[Ecology of reproduction of the aquatic warbler Acrocephalus paludicola on the Dikoe marsh in the Yaselda river head]
2008
Vergejchik, L.A. | Kozulin, A.V. | Grichik, V.V. | Minets, M.L. | Parejko, O.A., National Academy of Sciences (Belarus). Institute of Zoology
Results of the investigation of causes of changes of reproduction success of endangered species of the aquatic warbler (Acrocephalus paludicola) in the conditions of insufficient diet on the lowland sedgy marsh Dikoe in the Yaselda river head in the Republic of Belarus were presented. The investigated territory proved to be one of the largest habital areas of aquatic warblers in Belarus (1200 - 1500 warbling males) and amounted 14% of all Belarusian and 8% of all European population of the analysed species. The reproduction success indices (the probability of vitality from the stage of incubation to fledging) in 28 nests were calculated in accordance with Mayfield method and varied from year to year within the range from 36,3% to 2,89% that was considerably lower in comparison with the same indices on the Bebza marsh. The level of daily egg mortality rate due to predation (2,5%) was lower than the daily nestling predation rate (5,04%). Research results showed that the main reason of low reproduction success was the predation by red-toothed shrews (Sorex). It was assumed that high density of shrews on mesotrophic lowland marshes could be one of the factors limiting the abundance of the aquatic warbler species
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