Tomasz Janiszewski

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Bird feeding is one of the most widespread direct interactions between man and nature, and this has important social and environmental consequences. However, this activity can differ between rural and urban habitats, due to inter alia habitat structure, human behaviour and the composition of wintering bird communities. We counted birds in 156 squares (0.25(More)
Urban development has a marked effect on the ecological and behavioural traits of many living organisms, including birds. In this paper, we analysed differences in the numbers of wintering birds between rural and urban areas in Poland. We also analysed species richness and abundance in relation to longitude, latitude, human population size, and landscape(More)
The information on the phenotypic and ecological factors that influence hemoglobin concentration in free-living birds is scarce. In order to recognize sources of variation in hemoglobin levels of migratory shorebirds, we measured whole-blood hemoglobin concentration in 553 juvenile and 166 adult common snipe Gallinago gallinago during autumn migration(More)
In theory, larger colony size should be favoured by lower per-capita predation rates, whereas smaller colony size should be favoured by reduced parasitism, social stress and competition for food. We conducted an experimental cross-fostering of young between colonies of different size to test whether differences in fitness had an environmental or genetic(More)
Centres of avian colonies are usually associated with reduced predation risk and, thus, attract individuals of high quality, while poor-quality individuals are relegated to peripheral zones. Assuming that the incidence of extra-pair paternity (EPP) is dependent on individual quality, we could expect lower incidence of extra-pair offspring in the central(More)
Several different selective pressures have been suggested to explain an intense competition for early return to breeding grounds in birds. In this study we hypothesized that shortening day length during summer months may constitute additional selective force acting towards early breeding in avian species with long parental care. To test this hypothesis, we(More)
Moult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration. To this end, young birds tend to undergo the first post-juvenile moult before the onset of migration, but in some species the time window for the pre-migratory feather replacement is too(More)
Hematology and plasma biochemistry values were determined in 92 free-living Great Cormorant (Phalacrocorax carbo sinensis) chicks at Jeziorsko reservoir, central Poland. Percentage distribution of leukocytes, packed cell volume, plasma concentrations of hemoglobin and basic biochemical parameters were evaluated. These values may be treated as reference(More)
Early arrival at breeding grounds have important fitness consequences for migratory birds, both at individual and population level. The aim of this study was to investigate how the timing of arrival at the breeding territories affects the spatial patterns of reproductive success within a population of white storks (Ciconia ciconia). Data were gathered(More)