40850-021-00088-4

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Abstract

BackgroundAlthough acoustic communication plays an essential role in the social interactions of Rallidae, our knowledge of how Rallidae encode diverse types of information using simple vocalizations is limited. We recorded and examined the vocalizations of a common coot (Fulica atra) population during the breeding season to test the hypotheses that 1) different call types can be emitted under different behavioral contexts, and 2) variation in the vocal structure of a single call type may be influenced both by behavioral motivations and individual signature. We measured a total of 61 recordings of 30 adults while noting the behavioral activities in which individuals were engaged. We compared several acoustic parameters of the same call type emitted under different behavioral activities to determine how frequency and temporal parameters changed depending on behavioral motivations and individual differences.ResultsWe found that adult common coots had a small vocal repertoire, including 4 types of call, composed of a single syllable that was used during 9 types of behaviors. The 4 calls significantly differed in both frequency and temporal parameters and can be clearly distinguished by discriminant function analysis. Minimum frequency of fundamental frequency (F0min) and duration of syllable (T) contributed the most to acoustic divergence between calls. Call a was the most commonly used (in 8 of the 9 behaviors detected), and maximum frequency of fundamental frequency (F0max) and interval of syllables (TI) contributed the most to variation in call a. Duration of syllable (T) in a single call a can vary with different behavioral motivations after individual vocal signature being controlled.ConclusionsThese results demonstrate that several call types of a small repertoire, and a single call with function-related changes in the temporal parameter in common coots could potentially indicate various behavioral motivations and individual signature. This study advances our knowledge of how Rallidae use “simple” vocal systems to express diverse motivations and provides new models for future studies on the role of vocalization in avian communication and behavior.

Highlights

Acoustic communication plays an essential role in the social interactions of Rallidae, our knowledge of how Rallidae encode diverse types of information using simple vocalizations is limited
Rallidae often gather in groups and have complex life history traits, such as breeding displays, alarm context and agonistic behaviors involving the broadcasting of loud calls during the breeding season, suggesting that the acoustic component of social interactions plays an important role in breeding interactions [6, 22,23,24]
We addressed 2 questions related to the functions of acoustic signaling: (1) Are different call types used in different behavioral contexts, such as aggression, courtship, foraging, or parent-nestling communication? and (2) Are acoustic parameters such as the frequency or temporal spectral domains modulated in ways that permit a single call type to express diverse behavioral motivations, and to what extent does individual signature contribute to the acoustic variations?

Summary

Introduction

Acoustic communication plays an essential role in the social interactions of Rallidae, our knowledge of how Rallidae encode diverse types of information using simple vocalizations is limited. We compared several acoustic parameters of the same call type emitted under different behavioral activities to determine how frequency and temporal parameters changed depending on behavioral motivations and individual differences. Acoustic communication consisting of diverse types of syllables and elements expressing various meanings [13,14,15,16], the simple vocalizations, such as referential alarm calls can indicate categories of predators, or even predators’ behaviors [17,18,19]. Despite being subject to similar acoustic selective pressures and inhabiting the same habitats as other birds with complex vocalizations, how Rallidae express complex behavioral motivations using much simpler vocal types remains unclear [2]

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