Sources of variation in mortality of the Bearded Vulture Gypaetus barbatus in Europe

Abstract

We analyse the causes of mortality for the Bearded Vulture in Europe. Shooting (31%), intentional poisoning (26%), collision (18%) and unintentional poisoning (12%) were the most important causes of mortality. No differences were found between sexes or age classes (non-adults and adults) for any of the causes of death. When the four main categories of mortality were grouped in periods of 3 years from 1986 (coinciding with the species' reintroduction to the Alps) to 2006, mortality showed significant temporal variation. The results suggest that while the number of collision/electrocution deaths has remained stable or increased slightly, the number of cases of shooting has declined during the last 6 years, while at the same time intentional and unintentional poisonings have increased. We found substantial differences between causes of mortality recorded for birds located by chance (75% related to shootings and collisions with powerlines) and radio-tagged birds (86% related to intentional and unintentional poisoning), suggesting biases in methodology for monitoring mortality. The results suggest that human persecution continues to be the main factor contributing to unnatural mortality for European Bearded Vultures. Future management actions should concentrate on the creation of protocols for the collection of carcasses and detailed analyses to determine and mitigate anthropogenic sources of mortality.