Conventional approaches for the assessment of population abundance or trends are usually based on a single source of information, such as counts or changes in demographic parameters. However, these approaches usually neglect some of the information needed to properly understand the population as a whole, such as assessments of the non‐breeding proportion of the population and the drivers of population change. The Bearded Vulture Gypaetus barbatus is a threatened species and its Pyrenean population (the largest in Europe) inhabits parts of Spain, Andorra, and France. We developed an Integrated Population Model (IPM) using data from a long‐term study (1987–2016) in the three countries, including capture–mark–recapture of 150 marked individuals, to assess population size and age structure at the whole population scale, and obtain estimates of survival and breeding parameters of this population. The breeding population experienced a geometric mean population increase of 3.3% annually, falling to 2.3% during the last 10 yr. The adult proportion of the population increased with time, from 61% to 73%. There were 365 (95% Bayesian credible interval [BCI]: 354–373) adult breeding birds in 2016, representing 49% of the adult population and 36% of the total population (estimated at 1,026 individuals, 95% BCI: 937–1,119). The large number of non‐breeding adults probably led to higher mean age of first reproduction than previously estimated, and to an estimated 30–35% of territories occupied by polyandrous trios. Population growth rate was positively and strongly correlated with adult survival, which had a much greater effect on population growth than productivity. The effects of subadult and juvenile survival on population growth were weaker. We found strong evidence for a density‐dependent decrease in juvenile survival, productivity and adult survival, leading to reduced population growth with increased population size. Our approach allowed us to identify important conservation issues related to the management of supplementary feeding sites and geographic expansion of this population. Our study supports the use of IPMs as a tool to understand long‐lived species, allowing simultaneous estimates of the non‐breeding size of the population (which is critical for understanding population functioning), better estimates of population parameters, and assessment of demographic drivers.

Translocations are an increasing feature of threatened species conservation plans, but the impact of removal of individuals on the source population is seldom studied. Using computational Population Dynamics P System models and the Pyrenean Bearded Vulture population as a case study we looked at: the effect on the source population of alternative strategies for removal of individual birds for use in reintroduction projects; and the trade‐offs between the various management options. According to our models (over a 30 year prediction horizon) the removal of one clutch, juvenile or non‐territorial adult each year over an 11 year period, results in an annual loss of 1.57, 3.71 and 0.97 territories, respectively. We forecast the impact of a plausible removal scenario for the Pyrenees source population (the removal of five clutches and five non‐territorial adults each year over 11 years), leading to a predicted loss of 16 breeding territories. Nevertheless, changes in demographic parameters, mainly in productivity and adult survival, could substantially affect these predicted results. With the current demographic parameters, the removal scenarios that were estimated to not affect population size after 30 years (95% CI) are limited to: (1) the removal of five clutches and five non‐territorial adults during a single year; (2) the annual removal of five non‐territorial adults during a 6 year period; and (3) the annual removal of five clutches during a 6 year period. Our results suggest that removals from the Pyrenean Bearded Vulture source population should be performed with caution due to uncertainties arising from stochastic changes in survival and productivity.

Quantifying space use and segregation, as well as the extrinsic and intrinsic factors affecting them, is crucial to increase our knowledge of species‐specific movement ecology and to design effective management and conservation measures. This is particularly relevant in the case of species that are highly mobile and dependent on sparse and unpredictable trophic resources, such as vultures. Here, we used the GPS‐tagged data of 127 adult Griffon Vultures Gyps fulvus captured at five different breeding regions in Spain to describe the movement patterns (home‐range size and fidelity, and monthly cumulative distance). We also examined how individual sex, season, and breeding region determined the cumulative distance traveled and the size and overlap between consecutive monthly home‐ranges. Overall, Griffon Vultures exhibited very large annual home‐range sizes of 5027 ± 2123 km 2 , mean monthly cumulative distances of 1776 ± 1497 km, and showed a monthly home‐range fidelity of 67.8 ± 25.5%. However, individuals from northern breeding regions showed smaller home‐ranges and traveled shorter monthly distances than those from southern ones. In all cases, home‐ranges were larger in spring and summer than in winter and autumn, which could be related to difference in flying conditions and food requirements associated with reproduction. Moreover, females showed larger home‐ranges and less monthly fidelity than males, indicating that the latter tended to use the similar areas throughout the year. Overall, our results indicate that both extrinsic and intrinsic factors modulate the home‐range of the Griffon Vulture and that spatial segregation depends on sex and season at the individual level, without relevant differences between breeding regions in individual site fidelity. These results have important implications for conservation, such as identifying key threat factors necessary to improve management actions and policy decisions.

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1. Reintroduction programmes need regular assessments of their achievements and cost-efficiency so as to adapt management strategy. Ferrer et al. argue that the reintroduction of the bearded vulture, which has so far relied upon the release of captive-reared chicks, could instead use the extra number of young produced by supplementary feeding on poor-quality territories in the Pyrenees. They argue that this strategy would not affect the donor population while being much cheaper than a captive breeding programme. We question this assertion based on several grounds. 2. Ferrer et al. used incorrect data when estimating the effects of supplementary feeding on the production of young. Our reanalyses using the same data source but corrected for missing values show effect sizes of low magnitude and with substantial uncertainty, questioning any positive effect of supplementary feeding on productivity. Moreover, Ferrer et al.'s experiment actually lacks a genuine statistical control due to weak temporal stability in territory quality: we demonstrate that average productivity of territories of low-quality during the baseline period (2001)(2002)(2003)(2004)(2005)(2006) might actually have been increasing during the 'treatment' period (2007-2010) even without food supplementation due to a possible regression to the mean effect. 3. Our demographic reanalysis furthermore suggests that the donor population would not be that resilient to the extraction of young, resulting in trajectories far less optimistic (53-56 pairs in a time horizon of 50 years) than the 70 pairs reported. We also suggest that the costs of a captive breeding programme are substantially lower than suggested by Ferrer et al. 4. Synthesis and applications. The management recommendations proposed by Ferrer et al. appear unjustified. We thus urge governmental agencies to avoid making strategic political decisions and deploying conservation action on such a flawed base. We do not question here the utility of experimental approaches in reintroduction biology, but advocate independent assessment of study designs, data handling and quantitative analyses, notably when extraction of individuals from endangered populations is proposed as the best alternative option.