MODELING HABITAT SELECTION OF THE RED-FOOTED FALCON ( FALCO VESPERTINUS ): A POSSIBLE EXPLANATION OF RECENT CHANGES IN BREEDING RANGE WITHIN HUNGARY

Abstract

Due to a severe population decline and shrinkage of distribution range in the past decades, the redfooted falcon has gained top prior ity in both worldwide and Hungarian nature conservation. As a facultative colonial breeder, in Hungary, this species predominantly nests in rookeries. The number of rooks (Corvus frugilegus ) has also dramatically fallen recently, but population decline did not affect the large scale breeding distribution of this species. In our study we analyzed the presence of red� footed falcons at a colony in the case of current and historical breeding ranges based on landscape scaled habitat variables. We used a potential colony homerange size, estimated from observed homerange sizes in order t o determine the scale of influential habitat variables. According to our results, the primary cause of the observed range shift is the urbanization of rooks in definable regions of Hungary. The ratio of forests and open water surfaces within the potential homerange had negative, while the ratio of grasslands had a positive effect on the probability of redfooted falcon presence. None of our models predicted redfooted falcon presence at colonies outside the current breeding range, suggesting that a probable increase in redfooted falcon population numbers will not be accompanied by the expansion of the current breeding range.