Abstract:

A breeding bird census for reed-nesting passerine species was conducted at Lake Fertő
(Lake Neusiedler) in 2008. The basic goal of the study was to quantify the population size of the target species (in terms of breeding pairs). Between 15th March and 29th June 14 censuses were carried out. The final data base of observed territorial males contained 775 records. The census method was a modified form of the Finnish line-transect method. Sampling transects were selected by a stratified quasi-random method. Stratification was based on the official classification of reedbed units, determined for the whole Hungarian part of the lake during the reedbed survey conducted by Márkus in 2007. Each class was represented by at least three independent sample transects. The population size of the six most abundant territorial passerine species (the Savi’s Warbler, the Moustached Warbler, the Sedge Warbler, the Reed Warbler, the Great Reed Warbler and the Reed Bunting) was estimated. The population size of the Bluethroat could be estimated only within wide limits. The results appoint on the fact that the Lake Fertő (Lake Neusiedler) is likely to play a very important role in the meta-population system of reed-nesting passerine species within the Carpathian Basin. Regarding the Moustached Warbler, more than 90% of the population breeding in the Carpathian Basin is located at this lake. Census repeated in the next years could present very important data on population dynamics of the target species, providing valuable information for nature conservation offices.