Variation in the Number of Spermatozoa in Blue Tit and Great Tit Eggs

Extreme weather event in spring 2013 delayed breeding time of Great Tit and Blue Tit

The impact of climatic changes on life cycles by re-scheduling the timing of reproduction is an important topic in studies of biodiversity. Global warming causes and will probably cause in the future not only raising temperatures but also an increasing frequency of extreme weather events. In 2013, the winter in central and north Europe ended late, with low temperatures and long-retained snow co...

Humans and Tits in the City: Quantifying the Effects of Human Presence on Great Tit and Blue Tit Reproductive Trait Variation

Environmental conditions are key drivers of life-history evolution, and the urban environment is an extreme form of land-use readily inhabited by avian wildlife, whose life-history variation in such altered environment is still poorly understood. Recently, the study of environmental variables associated with urban living—which include shifts in temperature, light, noise or food availability—has...

Spatial and Temporal Variation of Lead, Cadmium, and Zinc in Feathers of Great Tit and Blue Tit Nestlings in Central Poland

In this study, we examined heavy-metal concentrations in feathers of nestling great tits Parus major and blue tits Cyanistes caeruleus at two different sites (urban parkland vs. deciduous forest) located in the Łódź agglomeration in relation to interyear variation. We found that tit species did not differ significantly in lead and cadmium concentrations. Zinc concentration was significantly hig...

Correlates of Variation in Flight Feather Quality in the Great Tit Parus major

Carotenoid availability in diet and phenotype of blue and great tit nestlings.

Carotenoids are biologically active pigments of crucial importance for the development of avian embryos and nestlings. Thus parental ability to provide nestlings with a carotenoid-rich diet may enhance offspring fitness. However, very little is known about the possible effects of carotenoid availability in the diet on growing nestlings in natural populations. We experimentally manipulated dieta...