National Repository of Grey Literature 3 records found  Search took 0.00 seconds. 
Interspecific nest parasitism in diving ducks - Common Pochard Aythya ferina and Tufted Duck Aythya fuligula and its effect on reproductive performnce
Neužilová, Šárka ; Musil, Petr (advisor) ; Weidinger, Karel (referee) ; Procházka, Petr (referee)
This PhD thesis is connecting three publications and one manuscript and focuses on the study of interspecific nest parasitism among particular duck species of family Anatidae. The first part describes the occurrence of interspecific nest parasitism, in the study area of Trebon between years 1999 and 2008 in three diving duck species (Aythini): the Common pochard (Aythya ferina), the Tufted duck (Aythya fuligula) and the Red-crested Pochard (Netta rufina) and two dabbling duck species the Gadwall (Anas strepera and the mallard (Anas platyrhynchos). The most of parasitic eggs was laid by Red-creasted Pochard and Common Pochard. In this period, inter-specific nest parasitism was recorded in 6.6% of nests. The values were compared with the results of studies in the same species between 1975 and 1980. when inter-specific nest parasitism was in 13.9% of nests. The difference in rate of nest parasitism is caused as a result of a decline in breeding populations of the studied species. In the second analysis, we investigate whether parasitically laid eggs are of different size than non-parasitic eggs in three diving duck species; the Common Pochards, the Tufted Ducks and the Red-Crested Pochards. Parasitic eggs of the Common Pochard were significantly longer than non-parasitic eggs of the same species and...
Investment in reproduction and nest defense in waterfowl
Javůrková, Veronika ; Albrecht, Tomáš (advisor) ; Remeš, Vladimír (referee) ; Weidinger, Karel (referee)
Investment in reproduction is considered to be crucial component of life history traits. Reproductive success is however constrained by generally unpredictable environmental conditions. Based on "bet hedging" theory, individuals are forced to eliminate such unpredictability via the mixed strategy to maximize their long-term fitness. Predation represents underlying factor affecting individual reproductive success, and it undoubtedly lies behind the evolution of alternative reproductive strategies such as extra-pair paternity and conspecific brood parasitism. Behavioral mechanisms related to nest defense are thought to be investment in reproduction in accordance with trade-off between actual and residual reproductive value. Despite the extensive interest in the principles associated with parental investment into the nest defense, studies describing in detail the pattern of particular antipredator strategies are rare. Similarly, mechanisms responsible for maintenance of egg- viability during prolonged egg-laying period in species delayed the onset of incubation are poorly understood. In accordance with mentioned themes, this thesis includes publications aimed at aspects of reproductive biology and antipredator behavior in Mallards (Anas platyrhynchos). Particular publications concretely documented: a)...

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