CHANGE OF TIMING OF AUTUMN MIGRATION IN ACROCEPHALUS AND LOCUSTELLA GENUS

摘要

Our research was done on trans-Sahara migrant Acrocephalus and Locustella species caught in Ocsa (Hunggary) with standardized conditions between 1987-2004. We have constructed the cumulative diagram of the migration for adults and juveniles for every year and we have established the dates of the 50 and 90% percentiles. We have represented these data in the function of years and the average temperatures of August. On these distributions we have made linear regressions and studied their parameters. The very close related species react to the climate change in different degrees and direction. Although the study period is short, we have found some significant changes in the timing of migration and correlations with the temperature. The early migrating species have advanced their autumn migration and the later-migrating species have delayed it. The migration strategies of the species are very complex, so it is hard to give a uniform explanation for the changes.