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The function and variability of song in two interacting nightingale species
Souriau, Abel ; Petrusková, Tereza (advisor) ; Kipper, Silke (referee) ; Linhart, Pavel (referee)
- ABSTRACT - The melodious and complex song of nightingales is a well-established model in studies focussing on the development and function of birdsong. Moreover, two sister species: the thrush nightingale (Luscinia luscinia) and the common nightingale (L. megarhynchos), meet in a recent secondary contact zone in Central Europe, in which their close ecological preference result in competitive interactions and interspecific hybridization. In sympatry, thrush nightingale males often replace part or all of their song repertoires with the songs of the common nightingale, a phenomenon called "mixed singing", while the opposite tendency has not been observed. Understanding the reasons behind the occurrence of thrush nightingale mixed singing, as well as exploring the similarities and difference in song structure between the two species, were the main aims of this thesis. In the first chapter, we tested the role of mixed singing on breeding common nightingale males and revealed its possible function in mediating territorial conflicts. Such advantage might be adaptive as it could help balance the potential costs of heterospecific song copying, and therefore help maintain the asymmetric song convergence between those species. The second chapter aims to explore further the function of thrush nightingale song...
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Low-amplitude songs in songbirds
Belfín, Ondřej ; Petrusková, Tereza (advisor) ; Vokurková, Jana (referee)
Research of bird vocalisation has been remarkably growing in the past seventy years. However, most of the published papers focused on common high-amplitude vocalisation. Despite having researchers who considered the existence of another rare low-amplitude signal more than a century ago, low-amplitude songs were overlooked until the beginning of the 20th century. Additionally, authors still using terms for the description of this scarcely recorded vocalisations inconsistently, which makes the comparison of published papers difficult. In total, I found published notes describing the existence or function of low-amplitude songs in at least 45 species, with ten species having at least two different types. This review is providing evidence that low-pitch songs might be quite widespread but overlooked signals playing a role in male- male as well as male-female interactions. Moreover, it is possible to distinguish between several types of low-amplitude songs based on their structural resemblance to the primary song. Getting all together, I am providing new terminology that might be helpful for further conclusions and could be used in future research of this hidden phenomenon.
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Utilization and potential of individual acoustic monitoring in birds
Kouřil, Jan ; Petrusková, Tereza (advisor) ; Schneiderová, Irena (referee)
Animal monitoring is a key tool for many disciplines and can be done many ways. One of them is acoustic monitoring, which is advantageous mainly for a research of animals with strong vocalisation. Bird vocalisations are one of the most conspicuous. It can carry many information about the singer, and identity is one of them. Vocal individuality has been documented in many bird species and it is considered as a widespread phenomenon. In species, where vocalisation is individually unique and also stable over time, it allows us to track and identify individuals from recordings of their vocalisations only, i.e. by individual acoustic monitoring. Using this approach, many ecological data (abundance, survival rate, etc.) might be successfully collected. So far, it was used mainly in species with simple, loud vocalisations which was difficult to monitor by commonly used physical marking due a dense habitats, cryptic coloration, low density of occurrence, etc. Most often, it used for owls, although the vocal individuality, or even its temporal stability, was documented in much more avian species. Compared to commonly used methods, individual acoustic monitoring is not used very often. However, it can be assumed that with the development an improvement of analytical methods, it will become a commonly used...
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Long term changes of song within individual passerine populations
Žabková, Michaela ; Petrusková, Tereza (advisor) ; Turčoková, Lucia (referee)
Song is a very important means of communication among passerines - it is species- specific, and they use it to communicate with other members of the same species, but also in interspecific recognition. However, the song differs not only between species but also between conspecifics or conspecific populations, both in space and time. In contrast to groups with congenital vocalisation, i.e. all other bird taxa with exception of hummingbirds and parrots, passerines learn their song during the life. In some species, i.e. open-ended learners, song can change throughout the life. Nevertheless, learning is not the only cause of the origin of spatiotemporal variability. This review is about changes in the song of the individuals as well as within the population of various species of passerines. Song variability can be caused by the changing environment in the surrounding area of the observed populations or ongoing social interaction among the individuals. The individual song stability is more common among species, that are closed-ended learners. Within populations song stability is rather rare.
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Variability of specific structures Tree Pipit
Kozlová, Zuzana ; Petrusková, Tereza (advisor) ; Musilová, Zuzana (referee)
Primary function of birdsong is for territorial defense or attraction of females. Birdsong also contains much more other information and can be used to inform males and females about quality of singing bird. It was demonstrated, that for different bird species condition of male correlates with what structures of birdsong are produced. More complex structures are produced by superior males. Females of some species prefer males with ability to produce more complex structures. This work deals with structures of singing of the tree pipit species (Anthus trivialis). These structures are also known as trills. It is assumed, that trills may contain some information about quality of male, which can be evaluated by males and females. Birdsong of tree pipit contains two types of trills - loud and soft. Loud trills are used in aggressive interactions between two males. Soft trills are not used in aggresive context and they differ in consistency - regularity, that can be expressed as tempo of trill. When measuring tempo of trills for every tree pipit male, the tempo is different among males and also correlates with their ability to maintain stable territory over the entire nestling season. Males with faster (more consistent) tempo of trill had stable territory, while males with slower (irregular) tempo of...
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Effect of a dummy on passerine behaviour in playback experiments
Kubátová, Hana ; Petrusková, Tereza (advisor) ; Linhart, Pavel (referee)
Playback experiment is a frequently used method for the scientific research of the bird song and its functions. A recording of vocalization is played in the territory of the tested male, and its responses are observed. Majority of the studies using playback recordings presents only the acoustic stimulus. Sometimes a dummy is also used to provide a visual stimulus. This review focuses on the effects of the dummy on the passerine behavior in the playback experiments. In the first part a comparison is made within the groups of experiments with the same field of interest. The main questions are: how often is a dummy used in these types of experiments, how do designs and results differ depending on its presence/absence and, if possible, how do researchers evaluate its use. Subsequently, I tried to compare experiments with and without dummy within same species, but because of the differences of the experimental designs and the differences in forms of presentation the results, which were often not comparable, it was difficult to make clear conclusions. Next part analyses the few available studies where both trials with and without a dummy were performed on the same individuals. The review shows that the dummy allows tested males to express additional behavioural patterns, which can be noted by the...
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Signaling function of plumage coloration in Yellowhammer males
Kauzál, Ondřej ; Petrusková, Tereza (advisor) ; Šálek, Miroslav (referee)
Sexual selection theory tries to explain evolution of apparently useless traits which mainly developed in males of numerous species. One such trait is also rich and vibrant coloration, typical for many of the bird species. These traits are difficult to be falsified, and therefore they honestly signal quality of the individual. Carotenoid coloration reflects the health condition and melanin coloration the social status, even though this traditional division might not be as strict according to the latest studies. Apart from these ways of maintaining honesty, recent studies are focusing more also on the effect of hormones, mainly two steroids: male sexual hormone - testosterone -, and the "stress" hormone - corticosterone. Both hormones could positively influence male's sexual traits such as ornamental coloration. On the other hand, elevated levels of these hormones possess risk to the organism (higher energetic expenditure, chronic stress), therefore also might potentially become costly. Using photographs of birds in standardized conditions as well as spectrophotometry I analyzed the plumage coloration of males of the Yellowhammer (Emberiza citrinella). Concentrations of testosterone and corticosterone deposited in feathers were analyzed using the LC-MS/MS. Also, for males in breeding season 2015,...
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Female choice based on colouration and song performance in passerines with sexual dichromatism
Kauzál, Ondřej ; Petrusková, Tereza (advisor) ; Svobodová, Jana (referee)
This thesis is about female mate choice and its influence on two most typical phenotype characteristics of sexually dimorphic passerines (Aves, Passeriformes): their colouration and song. This thesis reviews a range of scientific papers focused on this problematic. Results of these papers show that both colouration and song can serve as an honest signal and give information about health, condition and other characteristics of its bearer. Many papers also indicate that females put such male signals into account when choosing a mate. Special emphasis in this thesis is put on papers which dealt both with colouration and song. Although the number of such papers is very low, it is clear that the quite widely accepted opinion that brightly coloured birds do not sing quite melodic songs and vice versa is generally not quite correct. The biggest problem in the study of female mate choice is the lack of papers which dealt with more than one phenotype characteristics.
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Among-population variability in yellowhammer songs: causes and consequences
Bílková, Jana ; Petrusková, Tereza (advisor) ; Reif, Jiří (referee)
The inter-population geographic song variability can be found in many bird species. One of the most interesting types are dialects, characterized by sharp boundaries between populations of individuals sharing the same particular song type. Despite many years of investigation there is no satisfactory answer to the question how these borders persist over the years at nearly same sites. Distinctions between dialects allow recognition of males from different populations and could influence the territorial behaviour. Various habitats, however, degrade the sound differently; it is therefore possible that specific habitats are preferred by individuals with specific dialects. Both social interactions and acoustic properties of the locality could also be only secondary factors and the dialect distribution could be the result of the habitat distribution either in present or in recent past. In this diploma thesis, several hypotheses were tested on the example of Yellowhammer (Emberiza citrinella) - a songbird abundant in open land with simple song and easily recognizable dialects. The thorough data concerning the habitats and dialect distribution were obtained at the dialect borders at two localities in Czech Republic. The reactions of territorial males to both foreign and their own dialects were also...
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