RELATIONSHIP BETWEEN WEST-AFRICAN RAINFALL AND THE SURVIVAL OF CENTRAL-EUROPEAN SAND MARTINS RIPARIA-RIPARIA

The aim of this study was to investigate the effects of Sahelian rainfall on the central European Sand Martin Riparia riparia population for the period 1986-1992, The studied population breeds along the River Tisza in Hungary and is one of the largest in central Europe. The changes in the population size did not show a significant relationship to Sahelian rainfall, but a large decrease in 1991 coincided with the drought in three Sahelian areas. The survival rates of adults had a significant relationship to the rainfall of the southern Sahel but not to the other two studied areas (northern Sahel, central Sudan). The model selection included this relationship and raised the possibility of predicting the adult survival rate in autumn for the following wintering season, using African rainfall data, The analysis showed a significant difference in the survival rates between the sexes, with that of the female being lower. Differences in the changes of the population size and adult survival rate showed the importance of the recruitment of adults, and this may depend mainly on the survival of juveniles.