Kivonat:

In the current study the ringing databases of the EURING Data Bank and the Hungarian Bird Ringing Centre were analysed to investigate the natal and breeding site fidelity of the Great reed Warbler (Acrocephalus arundinaceus). We analyzed 269 individual capture-recapture data from the EURING Data Bank, and 106 individual capture-recapture data from the Hungarian Bird Ringing Centre. Based on the capture-recapture data, no significant difference was found among the breeding site fidelity of adults between the localities, when defined as country. There were no significant differences between the juvenile natal site fidelity and the adult breeding site fidelity throughout all of the the localities, but significant difference was found in natal site fidelity of juvenile birds between the countries with the highest (Hungary) and lowest (Germany) values. We also revealed in this work some difficulties emerging during the analysis of such diverse databases. The different fidelity calculation methods and so the usage of the different terms referring to the site fidelity makes it difficult to interpret the results of the former studies. Furthermore, we propose a method that offers more reliable values in the analysis of the natal and breeding site fidelity.