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Functions of a female song in passerines
Kubíková, Tereza ; Petrusková, Tereza (advisor) ; Mikula, Peter (referee)
Female song in passerines was overlooked for a long time because it was assumed that only males sang, even though the first records of female singing appeared at the end of the 19th century. The sporadic singing of females was usually explained by an increase in the level of sex hormone but in reality, females probably sing for the same reasons as males, i.e. to defend their territory, attract a mate, or prevent extra-pair copulation. These functions of female song were discovered when ornithologists began to focus more on tropical songbirds. In fact, in the tropics, many species show sexual dimorphism, making distinguishing females from males easier. Partners also make long-term partnerships and they usually defend year-round territories together so it is advantageous for them to be synchronized in their songs too. For this reason, females sometimes join their partners in singing to make duets. Today, the female song has been recorded in many temperate songbirds and the number of species is gradually increasing but it is probably still overlooked in many species because females can be mistaken for males or because they sing only for short periods of time so it can be more difficult to capture their song. Keywords: female song, birds, function of female song, temperate zone
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Acoustic and visual signalization in birds: Identification of key components and their role in sexual selection
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Svobodová, Jana (referee)
This bachelor thesis is focused on describing visual and acoustic signals in birds and their potential role in the process of sexual selection. Evidence that acoustic and visual signals are sexualy selected is summarized. The key characters that can be utilized in comparative studies are determined. In the first chapter of the thesis are briefly outlined mechanisms of sexual selection and evolution of costly secondary male ornamentation. In the second chapter basic avian ornaments (colouration, acoustic signals) are described. The emphasis is on visual and acoustic structures which are costly to produce and serve as honest indicators of individual condition. The third chapter is devoted to the possible trade-offs between visual and acoustic signalization in birds. The last section summarizes hypotheses about potential relationships between visual and acoustic signalization (and trade-offs between these two types of ornamental traits) in relation to changing environmental conditions.
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Macroecology and macroevolution of birdsong
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Osiejuk, Tomasz S. (referee) ; Šálek, Miroslav (referee)
Birdsong is one of the most astounding natural sounds which profoundly shaped our evolutionary thinking since the 19th century. Despite a strong interest in birdsong for over 100 years, our understanding of birdsong ecology and evolution over large spatial and phylogenetic scales is still very fragmentary. Answering many basic questions requires a global synthesis covering vast diversity of extant bird species and adoption of multidisciplinary approaches. In presented dissertation thesis, my co-workers and I have explored important patterns in macroecology and macroevolution of song in passerines (Order: Passeriformes), the most diverse and widespread bird order. We have focused on three key song phenomena: (1) song complexity, (2) song frequency and (3) the presence of song in female birds. We have exploited birdsong "big data" available on public citizen science databases and other open sources in order to fill several important gaps in the current knowledge. These data were analysed by a combination of phylogenetically-informed cross-species analyses and spatial macroecological approaches. Since the publication of Darwin's seminal work, elaborated songs are generally agreed to be the result of sexual selection. We developed a simple but reliable song complexity metric to explore a global diversity in...
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Macroecology and macroevolution of birdsong
Mikula, Peter
Birdsong is one of the most astounding natural sounds which profoundly shaped our evolutionary thinking since the 19th century. Despite a strong interest in birdsong for over 100 years, our understanding of birdsong ecology and evolution over large spatial and phylogenetic scales is still very fragmentary. Answering many basic questions requires a global synthesis covering vast diversity of extant bird species and adoption of multidisciplinary approaches. In presented dissertation thesis, my co-workers and I have explored important patterns in macroecology and macroevolution of song in passerines (Order: Passeriformes), the most diverse and widespread bird order. We have focused on three key song phenomena: (1) song complexity, (2) song frequency and (3) the presence of song in female birds. We have exploited birdsong "big data" available on public citizen science databases and other open sources in order to fill several important gaps in the current knowledge. These data were analysed by a combination of phylogenetically-informed cross-species analyses and spatial macroecological approaches. Since the publication of Darwin's seminal work, elaborated songs are generally agreed to be the result of sexual selection. We developed a simple but reliable song complexity metric to explore a global diversity in...
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Macroecology and macroevolution of birdsong
Mikula, Peter
Birdsong is one of the most astounding natural sounds which profoundly shaped our evolutionary thinking since the 19th century. Despite a strong interest in birdsong for over 100 years, our understanding of birdsong ecology and evolution over large spatial and phylogenetic scales is still very fragmentary. Answering many basic questions requires a global synthesis covering vast diversity of extant bird species and adoption of multidisciplinary approaches. In presented dissertation thesis, my co-workers and I have explored important patterns in macroecology and macroevolution of song in passerines (Order: Passeriformes), the most diverse and widespread bird order. We have focused on three key song phenomena: (1) song complexity, (2) song frequency and (3) the presence of song in female birds. We have exploited birdsong "big data" available on public citizen science databases and other open sources in order to fill several important gaps in the current knowledge. These data were analysed by a combination of phylogenetically-informed cross-species analyses and spatial macroecological approaches. Since the publication of Darwin's seminal work, elaborated songs are generally agreed to be the result of sexual selection. We developed a simple but reliable song complexity metric to explore a global diversity in...
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Macroecology and macroevolution of birdsong
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Osiejuk, Tomasz S. (referee) ; Šálek, Miroslav (referee)
Birdsong is one of the most astounding natural sounds which profoundly shaped our evolutionary thinking since the 19th century. Despite a strong interest in birdsong for over 100 years, our understanding of birdsong ecology and evolution over large spatial and phylogenetic scales is still very fragmentary. Answering many basic questions requires a global synthesis covering vast diversity of extant bird species and adoption of multidisciplinary approaches. In presented dissertation thesis, my co-workers and I have explored important patterns in macroecology and macroevolution of song in passerines (Order: Passeriformes), the most diverse and widespread bird order. We have focused on three key song phenomena: (1) song complexity, (2) song frequency and (3) the presence of song in female birds. We have exploited birdsong "big data" available on public citizen science databases and other open sources in order to fill several important gaps in the current knowledge. These data were analysed by a combination of phylogenetically-informed cross-species analyses and spatial macroecological approaches. Since the publication of Darwin's seminal work, elaborated songs are generally agreed to be the result of sexual selection. We developed a simple but reliable song complexity metric to explore a global diversity in...
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Environment and avian song: case of South African birds
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Linhart, Pavel (referee)
Relationship between animal signalization and environmental conditions, where these species are living, is one of crucial topics of ecology. Using two complementary statistical approaches (fourth-corner and RLQ analyzes) I investigated geographical variation in parameters of bird vocalization in South Africa (RSA) and Lesotho. Altogether, I used nine quantitative and five qualitative acoustic traits for 472 bird species and nine environmental variables which could significantly influence parameters of their vocalization. My results supported findings of previous studies about the important effect of body size on species-specific vocal characteristics. In passerines, analyzes corrected for body size showed that the number of elements and element types were increasing with variability of natural conditions and were highest in very arid and climatically unpredictable areas. Element and element type rate were positively associated with altitude. Minimal song frequency in passerines and frequency range of vocalization in other birds were negatively correlated with average temperature of warmest and coldest month of the year, respectively. Similarly, environmental variables significantly influenced distribution of several qualitative song traits in passerines. Passerines, where female song and...
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Acoustic and visual signalization in birds: Identification of key components and their role in sexual selection
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Svobodová, Jana (referee)
This bachelor thesis is focused on describing visual and acoustic signals in birds and their potential role in the process of sexual selection. Evidence that acoustic and visual signals are sexualy selected is summarized. The key characters that can be utilized in comparative studies are determined. In the first chapter of the thesis are briefly outlined mechanisms of sexual selection and evolution of costly secondary male ornamentation. In the second chapter basic avian ornaments (colouration, acoustic signals) are described. The emphasis is on visual and acoustic structures which are costly to produce and serve as honest indicators of individual condition. The third chapter is devoted to the possible trade-offs between visual and acoustic signalization in birds. The last section summarizes hypotheses about potential relationships between visual and acoustic signalization (and trade-offs between these two types of ornamental traits) in relation to changing environmental conditions.
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