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Territoriality in breeding Whitethroats were examined on colour-ringed individuals in two areas located in different geographical regions: Low Volga and Caucasus coast of the Black Sea. In the Caucasus region 29% of males were polyterritorial (6% — bigynous) whereas in the Volga region no cases of males polyterritoriality nor bigyny were observed. Literature reveals that in regions, where polygyny in the Whitethroat was observed, the breeding period is short and the species has only one breeding cycle in a season. In the areas where the breeding period is long, bigyny has not been found, but cases of double- broodness was observed. Author suggests that bigyny in the Whitethroat evolved as a response to the short breeding season, which does not allow males to have two successive broods in a season. The only way to increase their reproductive success is to establish a second territory immediately after the first female starts to lay.
Protection of high biodiversity in an intensively farmed areas is strongly related to managing the diverse structure of a landscape, for example by planting shelterbelts. The study was aimed at recognition of avifauna dynamics in young (with the age of 1–4 years at the beginning of the study) shelterbelts (N=9) and at estimation of their importance for farmland birds. Bird density was estimated by mapping method in successive years 1996–2001 and the data were combined and analysed in respect to age of shelterbelts. Eighteen breeding species were found (5–8 pairs km⁻¹), among them most abundant were Corn Bunting (Miliaria calandra) (with dominance of 33%), Yellow Wagtail (Motacilla flava) (19%) and Whitethroat (Sylvia communis) (12%). No trend in the changes of species richness and total density was recorded. The density of species preferring building nests and/or feeding in herb layer (like Yellow Wagtail, Skylark Alauda arvensis and Whinchat Saxicola rubetra) decreased during study period while the density of species associated to higher layers of vegetation like Yellowhammer (Emberiza citrinella), Red-backed Shrike (Lanius collurio) increased. According to earlier study, bird species richness and abundance in studied young shelterbelts were lower than in several dozens years old ones. However, in relation to species colonization both classes of shelterbelts (species building their nests on the ground or in low shrubs), young shelterbelts were as important as old ones.
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