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Intra‐Africa movements of most African migratory birds remain an enigma. We describe the migrations of Wahlberg's eagle Hieraaetus wahlbergi using GPS‐GSM transmitters on adult eagles in their South African (n = 3) and Kenyan (n = 7) breeding areas between 2018 and 2022. The dataset included 57 migratory tracks, 29 post‐breeding and 28 pre‐breeding. We found long‐distance migrants (LDMs; from South Africa) and short‐distance migrants (SDMs; from Kenya) using common non‐breeding areas centered in the Sudans and Central African Republic. The timing of annual phases was similar, but LDMs departed on their pre‐breeding migration on average later than SDMs (13 August versus 31 July) and arrived later on their breeding grounds (13 September versus 10 August). Conversely, the average departure date on the post‐breeding migration was 4 April for SDM and 23 March for LDMs. LDMs spent significantly less time of the year than SDMs on breeding grounds (44 versus 57%), and slightly but not significantly more time (40 versus 38%) on non‐breeding areas. The post‐breeding migration distance was on average 3413.9 ± 170.9 km for LDMs and 491.9 ± 158.5 km for SDMs. At non‐breeding areas, LDMs reached more northerly latitudes than SDMs, increasing the pre‐breeding migration distance to 4495.9 ± 372.5 km for LDMs versus 1701.9 ± 167.3 for SDMs. Daily flight distances back to the breeding areas averaged 153.4 ± 130.3 km for LDMs and 167.4 ± 122.3 km for SDMs and to non‐breeding areas were shorter for SDMs (124.8 ± 113.0 km) than LDMs (178.0 ± 134.4 km). Migration speed was similar across populations and for pre‐ and post‐breeding migrations. LDMs used more stopover days than SDMs. We conclude that Wahlberg's eagles from different parts of Africa have adapted their migration to differences in timing of the breeding season, distance of travel, and resources in the landscapes encountered during migration. [ABSTRACT FROM AUTHOR]

Natal dispersal is a crucial period for raptors with serious implications for individuals' survival and population demography. In this study we analyzed data from 18 GPS-tracked golden eagles in order to describe their dispersal ecology in northern Greece, where the species feeds mostly on tortoises. Young eagles in our population dispersed at 176 days post fledging, spent their first year of independence relatively close (40–60 kms) to their natal ranges and exhibited a variable temporary settlement behavior. Overall dispersal range sizes did not differ seasonally, but temporary settlement area range sizes were significantly larger in winter. Three eagles survived to territorial settlement and occupied ranges 20–60 kms from their natal areas. The application and refinement of the Scottish GET dispersal ranging model suggested that eagles used areas that had higher topographical relief and lower canopy cover during their natal dispersal. Habitat heterogeneity seems to also be influential during temporary settlement. Our study is the first to provide both such insights for golden eagles in southern eastern Europe and a method for delineating temporary settlement areas for the species. Our findings can be explained in terms of food and habitat availability. We highlight the importance of conserving heterogeneous open areas of complex topography and applying proactive management measures within temporary settlement areas for our population's conservation. [ABSTRACT FROM AUTHOR]

The hindlimbs of Accipitriformes are vital for capturing prey. Research on hindlimb musculature has primarily focused on species preferring avian and mammalian prey, whereas piscivorous species have received limited attention. This study aims to investigate the quantitative characteristics of hindlimb muscles in two piscivorous Accipitriformes, Pandion haliaetus and Haliaeetus albicilla, to discern potential muscular features associated with their specific food preference. The mass and proportion of all hindlimb muscles in both species were assessed based on their primary function (flexion or extension). A Kruskal‐Wallis test was employed to analyze possible differences in muscle mass between species. The allometric relationships between the muscles and body mass were explored with the reduced major axis method. Additionally, a study on the architectural parameters of the primary gripping muscles in P. haliaetus was conducted, using published information from other raptorial birds for comparison. The isometric scaling relationship predominated in the majority of individual muscles helping maintain a proportional relationship relative to body mass. Both species exhibited a similar pattern in terms of quantitative muscle features, implying a preservation of muscle characteristics linked to their predatory capabilities. The largest proportion of hindlimb muscle mass was dedicated to digit flexion in accordance with the grasping abilities of birds of prey. The muscles tibialis cranialis, flexor digitorum longus and flexor hallucis longus exhibited the greatest mass, high physiological cross‐sectional area values, and long fibre, categorizing them as high‐power specialists. These muscles are crucial in the flexion movements that produce the gripping action that characterizes birds of prey. Although no statistically significant differences were detected, each species displayed slightly distinct muscular characteristics, particularly in the architectural properties of the flexor muscles controlling digits II, III, and IV. These variations seem to be associated with differences in their prey preferences. [ABSTRACT FROM AUTHOR]

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]

At the top of many ecosystems, raptors, also known as birds of prey, hold major influence. They shape their surroundings through their powerful hunting skills and complex interactions with their environment. This study investigates the beak morphology of four prominent raptor species, Golden eagle (Aquila chrysaetos), Common buzzard (Buteo buteo), Peregrine falcon (Falco peregrinus) and Common kestrel (Falco tinnunculus), found in Türkiye. By employing geometric morphometric methods, we investigate shape variations in the beaks of these species to unravel the adaptive significance of their cranial structures. This analysis reveals distinct beak morphologies among the studied raptors, reflecting adaptations to their feeding habits, hunting techniques and ecological niches. The results from Principal component analysis and Canonical variate analysis demonstrate significant differences in beak morphology between the Falconiformes and Accipitriformes clades, as well as among all three groups. The overall mean beak shapes of Golden Eagles are quite similar to Common Buzzards, with both species having longer beaks. In contrast, Falcons exhibit a distinctly different beak morphology, characterized by wider and shorter beaks. Changes in beak shape can lead to changes depending on the skull. It is thought that skull shape variations among predator families may have an impact on beak shape. These findings highlight the importance of integrating morphometric analyses with ecological insights to enhance our understanding of the evolutionary processes shaping raptor beak morphology. [ABSTRACT FROM AUTHOR]

Although lethal interactions between wolves and other apex carnivores have been reported for a handful of species, the killing or consumption of wolves by free-ranging golden eagles has rarely been reported. Here, we present four opportunistic field observations documenting the consumption of a wolf pup by free-ranging golden eagles and predatory behavior of eagles towards wolf pups. Although we could not confirm the killing and consumption of wolves by eagles in a single predatory event, actual predation seems plausible based on our observations. We hypothesize that these intraguild apex predators' interactions, consisting on a smaller raptor predator attacking or consuming a lager mammal and social predator, are rare events, but provide valuable information on potential relationships across keystone apex predators. [ABSTRACT FROM AUTHOR]

In this study, mercury (Hg) concentrations were detected in feathers of golden eagle (Aquila chrysaetos), a bird that typically inhabits alpine and forest areas. The mercury rates in feathers were compared in two groups of eagles: first, estimated home range (breeding, hunting, etc.) was located only in forest and lowland meadow habitats; second, the home range also included alpine habitats—rocks and meadows. Consequently, mercury concentration based on the feather typology were observed and the mercury levels in feathers were also compared among different Slovak Western Carpathian districts. It was found that there was no significant difference between groups classified by elevation level, which we attribute to the fact that eagle hunting territories are broad, so that alpine-dwelling and forest-dwelling eagles do not only reflect the pollution of the environments they typically inhabit. Non-significant differences were found also within different feather types, which means that the type of feather is not crucial for tracking mercury in eagle feathers. As the measurement of feather appears to be a simple and non-invasive method, the detection of non-significant differences in diverse types of golden eagle feathers provides useful knowledge for the future environment monitoring. The average mercury concentration measured in eagle samples was lower than the mercury concentration causing health complications among birds of prey. Our assumption that due to past mining activity in the Spiš region, the highest concentration in this region would be observed was confirmed. [ABSTRACT FROM AUTHOR]

Food supply stands out as one of the most critical drivers of population demographics by limiting reproductive rates. In this study, we assessed fluctuations in diet composition and monitored various reproductive parameters over a nine-year period in a Golden Eagle population in an Eastern European peatland. The identification of 2439 prey specimens from 84 species revealed that the studied eagles primarily preyed upon birds (constituting 78.3% of prey numbers and 67.2% of prey biomass) and less on mammals (21.6% and 32.8%, respectively). Grouse emerged as the most important prey group (31% and 27%), followed by waterfowl (17%) and hares (8% and 14%). The most significant prey species, both in terms of numbers and weight, were the Black Grouse, Mountain Hare, Common Crane, and Capercaillie. The share of the Black Grouse decreased, while those of the White-fronted Goose, Roe Deer, and hares increased. The food niche, as measured by the Levins' index, was broad (6.6), and it expanded during the study. On average, 58.3% of Golden Eagle pairs initiated breeding annually, with 69.1% successfully completing it, and 0.41 young per occupied territory were produced annually; there was pronounced interannual variation in reproductive performance. These fluctuations were associated with the shares of White-fronted Goose, Capercaillie, Mountain Hare and Roe Deer in the diet, suggesting that these species may be gaining increasing importance for the Golden Eagle, particularly following the decline of the Black Grouse. [ABSTRACT FROM AUTHOR]

Throughout Europe, electrocution on distribution power lines is the main cause of mortality for fledgling Bonelli's Eagles (Aquila fasciata) released into the wild through hacking. To attempt to reduce electrocutions, we subjected 17 fledglings that had not previously had any contact with power line pylons to aversive conditioning. To this end, we installed electrified barrier wires on two distribution pylons (one each of the two most common pylon types in northern Spain), which were disconnected from the electric grid. The electrified barriers, which were in place from 2020 through 2022, lightly shocked fledglings alighting on them. We compared the subsequent behavior of conditioned fledglings with that of a control sample of 19 unconditioned fledglings released between 2015 and 2019. The results suggest that conditioning results in (1) a delay in juveniles' use of distribution power line pylons as perches in the wild; (2) juveniles' avoidance of pylons in temporary settlement areas; and (3) a nonsignificant increase in juvenile survival rates during the first year of life. This approach may have applicability in other population reinforcement projects, and in areas with high concentrations (communal roosts and vulture restaurants) of other large raptors. [ABSTRACT FROM AUTHOR]

Lead is a toxic metal that produces effects on the overall health of animals, resulting in mortality at high exposures, adverse physiological and behavioral effects at lower concentrations, and population declines in many species. Scavengers and predators are more susceptible to lead toxicity because of behavioral and physiologic factors, and long lifespans increase the risk of exposure cumulatively. Bonelli's eagle (Aquila fasciata) is a long‐living predator that may have reduced breeding success because of lead exposure. We analyzed the blood lead levels of 54 wild and captive Bonelli's eagles admitted to a recovery center in Spain from May 2014 to July 2015 and the lead relationship among physiological, clinical, and environmental variables. We detected blood lead using anodic stripping voltammetry. Lead levels were below the limit of quantification (3.3 μg/dL) in 100% of captive animals (n = 22); in contrast, 21.9% of wild birds (n = 32) had higher lead levels than captive birds (P = 0.020). Among wild animals, the 2 adults tested had detectable lead, the only eagle sampled in autumn had the highest lead levels of the study (14.7 μg/dL), and 16.7% of nestlings had detectable lead levels. There is no evidence that the lead levels differ between sexes. There were no symptoms associated with lead intoxication or any correlation between lead levels and hematological or biochemical values; however, subclinical lead exposure at early ages can be harmful and could influence neurological and body development. Researchers should determine if lead could be causing damage to wildlife from early ages to determine if lead exposure affects the conservation of the threatened population of Bonelli's eagles in Spain and elsewhere. [ABSTRACT FROM AUTHOR]

The nest building and courtship behaviours of the golden eagle are poorly represented in the scientific literature. The paper reports on the first detailed description of building a new nest by a pair of golden eagles. Reciprocal pendulum flight by the pair as part of a pre-breeding courtship display is described for the first time. The "mock attack" between the members of the pair is confirmed to serve the courtship function. [ABSTRACT FROM AUTHOR]

The paper describes the observation in Belarus of an adult greater spotted eagle breeding female pale morph "fulvescens", which retained the same light colour of plumage for five successive years. The data on the presence of pale morph adult birds in the collections of some zoo museums is also analysed. [ABSTRACT FROM AUTHOR]

In territorial raptors, breeding performance and foraging behaviour are affected by territory characteristics as the abundance and availability of different prey species varies between habitats. In this study, we examined the diet of two White-tailed Eagle pairs, occupying neighbouring territories in two adjacent inland lakes in Northern Greece. We assess the diet composition of the species in the southernmost part of its European range and evaluate any intraspecific differences in the diet that may reflect resource and/or niche partitioning between territories. We found that birds and specifically waterbirds comprise the largest and quantitatively most important part of the White-tailed Eagle´s diet, with fish being the second most important prey group that was only found in the nest remains from one territory. There was high diet overlap between the two territories and when considering only avian prey our results suggest that the species predates on heavier (and the most common) waterbird species. A main factor that could be driving differences in the abundance and availability of different prey species between territories could be lake physiography, as our results point to a segregation and a subsequent resource partitioning between territories, with each pair utilizing an adjacent lake and its associated habitats. Competition and territoriality therefore seem to be important intraspecific interactions that along with prey availability could promote changes in territory size and ultimately affect individual fitness. [ABSTRACT FROM AUTHOR]

Simple Summary: Birds of prey are important predators and scavengers at the top of the food chain, but their parasite diversity has not been well studied. The aim of this study was to identify several nematode specimens found in the gizzard of a booted eagle (Aquila pennata) during necropsy. Following morphological and molecular analysis, they were identified as Physaloptera alata, a circumstance which represents the first report of this species in a booted eagle from Portugal. A new genetic sequence for this parasite is now available in GenBank for future research on birds of prey. This information is crucial for understanding the parasitological fauna of these birds in Portugal, as well as for wildlife rehabilitation centers, disease ecologists, and wildlife professionals to take appropriate measures in the event of parasitic disease. Physaloptera spp. are parasitic nematodes that infect the gastrointestinal tracts of many carnivores and omnivores. Although they are distributed worldwide, Physaloptera spp. have not been studied in raptors in Portugal. In this study, we report Physaloptera alata in a booted eagle (Aquila pennata) in Portugal. Adult nematodes were discovered in the gizzard of a young booted eagle, and morphological features were consistent with those of the genus Physaloptera. DNA was extracted and a PCR assay performed to amplify a region of the 18S small subunit of the ribosomal RNA gene and the cytochrome c oxidase subunit I gene. The resulting PCR products were Sanger-sequenced, and comparison with the available sequences in the GenBank database confirmed the initial morphological classification as Physaloptera sp. Phylogenetic analysis clustered the sequence within the Physaloptera group. The presence of this parasite in raptors from Portugal is of particular importance to wildlife rehabilitation centers, disease ecologists, and wildlife professionals. Furthermore, we produced a new genetic sequence and have added it to the GenBank database of parasites in birds of prey. [ABSTRACT FROM AUTHOR]

Aim: A current biogeographic paradigm states that climate regulates species distributions at continental scales and that biotic interactions are undetectable at coarse‐grain extents. However, advances in spatial modelling show that incorporating food resource distributions are important for improving model predictions at large distribution scales. This is particularly relevant to understand the factors limiting the distribution of widespread apex predators whose diets are likely to vary across their range. Location: Neotropical Central and South America. Methods: The harpy eagle (Harpia harpyja) is a large raptor, whose diet is largely comprised of arboreal mammals, all with broad distributions across Neotropical lowland forest. Here, we used a hierarchical modelling approach to determine the relative importance of abiotic factors and prey resource distribution on harpy eagle range limits. Our hierarchical approach consisted of the following modelling sequence of explanatory variables: (a) abiotic covariates, (b) prey resource distributions predicted by an equivalent modelling for each prey, (c) the combination of (a) and (b), and (d) as in (c) but with prey resources considered as a single prediction equivalent to prey species richness. Results: Incorporating prey distributions improved model predictions but using solely biotic covariates still resulted in a high‐performing model. In the Abiotic model, Climatic Moisture Index (CMI) was the most important predictor, contributing 76% to model prediction. Three‐toed sloth (Bradypus spp.) was the most important prey resource, contributing 64% in a combined Abiotic‐Biotic model, followed by CMI contributing 30%. Harpy eagle distribution had high environmental overlap across all individual prey distributions, with highest coincidence through Central America, eastern Colombia, and across the Guiana Shield into northern Amazonia. Main Conclusions: With strong reliance on prey distributions across its range, harpy eagle conservation programmes must therefore consider its most important food resources as a key element in the protection of this threatened raptor. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explores the use of biometric analysis to identify the sex of Bonelli's eagles, a bird species with reverse sexual dimorphism where females are usually larger than males. By using linear discriminant analysis of biometric variables, we were able to obtain equations that accurately distinguished between male and female eagles, using just two measurements. The study included 137 Bonelli's eagles, 82 nestlings and 55 adults, sampled in eastern Spain from 2015 to 2022. The validation procedure reduced the number of variables used, increasing the accuracy of sexing and saving time. Results showed that the lateral tarsus length and dorso-ventral tarsus length measurements were the most effective in distinguishing between male and female eagles of all age classes, while other variables showed some overlap between sexes. This non-invasive method has multiple applications, including estimation of sex ratio for further studies on population dynamics and extinction risk assessments, which could contribute to the conservation of this endangered species. Biometric analysis allows the sexing of most vertebrates, particularly birds. Birds of prey, and, especially, the Bonelli's eagle (Aquila fasciata), show reverse sexual dimorphism (i.e., females are usually larger than males). In contrast to blood sampling, the use of morphometrics allows sex determination using a non-invasive method, and, therefore, it facilitates fieldwork. By means of a linear discriminant analysis of biometric variables, we obtained different equations that allow the sexing of nestlings and adult Bonelli's eagles. We sampled 137 Bonelli's eagles, 82 nestlings and 55 adults in eastern Spain during the period 2015–2022. The sexes obtained after linear discriminant analysis were compared with their molecular sexing. The validation procedure of the linear discriminant equations facilitated the reduction of the number of variables used and, consequently, optimised working time and sexing accuracy. After validation, some equations showed a 100% sexing efficiency for Bonelli's eagles, particularly for adults. Our results showed that the variables with smaller overlap between the sexes were the lateral tarsus length and dorso-ventral tarsus length, particularly in nestlings. The rest of the variables showed some overlap between the sexes in both age classes. The results we obtained enable the sexing of juvenile and adult Bonelli's eagles in the field using just these two measurements. Hence, this is an easy, accurate, quick and non-invasive method with multiple applications, including in studies on population dynamics, survival analysis or extinction risk assessments, which, ultimately, could contribute to the improvement of the conservation status of this endangered species. [ABSTRACT FROM AUTHOR]

Natal dispersal of large raptors is poorly understood, despite being a crucial transitional life-cycle phase affecting gene flow and population dynamics. A research-gap rarely examined concerns how young dispersing raptors strategize movements towards first settlement on a prospective breeding territory. First territory settlement is a critical decision for a lifetime and can take several years. With such importance, large raptors should theoretically devote considerable effort to acquire accurate information during prospection. Nevertheless, when discovery of territorial opportunities may be difficult, but easier in vacant territories, we posit two extremes in strategizing prospection behaviours: (1) "Quick, grab it when available with limited reconnaissance," as opposed to (2) "Slow, waiting game with frequent reconnaissance". We analysed pre-settlement data from 37 GPS-tagged nestling golden eagles, later recorded as having settled on their first territory. The number of eagles' unique daily visits to their later settled territories was a measure of prospection intensity. We documented substantial variation in prior visits, between less than 10 to several hundred. Analyses considered several potential predictors. We expected a positive association between number of prospecting visits and natal dispersal duration, since with more time to gather information there should be more visits. We also expected fewer prospecting visits in prior vacant territories. Neither of these expectations were supported. There was a non-significant tendency for more prospection visits by males. Our study provides novel information on a seldom-studied behaviour in a large raptor. It illustrates substantial variation in prospecting behaviour, but expectations of potential drivers behind this variation were not confirmed, urging further study. [ABSTRACT FROM AUTHOR]

Muscular stomach or gizzard is one of the most important parts of gastrointestinal tract in birds for mechanical and chemical digestion and can vary depending on the bird's eating habits. In the present study, the morphology of muscular stomach in common kestrel, steppe eagle, golden eagle and imperial eagle has been investigated and compared. Materials & Methods: In this study, common kestrel (n=4), steppe eagle (n=5), golden eagle (n=4) and imperial eagle (n=6) which died because of broken leg and wing, sent to the faculty of veterinary science at Bu-Ali Sina University of Hamadan. The gizzard samples were fixed in 10% formalin buffer solution and the histological process was carried. Finally, H&E, Masson's trichrome, Orcein and PAS staining were utilized. Results: The most important difference between the stomach of steppe, golden, and imperial eagles and common kestrel was the lack of keratinous layer in the surface of stomach in eagles. The histological structure of stomach in imperial eagle was more similar to that of steppe eagle. The differences of the stomach of imperial eagle were due to the presence of a thick muscle layer in several different rows with different directions in comparison with steppe and golden eagles. Conclusions: It can be concluded that, the structure of muscular stomach in common kestrel was similar to gizzard, while the stomach in three species of eagles did not have a keratinous layer. [ABSTRACT FROM AUTHOR]

Habitat alteration is a widespread threat severely affecting large raptors because of their low density and the huge area they inhabit. In this study, we assessed whether human-driven habitat alterations mediated dietary shifts of apex predators, focusing on the Eastern imperial eagle (Aquila heliaca). Following a bottom-up conception (before–after), we evaluated the effect of grassland change on the eagle's dietary shift and breeding success. Land use patterns underwent a significant transformation over the study period, creating a large decrease in grasslands. The territories lost an average of 25.79% of their grasslands. Habitat alteration mediated dietary shifts, but had no reproductive consequences for eagles. Eagles became 1.90 times more likely to predate on northern white-breasted hedgehog and 1.62 times more likely to forage on white stork in the period after grassland alteration. The frequency of tortoises also increased, and they were 4.04 times more likely to be predated on in the years after transformation. Conversely, brown hare was 0.51 times less likely to be consumed in the grassland loss period, while this likelihood was 0.54 times lower for rodents and 0.64 times lower for the European souslik. Doves, meanwhile, were 2.73 times more likely to be predated on in the years following grassland destruction. We found that the presence and biomass of songbirds correlated negatively with the breeding success of eagles, and biomass supply from European souslik was negatively associated with breeding success, while the white stork's presence and biomass resulted positively in more progeny. Diet diversity did not have an effect on the eagle's reproduction. The responses of these eagles may vary across territories, depending on how they rank their prey, as the territory effect was a powerful factor shaping dietary shifts for this top predator. Our results offer new evidence of the link between habitat alteration, dietary shifts, and reproductive success, contributing to our understanding of the enigmatic mechanism through which an apex predator successfully adapts to large-scale land use pattern transformation by increasing dietary specialization. We recommend restoration of habitat complexity, including preservation of field margins, grassland patches with scattered small shrub formations, and grassland margins between medium-sized arable lands, promotion of measures for traditional grassland management through gradual grazing, and a ban on the use of shredders. [ABSTRACT FROM AUTHOR]

Birds of prey frequently feature in reintroductions and the hacking technique is typically used. Hacking involves removing large nestlings from donor populations, transferring them to captivity, feeding them ad libitum. Potentially, via the hacking method, the stress of captivity and disruption of parental feeding may be detrimental. Alternatively, the provision of ad libitum food may be advantageous. Although hacking has underpinned reintroduction project successes there has been no research on how the method may affect the health and nutritional status of translocated birds during captivity. We compared blood chemistry data from 55 young White‐tailed Eagles, translocated from Norway as part of the species' reintroduction to Scotland, from sampling soon after arriving in captivity and again (≈42 days later) before their release. Numerous significant differences between the first and second samples were found, but no significant interactions showed that the sexes responded similarly to captivity. According to hematological and biochemical metrics, individuals showed several changes during captivity, including in red blood cell parameters, plasma proteins, and white cellular parameters related to the immune system, that indicated improved health status. Captivity with ad libitum food was associated with decreased urea and uric acid values: high values can indicate nutritional stress. Urea values became more normally distributed before release, indicating that ad libitum food had reduced nutritional differences between early nestlings in the season and later ones. Despite plentiful food, both sexes lost body mass before release, suggesting an inherent physiological mechanism to improve flight performance in fledglings. We conclude that hacking improved the health and nutritional status of released eagles which is likely to enable birds to cope with greater costs of exploratory behavior which they may require in reintroduction projects. In this context, we note the absence of survival differences between hacked and wild raptors in previous research. [ABSTRACT FROM AUTHOR]

Bonelli's eagle (Aquila fasciata) had become extirpated in parts of their Mediterranean distribution, such as on Mallorca Island (Balearic Islands, Spain). Thanks to reintroduction programs, a new breeding population was reintroduced to the island, between 2011 and 2017. To identify movement patterns within the island, we equipped each reintroduced individual with a GPS device before release to track their movements. Home range of reintroduced eagles were calculated using a KDE — kernel density estimation approach. Although we found that home range size differed for individuals among years and sex, we found a high degree of overlap in home range in the study population. The home range of each individual remained stable in size and shape and few explorative flights outside the delineated home range were observed. In conclusion, reintroduced Bonelli's eagles have adapted to Mallorca Island by breeding earlier than already established populations, reducing their dispersive behaviour, and accelerating establishment of home ranges. [ABSTRACT FROM AUTHOR]

We estimated the onset of natal dispersal for a large diurnal raptor with high propensity towards large-scaled exploratory movements during the post-fledging period, the White-tailed Sea Eagle (Haliaeetus albicilla). We analysed GPS tracking data of 21 juveniles with respect to the onset of natal dispersal comparing six methods available from the recent literature. While none of the methods significantly differed from the visual method, the Distance Threshold method underestimated the dispersal onset for some individuals. Likewise, coefficient of variation methods overestimated the dispersal onset in few cases, presumably because the temporal scale of available GPS fixes did not correspond to the scale of discrete dispersal movements. We conclude that all tested methods are generally suitable to estimate the dispersal onset, specifically if the research question does not depend on an exact but rather a rough estimate. A visual determination might increase flexibility to account for individual behavior and yields consistent results across individuals, but highly reduces the comparability across observers and studies. For research questions relying on exact estimates, we propose using a combination of an automated method and a visual determination as a back-up method for single individuals with clear under- or overestimation. An exploratory comparison showed that the temporal resolution of the GPS may further affect the accuracy of natal dispersal estimates. For individuals with clear movement patterns, high-resolution movement data could increase the accuracy of Coefficient of Variation methods. We underline the necessity for further investigation on the effects of temporal resolution on dispersal onset estimates. [ABSTRACT FROM AUTHOR]

The distribution, abundance, breeding success, and habitats of the imperial eagle in the mountains and adjacent lowlands of Western Slovakia were studied over the last 45 years (1977–2022), with a total of 65 breeding pairs documented. Of the 589 breeding attempts (range 2–42 per year) that were recorded, 420 were successful (74%) and produced 718 chicks altogether. Breeding success varied considerably across the years, with an average of 1.2 chicks per initiated and 1.7 chicks per successful breeding attempt. Three chicks fledged from 10.7% of the successful breeding attempts, two chicks from 50.2%, and one chick from 39.1% of them. Breeding numbers increased slowly between 1977 and 1997, with a marked increase after 1998. In two of the most recent years, 2020 and 2021, breeding numbers more than doubled. Since 2000, we have observed changes in breeding habitat preferences, where the population has shown more preference for lowland regions than mountains. Natural factors are probably driving the upward population trend, but there has also been action taken with several management measures. The conservation measures involved and their impact on population and range trends are analysed and discussed here. [ABSTRACT FROM AUTHOR]

The steppe eagle (Aquila nipalensis) is an endangered migratory raptor species that migrates in winter to Pakistan and neighbouring countries. In Pakistan, the species migrate at the end of autumn and utilise different habitats across the country. Very little information is available about the species' population status, distribution, and factors affecting its distribution in Pakistan. In the present study, we predicted the distribution of steppe eagles in Pakistan associated with different environmental variables. We used 149 presence points of the species from an online source (GBIF), published literature, and wildlife photographers. The MaxEnt analysis showed that highly suitable habitats were mostly present in Azad Jammu and Kashmir (AJK), federally administered areas and surrounding areas, southern areas of Sindh Province, and some parts of Khyber Pakhtunkhwa (KP) Province. In addition, some patches were also predicted by MaxEnt in Balochistan Province. Human population density (27.0%), chicken density (16.6%), temperature seasonality (11.1%), and rivers (10.3%) were identified as the main environmental factors that affect the habitat distribution of steppe eagle in Pakistan. Only a small percentage (2.62%) of the total Pakistan area was estimated to be a highly suitable area for steppe eagles, while 20.58% and 7.46% were identified as the least and moderately suitable areas, respectively. Conservation of identified habitats and mitigation of anthropogenic impacts to conserve this endangered eagle species are recommended for immediate and long-term conservation across Pakistan. [ABSTRACT FROM AUTHOR]

High-resolution GPS/GSM dataloggers provide spatial information of the highest quality, which outperform previous tracking methods, such as Argos telemetry or conventional VHF ground-tracking. As a result, this has improved our knowledge of home-range behavior and spatial ecology of many species, including large raptors. In this paper, we use high-resolution GPS/GSM dataloggers to assess the home-range size and the role of sex, season (breeding or non-breeding season), and breeding status (reproductive or non-reproductive individuals) on the space use of Bonelli's eagle (Aquila fasciata). To this end, 51 territorial individuals (25 females and 26 males) were equipped with GPS/GSM transmitters and were tracked over 7 years (2015–2021) in eastern Spain. Overall, we recorded 4,791,080 fixes that were analyzed through kernel density methods (50%, 75%, and 95% fixed kernels). The average individual home-range size according to the 95%, 75%, and 50% kernels was 54.84 ± 20.78 km2, 24.30 ± 10.18 km2, and 11.17 ± 4.90 km2, respectively. Overall, the home-range size of individuals occupying the same territory was similar, mainly due to the cooperative hunting behavior exhibited by the species. We did not find interannual differences in the home-range size (95% fixed kernel) of the majority of individuals, showing a strong territorial fidelity of the breeding pairs. In general, females' home-range size was slightly smaller than males' size due to the decrease in activity in the breeding season as a result of laying, incubation, and chick attendance at nests. No seasonal variation in the 95% kernel was found, but it was found in the 75% and 50% kernels. In regard to the breeding status, higher home-range size was recorded in the non-reproductive individuals. Moreover, we found a low neighbor overlap among the territories (4.18% ± 3.06%), which evidences a high level of intraspecific competition in the Bonelli's eagle. Finally, this study highlights the advantages of the use of accurate telemetry information to improve our understanding of the spatial ecology of the endangered Bonelli's eagle, which ultimately will serve to better inform management actions for its conservation. [ABSTRACT FROM AUTHOR]

The Optimal Foraging Theory predicts that, to maximize fitness, animals adapt their foraging strategy that provides the most benefit for the lowest cost, maximizing the net energy gained. While the diet of many breeding raptor populations is well known, studies on the foraging patterns of non-territorial birds of prey (floaters) are scarce. In this study, we examined the foraging pattern of non-territorial Eastern Imperial Eagle, scrutinizing different aspects of its feeding ecology and behavior. We built a simple model of the optimal foraging strategy of floater eagles including the success of foraging as a currency as well as environmental factors such as seasons, type of prey, habitat, foraging techniques, and eagle age as a limitation affecting the foraging efficiency of birds. We found that floaters focused their diet exclusively on European Souslik, accounting for almost half (44.2%) of the eagle's prey. Diet differences between floaters and breeders were due to higher Souslik and carrion consumption and lower Hedgehog predation by floater eagles. The diet diversity of breeding eagles (H = 3.297) was much higher than that of floaters (H = 1.748). Our model suggested that the foraging mode, habitat type, and season best explained the feeding success of non-territorial eagles (ΔAIC = 0.00, w = 0.42). Of all explanatory factors, "Kleptoparasitism" (β2 = −4.35), "Rodents" (β2 = −4.52), "Pasture" (β2 = 2.96), "Wheat" (β2 = 4.41), "In the air" (β2 = 4.16), and "Other habitats" (β2 = 4.17) had a pronounced effect. The factors "Spring–summer season" (β2 = −0.67) and "European Souslik" (β2 = −2.76) had a marginal effect in our models. Generally, the mean success rate of attack modes used by non-territorial eagles was 0.54 ± 0.50. Floaters successfully obtained food through: kleptoparasitism (43.10%), carrion feeding (24.14%), and high soar with vertical stoop (14.66%). Several important issues for the conservation of non-territorial Eastern Imperial Eagles arose from our research. The strong relation of floaters with the European Souslik calls for specific conservation measures aimed at the conservation of this type of prey and the restoration and appropriate management of its grassland habitats. The importance of the scavenging behavior of juvenile birds requires increased control of the use of poison baits and subsequent prosecution by state institutions. Protecting the most important temporary areas, improving institutional control against the use of poison baits, and intensifying awareness-raising campaigns among pigeon-fanciers and hunters are also of crucial importance for effective species conservation. [ABSTRACT FROM AUTHOR]

The black-and-chestnut eagle, a large bird of prey found in South America, has been documented preying on the toco toucan in Argentina. This is the first known record of this eagle species preying on a toco toucan, which is known for its strong beak that typically deters predators. The observation provides valuable insight into the ecological interactions between these species and challenges previous perceptions of the eagle as a potential threat to poultry. This information can help in understanding the role of the eagle in controlling populations of species like the toco toucan, which can cause conflicts with humans due to their consumption of fruits. [Extracted from the article]

The article presents the results of the Steppe Eagle (Aquila nipalensis) study in the Republic of Kalmykia. 135 breeding territories of eagles were examined and 155 birds were observed during summer registrations and counts. The average distribution density of the occupied breeding territories in 2021 in the main part of the area was 2.15 (1.54–2.99)/100 km², in the zone of the large number of food resources – 5.72 (4.45–7.35)/100 km². The percentage of occupied breeding territories was 71%, and 43% of the occupied territories were successful. The number of nestlings in broods ranged from 1 to 3, averaging 1.81±0.69 per successful nest (n=43) and 0.73±0.95 per occupied nest (n=105). The percentage of nests with dead clutches and nestlings was high at all registration plots. The main diet of eagles during the breeding period included the Little Ground Squirrel (Spermophilus pygmaeus) (44%) and several additional prey items. A preliminary assessment of habitat suitability for the Steppe Eagle in terms of food conditions was carried out using GIS methods. Based on the registration data and clarification of the breeding range borders (47086.7 km²), the number of the Steppe Eagle in Kalmykia was re-estimated at 789 (587–1059) pairs. The signs indicating a negative trend in the population intensified: the percentage of immature birds in breeding pairs was 27%, the percentage of abandoned breeding territories was 19%. There is a consolidation of breeding groups in the population nucleus with a simultaneous decrease in breeding density at the periphery. Among the negative anthropogenic factors in 2021 there were the following: mass mortality on power lines, destruction of the food potential by the locals, disturbance during breeding, probable taking away of nestlings from nests.

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]

We assessed the prerequisites for foraging resources availability in connection with breeding habitat choice for the golden eagle (Aquila chrysaetos), long-legged buzzard (Buteo rufinus) and peregrine falcon (Falco peregrinus) along the Balkan Mountains, by applying spatial distribution models of their main prey species. In the study area, the most probable foraging resources for the golden eagle were the rock partridge, the common quail and the European ground squirrel, for the long-legged buzzard - the common vole, and the peregrine falcon - the mistle thrush and the common wood pigeon. In most territories of the three birds of prey species, there were prerequisites for the presence of at least several prey species. Reptiles did not make a significant contribution as a food source for the golden eagle and long-legged buzzard. Spatial distribution models for assessing the preconditions for foraging resources availability in the breeding territories of birds of prey can be applied as indirect methods in a reliable alternative approach. Additionally, this allows the identification of possible contribution of certain prey species in the birds of prey food spectrum in a given area. [ABSTRACT FROM AUTHOR]

Admission records from wildlife rescue centres can help identify causes of morbidity for species of conservation concern, and to assess the effectiveness of rehabilitation. This study documents the causes of admission and outcomes of treatment in 68 white-tailed eagles admitted to rescue centres in the Czech Republic. We determine the factors that contribute to the outcome of rehabilitation. Most admitted birds were juveniles (1st calendar year [CY]; n = 25), followed by immatures (2nd-4th CY; n = 23) and adults (≥5 CY; n = 17). We categorised admission causes into (1) trauma-related cases (most often unknown trauma, followed by collision and intraspecific fights), (2) non-trauma cases (weakness, toxicosis and becoming stuck in mud or entangled in rope) and (3) orphaned young birds. Trauma-related admissions were most numerous totalling 59%, non-trauma admissions accounted for 35% with the remaining 6% comprising orphaned young birds. At least a third of eagle admissions were caused by anthropogenic factors. In total, 40% of admitted eagles were released back to the wild, 35% died or were euthanized and 25% remained permanently in captivity. Eagles admitted due to non-trauma-related causes had a significantly higher probability of being released into the wild than those admitted due to trauma. Immature eagles were less likely to be released than juvenile individuals. Admissions data are valuable for conservation research, allowing for trends in threats towards species of conservation concern to be quantified, over time, throughout human-dominated landscapes. [ABSTRACT FROM AUTHOR]

In this paper, we show how many fixes are enough to define the territory of two long-lived resident raptors marked by GPS transmitters. To this end, we analyzed high-resolution GPS data from 50 territorial Bonelli's eagles (Aquila fasciata) and 9 territorial Golden eagles (Aquila chrysaetos) equipped with GPS/GSM dataloggers. Our results show that between 2200 and 2800 fixes are enough to define the territory. This is interesting for movement ecology works where long-term GPS data series are not available. [ABSTRACT FROM AUTHOR]

The Millennium Ecosystem Assessment proposed four categories of ecosystem services as regulating, provisioning, supporting and cultural. Of these, cultural services have been the most difficult to quantify despite playing a key role in developing society’s supporting services to ecosystems. By reviewing a series of case studies related to the cultural services derived from raptors, we examine relations between tangible ecosystem services and ‘knowledge’ and ‘beliefs’ as part of supporting services from human societies to ecosystems. We identified types of raptor regulating and provisioning services and patterns in service--knowledge-beliefs that defined positive or negative outcomes for raptor conservation. We also demonstrate how possible interactions between physical, experiential, physical-symbolic and representative-symbolic cultural services and between different stakeholders can create incentives or obstacles for conservation. Predictable patterns in service-knowledge-beliefs provide a framework upon which socio-cultural and ethnobiological aspects of raptor conservation may be combined with ecological research to support conservation initiatives. Based on these patterns we present examples of how cultural services might be employed to better promote raptor conservation while respecting the beliefs and traditions of stakeholders.

Long‐term studies are required to reveal responses by long‐lived, top‐order predator populations to ongoing seasonal fluctuations. However, such investigations are rare in the Australian context. Between 2009 and 2019, the breeding density and productivity of an arid and a mesic wedge‐tailed eagle Aquila audax population, each occupying an area of 2800 km2, were compared (11–98 pairs monitored annually). Breeding pairs spaced themselves evenly in both study areas, with no significant difference between the average arid zone nearest‐neighbour distance of 5.32 ± 1.98 km (n = 44) and that determined for the mesic zone (4.88 ± 2.32 km, n = 54). This similarity in spacing suggests a maximum average density is tolerated by these territorial raptors. By contrast, annual breeding success (proportion of pairs fledging young) and productivity (fledged young per pair) differed significantly between the two populations, with rainfall (but not temperature) influencing reproduction. In the arid zone, the proportion of successful pairs per occupied breeding home range was consistently low each year (mean = 12 ± 7% fledged broods per pair, range 0–26%) and positively correlated with annual rainfall. In the mesic zone, it was consistently high each year (mean = 69 ± 9%, range 57–91%) and not significantly correlated with annual rainfall. Overall productivity figures showed similar differences, with 0.13 and 0.77 fledglings per pair per year for arid (n = 9 years) and mesic (n = 11 years) eagles, respectively. Such low arid zone productivity, the lowest ever recorded for the species, could have long‐term implications in the face of the increased frequency of extreme weather events. That breeding density can be independent of climatic factors provides new insight into the way a large Aquila species integrates with Australia's predominantly arid environment. This study provides an important baseline data set for continued research on long‐term occupancy and productivity trends. [ABSTRACT FROM AUTHOR]

The proventriculus is one of the most important parts of digestive tract in birds for mechanical and chemical digestion and can vary depending on the bird's eating habits. In the present study, the morphological and histological structure of proventriculus in common kestrel, steppe eagle, golden eagle and imperial eagle have been investigated and compared. In this study, Proventriculus of common kestrel (n=4), steppe eagle (n=5), golden eagle (n=4) and imperial eagle (n=6) were collected and fixed in 10% formalin buffer solution and the histological process were carried. Finally, H&E, Masson's trichrome, Orcein and PAS stainings were utilized. Histologically, slight differences were observed between the proventriculus of common kestrel and steppe eagle. Notable differences included a continuous and relatively thicker layer of mucosal muscle in the steppe eagle's proventriculus, and the distinct simple columnar epithelium of the submucosal glands type II ducts. The only notable structural difference in golden eagle was the presence of relatively dense connective tissue of lamina propria and one to three layers of continuous smooth muscle in its structure. The histological structure of imperial eagle's proventriculus had two differences with its structure in common kestrel. Firstly, the lamina propria was composed of relatively dense connective tissue and secondly, the muscle layer was relatively thinner than other species examined in this study, while the serosa layer had a considerable thickness. It can be concluded that the structure of proventriculus was similar in three species of eagles and common kestrel, and the main significant difference was related to the layers of mucosal muscle. [ABSTRACT FROM AUTHOR]

In bi-parentally built nests, there is evidence to suggest that nests are extended phenotypic signals that accurately indicate the quality of the building parent/s. Raptors often use a variety of materials to build their nests (natural, such as branches, but also non-natural objects), presumably due to their insulating properties, their suitability to advertise occupancy of the nest, and to decrease pathogen and parasite loads. However, in raptors where both sexes collaborate in nest construction, it is unclear whether nest building (taking the amount of material carried to the nest as the potential predictor) is an indicator of parental quality, and whether the effort expended by both sexes could constitute an honest signal of parental quality to their partners. Between 2011 and 2016, we monitored 16 nests of Bonelli's Eagles (Aquila fasciata), and we examined data on sex, type of material brought to the nest, breeding experience, nest quality, timing, and nest-building investment prior to egg-laying from 32 identifiable Bonelli's Eagles during the pre-laying period to investigate the relative contribution of the sexes to the amount of nest material gathered. Our results indicate that sex is not a determining factor in nest-building effort, and that females did not increase their parental effort in response to the male's contribution, and supply of materials did not increase during the pre-laying period. In contrast, our models showed that: (1) the type of material supplied to the nest by both sexes varied significantly throughout the pre-laying period and (2) nest-building effort was determined by individual experience and nest quality. Therefore, our study suggests that male nest-building behaviour and investment by Bonelli's Eagles cannot be considered as an extended phenotypic signal. The differential use of hard and green material by both sexes in the early and late stages of nest-building period, and the fact that the more experienced individuals contributed a larger amount of material on low quality nests, are discussed in the contexts of signaling nest occupancy to conspecifics and competitors and the decrease of ectoparasite loads during the pre-laying period. [ABSTRACT FROM AUTHOR]

Lead poisoning occurs worldwide in populations of predatory birds, but exposure rates and population impacts are known only from regional studies. We evaluated the lead exposure of 1210 bald and golden eagles from 38 US states across North America, including 620 live eagles. We detected unexpectedly high frequencies of lead poisoning of eagles, both chronic (46 to 47% of bald and golden eagles, as measured in bone) and acute (27 to 33% of bald eagles and 7 to 35% of golden eagles, as measured in liver, blood, and feathers). Frequency of lead poisoning was influenced by age and, for bald eagles, by region and season. Continent-wide demographic modeling suggests that poisoning at this level suppresses population growth rates for bald eagles by 3.8% (95% confidence interval: 2.5%, 5.4%) and for golden eagles by 0.8% (0.7%, 0.9%). Lead poisoning is an underappreciated but important constraint on continent-wide populations of these iconic protected species. [ABSTRACT FROM AUTHOR]

A main priority in conservation is the protection of species in their natural habitat. However, ex situ management of threatened species is a recognised strategy of conservation. Harpy Eagles (Harpia harpyja) are removed from the wild due to illegal capture, nest tree destruction, or other conflict sources. This study presents a review of the current ex situ Harpy Eagle populations in Brazil and worldwide, including information on the origin, sex, and year of entrance or year of birth under human care. Worldwide, until 2020 there were 205 Harpy Eagles in 77 different facilities in 16 countries, with 40 institutions in Brazil and 37 in other countries. The largest ex situ Harpy Eagle population is maintained in Brazil, with 139 individuals (75 females and 64 males) in 40 institutions. Of these institutions, there were 24 zoos, seven conservation breeding centres, six commercial breeders, two wildlife shelters, and one wildlife sorting centre. In Brazil, 62% (n = 86) of the individuals were hatched in the wild and 38% (n = 53) were bred in captivity under human care; for the wild individuals, only 73% (n = 64) have a known state of origin, with the majority from Pará state. This investigation provided relevant information to establish an ex situ demographic database. These individuals may potentially constitute a genetically and demographically viable safety population for future conservation strategies, as well as a source for research and education applied to Harpy Eagle integrated conservation. [ABSTRACT FROM AUTHOR]

The dramatic increase in human pressure, deforestation and general decrease in tree cover, overgrazing and erosion, pesticide use, over-hunting and fishing, and sometimes direct persecution of predators, all impact negatively on birds of prey population. The aim of this research was to examine species of birds of prey in Dagona Waterfowl Sanctuary in Northeastern Nigeria. Transect line method was used for the bird survey. The survey was carried out for a period of six (6) months using transect line method and each site was surveyed twice every month during the study period. Bird observation was carried out twice daily; morning between 6:00 to 10:00 a.m. and evening between 4:00 to 6:30p.m by walking slowly along the transect line. Birds were counted as birds seen and birds inflight were also counted. Transect line survey method detected a total of 550 individual birds of prey that belong to twenty (20) species of 2 families. Accipitridae with 17 species is the richest family in species number and Falconidae with 3 species. Out of the 20 species recorded 13 are resident, 4 Palearctic migrant and 3 intra-African migrant. Four species of global conservation concern were also recorded; the Vulnerable Tawny eagle (Aquila rapax), the Near threatened Red-necked falcon (Falco chicquera) and Pallid harrier (Circus macrourus) and the Endangered Martial eagle (Polemaetus bellicosus). This survey shows that, the Dagona Waterfowl sanctuary still retained a considerable number of birds of prey species that normally occur in West Africa. The management needs to increase conservation measures that will ensure the protection of the wetlands. [ABSTRACT FROM AUTHOR]

The extinct Haast's eagle or harpagornis (Hieraaetus moorei) is the largest known eagle. Historically, it was first considered a predator, then a scavenger, but most recent authors have favoured an active hunting ecology. However, the veracity of proposed similarities to carrion feeders has not been thoroughly tested. To infer feeding capability and behaviour in harpagornis, we used geometric morphometric and finite-element analyses to assess the shape and biomechanical strength of its neurocranium, beak and talons in comparison to five extant scavenging and predatory birds. The neurocranium of harpagornis is vulture-like in shape whereas its beak is eagle-like. The mechanical performance of harpagornis is closer to extant eagles under biting loads but is closest to the Andean condor (Vultur gryphus) under extrinsic loads simulating prey capture and killing. The talons, however, are eagle-like and even for a bird of its size, able to withstand extremely high loads. Results are consistent with the proposition that, unlike living eagles, harpagornis habitually killed prey larger than itself, then applied feeding methods typical of vultures to feed on the large carcasses. Decoupling of the relationship between neurocranium and beak shape may have been linked to rapid evolution. [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]

A secretive and cautious raptor, the Black Eagle (Ictinaetus malaiensis) is challenging to study. Its highly specialized foraging behavior makes it difficult to capture an individual for tracking. However, a tailless eagle provided an opportunity to describe the home range and movements of one bird for 3 yr from 2013 to 2016. A total of 43 independent photo records were provided by a bird photographers' community. The eagle regularly moved between summering and wintering habitats north and south of Taipei City, Taiwan; home range sizes were estimated as 54.1 and 47.1 km2, respectively. This noninvasive case study provides the first estimates of home range size and movement patterns for the Black Eagle, and highlights the contribution of community science to research on endangered raptors. [ABSTRACT FROM AUTHOR]

The Crested Eagle (Morphnus guianensis) is the second largest Brazilian forest eagle. Crested Eagles are distributed from southeastern Mexico to southern Brazil, northern Argentina, and Paraguay; however, the species is one of the least-studied Neotropical raptors. Our objective was to determine diet and feeding strategies for Crested Eagles in the Brazilian Amazon. We recorded Crested Eagle diet at four nests from 2010–2012 through a combination of direct observations from the ground, remote photographs (camera-traps), and pellets and prey remains collected in and under the nests. We identified a total of 79 prey individuals, composed of 21 different prey species. We found that Crested Eagles fed mainly on medium-sized rodents, and medium-sized to large mammals. Prey were mainly nocturnal (70%), including mostly scansorial, cavity-dwelling marsupials and rodents. Fewer prey were diurnal (20%) and these were typified by arboreal, gregarious mammals (monkeys); rare prey included one owl (Strigidae) and one porcupine (Coendou sp.). We suggest that this may indicate a diet not specialized on a particular prey species or group, but rather focused on specific prey behaviors or microhabitats. [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).