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Research on potentially adverse effects of wind farms is an expanding field of study and often focuses on large raptors, such as golden eagles, largely because of their life history traits and extensive habitat requirements. These features render them sensitive to either fatality (collision with turbine blades) or functional habitat loss (avoidance through wariness of turbines). Simplistically, avoidance is antagonistic to collision; although, the two processes are not necessarily mutually exclusive in risk. A bird that does not enter a wind farm or avoids flying close to turbines cannot collide with a blade and be killed. In the USA, collision fatality is implicated as the typical adverse effect. In Scotland, avoidance of functional habitat loss appears more likely, but this depends in part on the habitat suitability of turbine locations. Previous Scottish studies have largely concentrated on the responses of GPS-tagged non-territorial golden eagles during dispersal. Several arguments predict that territorial eagles may have lower avoidance (be less wary) of turbines than non-territorial birds. Hence, we contrasted the responses of GPS-tagged non-territorial (intruding) and territorial eagles to the same turbines at 11 operational Scottish wind farms. We show that territorial eagles rarely approached turbines, but, as in previous Scottish studies of non-territorial birds, the spatial extent of avoidance depended on the habitat suitability of both turbine locations and their wider surroundings. Unexpectedly, we found that territorial eagles were apparently as wary as intruding non-territorial conspecifics of the same turbines. Our results show that regardless of age or territorial status, Scottish golden eagles largely avoided wind turbine locations, but this avoidance was conditional, in part, on where those turbines were located. Responses to turbines were also strongly dependent on birds' identities and different wind farms. We speculate on how widespread our findings of avoidance of turbines by golden eagles are elsewhere in Europe, where there appear to be no published studies showing the level of collision fatalities documented in the USA. [ABSTRACT FROM AUTHOR]

We describe for the first time the visual fields of the largest tropical raptor, the Harpy Eagle (Harpia harpyja), a powerful keystone species that hunts almost exclusively in forested habitats. They have the largest blind area described to date of any diurnal raptor species, and relatively narrow binocular fields, which together may help explain the way they interact with their prey in the visually complex environments they inhabit. As a top predator, their spatial visual sampling is likely driven more by foraging needs than predator detection, and they thus serve as an excellent study species for understanding the tradeoffs between visually guided foraging and anti-predatory behaviors. Further studies on the position and the projection of retinal foveae, visual acuity, and color vision will improve our understanding of their visual capabilities and could play important roles in conservation of a vulnerable Neotropical species. [ABSTRACT FROM AUTHOR]

In 2022, by presidential decrees, the new coats of arms and flags of the following territorial units were registered in the General Armorial of the Republic of Moldova: the city of Taraclia (decree no. 346-IX of February 16); Găleşti village, Găleşti commune, Străseni district (no. 359-IX, March 7); Goteşti commune, Cantemir district (including the component villages of Goteşti and Constantineşti; no. 378-IX, March 15); Pleşeni commune, Cantemir district (including the component villages of Pleşeni, Hănăseni and Tătărăşeni; no. 427-IX, April 18); Vadul lui Isac village, Cahul district (no. 531-IX, July 8); Tvardita city, Taraclia district (no. 548-IX, July 18; the city's anthem was also recorded); the village of Cojuşna, Străseni district (no. 549-IX, July 18); Vatra city, Chişinău municipality (no. 633-IX, September 9); Donduşeni city (no. 684-IX, November 8); Putintei commune, Orhei district (including the component villages of Putintei, Dişcova and Vâprova; no. 686-IX, November 8); as well as the Talmaza village hymn, Stefan-Vodă district (no. 685-IX, November 8). The heraldic year 2022 was in line with previous years, with a comparable number of new insignia approved and registered and the introduction of other new elements into the national heraldic list. The heraldic movement was still more active in the center and south of the country. The main problem that continues from the previous years was the insufficient documentation of the history of localities and the unreliability of the historiography regarding our cities and villages. In addition, the elaborative process encounters obstacles due to the lack of an exhaustive corpus of particular historical heraldry and sigillography. The main authors and painters of symbols were the same (S. Andrieş-Tabac, Mariana Slapac, Andrei Gaydashenko and others), but their number is insufficient for the needs of the day. The methods of developing the symbols remained traditional, the process of the canting arms and the marking of natural, economic or cultural particularities prevailed. Three communes -- Goteşti, Pleşeni, Putintei -- chose the path of developing the entire set of coats of arms and flags for the commune and for all the component villages. The city of Tvardita simultaneously adopted its local coat of arms, flag and anthem. Among the first theoretical achievements for the Republic of Moldova, we mention the field of ermine on the coat of arms and the flag of the village of Cojuşna, the Roman eagle and the three closets in the symbols of the village of Vadul lui Isac, the construction of the flag of the village of Constantineşti, the supports of the coat of arms of the city of Tvardita. The continuity of the historical noble coats of arms was realized in the symbols of the village of Găleşti, of the commune of Putintei and its component villages. From an artistic point of view, the symbols of the city of Tvardita, those of the village of Vadul lui Isac, the coats of arms of the villages of Găleşti and Putintei, those of the cities of Vatra and Donduşeni, and the flag of the village of Goteşti stand out. An important achievement of the year in the field of territorial heraldry was the inclusion in the General Armorial of the Republic of Moldova, in the compartment of withdrawn insignia, of the 20 county coats of arms and flags that were developed and used in 1999-2003 (Decision of the National Committee for Heraldry no. 82-VI.01 of March 22). [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]

The White-tailed eagle, an apex predator, is currently recovering its populations across Europe and has already reached high numbers in many countries. This led to the saturation of eagles in optimal habitats and their encroachment on suboptimal ones. We aimed to compare the diet of White-tailed eagles in optimal and suboptimal conditions in northeastern Poland to investigate how population development affected prey composition, which is expected to be lacking in suboptimal eagle territories. We have monitored eagle nests with trail cameras to investigate their diet objectively and precisely. In order to compare territories of different quality, we have conducted modeling of habitat suitability using data on nest locations prior to their saturation. Using recorded photos of the prey, we measured their size and estimated their weight to check if the size and biomass of the prey are comparable between optimal and suboptimal territories. We found that eagles in the latter conditions were not limited by prey biomass but turned to alternative prey and brought larger prey. The alternative prey were large birds such as White storks and Common cranes, but also chicks of other avian predators that were robbed from their nests. Most probably, eagles cope with a lack of optimal prey by ranging farther and exploring non-optimal foraging habitats. We conclude that the diet flexibility of White-tailed eagle enables him to still increase its numbers despite already high densities. Our study also shows that this species might possibly impact the White stork population, as seen in the case of the Black stork and some seabird species. [ABSTRACT FROM AUTHOR]

The ice fly Diamesa steinboecki Goetghebuer, 1933 (Diptera: Chironomidae: Diamesinae) is exclusive to glacier-fed streams in the East Palaearctic region and is threatened by extinction due to global warming and glacier retreat. To date, no data are available on its thermal tolerance or ability to develop a heat shock response (HSR) or involve other biomarkers when exposed to higher-than-natural temperatures (i.e., >4–6 °C). Our study aimed to investigate the warmth resistance of IV-instar larvae of D. steinboecki in terms of (1) ability to survive heat shock and (2) gene expression of four genes known to be involved in the detoxification/stress response (cytochrome p450 (Cyp450), heat shock protein 70 (hsp70), hsp70 with intron and heat shock protein cognate 70 (hsc70)). Larvae were exposed to short-term shocks for 1 h at increasing temperatures (26, 28, 30, 32, 34, 36, 38, and 40 °C) to estimate the lethal temperature, obtaining high values (LT10 = 38.1 °C, LT50 = 39.2 °C, LT99 = 40.3 °C), suggesting a strong heat resistance up to 38 °C and a very rapid decline in survival thereafter. Moreover, gene expression analysis by real-time PCR was performed on larvae from the control (at 2 °C) and larvae found alive after the previous treatment at 26, 28, 30, 32, 34, 36, and 38 °C. Modulation of the expression was observed only for hsc70 and hsp70 genes. Specifically, hsc70 resulted in constitutive overexpression, even at 26 °C when all larvae were found alive without evidence of suffering. By contrast, hsp70 showed up and downregulation according to the specific temperature, suggesting the activation of an HSR at 28 °C, when some larvae were found alive but suffering (almost paralyzed). The results suggest that, based on LTs, D. steinboecki is more thermally tolerant than other Diamesa species (e.g., D. tonsa) from cold freshwaters, but, as in these, hsp70 and hsc70 are involved in surviving short-term heat shock. This makes the ice fly from the Alps different from Belgica antarctica and other cold-adapted organisms living in extremely cold habitats that, constantly exposed to cold, have lost the ability to develop an HSR. Further research is needed to investigate the response to prolonged exposure to temperatures higher that the natural one, giving new insights into the biological response to climate change of alpine species threatened by extinction. [ABSTRACT FROM AUTHOR]

Pallas's fish eagle, Haliaeetus leucoryphus (Pallas), is listed as endangered (EN) in the IUCN Red List of Threatened Species with a global population of 2,500 to 9,999 individuals. It is one of the least known species in Bhutan and assessing its foraging and nesting behavior will be one of the best conservation measures to monitor its status, ecology and conservation threats. Therefore, the nesting behavior of the eagle was observed for two months and chick feeding activities for sixteen weeks at 21 vantage points along a 75 km highway in the Punatshangchu River Valley, Bhutan. Fifty households residing 500 m from the river were interviewed using structured questionnaires to examine their perception towards the eagle. A total of 92% (n= 46) of respondents were aware of the presence of H. leucoryphus in their locality and 78% felt that it is a rare and endangered fishing eagle. However, 84% (n= 42) of respondents were not aware of nesting within their vicinity. The sexes of H. leucoryphus can be differentiated by their plumage and the fledgling was observed approximately one week after the end of the incubation period. It took 112 days for the fledging to leave the nest. The study revealed that the eagle preferred foraging between 7 and 9 AM in the morning and in the afternoon from 1 to 3 PM. The maximum foraging attempts occurred in a pool habitat 54% (n= 37) with a success rate of 78% (n= 54). The hunting and feeding of the fledgling was done by the male and prey delivery in the first two months consisted of 78.5% fish and 19.5% rodents. However, the feeding of fish declined by 35% in the next two months and its diet mainly consisted of small birds. Attacks on the fledgling were done by the crested serpent eagle (Spilornis cheela Latham) (48%), followed by the black eagle Ictinaetus malaiensis (Temminck) (33%). [ABSTRACT FROM AUTHOR]

Clade 2.3.4.4, H5 subtype highly pathogenic avian influenza viruses (HPAIVs) have caused devastating effects across wild and domestic bird populations. We investigated differences in the intensity and distribution of the hemagglutinin (HA) glycoprotein binding of a clade 2.3.4.4 H5 HPAIV compared to a H5 low pathogenic avian influenza virus (LPAIV). Recombinant HA from gene sequences from a HPAIV, A/Northern pintail/Washington/40964/2014(H5N2) and a LPAIV, A/mallard/MN/410/2000(H5N2) were generated and, via protein histochemistry, HA binding in respiratory, intestinal and cloacal bursal tissue was quantified as median area of binding (MAB). Poultry species, shorebirds, ducks and terrestrial birds were used. Differences in MAB were observed between the HPAIV and LPAIV H5 HAs. We demonstrate that clade 2.3.4.4 HPAIV H5 HA has a broader host cell binding across a variety of bird species compared to the LPAIV H5 HA. These findings support published results from experimental trials, and outcomes of natural disease outbreaks with these viruses.

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]

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]

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]

Primates understand the meaning of their own and other species' alarm calls, but little is known about how they acquire such knowledge. Here, we combined direct behavioural observations with playback experiments to investigate two key processes underlying vocal development: comprehension and usage. Especifically, we studied the development of con- and heterospecific alarm call recognition in free-ranging sooty mangabeys, Cercocebus atys, across three age groups: young juveniles (1–2y), old juveniles (3–4y) and adults (> 5y). We observed that, during natural predator encounters, juveniles alarm called to a significantly wider range of species than adults, with evidence of refinement during the first four years of life. In the experiments, we exposed subjects to leopard, eagle and snake alarm calls given by other group members or sympatric Diana monkeys. We found that young juveniles' locomotor and vocal responses were least appropriate and that they engaged in more social referencing (look at adults when hearing an alarm call) than older individuals, suggesting that vocal competence is obtained via social learning. In conclusion, our results suggest that alarm call comprehension is socially learned during the juvenile stage, with comprehension preceding appropriate usage but no difference between learning their own or other species' alarm calls. Significance statement: Under natural conditions, animals do not just interact with members of their own species, but usually operate in a network of associated species. However, ontogenetic research on primate communication frequently ignores this significant element. We studied the development of con- and heterospecific alarm call recognition in wild sooty mangabeys. We found that communicative competence was acquired during the juvenile stages, with alarm call comprehension learning preceding appropriate vocal usage and with no clear difference in learning of con- and heterospecific signals. We also found that, during early stages of life, social referencing, a proactive form of social learning, was key in the acquisition of competent alarm call behaviour. Our results show that primates equally learn to interpret alarm calls from their own and other species during their early stages of life and that this learning process is refined as the animals mature. [ABSTRACT FROM AUTHOR]

The first successful breeding of eastern imperial eagles (Aquila heliaca) in the Czech Republic, which lies at the north-western edge of its world breeding range, was confirmed in 1998. Here we summarise the dispersal, overwintering and expansion of the Czech population based on observational, ringing and telemetry data. The Czech breeding population had increased to at least 14 breeding pairs and 18 territorial pairs by 2022. Between 2017 and 2021, 19 nestlings were equipped with GPS/GSM devices. Two of the 16 surviving individuals (12.5%) spent their first winter in the Mediterranean (1,460 km and 1,671 km from natal nest), but did not repeat this migration pattern again. The other 14 tracked individuals wintered close to their natal areas. Maximal recorded distances from the natal nest and total area occupied (100% minimal convex polygons) were significantly lower in the first calendar year than the second. Signs of settlement prior to the first nesting attempt were already apparent by the third or fourth calendar year. Excluding exploratory trips during the floater period, final natal dispersals for two of the breeding males were 46 km and 92 km, respectively. Further spreading of the species’ Czech breeding range is expected in the future. [ABSTRACT FROM AUTHOR]

Divergence in the face of high dispersal capabilities is a documented but poorly understood phenomenon. The white‐tailed eagle (Haliaeetus albicilla) has a large geographic dispersal capability and should theoretically be able to maintain genetic homogeneity across its dispersal range. However, following analysis of the genomic variation of white‐tailed eagles, from both historical and contemporary samples, clear signatures of ancient biogeographic substructure across Europe and the North‐East Atlantic is observed. The greatest genomic differentiation was observed between island (Greenland and Iceland) and mainland (Denmark, Norway and Estonia) populations. The two island populations share a common ancestry from a single mainland population, distinct from the other sampled mainland populations, and despite the potential for high connectivity between Iceland and Greenland they are well separated from each other and are characterized by inbreeding and little variation. Temporal differences also highlight a pattern of regional populations persisting despite the potential for admixture. All sampled populations generally showed a decline in effective population size over time, which may have been shaped by four historical events: (1) Isolation of refugia during the last glacial period 110–115,000 years ago, (2) population divergence following the colonization of the deglaciated areas ~10,000 years ago, (3) human population expansion, which led to the settlement in Iceland ~1100 years ago, and (4) human persecution and exposure to toxic pollutants during the last two centuries. [ABSTRACT FROM AUTHOR]

Brahminy Kite, or Halistur Indus, is one of many protected eagle species in Indonesia. The eagle’s presence in the environment is very important because the eagle is one of the environmental health indicators. Unfortunately, based on the last research, the H. indus population in Java, Indonesia has decreased. Some factors that contribute to the decrease in the H. indus population include pesticide overuse, destruction of natural habitats, illegal hunting, and illegal trading. Therefore, the conservation programs of H. Indus are very important to maintain its population in nature. To support the preservation of H. indus, this study provides an overview of H. indus, including heart rate, respiratory rate, and body temperature which is expected to be useful for consevation programs. There are 15 Halistur Indus from The Kamojang Eagle Conservation Center, Sukakarya, Samarang, Garut, West Java, Indonesia, used as observation objects. This study applies a descriptive method to analyze the data. The observation data shows that the average Halistur Indus heart rate is 173.467/minute, with a standard deviation of 11.275 /minute. The respiratory rate was 76.400 ± 14.065 /minute, and the body temperature was 42.570 ± 0.290 ˚C. [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]

The javan hawk-eagle is a bird species endemic to Java, so the distribution area is limited in Java. The javan hawk-eagle is one of the indicators of environmental health in Gunung Ciremai National Park (TNGC). This study aims to analyze the habitat of the javan hawk-eagle and the behavior of the Javan hawk-eagle in Gunung Ciremai National Park. Observations focused on the area of direct encounter with the Javan hawk)eagle and were selected intentionally (purposive sampling). The habitat analysis was approached with vegetation analysis and habitat used method. The behavior of the javan hawk-eagle was observed by focal animal sampling to describe its daily activities. The results showed that habitat use during the javan hawk-eagle nesting season used plantation forest types (83.14%), natural forest (14.12%), and shrubs (2.75%). The characteristics of the javan hawk-eagle's resting place are strata A trees or strata B trees, which have horizontal and strong branches. The javan hawk-eagle chooses a tree to nest on an emergent tree, namely a pine tree (Pinus merkusii). The characteristics of the Javan hawk-eagle hunting area are natural forests with diverse and abundant potential for prey such as spotted doves and squirrels. The behavior of the javan hawk-eagle observed included resting 3 times, meeting for a total of 79 minutes, hunting 2 times for a total of 11 minutes, flying 8 times and meeting for a total of 48 minutes, and social interaction 5 times between 08.00 am and 11.00 am, with a total time of 108 minutes. [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]

We explore the potential factors that affect clutch initiation in four Neotropical large raptors (Harpy eagle—HE, Crested eagle—CE, Ornate hawk-eagle—OHE, and Black hawk-eagle—BHE) by analyzing 414 clutch events mostly obtained from captive individuals. Differences in how clutch initiation is associated with changes in photoperiod were found between HE and both hawk-eagles, and between CE and BHE. Changes in temperature at the time of clutch initiation only differed between HE and OHE, whereas changes in precipitation varied between BHE and all other species. Principal Component Analysis of these environmental cues showed that ellipses in the dataset of each species overlap, but only ellipses from CE and OHE had the same variation trends. This means that although these species live under similar ecological conditions, they exhibit three different patterns of response to environmental cues. Apparently, these patterns are not associated with phylogenetic relatedness because species belonging to the same clade do not show the same response pattern. Diet diversity analysis revealed that HE has the least varied diet, and CE and OHE the most varied diet. The fact that species who fit the same reproductive timing response to environmental cues show similar diets leads us to hypothesize that breeding in these eagles was most likely shaped by food availability. [ABSTRACT FROM AUTHOR]

The golden eagle (Aquila chrysaetos) and the white-tailed eagle (Haliaeetus albicilla), being apex predators and facultative scavengers, can bioaccumulate different environmental contaminants, including toxic elements that may adversely affect their health. We analyzed the levels of cadmium (Cd), lead (Pb), and other metals and metalloids, including arsenic (As), barium (Ba), beryllium (Be), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), selenium (Se), thorium (Th), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn) in liver samples taken from three golden eagles and 36 white-tailed eagles that were found dead across Poland to verify their exposure. We also used a systematic review to summarize the available literature data on Cd, Pb, and other studied elements in the liver of both eagle species. Analyses of trace elements in the liver samples of the Polish eagles revealed interspecific differences in Cd, Cu, and Mn and differences in Co, Mn, Tl, and Zn among study regions. All elements tested except Pb were below the suggested thresholds linked with adverse health effects in birds. The hepatic Pb found in almost half of all the tested individuals suggests environmental exposure to this toxic element. One of the tested white-tailed eagles had hepatic Pb above the threshold of sublethal poisoning. Although our results seem optimistic, as previous Polish studies showed a higher prevalence of birds with hepatic Pb exceeding the toxicity threshold, they indicate that exposure to this toxic metal could still pose an additional threat to the health of Polish eagles. [ABSTRACT FROM AUTHOR]

Bottom‐up control is an important regulator of marine mesopredators such as seabirds. The prevalence of top‐down control on these species is however less well understood. In particular, how native predators affect seabird populations has rarely been quantified.Here, we investigate how an increase in white‐tailed eagles in northern Norway, a stronghold for the species, affected a local population of 25,000 pairs of black‐legged kittiwakes, a red‐listed seabird, during a 42‐year period ending with colony extinction. We use a natural experiment of two neighbouring colonies with/without eagle predation to disentangle the effects of eagles from local kittiwake foraging conditions (using size of young herring as a proxy).At the colony where eagle predation occurred, and in contrast to the eagle‐free colony, kittiwake breeding success and population size declined with increased eagle abundance, the latter more strongly under poor foraging conditions. Breeding success increased with improving foraging conditions at both colonies.Simple population modelling shows that although conditions were insufficient to sustain the eagle‐exposed colony, the increased abundance of eagles sped up its extirpation by many years.Policy implications. Our study shows that top‐down effects from avian predators can be significant regulators of seabird populations, challenging their conservation where native, often protected, predators are rising. Such effects, and their possible interaction with other factors, must also be accounted for when using seabird demographic traits as environmental indicators and when developing more flexible and effective management and action plans. [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]

Large carnivores influence ecosystem dynamics in multiple ways, for example, by suppressing meso‐carnivores and providing carrions for smaller scavengers. Loss of large carnivores is suggested to cause meso‐carnivore increase and expansion. Moreover, competition between meso‐carnivores may be modified by the presence of larger carnivores. In tundra ecosystems, the smallest meso‐carnivore, the Arctic fox, has experienced regional declines, whereas its larger and competitively superior congener, the red fox, has increased, potentially due to changes in the abundance of apex predators.We explored if variation in the occurrence of wolverine and golden eagle impacted the occurrence and co‐occurrence of the Arctic fox and red fox in relation to varying abundances of small rodents within the Scandinavian tundra.We applied multi‐species occupancy models to an extensive wildlife camera dataset from 2011–2020 covering 98 sites. Daily detection/non‐detection of each species per camera trap site and study period (late winter; March–May) was stacked across years, and species occupancy was related to small rodent abundance while accounting for time of the year and status of simulated carcass.The Arctic fox was more likely to co‐occur with the red fox when the wolverine was present and less likely to co‐occur with the red fox when golden eagles were present and the wolverine was absent. Red foxes increased in occupancy when co‐occurring with the larger predators. The Arctic fox responded more strongly to small rodent abundance than the red fox and co‐occurred more often with the other species at carcasses when rodent abundance was low.Our findings suggest that the interspecific interactions within this tundra predator guild appear to be surprisingly intricate, driven by facets of fear of predation, interspecific mediation and facilitation, and food resource dynamics. These dynamics of intraguild interactions may dictate where and when conservation actions targeted towards the Arctic fox should be implemented. [ABSTRACT FROM AUTHOR]