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Role of evolutional mechanisms in designing of acoustic signals
Rulfová, Alena ; Policht, Richard (advisor) ; Linhart, Pavel (referee)
Acoustic communication is a wide-spread phenomen in all animal taxones. The theme of evolutional mechanisms and their functioning in acoustic communication has become more and more frequently studied during last years, and geographic variation in acoustic signals has been reported in various taxa such as insect, birds, anurans and mammals. However, some evolutional mechanism still remain poorly understood. The mechanisms comprise mainly stochastics forces such as genetic drift and bottleneck or cultural drift. Genetic drift causes stochastic changes in acoustic signals, whereas bottleneck probably primarily spawns reduction of acoustic variability. Some acoustic parameters are shaped by habitat and others by species' phylogeny. Physical environment and other ecological factors play important role in shaping vocalizations in most species, and thus distantly related populations occupying similar habitats may possess very simmilar vocalization. Because of that, revealing phylogenetic pattern is possible only by careful cladistic analysis of vocal characters in taxa that have simple songs or calls that are not learned, and whose habitat distributions are well understood. By finding the proper acoustic parameters we can also e.g. map connection between acoustic divergence and glaciations, history of colonisation...
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Song divergence of Philippine bulbuls (Pycnonotidae) on islands
Rulfová, Alena ; Policht, Richard (advisor) ; Turčoková, Lucia (referee)
Bulbuls (Pycnonotidae) are a biologically diverse group of songbirds that produce a variety of vocalisations. Their songs are very audible, yet the vocal behaviour of the majority of bulbul species has not been formally described or subject to bioacoustical study. The Philippine bulbul (Ixos philippinus) is a sedentary and endemic species of the Philippine archipelago. This thesis presents the first detailed descriptions of its song. The songs were recorded on five islands locations that covered eight different habitats. Nine song features of these species were compared, in order to understand song variations between different islands. In searching for correlations, habitat types and geographical distances between the islands were also measured. The songs of the species found on five islands were readily split up into three groups based on end frequency, syllable number and song duration. The correlations possibly relate to a late Pleistocene connection between the islands and colonization routes of the species. It was found that song frequency parameters in bulbul species is primarily affected by habitat, whilst the effect of current distances between islands was shown to be weak.
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Reference vocalization in African grey parrot (Psittacus erithacus)
Brojerová, Jana ; Lindová, Jitka (advisor) ; Policht, Richard (referee)
The ability to communicate referentially has been historically viewed as being uniquelly human. However, with the increasing amount of studies discussing the communicative faculty of animals in the context of the evolution of human language, there is now growing evidence that this ability is present in many animal species, too. Although we know a lot about mimetic abilities of domesticated African grey parrots' (Psittacus erithacus) and their competence to use human words in a referential way, we know very little about the elements of referentiality in their natural vocalization. Our goal in this work was to find, whether and in which context is functionally referential vocalization in this species of birds present. We were determining its presence by the experiment, in which we have exposed four captured African grey parrot, in the ownership of FHS UK Prague, to stimuli that in other animal species usually elicit functionally referential vocalization: predators and prefered type of food. We analysed the behaviour and vocalizations of the tested birds by analytic softwares Interact, respectively Soundforge 0.8. We find out, that despite the fact that birds reaponded to our experimental objects appropriatelly (i.e. "predators" caused more fear and the like), they give the major amout of...
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Acoustic communication of selected mammals and birds: identification of vocal categories and individuals
Policht, Richard ; Frynta, Daniel (advisor) ; Špinka, Marek (referee) ; Červený, Jaroslav (referee)
2 Summary Identification of vocal categories (e.g. call types, individuals, species) is a key task when we want to classify animal sounds. Same calls, especially broadband acoustic signals with varying frequency and amplitude modulation present problem for classification, because their energy is spread over a wide range of frequencies. In these sounds is difficult to decide which acoustical parameter to measure. To analyse complex vocalizations I applied a multiparametric method with using both temporal and spectral parameters. The most useful variables were variables describing distribution of the spectral energy. Frequency parameters were also useful in the case of tonal calls. I described vocal repertoire of Northern white rhinoceros and Bactrian camel. Both animals have low-frequency calls in their repertoire close to infrasound range, but it is evident that these signals are not used for long-distance communication. It seems that low-frequency components of their sounds are by product of their large body size. Growling sounds of camels are also interesting by their cohesive function, in contrast to growling sounds of rhinos and other mammals where such as calls are produced during aggressive interactions. I examined whether individual identity might be also encoded in very simple song types in...
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Song divergence of Philippine bulbuls (Pycnonotidae) on islands
Rulfová, Alena ; Policht, Richard (advisor) ; Turčoková, Lucia (referee)
Bulbuls (Pycnonotidae) are a biologically diverse group of songbirds that produce a variety of vocalisations. Their songs are very audible, yet the vocal behaviour of the majority of bulbul species has not been formally described or subject to bioacoustical study. The Philippine bulbul (Ixos philippinus) is a sedentary and endemic species of the Philippine archipelago. This thesis presents the first detailed descriptions of its song. The songs were recorded on five islands locations that covered eight different habitats. Nine song features of these species were compared, in order to understand song variations between different islands. In searching for correlations, habitat types and geographical distances between the islands were also measured. The songs of the species found on five islands were readily split up into three groups based on end frequency, syllable number and song duration. The correlations possibly relate to a late Pleistocene connection between the islands and colonization routes of the species. It was found that song frequency parameters in bulbul species is primarily affected by habitat, whilst the effect of current distances between islands was shown to be weak.
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Reference vocalization in African grey parrot (Psittacus erithacus)
Brojerová, Jana ; Lindová, Jitka (advisor) ; Policht, Richard (referee)
The ability to communicate referentially has been historically viewed as being uniquelly human. However, with the increasing amount of studies discussing the communicative faculty of animals in the context of the evolution of human language, there is now growing evidence that this ability is present in many animal species, too. Although we know a lot about mimetic abilities of domesticated African grey parrots' (Psittacus erithacus) and their competence to use human words in a referential way, we know very little about the elements of referentiality in their natural vocalization. Our goal in this work was to find, whether and in which context is functionally referential vocalization in this species of birds present. We were determining its presence by the experiment, in which we have exposed four captured African grey parrot, in the ownership of FHS UK Prague, to stimuli that in other animal species usually elicit functionally referential vocalization: predators and prefered type of food. We analysed the behaviour and vocalizations of the tested birds by analytic softwares Interact, respectively Soundforge 0.8. We find out, that despite the fact that birds reaponded to our experimental objects appropriatelly (i.e. "predators" caused more fear and the like), they give the major amout of...
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The effects of forest clearings on bird populations
Eršil, Lukáš ; Policht, Richard (advisor) ; Ferenc, Michal (referee)
The most widespread way of extraction of forest is still clearlcuting. It is almost impossible to find commercial forest without forest clearings. Forest clearing can be perceived as a special element in a connected forest. I am trying to find out the influence of these forest distributions on the bird community. I was interested how important the forest clearings will be in the different type of forests. In seven localities were collected set of environmental variability's and bird data, which were counted by point count method. There were deciduous and mixed forests as well as the coniferous monocultures. The data collection was conducted in the breeding season 2011 and 2012. I expected, that the forest glades ensure the heterogeneity in forest space and will increase the number of bird's species. I expected this influence more important in the coniferous than in the deciduous and mixed forests. This assumption was partly confirmed. The glades in the coniferous forests have higher influence, but it depends on the forest area. In large coniferous monocultures is the importance of glades high. In the case of deciduous and mixed forests the size of forests did not have a value. The tree richness has the bigger importance. With this variable correlate Common Chiffchaff, Eurasian Wren, Yellowhammer,...
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Role of evolutional mechanisms in designing of acoustic signals
Rulfová, Alena ; Policht, Richard (advisor) ; Linhart, Pavel (referee)
Acoustic communication is a wide-spread phenomen in all animal taxones. The theme of evolutional mechanisms and their functioning in acoustic communication has become more and more frequently studied during last years, and geographic variation in acoustic signals has been reported in various taxa such as insect, birds, anurans and mammals. However, some evolutional mechanism still remain poorly understood. The mechanisms comprise mainly stochastics forces such as genetic drift and bottleneck or cultural drift. Genetic drift causes stochastic changes in acoustic signals, whereas bottleneck probably primarily spawns reduction of acoustic variability. Some acoustic parameters are shaped by habitat and others by species' phylogeny. Physical environment and other ecological factors play important role in shaping vocalizations in most species, and thus distantly related populations occupying similar habitats may possess very simmilar vocalization. Because of that, revealing phylogenetic pattern is possible only by careful cladistic analysis of vocal characters in taxa that have simple songs or calls that are not learned, and whose habitat distributions are well understood. By finding the proper acoustic parameters we can also e.g. map connection between acoustic divergence and glaciations, history of colonisation...
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