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Sex and age differences in migration in Anatidae
Prokešová, Erika ; Musil, Petr (advisor) ; Klvaňa, Petr (referee)
The thesis is aimed at intraspecific differences in migratory birds of the order Anseriformes, family Anatidae. It is especially focused on the differences affected by sex and age too. Most of the Anatidae forms its pair-bonds early, not on the breeding grounds like other bird orders do, but on the wintering grounds already. However, it was observed that in some species both sexes don't migrate to the same wintering grounds. Moreover, there are geographical differences between each population really big, so it's not easy to investigate this phenomenon. The adult sex ratio is male-skewed because of their greater survival rate resulting in greater selection by females, especially in species which form their pair-bonds in the end of the winter season. This thesis summarizes the factors responsible for migratory differences during the non-breeding season, then compares conclusions of the studies conducted in this issue between individual subfamilies and tribes of the Anatidae. Key words: sex-dependent migration differences, age-dependent migration differences, early pair formation, Anserinae, Anatinae, dabbling ducks, diving ducks.
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Spatial variability in population structure of wintering Ducks
Prokešová, Erika ; Musil, Petr (advisor) ; Hořák, David (referee)
5 Abstract This thesis is aimed at spatial variability of population structure of our four most common and the most numerous species of ducks wintering in the Czech Republic. These analysed species are Mallard (Anas platyrhynchos), Tufted duck (Aythya fuligula), Common Merganser (Mergus merganser) and Northern Goldeneye (Bucephala clangula). The field data were collected by January International Waterbird Census in the Czech Republic between 2004 and 2013. Analysed habitat variables include: type of wetland, altitude, population size, level of urbanisation (size of settlement) and mean January air temperature in the investigated site. There was found no significant effect of type of wetland and local population density on population structure in any of these bird species. The next factor, altitude of sites was confirmed as significant only for Mallards, when increasing altitude decreased proportion of males in the population. Furthermore, effect of urbanization was found also in Mallard, when proportions of males increased with level of urbanization, i.e. in larger cities. Finally, , temperature of sites was confirmed to be significant factor affecting population size in the three analyzed species, i.e. in Mallard, Tufted Duck and Northern Goldeneye. Except Common Merganser, ratio of males grew with...
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Sex and age differences in migration in Anatidae
Prokešová, Erika ; Musil, Petr (advisor) ; Klvaňa, Petr (referee)
The thesis is aimed at intraspecific differences in migratory birds of the order Anseriformes, family Anatidae. It is especially focused on the differences affected by sex and age too. Most of the Anatidae forms its pair-bonds early, not on the breeding grounds like other bird orders do, but on the wintering grounds already. However, it was observed that in some species both sexes don't migrate to the same wintering grounds. Moreover, there are geographical differences between each population really big, so it's not easy to investigate this phenomenon. The adult sex ratio is male-skewed because of their greater survival rate resulting in greater selection by females, especially in species which form their pair-bonds in the end of the winter season. This thesis summarizes the factors responsible for migratory differences during the non-breeding season, then compares conclusions of the studies conducted in this issue between individual subfamilies and tribes of the Anatidae. Key words: sex-dependent migration differences, age-dependent migration differences, early pair formation, Anserinae, Anatinae, dabbling ducks, diving ducks.
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