Migrant birds face a number of threats throughout their annual cycle, including persecution, collision with energy infrastructure, and habitat and climate change. A key challenge for the conservation ...of migrants is the identification of important habitat, including migratory concentration areas, because species survival rates may be determined by events in geographically very limited areas. Remote‐tracking technology is facilitating the identification of such critical habitat, although the strategic identification of important sites and incorporation of such knowledge in conservation planning remains limited. We tracked 45 individuals of an endangered, soaring migrant (Egyptian vulture Neophron percnopterus), over 75 complete migrations that traversed three continents along the Red Sea Flyway. We summarize and contextualize migration statistics by season and age class, including migration start, midpoint, and end dates, as well as linear and cumulative migration distance, migration duration and speed, and route straightness. Then, using dynamic Brownian bridge movement models, we quantified space use to identify the most important migratory bottlenecks and high‐use areas on the flyway. These areas each accounted for < 5% of the overall movement range of the tracked birds, yet > 20% of all tracks passed through bottlenecks, and > 50% of the overall vulture time spent on migration fell within high‐use areas. The most important sites were located at the southeastern Red Sea coast and Bab‐el‐Mandeb Strait (Saudi Arabia, Yemen, Djibouti), the Suez Canal zone (Egypt), and the Gulf of Iskenderun (Turkey). Discouragingly however, none of the area within the major migratory bottlenecks was protected and < 13% of the high‐use areas were protected. This demonstrates a very concerning gap in the protected area network for migratory soaring birds along the Red Sea Flyway. Because reducing threats at migratory concentrations can be a very efficient approach to protect populations, our work provides clear guidelines where conservation investment is urgently needed to benefit as many as 35 migratory soaring‐bird species that regularly use the Red Sea Flyway.
Hunting dog depredation by wolves triggers retaliatory killing, with negative impacts on wildlife conservation. In the wider area of the Dadia-Lefkimi-Soufli Forest National Park, reports on such ...incidents have increased lately. To investigate this conflict, we interviewed 56 affected hunters, conducted wolf trophic analysis, analyzed trends for 2010–2020, applied MAXENT models for risk-map creation, and GLMs to explore factors related to depredation levels. Losses averaged approximately one dog per decade and hunter showing a positive trend, while livestock depredations showed a negative trend. Wolves preyed mainly on wild prey, with dogs consisting of 5.1% of the winter diet. Low altitude areas, with low to medium livestock availability favoring wolf prey and game species, were the riskiest. Dogs were more vulnerable during hare hunting and attacks more frequent during wolf post-weaning season or in wolf territories with reproduction. Hunter experience and group hunting reduced losses. Wolves avoided larger breeds or older dogs. Making noise or closely keeping dogs reduced attack severity. Protective dog vests, risk maps, and enhancing wolf natural prey availability are further measures to be considered, along with a proper verification system to confirm and effectively separate wolf attacks from wild boar attacks, which were also common.
One of the primary goals of conservation translocation programs should be the maintenance of both population demographic stability and genetic diversity. Here, we provide genetic management ...recommendations to inform a population reinforcement of the declining Egyptian Vulture population in the Balkans. Specifically, we examined whether the number of released individuals is sufficient to prevent genetic diversity loss due to random genetic drift and what the origin of the individuals should be that comprise the captive breeding pool. To this aim, we estimated and assessed genetic diversity levels and genetic structure of Egyptian Vulture populations across much of the species’ range using both neutral and non-neutral candidate loci involved in migration. We then evaluated the effects of the currently proposed population management scheme and candidate source populations on retaining allelic diversity. Our results show low differentiation values among populations and absence of genetic structure which point to past high gene flow. Furthermore, there was no predicted significant impact of different source populations on the genetic diversity of the recipient Balkan population. We also found that the declining Egyptian Vulture population in the Balkans still retains high levels of genetic diversity and therefore genetic diversity restoration is not currently needed. However, without any management, diversity is likely to decrease fast because of increased genetic drift as the population size continues to decline. Population reinforcement with nine birds per year for 20 years would provide sufficient demographic support for the population to retain > 85% of rare allelic diversity. Birds originating from the Balkans would ensure ecological and behavioral similarity and thus would be the best option for reinforcement. Nevertheless, our results demonstrate that to prevent further population contraction and loss of adaptive alleles, releasing individuals of different origin would also be appropriate.
One approach to stabilise small and declining populations is to breed individuals in captivity and release them into the wild to reinforce existing populations while working to reduce threats. ...Population reinforcement programmes require long‐term commitments to be successful and can divert limited resources from other conservation measures. A rigorous evaluation whether reinforcement can stabilise a population is therefore essential to justify investments.
Many migratory species incur high mortality during their first migration, and releasing captive‐bred birds at an older age may therefore benefit reinforcement programmes for migratory birds. We examine whether a small and declining population of a long‐distance migratory raptor—the Egyptian Vulture Neophron percnopterus—can be stabilised using population reinforcement that reduces mortality during the first migration. We used an integrated population model to evaluate realistic reinforcement and survival improvement scenarios to estimate how many captive‐bred birds would need to be released to stabilise the population.
Survival probability of wild juveniles during their first year (0.296; 95% CI 0.234–0.384) was too low for a stable population (population growth rate 0.949; 95% CI 0.940–0.956), but captive‐bred juveniles released in their second calendar year had improved survival (0.566; 95% CI 0.265–0.862) during their first year in the wild.
Reinforcement of 15 birds per year for 30 years was insufficient to achieve a neutral or positive population growth rate. However, reinforcement reduced the probability of extinction by 2049 from 48% without reinforcement to <1% if 12 or more birds were released every year for 30 years. A 6% increase in annual survival probability would likely lead to a stable population without any reinforcement.
Synthesis and applications. Although releasing captive‐bred birds can reduce high juvenile mortality during first migration and assist in postponing local extinction, further improvements of survival in the wild are required to safeguard a migratory population where threats in the wild will persist for decades despite management.
Translated Περίληψη
Μία προσέγγιση που στοχεύει στη σταθεροποίηση μικρών και μειούμενων πληθυσμών είναι η αναπαραγωγή ατόμων σε αιχμαλωσία και στη συνέχεια η απελευθέρωσή τους στην φύση για την ενδυνάμωση των υπαρχόντων πληθυσμών, ενώ παράλληλα συνεχίζονται οι διαχειριστικές δράσεις που στοχεύουν στον περιορισμό των απειλών. Τέτοια προγράμματα ενδυνάμωσης πληθυσμών, για να είναι επιτυχημένα, απαιτούν μακροπρόθεσμη δέσμευση και μπορούν να εκτρέψουν τους ήδη περιορισμένους πόρους από άλλα μέτρα διατήρησης. Είναι επομένως απαραίτητη μια διεξοδική αξιολόγηση του κατά πόσον οι δράσεις ενδυνάμωσης μπορούν να οδηγήσουν έναν πληθυσμό σε σταθεροποίηση, έτσι ώστε πιθανές επενδύσεις σε τέτοιες δράσεις να είναι δικαιολογημένες.
Πολλά μεταναστευτικά είδη πουλιών υφίστανται υψηλή θνησιμότητα κατά το πρώτο τους ταξίδι οπότε η απελευθέρωση ατόμων που έχουν αναπαραχθεί σε αιχμαλωσία αφού έχουν φτάσει σε μεγαλύτερη ηλικία μπορεί να ωφελήσει προγράμματα ενδυνάμωσης που στοχεύουν πληθυσμούς μεταναστευτικών ειδών. Εδώ, εξετάζουμε εάν ένας μικρός και μειούμενος πληθυσμός ενός μεταναστευτικού είδους αρπακτικού ‐ του Ασπροπάρη (Neophron percnopterus) ‐ μπορεί να σταθεροποιηθεί μέσω δράσεων ενίσχυσης που μειώνουν τη θνησιμότητα κατά την πρώτη μετανάστευση. Χρησιμοποιήσαμε πληθυσμιακά μοντέλα για να αξιολογήσουμε ρεαλιστικά σενάρια ενδυνάμωσης και αύξησης της επιβίωσης ώστε να εκτιμήσουμε πόσα άτομα που έχουν αναπαραχθεί σε αιχμαλωσία θα πρέπει να απελευθερωθούν για να επιτευχθεί η σταθεροποίηση του πληθυσμού.
Η πιθανότητα επιβίωσης των άγριων νεαρών ατόμων κατά το πρώτο έτος της ζωής τους (0,296, 95% CI 0,234 – 0,384) ήταν πολύ χαμηλή για να οδηγήσει σε έναν σταθερό πληθυσμό (ρυθμός αύξησης πληθυσμού 0,949, 95% CI 0,940 –0,956), αλλά τα νεαρά άτομα που είχαν αναπαραχθεί σε αιχμαλωσία και απελευθερώθηκαν στον δεύτερο χρόνο της ζωής τους, έδειξαν αυξημένη επιβίωση (0,566, 95% CI 0,265 – 0,886) κατά τη διάρκεια του πρώτου έτους τους στη φύση.
Η ενδυνάμωση του πληθυσμού με την απελευθέρωση 15 πουλιών ετησίως για 30 χρόνια δεν επαρκεί για την επίτευξη είτε σταθερού είτε θετικού ρυθμού αύξησης του πληθυσμού. Ωστόσο, η δράση ενδυνάμωσης μπορεί να μειώσει την πιθανότητα εξαφάνισης από 48% σε λιγότερο από 1% έως το 2049, εάν 12 ή περισσότερα πουλιά απελευθερώνονταν κάθε χρόνο για 30 χρόνια. Επίσης, εάν η ετήσια πιθανότητα επιβίωσης αυξανόταν κατά 8% θα οδηγούσε σε έναν σταθερό πληθυσμό χωρίς να χρειάζεται καμία δράση ενίσχυσης.
Σύνθεση και εφαρμογές. Παρόλο που η ενδυνάμωση του πληθυσμού μπορεί να μειώσει την υψηλή θνησιμότητα των νεαρών ατόμων κατά την πρώτη τους μετανάστευση και να βοηθήσει στην αναστολή μιας τοπικής εξαφάνισης, απαιτείται περαιτέρω βελτίωση της επιβίωσης τους στην φύση για την διασφάλιση ενός μεταναστευτικού πληθυσμού ο οποίος θα συνεχίσει να αντιμετωπίζει απειλές για δεκαετίες παρά τη διαχείριση.
Although releasing captive‐bred birds can reduce high juvenile mortality during first migration and assist in postponing local extinction, further improvements of survival in the wild are required to safeguard a migratory population where threats in the wild will persist for decades despite management.
Assessing the effectiveness of conservation measures to reverse population declines is essential to evaluate management strategies. Management solutions such as direct protection or supplementary ...feeding typically aim at reducing mortality or increasing productivity, but demonstrating such demographic consequences of adopted management is often difficult. Here we assess the effectiveness of large-scale management actions aimed at the conservation of an endangered vulture on the Balkan Peninsula by extending a novel analysis to estimate seasonal adult survival from observations of unmarked individuals. We monitored Egyptian Vulture Neophron percnopterus breeding success and territory occupancy over 11years in three countries during which both nest guarding and supplementary feeding were carried out. We found little evidence that nest guarding and supplementary feeding increased breeding propensity (mean=0.88±0.32 standard deviation, n=463), breeding success (0.82±0.39), or the number of fledglings raised by successful pairs (1.3±0.74). We estimated adult survival during the 23-week breeding season (mean=0.936, 95% credible interval 0.889–0.968) and found no significant increase due to management. In the last 13years 43 dead adult birds have been found during the breeding season, and 77% of confirmed mortalities were due to poisoning. Overall, the current management measures may have so far failed to halt ongoing population declines because the beneficial effects are insufficient to offset the loss of adult birds for example due to poisoning. We suggest that additional measures to slow the decline of Egyptian Vultures in the Balkans are required. In the short term, we urge governments to enforce anti-poison regulations that already exist. In the medium term, alternative approaches need to be developed that reduce the use of poisons and the associated accidental mortality of vultures and other wildlife species.
The Convention of Migratory Species aims to protect migratory animals throughout their range, but efficient mitigation of threats facing migratory birds is hindered by poor knowledge about the ...magnitude and geographic range of threats. We used an expert assessment to prioritise which threats to mitigate in 13 countries along the eastern Mediterranean flyway to protect globally threatened Egyptian Vultures Neophron percnopterus. We informed this assessment by satellite tracking 71 birds to quantify where and how mortalities occurred, surveying 4216 km of powerlines to detect carcasses, conducting 910 interviews to quantify poison use, and by surveying markets and hunters to assess direct persecution. Mortality of 50 birds occurred in Europe and the Mediterranean Sea (44%), the Middle East (18%), and Africa (38%), and mortality causes varied geographically. Inadvertent poisoning resulting from rural stakeholders targeting predators occurred along most of the flyway. On the breeding grounds in eastern Europe and in Saudi-Arabia, poisoning and collision and electrocution are the priority threats to mitigate. Electrocution on small and poorly designed electricity pylons was the priority threat in Turkey, Jordan, Egypt and Ethiopia. Direct persecution for belief-based use of vulture products was the priority threat in Nigeria and Niger, while other illegal killing was the priority threat in Lebanon and Syria. Our work cannot quantify which threat has the greatest demographic impact on Egyptian Vultures. Nonetheless, because all threats we assessed are relevant for many other migratory birds, our assessment highlights the priority threats that range states need to address to protect migratory birds.
The Eurasian black vulture (
Aegypius monachus) is a globally endangered species, vulnerable in Europe and endangered in Greece. We modelled its nesting preferences in Dadia reserve, northeastern ...Greece using logistic models at multi-scale level combined by Bayesian statistics. Compared with the random sites, the vultures nested at trees with greater diameter (DBH), lower height, and lower total number of trees around the nest tree, steeper slopes and greater distance from forest roads. Our results indicate that conservation and management guidelines for black vultures must aim: (1) to preserve old, isolated mature trees in the reserve, (2) to maintain the zones of strict protection as vulture sanctuary, including most of the suitable nesting habitat, (3) to protect the apparently suitable but still unused habitat in the rest of the reserve from disturbance and logging, (4) to monitor any changes in habitats and use our models to evaluate and predict their effect on vulture nesting in the reserve.
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