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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]

Large‐scale rewilding has been proposed as an effective method to combat the global biodiversity crisis, although there is a lack of data to support this. Rewilding generally refers to a process that allows nature to recover by reducing human interference, without the predefined end‐goal that more traditional restoration projects usually have. The Chernobyl Exclusion Zone (CEZ) is perhaps the most famous example of passive rewilding (rewilding with little or no management), but until now, most research has focused on the impact of radiation on wildlife rather than on rewilding. Here, we analyze species composition change of raptors in the Belarusian CEZ over a 22‐year period, starting 12 years after the accident, alongside national raptor monitoring data. Generalist and farmland‐associated mesopredators, super‐abundant at the beginning of our study, strongly declined, as open habitats (former agricultural land) rewetted or became overgrown. Increase in waterlogged areas saw wetland specialists increase in abundance, including two species locally extinct from the area before the accident: Greater Spotted Eagle (Endangered in Europe) and White‐tailed Eagle. Greater Spotted Eagles are an indicator of wetland habitat quality, and while declining throughout Europe in recent decades, they have increased from zero to at least 13 pairs, over the whole Belarusian CEZ. Our research is evidence that rewilding could be an effective way of restoring species and species interactions found in near‐natural habitats, and if human interferences in ecological processes are reduced, a priori restoration goals and continued management are not always necessary to conserve threatened species. [ABSTRACT FROM AUTHOR]

Hybridization is a significant threat for endangered species and could potentially even lead to their extinction. This concern applies to the globally vulnerable Greater Spotted Eagle Aquila clanga, a species that co-occurs, and potentially interbreeds, with the more common Lesser Spotted Eagle Aquila pomarina in a vast area of Eastern Europe. We applied single nucleotide polymorphism (SNP) and microsatellite markers in order to study hybridization and introgression in 14 European spotted eagle populations. We detected hybridization and/or introgression in all studied sympatric populations. In most regions, hybridization took place prevalently between A. pomarina males and A. clanga females, with introgression to the more common A. pomarina. However, such a pattern was not as obvious in regions where A. clanga is still numerous. In the course of 16 years of genetic monitoring of a mixed population in Estonia, we observed the abandonment of A. clanga breeding territories and the replacement of A. clanga pairs by A. pomarina, whereby on several occasions hybridization was an intermediate step before the disappearance of A. clanga. Although the total number of Estonian A. clanga × A. pomarina pairs was twice as high as that of A. clanga pairs, the number of pairs recorded yearly were approximately equal, which suggests a higher turnover rate in interbreeding pairs. This study shows that interspecific introgressive hybridization occurs rather frequently in a hybrid zone at least 1700-km wide: it poses an additional threat for the vulnerable A. clanga, and may contribute to the extinction of its populations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 725–736. [ABSTRACT FROM AUTHOR]

We report the isolation and characterization of a highly pathogenic avian influenza A/H5N1 virus from Crested Hawk-Eagles smuggled into Europe by air travel. A screening performed in human and avian contacts indicated no dissemination occurred. Illegal movements of birds are a major threat for the introduction of highly pathogenic avian influenza. [ABSTRACT FROM AUTHOR]

Universal energy access is one of the targets of the Sustainable Development Goals (SDGs), and thus the deployment of electricity grids is expected to expand globally in the coming decades. However, the installation of power lines is not biodiversity-friendly. In particular, electrocution on power pylons is a major cause of bird mortality worldwide, including for some severely endangered species. Over the last decades, different studies have improved our understanding of the factors influencing the risk of electrocution in birds, but until now spatial gaps in our knowledge of these impacts and the factors driving global patterns of bird electrocution have not been assessed. In this study, we evaluated data from a total of 114 studies that provided information on bird mortality rates on power lines, and we analyzed the factors driving electrocution rates for all bird species, and then for all raptors and large eagles separately. Our results showed a high spatial distribution bias, as more than 80% of the studies were carried out in developed countries, mostly in Europe and North America. By contrast, no systematic studies have been found for Oceania and very few for South America and Africa. Europe showed the highest electrocution rates for birds, South America for raptor species and Africa for eagles. Socio-economic factors best-explained bird and raptor electrocution rates, while climate-related factors were the most influential for eagles. Contrary to our expectations, factors related to pylon design were the least influential on overall electrocution rates. Variables related to study design showed highly variable levels of influence. This could be due to the lack of standardized protocols. Although bird electrocution has been extensively studied, there are large areas where no studies have been carried out or for which data are inaccessible. This could be because in these areas the power distribution network is still sparse, or that most studies are not public or accessible to the international community. Researchers and managers should promote the publication of studies, as awareness is the first step to solving these problems. The factors identified could be applied globally to the design and planning of power grids and the identification of mortality hotspots. This would help mitigate the creation of new mortality hotspots, especially in developing countries where the installation of new power lines has been growing exponentially in recent years., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Lead poisoning from spent ammunition is known to affect many avian species. Birds of prey ingest lead when feeding on game shot with lead gunshot or bullets. Raptors with scavenging habits are particularly vulnerable to ingesting lead in areas with intensive hunting and are good indicators of the risk of poisoning from lead ammunition. To assess how much facultative and obligate avian scavengers suffer lead contamination in south-central Europe, between 2005 and 2019 we collected and analysed 595 tissue samples from 252 carcasses of 4 species (golden eagle, bearded vulture, griffon vulture, cinereous vulture). Lead concentrations in organs showed a similar pattern across species with long and small bones revealing the highest median values (5.56 and 6.8 mg/kg w.w., respectively), the brain the lowest (0.12), and the liver and kidney the intermediate (0.47 and 0.284). Overall, 111 individuals (44.0%) had lead concentrations above background thresholds in at least one tissue (i.e. >2 mg/kg w.w. in soft tissues, >8.33 in bone) and 66 (26.2%) had values indicating clinical poisoning (>6 mg/kg w.w. in liver, >4 in kidney, >16.6 in bone). Tissue lead concentrations and incidence of clinical and sub-clinical poisoning were higher in golden eagles and griffon vultures than in bearded and cinereous vultures, likely due to different feeding habits. In all species we found a rapid increase in lead values with age, but differences between age classes were significant only in the golden eagle. Birds with lead fragments in their digestive tract, as detected by X-rays, had higher median lead concentrations, suggesting that hunting ammunition is the main source of lead poisoning. Our results imply that lead impacts the demography of these long-lived species with delayed sexual maturity and low reproduction rate. A rapid transition towards lead-free bullets and gunshot is therefore required across Europe., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Lead contamination is a widely recognised conservation problem for raptors worldwide. There are a number of studies in individual raptor species but those data have not been systematically evaluated to understand raptor-wide lead exposure and effects at a pan-European scale. To critically assess the extent of this problem, we performed a systematic review compiling all published data on lead in raptors (1983-2019) and, through a meta-analysis, determined if there was evidence for differences in exposure across feeding traits, geographical regions, between hunting and non-hunting periods, and changes over time. We also reviewed the impact of lead on raptors and the likely main source of exposure. We examined 114 studies that were unevenly distributed in terms of time of publication and the countries in which studies were performed. Peer-reviewed articles reported data for 39 raptor species but very few species were widely monitored across Europe. Obligate (vultures) and facultative scavengers (golden eagle, common buzzard and white-tailed sea eagle) accumulated the highest lead concentrations in tissues and generally were the species most at risk of lead poisoning. We found no evidence of a spatial or decadal trend in lead residues, but we demonstrated that high lead blood levels relate to hunting season. Exposure at levels associated with both subclinical and lethal effects is common and lead from rifle bullets and shot is often the likely source of exposure. Overall, our review illustrates the high incidence and ubiquity of lead contamination in raptors in Europe. However, we did not find studies that related exposure to quantitative impacts on European raptor populations nor detailed studies on the impact of mitigation measures. Such information is urgently needed and requires a more harmonised approach to quantifying lead contamination and effects in raptors across Europe., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Animals living on the earth's surface are protected from the damaging effects of solar ultraviolet (UV) radiation by melanin pigments that color their integument. UV levels that reach the earth's surface vary spatially, but the role of UV exposure in shaping clinal variations in animal pigmentation has never been tested. Here, we show at a continental scale in Europe that golden eagles Aquila chrysaetos reared in territories with a high solar UV-B radiation exposure deposit lower amounts of the sulphurated form of melanin (pheomelanin) in feathers and consequently develop darker plumage phenotypes than eagles from territories with lower radiation exposure. This clinal variation in pigmentation is also explained by terrestrial γ radiation levels in the rearing territories by a similar effect on the pheomelanin content of feathers, unveiling natural radioactivity as a previously unsuspected factor shaping animal pigmentation. These findings show for the first time the potential of solar and terrestrial radiations to explain pigmentation phenotype diversity in animals, including humans, at large spatial scales.

Neandertals were top predators who basically relied on middle- to large-sized ungulates for dietary purposes, but there is growing evidence that supports their consumption of plants, leporids, tortoises, marine resources, carnivores and birds. The Iberian Peninsula has provided the most abundant record of bird exploitation for meat in Europe, starting in the Middle Pleistocene. However, the bird and carnivore exploitation record was hitherto limited to the Mediterranean area of the Iberian Peninsula. Here we present the first evidence of bird and carnivore exploitation by Neandertals in the Cantabrian region. We have found cut-marks in two golden eagles, one raven, one wolf and one lynx remain from the Mousterian levels of Axlor. The obtaining of meat was likely the primary purpose of the cut-marks on the golden eagle and lynx remains. Corvids, raptors, felids and canids in Axlor could have likely acted as commensals of the Neandertals, scavenging upon the carcasses left behind by these hunter-gatherers. This could have brought them closer to Neandertal groups who could have preyed upon them. These new results provide additional information on their dietary scope and indicate a more complex interaction between Neandertals and their environment.

Generalized feather abnormalities are rarely documented in free-living birds. Pinching off syndrome (POS) is a feather abnormality in which all remiges and retrices become malformed and are lost during the nestling stage, rendering the bird unable to fly. To determine the frequency of occurrence and geographic distribution of this syndrome in white-tailed sea eagles (Haliaeetus albicilla) in Europe, we sent questionnaires to ornithologists in 19 countries within the European range of this species. We also searched for reported cases of sea eagles with feather abnormalities that met the criteria of POS. Overall, 32 nestlings or fledglings with POS were identified between 1975 and 2006. The geographic distribution of cases was primarily restricted to 4 European countries: Germany (17 cases), Poland (11 cases), the Czech Republic (3 cases), and Great Britain (1 case). Eleven eagles from Germany and 2 eagles from the Czech Republic were examined clinically. In 15 birds in which sex was determined, 8 were female and 7 were male. From 2000 to 2005, the 5-year incidence of POS in white-tailed sea eagles in Germany was 3.5 cases per 1000 birds. Although the etiology of this syndrome in wild sea eagles is unknown, our results support a possible genetic cause.