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Mean pairwise genetic relatedness within groups with error bars around the mean. U and L are the upper and lower 95% confidence bounds of the null hypothesis of no difference across populations (from 1000 permutations).
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In songbirds, territorial songs are key regulators of sexual selection and are learned from conspecifics. The cultural transmission of songs leads to divergence in song characteristics within populations, which can ultimately lead to speciation. Many songbirds also migrate, and individual differences in migratory behaviours can influence population...
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This paper presents a workflow framework of computational tools to be used in the process of forced alignment and analysis for endangered languages. We introduce a roadmap which uses established methodologies in the area of data processing and analysis, with a strong focus on socio-phonetic studies. The tools are organized into practical stages tha...
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... En todo caso, según se ha podido comprobar en la península Ibérica(Collins et al., 2009), los machos de las poblaciones migradoras emiten gorjeos más complejos y de mayor duración que los machos de las poblaciones sedentarias, mientras que los silbidos emitidos por los machos sedentarios son más cortos y repetitivos que los emitidos por los machos migradores, lo que parece indicar que las poblaciones sedentarias sufrirían una mayor selección debida a la competencia entre machos, mientras que en las migradoras actuaría más intensamente la selección sexual. Que los machos silben mucho y apenas gorjeen tras emparejarse, como se indicó anteriormente, induce a pensar que el punto de vista deLeedale et al. (2015) se halla más cercano a la realidad, pero desde luego es necesario proseguir con las investigaciones sobre este tema.En relación a la base genética de los dialectos identificados, los estudios realizados en Francia porLinossier et al. (2016) concluyen que el canto de las capirotadas es versátil y cuenta con un amplio repertorio basado en un reparto de sílabas y secuencias silábicas que también puede contener imitaciones de otras especies y que, en definitiva, parece estar más relacionado con la divergencia cultural que con la genética, ya que aunque las aves en su primer año podrían aprender muchas sílabas, en temporadas sucesivas adaptarían su repertorio silábico para que se pareciese más al de sus vecinos.Aparicio, R.J., Aparicio, D. (2023). Curruca Capirotada -Sylvia atricapilla. ...
A comprehensive review of the natural history of the Eurasian blackcap Sylvia atricapilla in Spain.
... The correlation between the two estimates (Pearson's correlation, r = 0.8, df = 318, P < 10 -15 ) indicated that the k-means clustering method serves as a reliable surrogate for repertoire size. Therefore, to estimate the repertoire size in our study, we calculated the number of k-mean clusters that could be detected for a given individual based on 20 songs (see also Linossier et al. 2016). We also calculated song rate (the number of songs in a minute calculated as 60/median of song intervals), which inherently corresponded to the same hierarchical level. ...
Animal signals should consistently differ among individuals to convey distinguishable information about the signalers. However, behavioral display signals, such as bird song are also loaded with considerable within-individual variance with mostly unknown function. We hypothesized that the immediate social environment may play a role in mediating such variance component, and investigated in the collared flycatcher (Ficedula albicollis) if the identity and quality of listeners could affect song production in signalers. After presenting territorial males with either a female or male social stimulus, we found in the subsequent song recordings that the among-stimulus effects corresponded to non-zero variance components in several acoustic traits indicating that singing males are able to plastically adjust their songs according to stimulus identity. Male and female stimuli elicited different responses as the identity of the female stimuli affected song complexity only, while the identity of male stimuli altered also song length, maximum frequency, and song rate. The stimulus-specific effect on song in some cases decreased with time, being particularly detectable right after the removal of the stimulus and ceasing later, but this pattern varied across the sex of the stimulus and the song traits. We were able to identify factors that can explain the among-stimulus effects (e.g., size and quality of the stimuli) with roles that also varied among song traits. Our results confirm that the variable social environment can raise considerable variation in song performance, highlighting that within-individual plasticity of bird song can play important roles in sexual signaling.
... It was shown that the pairing success is related to syllable composition in the song of the male Collared Flycatcher (Garamszegi et al. 2012). In addition, geographical song content variation was investigated in the Blackcap (Linossier et al. 2016), and long-term time patterns were described in the Collared Flycatcher (Vaskuti et al. 2016). In recent studies, the Ficedula Toolbox was employed to help in describing the repeatability of repertoire size (Zsebők et al. 2017) and to develop a new robust repertoire sizecomparison method (Zsebők et al. 2018). ...
Qualitative and quantitative assessments of bird song repertoires are important in studies related to song learning, sexual selection and cultural evolution. Despite methods for automatic analysis, it is still necessary to engage in manual cutting, segmenting and clustering of bird song elements in many cases. Here, we describe a program, the Ficedula Toolbox, which has been made available for free to the bird song research community and has recently come into extensive use. The main advantages of this package are the opportunity to conduct all processing steps in one framework and the option of carrying out computer-aided manual clustering. Output files are ready for further analyses, such as estimation of repertoire size, sequential analysis and repertoire overlap calculation. With this program, findings based on empirical data from the Collared Flycatcher (Ficedula albicollis) song show high inter-observer similarity, and thus, reproducible results. The toolbox may be especially applicable to the analysis of song in species with moderately high repertoires.
... However, finding the appropriate parameters for such complex features will be challenging, as one must consider the large variance in the parameters of syllables constituting the song. An alternative solution can involve calculating first the pairwise similarity between songs, for example, based on spectrographic features like frequency contours (Tchernichovski et al. 2000;Linossier et al. 2016). Following this, the MST length can be calculated based on the distance matrix of the songs. ...
The comparison of acoustic complexity across individuals is often essential for understanding the evolution of acoustic signals. In many animal taxa, as a proxy of acoustic complexity, repertoire size is intensively studied; however, its estimation is challenging in species with large repertoires, as this process is time-consuming and may involve considerable subjectivity for the classification of signal elements. Here, we propose a novel application of the minimum spanning tree (MST) method for comparing individuals’ signal complexity, an approach that does not require classification process. We suggest that the differences in the MST length predict the differences in the repertoire sizes between individuals. To evaluate these proposals, first, we performed a simulation study investigating the effect of the practically important variables (repertoire size, number of acoustic parameters, sample size, distribution of element types and within-group variance) on the MST length. Second, we compared repertoire size estimates from the same song data from male collared flycatchers obtained using the fully manual, computer-aided manual and MST methods. In our simulation study, we found that the repertoire size strongly correlated with MST length. We also found significant effects of sample size, number of parameters and within-group variance, as well as how uniformly the samples were distributed between the groups, on the MST length. Our empirical data also revealed a strong correlation between the computer-aided manual estimation of repertoire sizes and MST length, which was comparable to the correlation between the estimations of repertoire size obtained using the two different manual methods. Therefore, we suggest using the MST method to compare the acoustic complexity among individuals in birds and other animals, with the practical restrictions suggested by our simulation results.
... It may be either an initial step when sexual acoustic communication evolves along different trajectories in allopatric populations due to sexual selection (e.g. Grace & Shaw, 2011;de Oliveira Gordinho et al., 2015), ecological constraints (Zuk, Simmons & Cupp, 1993;Ballentine, 2006;Cocroft, Rodriguez & Hunt, 2010), genetic drift or mutation (Campbell et al., 2010;Goodman et al., 2015) and cultural evolution (Lachlan & Servedio, 2004;Linossier et al., 2016) or it may arise during the secondary contact of previously isolated populations diverged in traits unrelated to sexual communication during allopatry. In those cases, divergence in sexual acoustic communication may take part in the reinforcement of the genetic isolation between them (Gerhardt, 2013). ...
Divergence of the acoustic signals used in mate calling may be an important driver of speciation. Male song may vary accordingly to, in mismatch with or independently of female preferences. Therefore, to estimate the importance of male signal variation between subspecies, female preferences against subspecies-specific signal variants must be tested. We examined the female response probability in the two subspecies of the bush-cricket Isophya kraussii for consubspecific and heterosubspecific male signals, and also for the song of a closely related species (I. camptoxypha), which is sympatric with one, but allopatric to the other subspecies. Performing no-choice playback experiments, we found that females of both subspecies responded to the male song of their own subspecies with significantly higher probability than to heterosubspecific and heterospecific songs. Response specificity for consubspecific vs. heterosubspecific signals was not significantly asymmetric comparing the two subspecies. A significant difference was found, however, in the discrimination of heterospecific calls: females showed stronger discrimination against the song of I. camptoxypha in the subspecies sympatric with that species. Our results are best explained by a tightly covarying, stepwise coevolution of male signals and female preferences.
Animal migration is multifaceted in nature, but the relative strength of different cues that trigger resulting patterns of migration is not well understood. Partially migratory populations offer an opportunity to test hypotheses about migration more broadly by comparing trait differences of migrants and residents. We quantitatively reviewed 45 studies that statistically modeled migration propensity, extracting132 effect sizes for internal and external proximate drivers across taxa. Our meta-analysis revealed that internal and external drivers had medium (Cohen’s d > 0.3) and large (Cohen’s d > 0.5) effect sizes on migration propensity respectively. Predator abundance and predation risk had a large effect, as did individual behaviour (e.g., personality). The abiotic environment and individual physiology had a medium effect on migration propensity. Of the studies that examined genetic divergence between migrants and residents, 64% found some genetic divergence between groups. These results clarify broad proximate drivers of migration and offer generalities across taxa.
Acoustic communication plays a critical role in the lives of most species of birds. The focus of this chapter is on the ways that birds produce both nonvocal and vocal sounds. The anatomy of the avian syrinx and how it varies among different taxa of birds is discussed. The mechanism by which the syrinx produces sounds is explained and the types and functions of those sounds (calls and songs) are discussed in detail. Different species of birds vary dramatically in the size of their vocal repertoires, including call and song types, and possible explanations for such variation are provided. Many aspects of the singing behavior of birds are discussed, including the mechanisms by which the central nervous system controls singing behavior and differences between the sexes in those mechanisms, variation within and among species in song structure, the various functions of bird song, intra- and interspecific variation in the size of song repertoires, and the process of song learning. Also discussed are vocal mimicry, duetting, group choruses, and the roles of vocalizations in male cooperative courtship.
Populations within a species can show geographic variation in behavioral traits that affect mating decisions or limit dispersal. This may lead to restricted gene flow, resulting in a correlation between behavioral variation and genetic differentiation. Populations of a songbird that differ in a learned behavioral trait, their song dialects, may also differ genetically. If song dialects function as mating barriers, evolutionary processes such as genetic drift should lead to divergence in allele frequencies among dialect populations. The Puget Sound white-crowned sparrow (Zonotrichia leucophrys pugetensis) is an excellent study system with a well-defined series of song dialects along the Pacific Northwest coast. A previous study found low genetic differentiation based on four microsatellite loci; however, available loci and analyses techniques have since dramatically improved and allow us to reassess gene flow in this species. We also add extra samples to fill in gaps and add a new level of analysis of geographic variation. Based on acoustic similarities, we group six song dialects into two geographically larger “northern” and “southern” song themes. One southern dialect is acoustically more similar to dialects in the north, which makes the genetic profile of birds singing this dialect particularly interesting. Traditional F-statistics, analysis of molecular variance as well as Bayesian techniques confirmed the earlier result that geographic variation in song does not correlate with the neutral genetic structure of the sampled dialect populations. The song themes also did not differ genetically, and the origin of the extralimital northern-theme dialect cannot be determined. We compare this result to findings in several other species and discuss how the timing of learning and dispersal allow vocalizations to vary independently of patterns of genetic divergence.
Migratory species that alternate between sympatry and allopatry over the course of an annual cycle are promising subjects for studies seeking to understand the process of speciation in the absence of strict geographic isolation. Here we sought to identify cryptic species and assess rates of gene flow in a clade of neotropical migrant songbirds in which geography and taxonomy are currently out of sync: the Red-Eyed Vireo (V. olivaceus) Species Complex. Phylogenetic, clustering, and statistical species delimitation analyses found that V. olivaceus includes two non-sister lineages migrating in opposite directions across the equator. Analyses of gene flow identified low levels of introgression between two species pairs, but none between northern and southern olivaceus. We also identified substantial well-supported conflicts between nuclear and mitochondrial topologies. Although the geographic distribution of mito-nuclear discordance is suggestive of hybridization and mitochondrial capture, we found no evidence of introgression in the nuclear genome of populations with discordant mitochondrial gene trees. Our study finds that species boundaries match breeding range and migratory phenology rather than the existing taxonomy in this group, and demonstrates the utility of genomic data in inferring species boundaries in recently diverged clades.
