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Abstract Modern humans widely shaped present ecosystems through intentional and unintentional geographical redistribution of wildlife, both in historical and pre‐historical times. However, the patterns of ancient human‐mediated indirect changes in wildlife range are largely unknown, and the mechanisms behind them remain obscure. We used a multidisciplinary approach to (a) reconstruct the process of colonization of the Mediterranean Basin by a long‐lived bird of prey, the Bonelli's eagle (Aquila fasciata), and (b) test the hypothesis that this colonization was unintentionally favoured by anatomically modern humans through a release of competition by dominant species, primarily golden eagles (A. chrysaetos). The fossil record of Bonelli's eagles in the Mediterranean Basin was restricted to the last c. 50 ky. This timing matches the period of modern human presence in Europe. Distribution modelling showed that Bonelli's eagles find more suitable conditions in interglacial periods, while glacial maxima are largely unfavourable unless in coastal refugia. In agreement with this, all Bonelli's eagle's fossils were found in coastal areas, and demographic inference from genetic data revealed a drop in the effective population size by around the last glacial maximum. In today's communities, we found a strongly asymmetric competitive relationship between (subordinate) Bonelli's and (dominant) golden eagles, with the former occupying far more humanized areas than the latter both at the landscape scale and the local (i.e. nesting cliff) scale. Moreover, the nesting habitat overlap analysis indicated that, in the absence of the other species, a notably higher population of Bonelli's eagle, but not of golden eagle, could be expected. Our findings are consistent with the human‐mediated competitor release hypothesis, by which anatomically modern humans could have unintentionally favoured the large‐scale colonization by Bonelli's eagles of a previously competitively hostile Mediterranean Basin. Reconstructing the role of ancient humans in shaping present ecosystems may help to understand the historical, current and future population trajectories of competing species of conservation concern under the ongoing scenario of global environmental change. It also illustrates how human‐mediated apparent competition may promote large‐scale redistribution and colonization of wildlife, including long‐lived species. Read the free Plain Language Summary for this article on the Journal blog.

Competition within and between species affects community structure and is well documented in raptors. We investigated the spatial distribution of two sympatric raptors in Cyprus, the Bonelli's Eagle (BE) and the Long-legged Buzzard (LLB). Both species are facultative tree/cliff nesters, with overlapping nesting and foraging areas. In 2021, the BE population consisted of 40 pairs with a density of 1,3 pairs/100 km2, and the LLB population of 113 pairs with 2,9 pairs/100 km2. About 80% of BE nesting sites and 43% of LLB nesting sites were situated within the Natura 2000 (N2K) protected areas network while 97% of BE nesting sites and 91% of LLB's were situated within 2.5 km from N2K areas. The spatial distribution was compared between and within species based on Nearest Neighbour Distance (NND) analysis. Average intraspecific NND for BE was 6.158 ± 2.207 m (SD), almost double compared to LLB which was 3.151 ± 1.730 m (SD). The distribution of BE nesting territories showed a regular spacing, indicating a stronger effect of intraspecific competitive interactions, whereas LLB nesting territories did not differ significantly from random. Average interspecific NND for BE was 5.339 ± 3.719 m (SD) and for LLB 5.673 ± 3.931 m (SD). Only the LLB had a regular pattern, suggesting that LLB pairs take into account neighbouring BE active territories when establishing their own, while the opposite is not the case. Therefore, the LLB, which is the smaller of the two raptors, avoids BE nesting sites by placing its nests further than to conspecifics. NNDs in 2021 were lower compared to previous studies in Cyprus, in 2005 for LLB and 2009 for BE, indicating an increase in both species' densities. [ABSTRACT FROM AUTHOR]

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The Bonelli’s Eagle exhibits a wide geographic distribution yet remains relatively understudied on the island of Cyprus. Between 1999 and 2002, we examined 32 pairs of Bonelli’s Eagles, totaling 64 breeding attempts. During this period, a total of 116 eggs were laid, with an average clutch size of 2.0 ± 0.1 eggs per pair. Incubation, predominantly performed by the female, lasted an average of 38.7 ± 0.2 days. Of the eggs laid, 71 hatched, resulting in an average hatching rate of 82.6%. Hatchability varied, with the highest rate (91.3%) observed in 1999 and the lowest (76.2%) in 2001. Nestlings spent an average of 61 ± 0.5 days in the nest before fledging. Remarkably, 92.6% of pairs successfully fledged young (n = 60), with a mean breeding success of 1.6 ± 0.1 fledglings per pair. Significant differences were observed in the average number of eggs laid, hatched, and young fledged between the two types of habitats. Nest sites varied in altitude, ranging from 170 to 1,242 meters, with a nearest-neighbor distance between adjacent nests averaging 7.86 ± 0.43 kilometers. [ABSTRACT FROM AUTHOR]

The Bonelli's Eagle (Aquila fasciata) is a critically endangered species in Israel, with electrocution on power lines posing a serious threat to its population. Because retrofitting of electricity pylons to prevent mortality is a slow and costly process, it is important to prioritize the pylons in the network for quick and efficient mitigation of eagle mortality. To determine which pylons need to be retrofitted, we applied a three-stage maximum entropy modeling process for identifying the risk factors posed by different environmental variables. The environmental feature with the highest correlation to electrocution is the distance to reservoirs (i.e. many electrocution events occur near water reservoirs). The reservoirs are foraging hotspots for Bonelli's Eagles in Israel's arid environment. Electricity pylons powering the reservoirs' pumping facilities tend to be the highest perches in the vicinity of many of the reservoirs, creating an ecological trap. The strong attraction of reservoirs to eagles may explain the high level of selectivity indicated by the model, suggesting that retrofitting only 3.6% of the pylons in the network would achieve 77% reduction in eagles' electrocution probability. Moreover, insulating pylons according to the model will also likely reduce electrocutions of other avian species, including Eastern Imperial Eagle (Aquila heliaca) and White-tailed Eagle (Haliaeetus albicilla). The modeling process presented here yielded 2 electrocution risk maps, one to facilitate prioritization of mitigation in Israel's existing power network and the second to support planning and designing new infrastructure. The model may help reach conservation goals for the Israeli Bonelli's Eagle and the modeling approach may also be useful in prioritizing pylon retrofitting in other arid landscapes. [ABSTRACT FROM AUTHOR]

Reintroduction projects are gaining popularity; however, their relatively elevated cost and chance of failure make them debatable, hence assessing their effectiveness is essential. Within the early stages of raptors, the post-fledging dependency period (PFDP) is the one in which individuals must face dangers without having completely developed their skills. Thereby, comparing PFDP patterns concerning reintroduced and wild individuals is of major interest as it would help to plan and improve future conservation actions. We analyzed the behavior of 38 juvenile Bonelli's Eagles (Aquila fasciata) (15 reintroduced and 23 wild) tracked through GPS telemetry, tagged as nestlings in two insular environments. The study period encompassed 9-yr movement data from reintroduced chicks in Mallorca (Spain) and wild chicks from Sicily (Italy). Movement parameters (i.e., age of first flight, age of dispersal, length of the PFDP, revisits to the natal or release area, and residence time in them) were analyzed together with their behavior for reintroduced and wild individuals. Similar movement patterns were obtained for both origins, although wild individuals revisited the natal site more often and dispersed earlier. Behavior was also similar, though it varied throughout the PFDP, observing a more abrupt progress in wild individuals and an earlier development of travelling and hunting behaviors. Observed differences are probably related to food availability, which can improve body condition and thus delay onset of dispersal, together with parental presence, which can prompt an earlier ending of the PFDP by encouraging juvenile independence. In conclusion, our study provides valuable insights into the behavior of reintroduced Bonelli's Eagles during their PFDP and how it compares to their wild counterparts. Our results suggest that reintroduced individuals can successfully adapt to their environment and behave similarly to wild individuals. These findings can aid in the planning and improvement of future reintroduction projects and conservation actions for this endangered species. [ABSTRACT FROM AUTHOR]

Entre 2015 y 2022 se han introducido en Álava-Araba (Kanpezu y Rioja alavesa) mediante hacking un total de 36 pollos volantones de Águila de Bonelli marcados con GPS (Aquila fasciata)procedentes de cría en cautividad y de extracciones de la población natural de Andalucía. Los individuos reintroducidos se dispersaron preferentemente hacia el valle del Ebro (La Rioja, Navarra y Aragón), otros siguiendo el río Duero hacia Castilla-León, Extremadura, Portugal y Andalucía, y algunos cruzando la Meseta norte hasta la cuenca del río Tajo (Toledo). La distancia media de dispersión juvenil fue de 286 Km (0-773 km). El proceso de dispersión no fue lineal sino itinerante realizando sucesivas sedimentaciones temporales en zonas ricas en alimento y sin población reproductora. Las altas tasas de mortalidad fueron similares a las observadas para la población silvestre, con una tasa de supervivencia del 64.7 % durante el primer año, 87.5 % en el segundo y 90.0 % a partir del tercer año de vida. La electrocución en tendidos eléctricos de distribución fue la principal causa de mortalidad (27.3 %), seguida de la predación y competencia con el Águila real (27.3 %) y de la colisión (13.6 %). A pesar de proceder de cría en cautividad las águilas mostraron una fuerte filopatría hacia las zonas de liberación, regresando todas ellas en el 2º y 3eraño, preferentemente en los meses de febrero-marzo de cada temporada. Gracias al reforzamiento poblacional se han formado tres nuevos territorios en el Alto valle del Ebro. ABSTRACT: Between 2015 and 2022, a total of 36 fledglings of Bonelli’s Eagle (Aquila fasciata)bred in captivity (n=28) and extractions from the Andalusian population (n=8), were released by hacking in Álava-Araba (Kanpezu and Rioja Alavesa). All of them were radio-tracked by GPS so that the dispersal patterns, mortality rates and the place and causes of deaths are known. The GPS signal of five of these fledglings was lost (n=4) or the transmitter was lost (n=1) and their current destination is unknown. These juvenile birds dispersed preferentially towards the Ebro valley (La Rioja, Navarra and Aragón), others following the Duero river towards Castilla-León, Extremadura, Portugal and Andalusia, and some crossed the Northern Meseta to the Tajo basin (Toledo). The distance of juvenile dispersal ranged from 0 to 773 km from the release site, with an average of 286 km (n=23). The dispersal process was not linear but rather itinerant, successive temporary settlements occuring in areas rich in food and without a breeding population. The high mortality rates found among the released juveniles were similar to those observed for the wild population, with a survival rate of 64.7 % during the first year, 87.5 % in the second and 90.0 % from the third year of life. We know the cause of death or recovery of 19 birds (n= 22 events). Electrocution in distribution power lines was the main cause of mortality (27.3%), followed by predation and competition with the Golden Eagle (27.3%) and collision (13.6%). Despite being bred in captivity, the eagles showed a strong philopatric tendency towards the release zones, all of them returning in the 2nd and 3rd year, mainly in the months of February-March of each season. Through population reinforcement, three new territories have been formed in the Upper Ebro Valley: one in Kanpezu, which already obtained a juvenile in 2021, another in the Ribera de Navarra, still without breeding, and another in Rioja Alavesa occupied at this time by a single female.

Bonelli's eagle (Aquila fasciata) is an endangered raptor species in Europe, and trichomonosis is one of the menaces affecting chicks at nest. In this paper, we attempt to describe the oral microbiome of Bonelli's eagle nestlings and evaluate the influence of several factors, such as captivity breeding, Trichomonas gallinae infection, and the presence of lesions at the oropharynx. The core oral microbiome of Bonelli's eagle is composed of Firmicutes, Bacteroidota, Fusobacteria and Proteobacteria as the most abundant phyla, and Megamonas and Bacteroides as the most abundant genera. None of the factors analysed showed a significant influence on alfa diversity, but beta diversity was affected for some of them. Captivity breeding exerted a high influence on the composition of the oral microbiome, with significant differences in the four most abundant phyla, with a relative increase of Proteobacteria and a decrease of the other three phyla in comparison with chicks bred at nest. Some genera were more abundant in captivity bred chicks, such as Escherichia-Shigella, Enterococcus, Lactobacillus, Corynebacterium, Clostridium and Staphylococcus, while Bacteroides, Oceanivirga, Peptostreptococcus, Gemella, Veillonella, Mycoplasma, Suttonella, Alloscardovia, Varibaculum and Campylobacter were more abundant in nest raised chicks. T. gallinae infection slightly influenced the composition of the microbiome, but chicks displaying trichomonosis lesions had a higher relative abundance of Bacteroides and Gemella, being the last one an opportunistic pathogen of abscess complications in humans. Raptor's microbiomes are scarcely studied. This is the first study on the factors that influence the oral microbiome of Bonelli's eagle. [ABSTRACT FROM AUTHOR]

Anticoagulant rodenticides (ARs) are one of the most toxic groups of compounds currently used worldwide for rodent pest control. Toxic baits are often, directly or indirectly, ingested by non-target animals, resulting in secondary poisoning and frequently affecting apex predators. Their presence in many species of raptors is quite common, particularly scavenger species, with some of these acting as sentinels for the presence of these substances in the environment. However, there is less data on the presence of ARs in Bonelli's eagle, one of the most endangered eagle species in Spain and which is experiencing a negative population trend in Europe. This medium-sized eagle feeds predominantly on live species, and rarely consumes carrion. In this study, 17 carcasses of Bonelli's eagles from the Eastern Spain were necropsied. Both first and second generation ARs in their livers were analyzed by HPLC-MS-TOF revealing that all the eagles studied had been exposed to at least 5 ARs, out of a total of 10 ARs analyzed, with 7 being the highest number of ARs detected in a sample. Second generation ARs were the most prevalent, particularly bromadiolone and brodifacoum, with the highest concentrations in 94% of the cases. More than a third of the eagles presented a liver concentration of greater than 200 ng/g ARs, suggesting AR poisoning. The elevated presence of these compounds in Bonelli's eagles could be a new cause of mortality for this species or could explain other causes of death, such as the increased mortality in power lines, and should be taken into account for their conservation. At the same time, the presence of these compounds in the environment also represents a risk to public health, as the most frequent species in the diet of Bonelli's eagle (rabbits and partridges) are also hunted and consumed by hunters and their families. [Display omitted] • Anticoagulant rodenticides (AR) are present in 100% of the Bonelli's eagles analyzed. • AR hepatic levels exceeded the potentially lethal threshold in 35% of the eagles analyzed. • A traumatic cause of death may be favoured by exposure to ARs. • ARs exposure is associated with increasing intensity of urbanization and rainfed agriculture. • Bonelli's eagles may be a good sentinel species of AR risk for humans. [ABSTRACT FROM AUTHOR]

Interspecific competition occurs when two sympatric species utilize the same limited supply of a basic resource, such as food; the degree of diet overlap is an essential metric for examining potential competition between the species. The Long-legged Buzzard (Buteo rufinus) is a relative newcomer to the island of Cyprus, where it is sympatric with the larger Bonelli's Eagle (Aquila fasciata), a potential competitor for both food and space (nesting territories). We studied the diet of the Long-legged Buzzard in the 2005, 2006, and 2018 nesting seasons through analysis of pellets and prey remains collected at 38 sites. The most abundant prey class was mammals (68.8% frequency, 58.9% biomass), followed by reptiles (16.8% frequency, 36.3% biomass), and birds (4.3% frequency, 4.6% biomass). The most numerous prey species were black rats (Rattus rattus), starred agamas (Stellagama stelio), house mice (Mus musculus), and large whip snakes (Dolichophis jugularis), but in terms of biomass, the most important prey items were black rats, large whip snakes, long-eared hedgehogs (Hemiechinus auritus dorotheae), and starred agamas. We compared the diet of the Long-legged Buzzard to that of the Bonelli's Eagle, whose diet was dominated by birds (62.1% frequency, 76.1% biomass) and to a lesser degree by mammals (29.5% frequency, 21.9% biomass). The mean prey biomass for the Long-legged Buzzard was estimated as 167 g, compared to 350 g for the Bonelli's Eagle; this difference reflected the almost two-fold difference in mass between females of the two species. Diet overlap measured with Pianka's index was <0.5, suggesting an intermediate niche overlap mainly due to utilization of an abundant prey resource, such as the black rat. Niche breadth for the Long-legged Buzzard measured using Levins' index ranged from 0.485 in 2005 to 0.081 in 2018. This decrease in niche breadth over time in a generalist species can occur when there is a superabundance of a particular prey. The mean Levins' index for the Bonelli's Eagle was also low, 0.271 (1999–2001). Based on the diet comparison, we concluded that there was no evidence for interspecific competition in terms of food. La competencia interespecífica ocurre cuando dos especies simpátricas utilizan el mismo suministro limitado de un recurso básico, como por ejemplo la comida; el grado de solapamiento de la dieta es una métrica esencial para examinar la competencia potencial entre las especies. Buteo rufinus es una especie relativamente nueva en la isla de Chipre, donde se presenta en simpatría con Aquila fasciata, de mayor tamaño, un competidor potencial tanto por comida como por espacio (territorios de nidificación). Estudiamos la dieta de B. rufinus en las temporadas de cría de 2005, 2006 y 2018 mediante el análisis de egagrópilas y restos de presas recolectados en 38 sitios. Las presas más abundantes fueron los mamíferos (68,8% de frecuencia, 58,9% de biomasa), seguido de los reptiles (16,8% de frecuencia, 36,3% de biomasa) y las aves (4,3% de frecuencia, 4,6% de biomasa). Las especies de presa más numerosas fueron Rattus rattus, Stellagama stelio, Mus musculus y Dolichophis jugularis, si bien en términos de biomasa las presas más importantes fueron R. rattus, D. jugularis, Hemiechinus auritus dorotheae y S. stelio. Comparamos la dieta de B. rufinus con la de A. fasciata, cuya dieta estaba dominada por aves (62,1% de frecuencia, 76,1% de biomasa) y en menor medida por mamíferos (29,5% de frecuencia, 21,9% de biomasa). La biomasa de la presa promedio para B. rufinus se estimó en 167 g, en comparación con 350 g para A. fasciata; esta disparidad reflejó la diferencia de masa de casi el doble entre las hembras de las dos especies. El solapamiento de dieta medido con el índice de Pianka fue <0,5, lo que sugiere un solapamiento de nicho intermedio debido principalmente a la utilización de un recurso de presa abundante como R. rattus. La amplitud de nicho para B. rufinus, medido con el índice de Levins, fluctuó entre 0,485 en 2005 y 0,081 en 2018. Esta disminución en la amplitud de nicho a lo largo del tiempo en una especie generalista puede ocurrir cuando hay una sobreabundancia de una presa en particular. El índice de Levins medio para A. fasciata también fue bajo, 0,271 (1999–2001). Basados en la comparación de la dieta, concluimos que no hubo evidencia de competencia interespecífica en términos de alimentación. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

Unmasking the ecological processes responsible for the dynamics of a population is a necessary step toward understanding its threats and viability. We examined a fitness proxy (reproductive success) of an endangered raptor in relation to its ecological niche and spatial distribution to provide insights into the dynamics and potential threats to the population. We first studied how biotic and abiotic conditions drive both the spatial distribution of Bonelli's eagle (Aquila fasciata) and its long‐term reproductive success in a large area of northwestern Spain. We focused on the relationship between these two characteristics of the population. Our results showed that biotic factors (occurrence of competitors such as the golden eagle or prey availability) were more associated with the spatial distribution of the species than with its reproductive success. In contrast, abiotic factors describing climate were linked to reproductive success. Most interestingly, we found a mismatch between spatial suitability and reproductive success because reproduction was compromised in the areas that were more suitable for the occurrence of the species. The results suggest that productivity (less than one chick per year), measured as long‐term reproductive success, may compromise the population viability and suggest the presence of an underlying mechanism in the population. Our results highlight the benefits of simultaneously considering both large‐scale spatial distribution patterns and measures of fitness, which often require larger investments of time, for endangered species conservation programs. [ABSTRACT FROM AUTHOR]

Accurate estimations of adult mortality are essential for understanding population dynamics and achieving efficient management actions that are directed toward long-lived species. Several noninvasive methods may be used to monitor endangered long-lived birds like raptors, but their performance in real-world scenarios remains poorly studied. We used eight Bonelli's Eagle (Aquila fasciata) breeding pairs (1) to compare the efficiency of direct observations with binoculars and telescopes (2004–2016), camera trapping (2012–2016), and feather genetic analysis (2004–2015) for detecting and identifying individuals over time, (2) to conduct a cost-benefit analysis of methods, and (3) to evaluate the accuracy of the direct observation method for estimating survival by comparing it with camera trapping and feather analysis. Both the feather genetic analysis and camera trapping approaches allowed us to successfully identify individuals and to detect replacements that we did not notice during direct observations. The classic direct observation method overestimated adult survival, which could hamper an accurate understanding of the demographic dynamics of this population. Feather analysis gave a low detection rate of individuals (47%), probably due to difficulties in finding feathers in the rugged habitat of this species. However, identification success at the individual level with this method was 96%. Remote camera surveys had both a high detection rate (100%) and identification success (93%). Given that costs associated with camera surveys were lower than the costs of genetic procedures, we concluded that camera trapping is the most efficient indirect method to assess adult survival in this and other raptors with external features that make individual identification possible. However, because no method showed complete efficiency, genotyping of feathers collected at the end of the breeding season could be a useful additional method, especially when camera trapping is not possible or when it fails. [ABSTRACT FROM AUTHOR]

Summary: Understanding the environmental drivers of demographic processes is a prerequisite for providing the evidence-based conservation guidance and management actions required to address management goals at population level. Human activities, to which most species are not adapted, are having an ever-increasing impact on the environment. Most policies and strategies focus on broad-scale conservation actions and disregard the fact that this type of action may not be adequate at local scale. In addition, even though the main conservation targets are well known, managers and practitioners lack an explicit framework in which to identify the varying requirements of site-specific conservation actions. Our aim was to provide an accurate tool for prioritizing specific local-scale conservation actions for endangered territorial birds. In this study we describe our proposed framework using a population of the endangered Bonelli's Eagle Aquila fasciata as a case study. We identified the most relevant environmental drivers linked to demographic parameters (occupation, productivity and survival) at local scale shaping the dynamics of the Bonelli's Eagle population in Catalonia (Spain). This information will be useful for designing specific local-scale conservation actions in eagles' territories with low demographic parameter values. This is a good example of how applied research and achievable conservation practices are applicable to other Bonelli's eagle populations and to those of other endangered raptors. [ABSTRACT FROM AUTHOR]

Bonelli's eagle (Hieraaetus fasciatus), a threatened species in Western Europe, has suffered a critical and severe decline in last two decades. In this article, a qualitative analysis of an ecoepidemiological model which consists of two prey and a predator is carried out. We proposed and designed a spatiotemporal model to predict the distribution of a territorial predator, Bonelli's eagle and its two main prey species (rabbit and red‐legged partridge). Bounded positive solution, feasibility of the equilibria, and their stability analysis are determined for the nonspatial counterpart of the system. Criteria for diffusion‐driven instability caused by local random movements of rabbits, partridges, and Bonelli's eagle are obtained. Possible implications of the result for Bonelli's eagle conservation are discussed. We show that the inclusion of second prey in the system can drastically change the dynamics from the single prey case. We also found that the presence of a second prey is beneficial for the conservation of the threatened Bonelli's eagle population in Europe. Results obtained from theoretical analysis of the nonspatial model agree very well with the numerical simulation results. Lastly, via numerical simulation, we illustrate the effect of diffusion of the dynamical system in the spatial/spatiotemporal domain by different pattern formations. [ABSTRACT FROM AUTHOR]

Avian trichomonosis is a parasitic disease that affects wild birds. The objective of this work was to determine the importance of avian trichomonosis in Bonelli's eagles to improve conservation measures in this population. One hundred and eighty-eight birds were studied: 181 chicks, two juveniles, one subadult and four adults. The birds were externally examined and gross lesions at the oropharynx registered. Samples from the oropharyngeal cavity were obtained for Trichomonas spp. detection by culture and PCR, and positive samples were subjected to a multilocus sequence typing approach, including the ITS1/5.8S/ITS2 region (ITS), ribosomal RNA small subunit (18S) and Fe-hydrogenase gene (FeHyd). Global prevalence of T. gallinae infection was 37.8% in total, 45.5% in nestlings. Thirty-three percent of the birds developed lesions that ranged from mild (n = 41) to moderate (n = 14) or severe (n = 7). Multilocus sequence typing analysis showed five different MLS types, ITS-A/18S-VI/FeHyd-A1 and ITS-D/18S-II/Fe-C4 being the most frequent. An association between ITS-A/18S-VI/FeHyd-A1 and moderate or severe lesions was observed, but birds with type ITS-A/18S-VI/FeHyd-A2 also developed lesions. On the contrary, birds with MLS type ITS-D/18S-II/FeHyd-C4 displayed only a low proportion of mild lesions. Chicks raised in nests were at higher risk for T. gallinae infection and development of lesions than chicks raised in captivity. Discordances between samples cultured in TYM and samples subjected to PCR from oropharyngeal swabs were observed, swab-ITS-PCR being more sensitive. RESEARCH HIGHLIGHTS 45.5% of Bonelli's eagles in the nest carried T. gallinae and 39.4% showed lesions. PCR from oral swabs showed higher sensitivity than culture in TYM for detection of T. gallinae. MLS types ITS-A/18S-VI/Fe-A1 (and A2) are a risk factor for the development of lesions. [ABSTRACT FROM AUTHOR]

Seven species of eagle breed in France: Golden Eagle (Aquila chrysaetos), Lesser Spotted Eagle (Aquila pomarina), Bonelli’s Eagle (Aquila fasciata), Booted Eagle (Hieraaetus pennatus), Short-toed Eagle (Circaetus gallicus), Osprey (Pandion haliaetus) and White-tailed Eagle (Haliaeetus albicilla). Populations of all species have increased since the beginning of the 2000s and breeding pairs are estimated at: 2500-3300 in 2012 (Short-toed Eagle), 585-810 in 2012 (Booted Eagle), 450-500 in 2012 (Golden Eagle), 80-90 in 2015 (Osprey),33 in 2016 (Bonelli’s Eagle) and 1 each in 2018 (Lesser spotted Eagle and White-tailed Eagle). These two latter species became new breeding species in 2003 and 2011 respectively. Productivity, expressed as fledgling/pair/year, is estimated to be on average 0.57 (Short-toed Eagle), 1.56 (Osprey), 1.18 (Bonelli’s Eagle), 0.82 (Lesser spotted Eagle), 1.1 (White-tailed Eagle) and from 0.26 (min) to 0.70 (max) (Golden Eagle). The main threats to reproduction relate to decreases in habitat quality (resulting from disturbance, habitat loss and wind farms) and the increase of mortality (from power lines, poaching and poisoning).

Radiographs are an important diagnostic tool available in wildlife hospitals to evaluate the size of the avian heart. Despite the large variety wild birds in the Iberian peninsula, clinical studies addressing these species are lacking. To establish reference values for cardiac size in the Bonelli's eagle (Aquila fasciata), ventrodorsal radiographs of 20 healthy birds were obtained, and the width of the cardiac silhouette, sternum, thorax, coracoid, and hepatic silhouette were measured. The ratios between cardiac width and other mentioned indices were calculated. Results showed that cardiac silhouette width should occupy 81%–93% of sternal width, 48%–57% of thoracic width, and 506%–673% of coracoid width. The cardiac silhouette width was strongly correlated with sternal and thoracic widths. A moderate correlation was found between the width of the heart and the width of the coracoid. No significant correlation was found between width of the cardiac silhouette and the hepatic silhouette. These results support that sternal and thoracic widths should be used preferentially when evaluating the width of the cardiac silhouette in this species. The values obtained in this study can be used as a reference for normal cardiac size when evaluating radiographs of Bonelli's eagles. [ABSTRACT FROM AUTHOR]

Monitoring progress towards global goals and biodiversity targets require reliable descriptions of species distributions over time and space. Current gaps in accessible information on species distributions urges the need for integrating all available data and knowledge sources, and intensifying cooperations to more effectively support global environmental governance. For many areas and species groups, experts can constitute a valuable source of information to fill the gaps by offering their knowledge on species-environment interactions. However, expert knowledge is always subject to uncertainty, and incorporating that into species distribution mapping poses a challenge. We propose the use of the dempster-shafer theory of evidence (DST) as a novel approach in this field to extract expert knowledge, to incorporate the associated uncertainty into the procedure, and to produce reliable species distribution maps. We applied DST to model the distribution of two species of eagle in Spain. We invited experts to fill in an online questionnaire and express their beliefs on the habitat of the species by assigning probability values for given environmental variables, along with their confidence in expressing the beliefs. We then calculated evidential functions, and combined them using Dempster's rules of combination to map the species distribution based on the experts' knowledge. We evaluated the performances of our proposed approach using the atlas of Spanish breeding birds as an independent test dataset, and further compared the results with the outcome of an ensemble of conventional SDMs. Purely based on expert knowledge, the DST approach yielded similar results as the data driven SDMs ensemble. Our proposed approach offers a strong and practical alternative for species distribution modelling when species occurrence data are not accessible, or reliable, or both. The particular strengths of the proposed approach are that it explicitly accounts for and aggregates knowledge uncertainty, and it capitalizes on the range of data sources usually considered by an expert. [ABSTRACT FROM AUTHOR]

The conservation and management of mobile species, populations and dynamic habitats, presents significant challenges since such species face diverse threats during various stages of their life cycle. Protected areas (PAs) are essential tools in conservation efforts, aiming to preserve native species and their habitats. However, larger mobile animals, such as the Bonelli's eagle (Aquila fasciata), may require much larger areas outside PAs for essential life moments, including foraging, resting, and wintering. As a result, the efficacy of PAs in conserving such species may be questionable. We designed an experiment in an eastern Spain PA that is home to nesting Bonelli's eagles to determine if increasing food availability through experimental feeding within the PA could result in an effective reduction of space use outside the protected area by the eagles and lead to reduce death risk. Over the period of 2016 to 2021, we tracked 10 Bonelli's eagles from six different territories using GPS-GSM transmitters. We evaluated their space use before, during, and after the feeding experiment. Our results indicate that the availability of food within PAs restricted the eagles' movement, resulting in a higher concentration of locations inside the PAs. The eagles spent less time outside the PAs when they were fed and less time in highly human-dominated habitats. Consequently, this reduced mortality risks that were higher outside the PAs. Our findings suggest that management decisions aimed at increasing food availability within PAs, could be critical in conserving endangered species populations such as the Bonelli's eagle in Mediterranean landscapes. [Display omitted] • Availability of food within PAs restricted the eagles' movement. • Eagles spent less time on human-dominated habitats when they were fed. • Increasing food availability within PAs could improve its role in conservation. • Improving natural prey populations could be the key of predators' conservation. • Several predator endangered species can benefit from this PAs management. [ABSTRACT FROM AUTHOR]

The habitat requirements and biology of the nesting Bonelli’s Eagle (Aquila fasciata) in the Moulouya river gorges of southwestern Middle Atlas were studied from 2005–2015. Fifteen to fifty-eight Bonelli’s Eagle territories were occupied in one decade and produce in averaged 1.34 fledglings per occupied site. Population of Bonelli’s Eagles in the Moulouya river gorges seems healthy, though much of the apparent growth in population must be attributed to the increase in Houbara Buastard (Chlamydotis undata), Black-bellied Sandgrouse (Pterocles orientalis) and Barbary Partridge (Alectoris barbara) in an area of 80.000 km² near the study area were a conservation and hunting game reserve was established.

In the current study we present data collected during the last two decades on the island of Crete (Greece) regarding the nesting habitat of two sympatric species namely the Golden Eagle (Aquila chrysaetos) and the Bonelli’s Eagle (Aquila fasciata). The factors that determine the species nest site selection were identified via a logistic regression model and nesting habitat suitability maps were constructed by using maximum entropy models and a Geographic Information System. At the spatial scale considered, the best predictors of nesting habitat were topographical variables such as altitude and slope indicative for the requirement of rugged terrain. The predictive maps represented by the subset of topographic variables were also able to predict nest-site selection by both species more adequately than subsets of bioclimatic or human disturbance variables. Based on the overlap of the available nesting habitat of the two eagle species, an ecological separation was detected most probably related to their diet spectrum and consequently foraging range. Compared to the Golden Eagle the Bonelli’s Eagle was found breeding on lower altitude, more often on sea cliffs or the ends of gorges and in the periphery of mountain areas. In the latter case human-induced mortality and land use changes are regarded as significant factors for the observed pattern.

Abstract: Natal or prebreeding dispersal is a key driver of the functioning, dynamics, and evolution of populations. Conditions experienced by individuals during development, that is, rearing conditions, may have serious consequences for the multiple components that shape natal dispersal processes. Rearing conditions vary as a result of differences in parental and environmental quality, and it has been shown that favorable rearing conditions are beneficial for individuals throughout their lives. However, the long‐term consequences of rearing conditions on natal dispersal are still not fully understood in long‐lived birds. In this study, we aim to test the following hypotheses to address the relationship between rearing conditions and certain components of the natal dispersal process in Bonelli’s eagle (Aquila fasciata): (1) The body condition of nestlings depends on the quality of the territory and/or breeders; and (2) the survival until recruitment, (3) the age of recruitment, and (4) the natal dispersal distance (NDD) all depend on rearing conditions. As expected, nestlings reared in territories with high past productivity of chicks had better body condition, which indicates that both body condition and past productivity reflect the rearing conditions under which chicks are raised. In addition, chicks raised in territories with high past productivity and with good body condition had greater chances of surviving until recruitment. Furthermore, birds that have better condition recruit earlier, and males recruit at a younger age than females. At last, although females in good body condition exhibited higher NDD when they recruited at younger ages, this pattern was not observed in either older females or males. Overall, this study provides evidence that rearing conditions have important long‐term consequences in long‐lived birds. On the basis of our results, we advocate that conservation managers work actively in the promotion of actions aimed at improving the rearing conditions under which individuals develop in threatened populations. [ABSTRACT FROM AUTHOR]

Abstract: Illegal trade in wildlife has been identified as one of the main challenges to wildlife conservation. In 2010, an illegal trade‐ring trafficking in birds of prey was uncovered in Sicily (southern Italy). This illegal trade targeted the three most endangered species in Italy: Bonelli's eagle Aquila fasciata, Lanner falcon Falco biarmicus and Egyptian vulture Neophron percnopterus, all of them long‐lived territorial raptors threatened with extinction across their European distribution. Illegal harvest primarily involved young birds and eggs taken from nests. After the discovery of these activities, surveillance camps and camera traps connected to the mobile Global System for Mobile communications network were established in nine Bonelli's eagle breeding sites in which illegal harvest was reported. Surveillance activities resulted in a sharp reduction in illegal harvest that has contributed to the recent increase in population size and number of breeding pairs of Bonelli's eagle in the island. This population represents 95% of the entire Italian population and is catalogued as Critically Endangered in this country. Importantly, our results highlight the impact of illegal harvest on the population dynamics of endangered species as demonstrated by a population viability analysis. This is particularly important in the case of insular species for which demographic recovery due to immigration from other geographic areas is unlikely. Systematic patrols by forestry police authorities, a resolute application of Convention on International Trade in Endangered Species legislation via legal punishment, and the requirement of including all live captive specimens used for falconry in an obligatory DNA data bank would contribute to reducing the risk of extinction for small populations of endangered species of birds of prey. [ABSTRACT FROM AUTHOR]

Lead is highly toxic for wildlife, with pernicious consequences especially in long-lived predators. The causes of lead ammunition ingestion in Bonelli's eagle ( Aquila fasciata ) and its effects on breeding success were studied in one of the most important populations of this endangered species in Europe. Regurgitated pellets belonging to different pairs from 2004 to 2014 were analyzed, both in the breeding (1363 pellets from 12 territories) and non-breeding (172 pellets from 9 territories) seasons. From these territories, 57 molted feathers to study lead contamination were analyzed, and breeding success was monitored for 41 breeding attempts. The occurrence of lead shots in pellets was detected using X-ray photographs. Pellets were also used to describe eagle diet. Lead shots in pellets were present in 83.3% of the territories. The frequency of occurrence of lead shots in pellets (2.81% in spring and 1.31% in autumn) was primarily related to the consumption of red-legged partridge in the breeding season (when partridges are hunted from blinds using calling lures), and secondarily to rabbit consumption in the non-breeding season (coinciding with the main hunting season). Thus, our results indicate that injured small-game were the main source of lead contamination in the Bonelli's eagle. For the first time for a raptor species, a positive relationship between the frequency of occurrence of lead shots in pellets and lead concentration in eagles' feathers has been documented. Lead concentration in feathers (mean ± SD: 816 ± 426 μg kg − 1 , with no sex-related differences) was high for a species that rarely eats carrion or aquatic birds (the main prey-related lead source for raptors). This had negative effects on breeding success, which could jeopardize Bonelli's eagles in other European populations that are sustained by juvenile dispersal from the study population. Our work shows that some game modalities pose a potential threat to endangered raptors. [ABSTRACT FROM AUTHOR]

Reintroductions have been increasingly used for species restoration and it seems that this conservation tool is going to be more used in the future. Nevertheless, there is not a clear consensus about the better procedure for that, consequently a better knowledge of how to optimize this kind of management is needed. Here we examined the dynamics of released long-lived bird populations (lesser kestrel, Falco naumanni, Bonelli's eagle Aquila fasciata, and bearded vulture Gypaetus barbatus) in object-oriented simulated reintroduction programs. To do that, number of young per year and number of years of released necessary to achieve a successful reintroduced population were calculated. We define a successful reintroduction as one in which when the probability of extinction during two times the maximum live-span period for the species (20, 50, and 64 years respectively) was less than 0.001 (P<0.001) and they showed a positive trend in population size (r>0.00). Results showed that a similar total number of young (mean 98.33±5.26) must be released in all the species in all the scenarios in order to get a successful reintroduction. Consequently, as more young per year are released the new population is going to be larger at the end of the simulations, the lesser the negative effects in the donor population and the lowest the total budget needed will be. [ABSTRACT FROM AUTHOR]

The habitat selection of 14 individual breeding Bonelli's eagles equipped with satellite tracking devices was evaluated using a multiscale approach during different periods of the annual cycle over 8 years. We studied whether habitat structure and prey availability influence habitat use through the use of vegetation templates and censuses of potential prey. The results showed heterogeneous selection of wooded, rocky, and scrub areas alternating with agricultural areas at a regional scale. At the home range scale, forests and scrubland were mainly selected over the entire year, except during the breeding season, when, surprisingly, humanized areas were selected. Although Bonelli's eagle is considered a forest raptor, during the breeding season they select other types of habitat (i.e., urban areas and dense scrub). This may be related to the high prey availability (especially pigeons) in these areas. Because habitat selection differs at different scales, understanding the effects of this plasticity may be necessary to establish protected areas including urban areas and implement habitat management actions. [ABSTRACT FROM AUTHOR]

In recent years, long-term studies based on movement monitoring tools have improved our knowledge about spatial ecology and home range behaviour of endangered species. In order to study individual spatial-temporal variations in size, use and fidelity of home ranges and other spatial parameters (kernel at different levels), and determine the influence of sex and different annual periods in these variations, 17 adult breeders (of both sexes) of an endangered territorial raptor, Bonelli's Eagle ( Aquila fasciata), were equipped with GPS satellite transmitters and tracked over a 7-year period in Aragón (northeast Spain). The home range (kernel 95 %) of these eagles showed high individual variations as well as other spatial parameters (kernels 75, 50 and 5 %). No interannual variations for the same individual were found. Females changed home range size and use during the year, it being different in the breeding season. Home range fidelity was high for all individuals (overlap 76.18 %) over the three annual periods in all years. Nevertheless, fidelity to nesting areas was low (only 30 %) during the same periods. This work highlights the importance of long-term monitoring studies to elicit information on home range behaviour for developing accurate conservation guidelines. Maintenance of home range size and fidelity across years assures that the adoption of any conservation management plan would have a lasting impact over time. In addition, protection zones should be increased to critical areas (kernel 75 %) and restriction of specific activities causing disturbance during the breeding season should be implemented. [ABSTRACT FROM AUTHOR]

Identifying the priority habitats of endangered species is crucial to implementing effective conservation actions. We characterize the key habitats used by Bonelli's Eagle Aquila fasciata, an umbrella and flagship species that is endangered in Mediterranean countries. We radiotracked 17 breeding individuals (10 males and seven females) in Catalonia ( NE Iberian Peninsula) and used compositional analysis to determine the key habitats in home-ranges of both sexes. The main habitats identified within the home-range area were scrubland, coniferous forests, cropland, sclerophyllous forests, rock outcrops and urban areas, with little difference in habitat use between the sexes. Bonelli's Eagles preferred rocky habitats as breeding areas and scrubland as foraging areas, as these hold the highest abundance of their main prey, Rabbits Oryctolagus cuniculus and Red-legged Partridges Alectoris rufa. Habitat selection varied seasonally in foraging areas: scrubland was the most preferred habitat type during the breeding season, whereas rocky areas were preferred during the non-breeding season (although scrubland was also highly selected). Urban areas were avoided both as breeding and as foraging areas. Home-range size was inversely correlated with the proportion of scrubland, suggesting that this is a key habitat for Bonelli's Eagle. To conserve this species effectively, policies that ensure the preservation of the cliffs used as breeding sites, as well as suitable management of the scrubland used for foraging, should be implemented in the areas inhabited by this species. The promotion of traditional land uses and management techniques that will enhance open areas in Mediterranean landscapes should in the future play an essential role in the conservation of Bonelli's Eagle in Mediterranean habitats. [ABSTRACT FROM AUTHOR]

The article presents a case study on the occurrence of two events of siblicide in Bonelli's Eagle (Aquila fasciata) which caused by its aggressive behavior. Topics discussed include decrease in the fertility rates and prey availability, increase in the mortality rates, resulting death of nestlings, impact of poor environmental conditions, removal of upper area skin and effect of aggression.

The exposure to persistent pollutants such as organochlorine compounds (OCs) or metals has been associated with declines in top predator populations, which can accumulate high amounts of these pollutants from their prey. However, understanding how variation in OC and metal accumulation in wild species affects their biochemical and physiological responses is a big challenge, especially for endangered predators like the Bonelli's eagle ( Aquila fasciata ). This bird of prey is an interesting study model because the differences in diet composition among populations and territories can account for important pollutant uptake variations. We compared OC and metal accumulation in blood of Bonelli's eagle nestlings from three populations across Spain as a function of origin, age class (nestlings vs. adults), sex and number of siblings per nest, and related accumulation patterns to responses indicative of body condition, biochemistry and antioxidant status. Nestlings from Catalonia, the most industrialized area, showed the highest concentrations of PCBs and arsenic, and the lowest concentrations of zinc. The two former substances, together with DDTs, exerted an overall influence on nestling's physiology. PCBs and arsenic were associated with reduced retinol levels, pointing to oxidative damage in exposed individuals, which was also consistent with the low zinc levels in individuals from the polluted region. Increased plasma DDT levels were related to reduced body condition and lower levels of triglycerides. Mercury accumulation in Castile and Leon was higher in nestlings that were alone in the nest than in nestlings that shared it with a sibling; this suggests an increased mercury uptake from secondary prey in territories where preferred prey (i.e. rabbits) are scarce, which are also the territories where productivity is reduced. Overall, the results reveal a spatial variation in pollutant accumulation patterns and associated physiological effects, and suggest the major role that territory quality may have in such patterns. [ABSTRACT FROM AUTHOR]

1. Mortality caused by power lines is a conservation problem for many vulnerable bird species. Many large species are especially threatened by electrocution as they frequently perch on pylons leading to electrocution that typically causes death. Electrocution mitigation measures have been implemented to protect several species; however, a resulting decrease in mortality due to these measures has not previously been demonstrated at the population scale. 2. In this study, we used data from a long-term capture-recapture programme (combining resightings of live birds and recovery of dead birds) carried out on the French population of the Bonelli's eagle Aquila fasciata from 1990 to 2009 to estimate the impact of the insulation of power lines on key demographic rates. 3. We found that the survival probability of all age classes increased after the insulation of dangerous power lines, due to a decrease in mortality caused by electrocution. This decrease was partially compensated for by an increase in other causes of death. 4. Our findings show that insulation of power lines has a strong positive impact on juveniles and immature birds and a lesser impact on adults. The overall increase in survival due to power line insulation led to a sharp increase in predicted population growth rates (from 0.82 to 0.98), although our findings still suggest that the population is not self-sustaining. Elasticity values indicate that adult survival is the key parameter in the population dynamics of this species, and since adult mortality caused by electrocution seemed close to zero, our ability to act on this parameter is limited. 5. This study demonstrates that insulation of power lines is relevant for the conservation of large bird species at a population scale as it allows the survival rate of all age classes to increase and thus in turn has a strong positive impact on population growth rates. 6. Synthesis and applications. We demonstrated that mortality rates induced by electrocution are considerable and have major consequences for the population viability of birds. We also demonstrated that electrocution mitigation measures can lead to a sharp increase in survival through reducing mortality from electrocution leading to improved population viability. In the light of these results, there is an urgent need that conservationists contact power line stakeholders not only to urge them to generalize retrofitting actions but also, in planning new infrastructure development, to plan for less harmful power lines, since this will be far less costly than developing a posteriori mitigation actions. [ABSTRACT FROM AUTHOR]

Electrocution on power lines negatively affects a wide range of groups of birds. Nevertheless, the overall demographic consequences of electrocution are still poorly understood. Typically, little demographic data is available for endangered species and so approaches aimed at guiding conservation measures that bear in mind this uncertainty are urgently required. In the present study, we develop a procedure based on population modeling that is useful both for obtaining unbiased estimates of mortality caused by electrocution and for estimating the mitigation effort required to restore threatened populations — even if uncertainty regarding parameter estimates exists. We used as a case study the Bonelli's eagle ( Aquila fasciata ) population in the NE Iberian Peninsula. Firstly, we used multievent models to estimate mortality while accounting for imperfect detection and uncertainty in state assignment. The fraction of mortality caused by electrocution ( α ) was not directly estimable from the multievent models and so to estimate this parameter we developed a method that used in addition basic monitoring information. Accordingly, α was estimated at 0.26 and 0.62 for, respectively, territorial and non-territorial individuals in the period 2008–2014. Secondly, we applied viability analysis to gauge the effort that would be required to mitigate electrocution and guarantee population self-sustainability. Our results highlight the fact that even low levels of electrocution can drive a local population to extinction. Overall, our study establishes a framework for estimating the demographic effects of electrocution and provides conservation managers with information on the effort needed to mitigate human-induced mortality and restore threatened populations. [ABSTRACT FROM AUTHOR]

The article presents a study related to predation of a Eurasian Eagle-owl. Topics discussed include super predation, defined as an interaction in which a predator kills and eats another predator; super predation in Eurasian Eagle-Owl; and species that have been recorded killing Eurasian Eagle-Owls such as Golden Eagles (Aquila chrysaetos) in Sweden, Finland, and Mongolia.

Bonelli's eagle ( Aquila fasciata ) is a large bird of prey that breeds in warm regions of the Palearctic. In Europe, it is mainly found in the Mediterranean region, in open or partially-open landscapes in mountainous areas. They normally feed on mammals, up to the size of a hare, medium-sized birds and large reptiles. The remains of Bonelli's eagles have been found at Pleistocene archaeological sites, raising the possibility that they were active bone accumulating agents in caves and shelters, a practice evidenced by contemporary studies that show their nests are usually located on rocky cliffs. Taphonomic studies on prey remains consumed by these raptors do not exist and their role in bone accumulations at archaeological sites is not understood. We analyse non-ingested bone remains and pellets recovered at well-known Bonelli's eagle nests situated in the south of Spain and Portugal with the aim of characterising their accumulations. Specifically, we detail taxonomic and anatomical representation, bone breakage, beak marks and digestion damage. Results show that European wild rabbit ( Oryctolagus cuniculus ), red-legged partridge ( Alectoris rufa ) and pigeons ( Columba spp.) are the dominant prey. The taphonomic pattern varies depending on the type of prey and the origin of skeletal materials (non-ingested versus pellets). Comparisons with other agents of bone accumulation (birds of prey and terrestrial carnivores) suggest that the taphonomic signature of Bonelli's eagle differs from most other predators. [ABSTRACT FROM AUTHOR]

This paper presents the first study of foraging behaviour and hunting success in Bonelli's Eagle. Attack success was modelled as a function of biological and environmental variables using observations made during a long-term monitoring. The overall attack success was 28.2%, based on 110 attack observations recorded between 1985 and 2008 in southeastern Spain. Group size of prey was the most explicative independent variable, indicating that the probability of attack success declined with increasing prey group size. Surprise was the main and most successful attack mode, mainly on preys foraging on the ground. The probability of success in surprise and non-surprise attacks probably declined with prey group size due to the effects of vigilance and confusion, respectively. The best model for attack success also suggested that attacks were more likely to be successful when directed at prey in areas with low bush canopy cover. This finding highlights the importance of open habitat types which provide foraging opportunities for the Bonelli's Eagle. Management measures for increasing open habitats in territories may create a habitat structure more favourable for prey detection by Bonelli's Eagles. [ABSTRACT FROM AUTHOR]

Diet analyses are central to the study of avian trophic ecology, and stable isotope analyses have made an increasing contribution in the last two decades. Few isotopic studies have assessed the diet of raptor species, which are more frequently analysed by conventional diet methods such as pellet analysis. In this study, we compare prey consumption estimates of nestling Bonelli's Eagles Aquila fasciata from conventional pellet analysis (in terms of items and biomass) and stable isotopic mixing models ( SIAR) using δ13C, δ15N and δ34S of feathers. The pellet analysis showed that European Rabbits Oryctolagus cuniculus, pigeons (mainly Common Wood Pigeons Columba palumbus and Domestic Pigeons Columba livia dom.), Red-legged Partridges Alectoris rufa, passerines, Yellow-legged Gulls Larus michahellis and Eurasian Red Squirrels Sciurus vulgaris were the main prey, so they were selected for diet reconstructions in SIAR. At the population level, mean prey consumption estimates were similar for pellets (both items and biomass) and SIAR. At the territory level, the weighted kappa statistic showed good ordinal scale agreement in main prey consumption between items or biomass and SIAR. Although the intraclass correlation coefficient showed poor method agreement when considering all prey in the same analysis, the intraclass correlation coefficients for each prey category showed significant agreement between pellets and SIAR when estimating the consumption of Rabbits, pigeons and Gulls, with lower agreement for passerines and Squirrels. Lastly, there was poor method agreement for estimates of Partridges. Our results suggest an overall agreement between the pellet analysis and SIAR when estimating nestling Bonelli's Eagle diet at both the population and, to a lesser extent, the territory level, supporting the usefulness of isotopic mixing models when identifying the terrestrial and marine components of raptor diets. [ABSTRACT FROM AUTHOR]

In bird species that have a high movement capacity, dispersal may connect subpopulations over vast geographical regions, with important consequences for the design of conservation management strategies. Here we used a molecular approach to infer the patterns and rates of dispersal among eight Mediterranean subpopulations of the endangered Bonelli's Eagle, based on 245 individuals screened at 17 microsatellite loci. There was moderate genetic differentiation between subpopulations sampled in the western (Iberia and Morocco) and eastern (Cyprus) Mediterranean, whereas differentiation among subpopulations in the former region was weak to moderate and followed a pattern of isolation by distance. Within the western Mediterranean, the small, peripheral and ecologically unique population of southwest Portugal had the lowest genetic diversity and the highest differentiation. The remaining subpopulations formed two loose clusters, one including Morocco and southwest and eastern Spain, and the other northeast Portugal and western and central Spain. Few recent migrants were detected, and they originated primarily from adjacent subpopulations. Our findings suggest that western Mediterranean Bonelli's Eagles may have a large-scale metapopulation structure, with subpopulations connected to some extent by distance-dependent dispersal, probably influenced by natal philopatry and the geographical configuration of subpopulations. The combination of marked ecological and genetic divergence suggests that the peripheral subpopulation of southwest Portugal may be regarded as a distinct management unit. [ABSTRACT FROM AUTHOR]

The article discusses research on the Bonelli's Eagle or Aquila (A) fasciatus found in Cyprus. It notes that the A. fasciatus is endangered in Europe with ten active nests discovered in the Pendactylos Mountains in 2011 and 2012. The species feeds opportunistically on a diet of Black Rats and has been the target of hunters. The International Union for Conservation of Nature has included the Bonelli's Eagle in the Red List of threatened species due to its wide global distribution.

Population viability analysis (PVA) has become a basic tool of current conservation practice. However, if not accounted for properly, the uncertainties inherent to PVA predictions can decrease the reliability of this type of analysis. In the present study, we performed a PVA of the whole western European population (France, Portugal, and Spain) of the endangered Bonelli's Eagle (Aquila fasciata), in which we thoroughly explored the consequences of uncertainty in population processes and parameters on PVA predictions. First, we estimated key vital rates (survival, fertility, recruitment, and dispersal rates) using monitoring, ringing, and bibliographic data from the period 1990-2009 from 12 populations found throughout the studied geographic range. Second, we evaluated the uncertainty about model structure (i.e., the assumed processes that govern individual fates and population dynamics) by comparing the observed growth rates of the studied populations with model predictions for the same period. Third, using the model structures suggested in the previous step, we assessed the viability of both the local populations and the overall population. Finally, we analyzed the effects of model and parameter uncertainty on PVA predictions. Our results strongly support the idea that all local populations in western Europe belong to a single, spatially structured population operating as a source-sink system, whereby the populations in the south of the Iberian Peninsula act as sources and, thanks to dispersal, sustain all other local populations, which would otherwise decline. Predictions regarding population dynamics varied considerably, and models assuming more constrained dispersal predicted more pessimistic population trends than models assuming greater dispersal. Model predictions accounting for parameter uncertainty revealed a marked increase in the risk of population declines over the next 50 years. Sensitivity analyses indicated that adult and pre-adult survival are the chief vital rates regulating these populations, and thus, the conservation efforts aimed at improving these survival rates should be strengthened in order to guarantee the long-term viability of the European populations of this endangered species. Overall, the study provides a framework for the implementation of multi-site PVAs and highlights the importance of dispersal processes in shaping the population dynamics of long-lived birds distributed across heterogeneous landscapes. [ABSTRACT FROM AUTHOR]

The French population of the Bonelli's eagle Aquila fasciata has suffered a sharp decline over the last decades, resulting in the implementation of several conservation actions since 1990. In parallel, a capture-recapture (CR) program has been conducted to monitor the population. Field practitioners suspected that certain breeding sites were responsible for most of the adult deaths and were interested in confirming this hypothesis in order to focus their actions on these particular sites. Our study sought to determine whether there was indeed a quantifiable difference in the quality of the eagle's breeding sites. Since Bonelli's eagles are highly faithful to their breeding site, we tested whether the turnover of breeding individuals observed at different sites resulted from a mixture of two different turnover rates. We also used the recent multi-event CR modeling approach to test whether or not we could detect adult survival heterogeneity in the population. Our study revealed that there was a difference in breeding-site quality a decade ago, before large efforts were made to insulate high-voltage power lines, but failed to detect a difference in breeding-site quality more recently. No survival heterogeneity was detected. These counterintuitive results could be due to a lack of statistical power or because the conservation actions performed over the last 20 years cloud the issue. When no a priori information is available on habitat quality differences, we advocate for the use of a mixture modeling approach since it is consistent and fairly general. [ABSTRACT FROM AUTHOR]

Animal movement patterns and use of space depend upon environmental resources (i.e., food availability), and on conspecific and interspecific interactions. We studied the home range of seven territorial Bonelli's Eagles ( Aquila fasciata) tracked by GPS satellite telemetry over a period of 4-5 years to determine home range characteristics and annual and individual variations. Bonelli's Eagles hold an annual home range of Minimum Convex Polygon (MCP) = 205.6 km (range 44.7-704.8 km) and Kernel 95 % = 44.4 km (range 31.8-91.9 km). Eagles showed slight temporal variation in home range sizes, but a wide variation in use of space. Only 27.3 % of the accumulated home range was used during all seasons, while 30.3 % was used only during a single season. Areas around the nest, main hunting areas and roosting sites were utilised regularly every year in both breeding and non-breeding seasons. Accumulated home ranges were stabilised in year 3 of monitoring. Individuals displayed strong territoriality, even in non-breeding seasons, although eagles also made long trips (>15 km) well beyond their territorial boundaries, as assessed for the first time by GPS satellite telemetry. The overlap was slight for two adjacent pairs. In addition, we noticed a strong relationship between topographical landmarks and home range segregation. This study reinforces the idea that combining information on season patterns, conspecific distribution and topography can help define both the shape and size of home ranges more realistically. [ABSTRACT FROM AUTHOR]

Background: The population of Bonelli's eagle (Aquila fasciata) has declined drastically throughout its European range due to habitat degradation and unnatural elevated mortality. There are less than 1500 breeding pairs accounted for in Europe, and the species is currently catalogued as Critically Endangered in Italy, where the 22 territories of Sicily, represent nearly 95% of the entire Italian population. However, despite national and European conservation concerns, the species currently lacks a specific conservation plan, and no previous attempts to estimate the risk of extinction have been made. Methodology/Principal Findings: We incorporated the most updated demographic information available to assess the extinction risk of endangered Bonelli's eagle in Italy through a Population Viability Analysis. Using perturbation analyses (sensitivity and elasticity), and a combination of demographic data obtained from an assortment of independent methods, we evaluated which demographic parameters have more influence on the population's fate. We also simulated different scenarios to explore the effects of possible management actions. Our results showed that under the current conditions, Bonelli's eagle is expected to become extinct in Italy in less than 50 years. Stand-alone juvenile mortality was the most critical demographic parameter with the strongest influence on population persistence with respect to other demographic parameters. Measures aimed at either decreasing juvenile mortality, adult mortality or decreasing both juvenile and adult mortality resulted in equivalent net positive effects on population persistence (population growth rate λ>1). In contrast, changes aimed at increasing breeding success had limited positive effects on demographic trends. Conclusions/Significance: Our PVA provides essential information to direct the decision-making process and exposes gaps in our previous knowledge. To ensure the long-term persistence of the species in Italy, measures are urgently needed to decrease both adult mortality due to poaching and juvenile mortality due to nest plundering, the top ranking mortality causes. [ABSTRACT FROM AUTHOR]