Thesis (Ph. D.)--University of Missouri - Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri - Columbia, 1996. / Includes bibliographical references (p. 30-38, 41, 74-77, 107-111, 129-132). Also available on the Internet.

Breeding site fidelity and its effect on reproductive success was investigated in two diving ducks species, i.e. Common Pochard (Aythya ferina) and Tufted Duck (Aythya fuligula) in the Trebon region and the surroundings using caught and individually marked females, searching for nests, and monitoring of marked individuals and its broods. In both studied species, the fidelity ratio (apparent survival, MARK software) was around 65 %. Evaluating the influencing factors, impact of previous reproductive success in the phase of rearing ducklings was found to be the only one statistically significant factor. Furthermore, we compared reproductive parameters (i.e clutch size, laying date, reproductive success) in the first and subsequent year of study. The statistically significant relationship was found between the timing of nesting in the first and in any subsequent year in the Tufted Duck . When comparing the reproductive success in relation to hatched or unhatched clutches and reared or not reared ducklings, we do not confirm any significant shift. Successful females were not able to improve or even repeat their reproductive success in the following years, which could result in subsequent lower degree of fidelity. Subsequently, there is a female dispersion and reduction of the reproductive success of...

Conspecific brood parasitism (CBP) is a situation, when female (a parasite) lays egg or eggs in a nest of other conspecific female (a host). Then she leaves the nest and doesn't provide any subsequent parental care, such incubation and care for young. To distinguish between parasitic and host egg or young could be difficult, because there are not obvious morphological differences. CBP was documented in more than 234 species and its frequency is different between species, but also between population of the same species. The main aim of my master thesis was to describe the degree of parasitism in two population of Common Pochard (Aythya ferina). The field work was carried out from 2004-2006 in Třeboň Biosphere Reserve and form 2008-2010 in Poodří Landscape Protected Area. We found that the degree of CBP is relatively high. In Třeboň was found 72 % (41) of parasitized nests and 32 % (165) of parasitic eggs and in Poodří 93 % (39) of parasitized nests and 37 % (153) of parasitic eggs. The mean number of eggs per clutch was around 9 and mean number of host eggs per clutch was 6 in Třeboň. The mean number of eggs per clutch in Poodří was about 10, and the mean number of host eggs was also about 6. The mean number of parasitic eggs per clutch was 3 resp. 4. It was also found, that parasitized nests are...

This study is aimed at analysis of long-term and short-term changes in numbers of Red-crested Pochard (Netta rufina) in Třeboň region. This species is increasing in long-term period and it is also spreading into new localities in the Czech Republic. There were recorded two waves of arrival of Red-crested Pochard arrive, i.e. in April and in May. The total numbers were decreasing at the end of breeding season (from the beginning of July) in study area. The water surface area and area of littoral vegetation were found to be the most important factors affecting preference of individual ponds in pre-breeding season. Furthermore, water transparency seems to be important factor affecting numbers of broods, ducklings and adults in post-breeding season. Low numbers of broods per 1 female were recorded in years with high numbers of Red- crested Pochard at the start of breeding season. However, the frequency of brood parasitism was higher in these years. Key words: Netta rufina, Red-crested Pochard, population dynamics, ducks, breeding, numbers, brood parasitism, south Bohemia

I investigated differences in egg volumes for two common species diving ducks ? Common pochard (Aythya ferina) and Tufted ducks (Aythya fuligula). I tested selected reproductive and environmental factors with potential influence on egg volume and sex of embryo in clutches. Further, I examined egg volume in connection with the nest parasitism and compared parasitic and non-parasitic eggs in context of egg volume. I also estimated rate of nest parasitism in studied ducks population.

Presented thesis is mainly concerned with the conspecific brood parasitism (CBP) in birds. CBP is an alternative reproductive strategy when a parasitic female lay egg or eggs to other (host) female's nest of the same species. Then the parasitic female leaves the host's nest and does not provide any energetic investment in a subsequent parental care. Distinguish parasitic eggs or young is problematic because there are no obvious morphological differences. Thus, the use of molecular method is crucial for proper determination of CBP. CBP can be used as 'a best-of-bad-job' when female does not have her own nest or lost her nest for example through predation. Other option is that female can increase her fecundity ('fecundity enhancement' hypothesis) when she lay parasitic egg/eggs and care about her own clutch afterward. Two different model species were studied. The first one was a precocial diving duck - the common pochard (Aythya ferina; Anseriformes; Anatidae). Protein fingerprinting was used for detection of CBP and for distinguishing between eggs of individual females. It was found that the rate of CBP was relatively high in this species (91%, 72%; Chapter 1, 4). Further results indicated that the host clutch size decreased with the number of parasitic eggs in the clutch. The study of individual...