Movement Ecology of Pre-Adult Cinereous Vultures Aegypius Monachus: Insights from a Reintroduced Population

Summary Understanding the movement ecology of threatened species is fundamental to improving management and conservation actions for their protection, mainly during the pre-adult stage and particularly when a species is subject to population reinforcement or reintroduction projects. An example is the case of the Cinereous Vulture Aegypius monachus on the Iberian Peninsula, an endangered species that has been reintroduced in different regions during the last two decades. Here, we explore differences between the spatial ecology of reintroduced pre-adult Cinereous Vultures, according to age-class, sex, and season (breeding and non-breeding). We used GPS-tag data from 51 pre-adult individuals reintroduced into Catalonia (north-east Spain) to describe their use of space, i.e. home-range size, core area, and minimum convex polygon (MCP) and movement patterns, i.e. cumulative distance, maximum displacement, maximum daily dispersal, and maximum annual dispersal. Our study showed significant variation in the use of space and movement patterns among pre-adult birds and the influences of age, sex, and season. Age was the most influential factor, determining range areas and movement patterns. Similar to other vulture species, home range and core areas increase with age, with subadult vultures exhibiting larger ranges than young first year, juveniles, and immature birds, but the MCP measures were larger for juveniles. Movement patterns were also influenced by age-class, with juveniles making longer movements, followed by immatures and subadults (with similar values), and shorter movements for birds during their first year of life. Overall, males made shorter movements and explored smaller foraging areas than females. Season had an important effect on movement patterns, and the daily and dispersal movements were longer during the breeding period (February–August). Our findings fill a knowledge gap regarding the dispersal behaviours of Cinereous Vultures, information that will enable the improvement of management and conservation decisions.