After the quasi-extinction of much of the European vertebrate megafauna during the last few centuries, many reintroduction projects seek to restore decimated populations. However, the future of numerous species depends on the management scenarios of metapopulations where the flow of individuals can be critical to ensure their viability. This is the case of the bearded vulture Gypaetus barbatus, an Old World, large body-sized and long-lived scavenger living in mountain ranges. Although persecution in Western Europe restrained it to the Pyrenees, the species is nowadays present in other mountains thanks to reintroduction projects. We examined the movement patterns of pre-adult non-breeding individuals born in the wild population of the Pyrenees (n = 9) and in the reintroduced populations of the Alps (n = 24) and Andalusia (n = 13). Most birds were equipped with GPS-GSM radio transmitters, which allowed accurate determination of individual dispersal patterns. Two estimators were considered: i) step length (i.e., the distance travelled per day by each individual, calculated considering only successive days); and ii) total dispersal distance (i.e., the distance travelled between each mean daily location and the point of release). Both dispersal estimators showed a positive relationship with age but were also highly dependent on the source population, birds in Andalusia and Alps moving farther than in Pyrenees. Future research should confirm if differences in dispersal distances are the rule, in which case the dynamics of future populations would be strongly influenced. In summary, our findings highlight that inter-population differences can affect the flow of individuals among patches (a key aspect to ensure the viability of the European metapopulation of the endangered bearded vulture), and thus should be taken into account when planning reintroduction programs. This result also raises questions about whether similar scenarios may occur in other restoration projects of European megafauna.

Between 2000 and 2009 we studied the diet and breeding success of Egyptian Vultures Neophron percnopterus in southern Spain. Wild species accounted for 74.9% of prey items (n = 1071) with a predominance of mammals (62.3%), followed by birds (20.8%) and reptiles (13.1%). Spatially, the diet was highly varied and not restricted to carcasses of livestock; wild Rabbits Oryctolagus cuniculus accounted for 54% of the overall remains. The spatial variability may reflect regional and local disparity in the availability of main prey. The temporal relationship between variation in trophic diversity and Vulture nesting productivity (both values showing a long‐term decrease) might suggest a causal link between variation in diet and reproductive output. We hypothesize that high turnover rates could explain productivity variation as a consequence of the recruitment of less experienced individuals to the breeding population. This could in turn generate covariation between diet and reproductive output.

32Large body-sized avian scavengers, including the Egyptian vulture (Neophron 33 percnopterus), are globally threatened due to human-related mortality so guidelines 34 quantifying the efficacy of different management approaches are urgently needed. We 35 used 14 years of territory and individual-based data on a small and geographically 36 isolated Spanish population to estimate survival, recruitment and breeding success. We 37 then forecasted their population viability under current vital rates and under 38 management scenarios that mitigated the main sources of non-natural mortality at 39 breeding grounds (fatalities from wind farms and illegal poisoning). Mean breeding 40 success was 0.68 (SD=0.17) under current conditions. Annual probabilities of survival 41 were 0.72 (SE=0.06) for fledglings and 2 yr old non-breeders, 0.73 (SE=0.04) for non-42 breeders older than 2 yrs old and 0.93 (SE=0.04) for breeders. Probabilities of 43 recruitment were 0 for birds aged 1 to 4, 0.10 (SE=0.06) for birds aged 5 and 0.19 44 (SE=0.09) for older birds. Population viability analyses estimated an annual decline of 45 3-4% of the breeding population under current conditions. Our results indicate that only 46 by combining different management actions in the breeding area, especially by 47 removing the most important causes of human-related mortality (poisoning and 48 collisions on wind farms), will the population grow and persist in the long term. 49 Reinforcement with captive breeding may also have positive effects but only in 50 combination with the reduction in causes of non-natural mortality. These results, 51 although obtained for a focal species, may be applicable to other endangered 52 populations of long-lived avian scavengers inhabiting southern Europe.53 54

Natal dispersal, the movement between the birth and the first breeding site, has been rarely studied in long-lived territorial birds with a long-lasting pre-breeding stage. Here we benefited from the long-term monitoring programs of six populations of Egyptian vultures (Neophron percnopterus) from Spain and France to study how the rearing environment determines dispersal. For 124 vultures, we recorded a median dispersal distance of 48 km (range 0–656 km). Linear models were used to assess the effect of population and individual traits on dispersal distance at two spatial scales. Dispersal distances were inversely related to vulture density in the natal population, suggesting that birds perceive the abundance of conspecifics as a signal of habitat quality. This was particularly true for declining populations, so increasing levels of opportunistic philopatry seemed to arise in high density contexts as a consequence of vacancies created by human-induced adult mortality. Females dispersed further than males, but males were more sensitive to the social environment, indicating different dispersal tactics. Both sexes were affected by different individual attributes simultaneously and interactively with this social context. These results highlight that complex phenotype-by-environment interactions should be considered for advancing our understanding of dispersal dynamics in long-lived organisms.

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