The long-term trend, reproductive performance and colony shifting of the Eurasian Griffon Gyps fulvus in Croatia

Abstract

The Eurasian Griffon population in Croatia declined during most of the 20 th century. Here the results related to the population trend and reproduction parameters and phenomena called colony shifting based on a 40-year research (1981 – 2021) are presented. The population declined from about 110-150 pairs in 10 colonies in 1981 to 78-95 pairs in 6 colonies in 1999, and subsequently increased to 141-150 pairs in 6 colonies in 2013. Since 1999, there have been no Griffons nesting in Paklenica, and it is possible that they all shifted to Kvarner, where 13% increase was recorded in 2000. In 2021, the total number was about 120 pairs on 5 islands: Cres, Plavnik, Krk, Prvić and Pag. Population density was estimated at 32.5 adult individuals/100 km 2 and 13.75 breeding pairs/100 km 2 . Detailed population surveys were conducted during 15 years (2000 – 2014) to document cliffs’ saturation/occupancy