Integration of critically endangered Rüppell’s Vultures with Griffon Vultures in a newly colonized European region

Abstract The critically endangered Rüppell’s Vulture ( Gyps rueppelli ), originally from sub-Saharan Africa, has recently begun to establish itself in Europe, specifically in the Iberian Peninsula. This study focuses on understanding the spatial ecology of Rüppell’s Vultures during the breeding season, analyzing movement patterns and home-range sizes of three individuals tagged with GPS in southern Spain. The results show significant differences in home-range sizes between adult and immature vultures, with the immature individual exhibiting larger ranges and exploratory behavior, while adults, particularly during breeding, displayed more localized movements. The integration of Rüppell’s Vultures with Griffon Vultures ( Gyps fulvus ), including hybrid breeding attempts, raises conservation concerns regarding potential genetic amalgamation. The study highlights the need for transboundary conservation strategies, as some individuals occasionally enter Portuguese territory during the breeding season. These findings provide crucial insights for the conservation management of this species in Europe, where the vultures’ expanding presence requires coordinated efforts to address threats such as energy infrastructures. Ongoing monitoring is necessary to assess whether these individuals represent a temporary presence or a long-term colonization process.