DOI: 10.5061/dryad.x0k6djhxd
title: Data from: Vocal performance in birdsong is an aggressive signal in both females and males: Experimental evidence from a field study in European robins

description: Birdsong often serves as a territorial signal, and vocal performance (the
 degree of vocalising close to vocal production or respiratory limits) can
 play a role in expressing a sender’s aggressiveness. However, this is
 rarely studied in females, in which song has historically been considered
 non-functional. Here, we investigate male and female European robins,
 Erithacus rubecula, in which both sexes sing to defend their exclusive
 winter territory. We compared spontaneous song to song experimentally
 provoked by playbacks simulating territorial intrusions. Our study is the
 first to show that both sexes similarly increased vocal performance when
 territorially challenged, regardless of the simulated intruder’s sex. This
 provides evidence that female song is perceived as equally territorially
 challenging as male song and expresses aggressiveness similarly.
 Additionally, females sang shorter songs than males, and in both sexes,
 vocal performance was lower when singing longer songs, an effect that was
 stronger in females in one of our metrics. We propose that females might
 sing shorter songs to maintain a high level of vocal performance. This
 might be a strategy to cope with sex-specific effects of sustained singing
 on vocal performance.
description: # Vocal performance in birdsong is an aggressive signal in both females
 and males: Experimental evidence from a field study in European robins
 Dataset DOI: [10.5061/dryad.x0k6djhxd](10.5061/dryad.x0k6djhxd) ##
 Description of the data and file structure The study was carried out on
 the campuses of the Universities Paris-Saclay and Paris-Nanterre, in
 France. Songs of 26 territorial European robins, 13 males and 13 females,
 were recorded from October 2019 to November 2022. We present measurements
 of bioacoustic parameters (in numeric form) obtained using Avisoft SASLab
 Pro software, accompanied by the corresponding metadata. ## Files and
 variables We provide 5 csv files along with the R script file
 ([Rscript_Bosca_etal_2025.R](https://datadryad.org/downloads/pre_submit/4157024 "Download from Dryad")) used in our analysis: * data_VGD.csv * data_GED.csv * data_SD.csv * data_elements.csv * data_lqmm.csv They contain the datasets required to replicate our statistical analyses. Please find below a description of our variables as you will find them in those 5 files. Note that, for all tables, the cells corresponding to spontaneous song data (for which no playback experiment was conducted, see the article for further details) are naturally filled with "NA" in the columns specific to playback (e.g., Song_onset_delay, Playback_track, Playback_sex). Please also note that if some silent gaps appear to be missing (e.g., in the silent gap counts in data_VGD.csv and data_GED.csv), this is expected, as some silent gaps were removed from the final dataset (see Electronic Supplementary Material, Text S5, Fig. S2). ### R script file ([Rscript_Bosca_etal_2025.R](https://datadryad.org/downloads/pre_submit/4157024 "Download from Dryad")) This script contains the code used to generate the results presented in our article. Almost every line of code is accompanied by a description (preceded by a "#") explaining its purpose. First, we provide the code required to install and load the necessary packages to run the analyses (lines 8 to 12). Then, the user is asked to define a variable named "wd" (for *working directory*, line 15), which allows the files to be easily loaded from their working environment (lines 18 to 22). Lines 25 to 32 ensure that every variable in each dataset is in the correct format (*factor* or *numeric*).\ Lines 35 to 42 create the variables that require centring (see the article for further details).\ Lines 48 to 72 generate the 10th quantile models used to compute our variables Vocal gap deviation (VGD) and Gap element duration (GED). Finally, lines 78 to 483 contain the code necessary to: * write the linear models used in our analyses, * check assumptions such as normality and absence of collinearity, * perform model selection and model averaging, * extract the results presented in the article (formatted to three decimal places). Additional details about each step are provided directly in the script through the "#" comments.  ### data_VGD.csv This file contains the data regarding Vocal Gap Deviation, along with the corresponding metadata: | Variable | Type | Description | | :---------------------- | :------ | :-------------------------------------------------------------------------------------------------------------------------------------------------------- | | Subject | Factor | Identity of the focal subject. | | Sex | Factor | Sex of the focal subject (binary: M = male / F = female). | | Tarsus\_length | Numeric | Length of the tarsus (in mm) of the focal subject. | | Frequency\_ratio | Numeric | Frequency ratio between the end of the previous element and the beginning of the next, for each focal silent gap -- used in the supplementary model S1. | | Gap\_duration | Numeric | Duration of the focal silent gap (in ms) -- used in the supplementary model S2. | | Context | Factor | Context in which the focal silent gap has been recorded (binary: Spontaneous / Provoked). | | Song | Factor | Identification number of the song in which the focal silent gap is located. | | Silent\_gap | Factor | Identification number of the focal silent gap. | | Vocal\_gap\_deviation | Numeric | Vocal gap deviation was calculated according to the method described in the article and the cited literature. | | Elapsed\_song\_duration | Numeric | Duration of the ongoing song up to a given focal silent gap (in s). | | Total\_song\_duration | Numeric | Duration of the song in which a given focal silent gap is located (in seconds). | | Song\_onset\_delay | Numeric | Time between the beginning of the playback and the beginning of the focal song (in seconds). | | Playback\_track | Factor | Identification number of the stimulus used during the playback session during which the focal silent gap was recorded. | | Playback\_sex | Factor | The sex of the bird whose songs were used to construct the stimulus was used during the playback session, during which the focal silent gap was recorded. | ### data_GED.csv This file contains the data regarding Gap vs. Element Deviation, along with the corresponding metadata: | Variable | Type | Description | | :---------------------- | :------ | :---------------------------------------------------------------------------------------------------------------------------------------------------- | | Subject | Factor | Identity of the focal subject. | | Sex | Factor | Sex of the focal subject (binary: M = male / F = female). | | Tarsus\_length | Numeric | Length of the tarsus (in mm) of the focal subject. | | Context | Factor | Context in which the focal silent gap has been recorded (binary: Spontaneous / Provoked). | | Song | Factor | Identification number of the song in which the focal silent gap is located. | | Silent\_gap | Factor | Identification number of the focal silent gap. | | Gap\_element\_deviation | Numeric | Gap vs. element deviation calculated according to the method described in the article and the cited literature. | | Elapsed\_song\_duration | Numeric | Duration of the ongoing song up to a given focal silent gap (in s). | | Total\_song\_duration | Numeric | Duration of the song in which a given focal silent gap is located (in seconds). | | Song\_onset\_delay | Numeric | Time between the beginning of the playback and the beginning of the focal song (in seconds). | | Playback\_track | Factor | Identification number of the stimulus used during the playback session during which the focal silent gap was recorded. | | Playback\_sex | Factor | Sex of the bird whose songs were used to construct the stimulus was used during the playback session, during which the focal silent gap was recorded. | ### data_SD.csv This file contains the data regarding Sound Density, along with the corresponding metadata: | Variable | Type | Description | | :-------------------- | :------ | :--------------------------------------------------------------------------------------------------------------------------------------------- | | Subject | Factor | Identity of the focal subject. | | Sex | Factor | Sex of the focal subject (binary: M = male / F = female). | | Tarsus\_length | Numeric | Length of the tarsus (in mm) of the focal subject. | | Context | Factor | Context in which the focal song has been recorded (binary: Spontaneous / Provoked). | | Song | Factor | Identification number of the focal song. | | Total\_song\_duration | Numeric | Total duration of the focal song (in s). | | Sound\_density | Numeric | Sound density of the focal song, calculated as described in the article and the cited literature. | | Song\_onset\_delay | Numeric | Time between the beginning of the playback and the beginning of the focal song (in seconds). | | Playback\_track | Factor | Identification number of the stimulus used during the playback session during which the focal song was recorded. | | Playback\_sex | Factor | Sex of the bird whose songs were used to construct the stimulus was used during the playback session during which the focal song was recorded. | ### data_elements.csv This file contains the data regarding Element Duration, along with the corresponding metadata: | Variable | Type | Description | | :---------------------- | :------ | :------------------------------------------------------------------------------------------------------------------------------------------------- | | Subject | Factor | Identity of the focal subject. | | Sex | Factor | Sex of the focal subject (binary: M = male / F = female). | | Tarsus\_length | Numeric | Length of the tarsus (in mm) of the focal subject. | | Context | Factor | Context in which the focal element has been recorded (binary: Spontaneous / Provoked). | | Song | Factor | Identification number of the song in which a given focal element is located. | | Element | Factor | Identification number of the focal element. | | Element\_duration | Factor | Duration of the focal element (in s). | | Total\_song\_duration | Numeric | Duration of the song in which a given focal element is located (in s). | | Elapsed\_song\_duration | Numeric | Duration of the ongoing song up to a given focal element (in s). | | Song\_onset\_delay | Numeric | Time between the beginning of the playback and the beginning of the focal element (in seconds). | | Playback\_track | Factor | Identification number of the stimulus used during the playback session during which the focal element was recorded. | | Playback\_sex | Factor | Sex of the bird whose songs were used to construct the stimulus was used during the playback session, during which the focal element was recorded. | ### data_lqmm.csv This file contains the data regarding the two trade-offs, along with the corresponding metadata: | Variable | Type | Description | | :-------------------------- | :------ | :---------------------------------------------------------------------------------------------------------------- | | Subject | Factor | Identity of the focal subject. | | Song | Factor | Identification number of the song in which a given focal silent gap occurs. | | Silent\_gap | Factor | Identification number of the focal silent gap. | | Frequency\_ratio | Numeric | Frequency ratio between the end of the previous element and the beginning of the next, for each focal silent gap. | | Gap\_duration | Numeric | Duration of the focal silent gap (in ms). | | Previous\_element | Factor | Identification number of the element before each focal silent gap. | | Previous\_element\_duration | Numeric | Duration of the element before each focal silent gap. | ## Code/software Statistical analyses were conducted using R version 4.3.1 ([https://cran.r-project.org](https://cran.r-project.org)).