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Adjustment of reproductive timing within the annual cycle is a crucial issue for both offspring and parents' survival, and breeding success. Early laying date is closely related to successful breeding outcome and better survival. Obtaining long datasets on threatened long-lived species' breeding performance can contribute to their conservation. Using field observations and telemetry information, here we analyse how laying date of an endangered long-lived raptor varies with nest characteristics, individual factors and climatic variables during an 18-year (2004–2021) study period in eastern Spain. To this end, we estimated how environmental and individual variables affect laying date. Our results showed that average laying date in our study area took place on February 17th. Laying date showed no trend during the study period. Nests placed in higher elevations showed delayed laying dates. Territories occupied by adults with previous successful experience and high brood size showed earlier laying dates. Current year laying date was highly correlated with previous year laying date. Colder territories delayed laying date and the minimum temperature of the previous December were negatively correlated to previous laying date. Our results highlight the importance of experienced birds able to adjust timing of reproduction to maximise biological fitness. High adult mortality allows sub-adults to settle as breeders and jeopardises species' persistence. Therefore, the reduction of mortality of territorial birds is of the outmost importance to improve the conservation status of declining long-lived species such as the Bonelli's eagle (Aquila fasciata). [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]

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 cloud environment, the optimal placement of virtual machines on available physical machines is challenging task. The available resources can be properly managed and the resource wastage can be reduced with the help of optimal placement of virtual machines. The proposed EAGLE modified approach performs better than the existing four optimization approaches namely multi resource alignment, first fit, two stage best fit, EAGLE for optimal placement of virtual machines in cloud computing. These algorithms are simulated using the designed simulator for different sets of workloads. The CPU utilization or power consumption varies from 68 to 88% for first fit, 69–90% for multi resource alignment, 66–87% for two stage best fit, 66–84% for EAGLE, and 66–84% for EAGLE MOD. The memory utilization varies from 40 to 60% for first fit, 50–69% for multi resource alignment, and 38–65% for two stage best fit, EAGLE, and EAGLE MOD. The average resource fragmentation are 30.4388% for first fit, 28.6983% for multi resource alignment, 33.2822% for two stage best fit, and 25.8717% for EAGLE and EAGLE MOD. The average resource fragmentation are 30.4388% for first fit, 28.6983% for multi resource alignment, 33.2822% for two stage best fit, and 25.8717% for EAGLE and EAGLE modified.The presented algorithms are compared on the basis of central processing unit (CPU) utilization, memory utilization, failure tasks, and resource fragmentation evaluation parameters. [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]

Wildlife managers and livestock owners can choose from a multitude of interventions to prevent carnivore attacks on domestic animals, ranging from light and sound deterrents to fencing and lethal control. To guide management and make the best and most cost-effective choice of interventions, knowledge about where and when these measures are needed the most is important. By identifying spatiotemporal patterns of carnivore attacks, resources can be used more efficiently to prevent such attacks. We used a Swedish nationwide, long-term data set to identify inter- and intra-seasonal variation in probability, number, and severity (number of killed or injured per attack) of large carnivore attacks on sheep. Our results show that there are specific "times of trouble", regarding the number of attacks from golden eagle (Aquila chrysaetos) in late spring, and from brown bears (Ursus arctos), lynx (Lynx lynx), and wolves (Canis lupus) in late summer. Additionally, for brown bears and wolves, the severity of attacks varied throughout the grazing season with a peak in the latter part of the summer. The results can be used for guidance of temporal prioritisation of preventive interventions to reduce the probability, number, and severity of large carnivore attacks on sheep. [ABSTRACT FROM AUTHOR]

The success of Eagle Owl breeding in artificial niches and natural nests was studied. Manufacturing and installing artificial nests for Eagle Owls in Mordovia, central European Russia is employed as a factor to increasing the number of both successfully breeding pairs and the population size. At the same time, no differences were found for artificial and natural nests in terms of reproductive success, clutch size, and the number of fledglings. In 51% of nesting cases, pairs laid three eggs, compared to two eggs in 43% or four eggs or one egg each in 3%. The average clutch size was 2.54 ± 0.08 eggs. Over the years of our study of owl nesting in Mordovia, 13.6% pairs raised one chick, compared to two and three chicks in 36.4 and 50%, respectively. The number of reared chicks per successful nest averaged 2.36 ± 0.11. The mortality rate in nests was lower in artificial nesting sites (30%) than in natural ones (40.6%). [ABSTRACT FROM AUTHOR]

The Harpy Eagle (Harpia harpyja) is threatened with extinction throughout its distribution in the neotropical forests. In the Atlantic Forest, deforestation has reduced the number of suitable habitats, with only a few remnant forest fragments hosting active nests; currently, the only known nests in this region are in the Central Atlantic Forest Ecological Corridor (CAFEC), in Brazil. Little is known about Harpy Eagle diets in this region, despite this information being essential for developing effective conservation strategies. We classified the composition, frequency, richness, ecological attributes, and conservation status of the species that make up the Harpy Eagle's diet in its last refuges in the CAFEC. Between 2017 and 2021, we collected and analyzed 152 prey remains and 285 camera trap photographs from seven active nests. We identified at least 16 mammal species (96.7%), one parrot and other bird remains (3.3%). The Harpy Eagle's diet consisted mainly of medium-sized arboreal, folivorous, frugivorous, and diurnal mammals. Five prey species are currently threatened with extinction at global, six at national and seven at regional levels. The majority of the diet consists of Sapajus robustus, which is threatened, and Bradypus variegatus, which is not threatened. In addition to the effects of habitat loss and hunting, the Harpy Eagle may also suffer from the decline in the populations of their prey in the Atlantic Forest. [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]

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]

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]

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]

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]

Avian trichomonosis is a parasitic disease caused mainly by Trichomonas gallinae and other Trichomonas species. It can be asymptomatic, or it can produce a necrotic lesion in the upper digestive tract and spread to other organs, causing the death of the infected birds. In this study, we aimed to evaluate an adapted real-time PCR method for the diagnosis of different genotypes and species of avian oropharyngeal trichomonads. Fifty-six samples from the oropharynx of Bonelli's eagles (Aquila fasciata) obtained between 2018 and 2019 were analyzed using the real-time PCR and the end-point PCR, both targeting trichomonads ITS, and the results were compared by a coefficient of agreement. All positive samples were sequenced. The analysis showed a higher percentage of detection of real-time PCR ITS compared with end-point PCR ITS (64.3 vs 55.4%), and good agreement value (Kappa = 0.816). Melting temperature value for resulting amplicons of real-time PCR for avian trichomonads was 83.45 ± 0.72 °C. Genotypes A, D, and III were found among the sequences. Moreover, Trichomonas gypaetinii, a common species in scavenger birds, is reported for the first time in Bonelli's eagles. [ABSTRACT FROM AUTHOR]

The article titled "An optimized eagle adaboost model for brain tumor classification and severity analysis system" has been retracted by the Editor-in-Chief and the publisher due to concerns identified during an investigation. These concerns include unsupported citations, non-standard phrasing, and image irregularities. The Editor-in-Chief no longer has confidence in the results and conclusions of the article. The authors have not responded to correspondence regarding the retraction. The full text of the retracted article is available as supplementary information. [Extracted from the article]

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 significance of raptor predation has been repeatedly emphasized in studies on arboreal primates; however, there are few studies on the predation of primates by raptors in primate-rich forest environments. Among the raptor species, the crowned eagle in Africa is known to be a primate-predator. In this study, a video camera was set up at the nesting site of a crowned eagle pair in the Mahale Mountains National Park in Tanzania, and the prey species delivered to the nest by the pair were identified by analyzing the video footage. Of the 46 prey deliveries recorded during 4.5 months of recording in the nestling season, primates accounted for 26 cases, of which 16 were red-tailed monkeys, the most abundant primates in the area. No prey was clearly identified as red colobus, despite a seemingly high density of this monkey species. This result suggests that predation by the eagles was biased toward the red-tailed monkey in Mahale, whereas no such bias toward the same monkey species was reported in a previous study conducted in Kibale. Furthermore, among different predator species in Mahale, only the crowned eagle prey primarily on red-tailed monkeys. Although chimpanzees and leopards inhabiting the study area are also significant predators of monkeys, these two species prefer red colobus to red-tailed monkeys. This suggests that these two monkey species living in the same forest have different primary predatory threats. [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]

Data on the migration routes and wintering sites were collected from nine juveniles and one adult imperial eagle (Aquila heliaca). Six of thetagged birds were in family relationships: two siblings, one adult bird and its chick, and two birds born a year apart. The onset of the autumn migration appeared to be the same for all birds, and it started at the end of September to early October. The second migration turned out to be shorter than the first one for all immature eagles. This was because they flew using more direct routes to their previous wintering sites and because some of them had ended their second migration before they arrived atthe first wintering sites. Both siblings had different migration routes, but wintered in the same region. The adult bird and its eaglet started migrating separately, but had the same routes and wintering sites. Both birds born a year apart had the longest routes and reached the southern part of the Arabian Peninsula. The oldest eagle flew across the Bab El Mandeb Strait and spent the winter in the Ethiopian Highlands. The youngest eagle reached an island located in the strait, but then turned back. The coinciding wintering sites, albeit using different migration routes, by related birds seems to prove that the wintering locations, but not the migration routes, are genetically determined in the Imperial Eagles from the Volga region population. [ABSTRACT FROM AUTHOR]

Environmental pollution with antibiotics and antibiotic resistant bacteria represents a significant ecological problem around the world. In this study, we wanted to identify multiple clinically important genotypes of Escherichia coli (E. coli) in one of the largest populations of white-tailed eagles (Haliaeetus albicilla–H. albicilla) nesting in the protected area of Danube floodplains. This is the first such study of the species, covering the nesting community (20 of 21 active nests) of H. albicilla in one nature reserve. High resistance to fluoroquinolone was detected in one multidrug-resistant E. coli isolate, and this type of resistance was induced by the mutations on topoisomerase genes gyrA, parC, and parE. This isolate also carried resistance genes sul1 and tetB and the virulence gene iutA. Molecular typing by randomly amplified polymorphic DNA (RAPD) in combination with phylogenetic typing revealed high diversity among 11 E. coli isolates. With five different replicon types found (IncFIB, IncFIA, Inc FIC, IncY, and IncI1), the majority of isolates had multi-replicon status with a pronounced capacity of horizontal transfer of resistance and virulence genes. The coexistence of at least two virulence genes linked to development of a pathogenic phenotype and multi-replicon status in three E. coli isolates implies the potential for causing extra-intestinal infections, as well as horizontal transfer of pathogenic genetic determinants in the bacterial community. Resistance to synthetic antibiotics such as fluoroquinolones in an E. coli isolate from white-tailed eagle clearly points to the indirect anthropogenic sources of antibiotic pollution and antibiotic resistant bacteria present in wildlife food chains. [ABSTRACT FROM AUTHOR]

Recent phylogenetic and morphologic studies of Trichomonas spp. suggests that there are more than 3 species that infect the upper alimentary tract of wild birds, which include T. gallinae, T. stableri, and T. gypaetinii. In this study, investigations were conducted on the prevalence of trichomonads in the upper alimentary tract of 12 Steller's sea eagles (Haliaeetus pelagicus) and 18 white-tailed sea eagles (H. albicilla). All birds were rescued from the wild and kept at a rehabilitation facility in Hokkaido, Japan, for variable durations and did not show any symptoms of trichomonosis. The ITS1-5.8SrRNA-ITS2 (ITS) genomic region of Trichomonas spp. was detected from 29 samples by PCR, and flagellates were confirmed from 4 samples by culture. Morphologic observations and measurement recordings were conducted under a light microscope on trophozoites obtained from the cultured isolates. Genomic sequences of the ITS, 18S ribosomal RNA (18S rRNA), Fe-hydrogenase, and RNA polymerase II largest subunit (Rpb1) regions were determined by direct sequencing, and phylogenetic analyses were conducted with previously published sequences of Trichomonas spp. All isolates were concluded as T. gypaetinii based on morphologic and molecular characterizations of the ITS and 18S rRNA genes. This is the first study to isolate T. gypaetinii from Haliaeetus eagles and further provide novel sequences of the Fe-hydrogenase and Rpb1 genes of T. gypaetinii. Both genomic regions also confirmed that T. gypaetinii belong to independent clusters from other Trichomonas spp. [ABSTRACT FROM AUTHOR]

Dispersal is a key process affecting the dynamic and genetic structure of populations. To increase our knowledge on first-year dispersal in the white-tailed eagle (WTE), 35 nestlings in the Czech Republic, Hungary, and Austria were equipped with GPS/GSM loggers while on the nest between 2016 and 2019. Twenty-nine individuals surviving until March 31 were used to assess post-fledging areas, first-year dispersal distance and direction, temporary settlement areas, and habitat selection. The first flight from the nest was observed between May 19 and July 8. Start of dispersal from post-fledging areas occurred between July 1 and November 14. Post-fledging areas were significantly larger in males (p = 0.001, median 1236 km2, n = 15) than females (median 139 km2, n = 12). Maximal dispersal distance ranged from 93 to 433 km from the native nest (median = 187 km) and did not correlate with Simpson's Diversity Index computed for habitats in individual 100% minimum convex polygons (MCP). Median sizes of minimum convex polygons were 26,888 km2 for 100% MCP and 13,376 km2 for 95% MCP (n = 29). Median sizes of kernel density estimates (KDE) were 3393 km2 for 80% KDE and 1137 km2 for 50% KDE. After start of dispersal, young WTEs returned to the proximity of the parental nest for night roosting sporadically. No sex-specific differences in dispersal distance were recorded. While young individuals from the three subpopulations are likely to occur in the same area during the first year of life, future nesting site identification will enable us to assess real gene flow and the connectivity level among them. As this study has illustrated, future conservation efforts to protect young WTEs will require cross-border cooperation. [ABSTRACT FROM AUTHOR]

Habitat use studies provide invaluable information for the conservation of species that suffer from habitat loss or degradation. We used satellite telemetry to study the habitat use of white-tailed eagles (Haliaeetus albicilla) in relation to six habitat classes (artificial surfaces, agricultural areas, forests, semi-natural areas, wetlands and waterbodies) and five forest age classes (0–9, 10–19, 20–59, 60–99 and ≥ 100 years old) during the post-fledging period in Finland. The post-fledging period, defined here as the period between fledging and dispersal from the natal area, is a critical life-history stage. Our primary objective was to provide information that could be integrated into landscape planning, including wind-energy development (which poses a threat to white-tailed eagles). We found that the habitat classes that were selected by the young white-tailed eagles were forests, semi-natural areas (i.e., transitional woodland and bare rock) and wetlands. When using forests, the eagles selected stands of 0–9 years old, presumably due to the use of retention trees surrounded by a clear-cut as perching sites. Conversely, the habitat classes that were avoided were artificial surfaces, agricultural areas and (the immediate vicinity of) waterbodies. We conclude that the conversion of natural habitats into built and agricultural areas is detrimental to young white-tailed eagles because it reduces habitat availability. They, however, appear to be capable of using forests recently impacted by forestry if perch trees are present. Careful landscape planning is needed to protect priority habitats and avoid conflicts with an expanding white-tailed eagle population (e.g., by building wind farms in areas already environmentally disturbed). [ABSTRACT FROM AUTHOR]

Predator odors are natural stressors that induce anti-predator defensive responses, which have developed under evolutionary pressures to maximize the fitness of an individual to avoid dangerous confrontations. In this study, we analyzed the defensive responses of a subterranean rodent species, the plateau zokor (Eospalax baileyi), to predation threat, and examined the trade-offs between defensive responses and foraging. Plateau zokors were exposed to 1, 3, and 6 g of eagle owl (Bubo bubo) feces, and the anti-predator behavioral, hormonal, and hypothalamic corticotropin-releasing factor and c-fos mRNA expression responses were analyzed and compared with the control (distilled water). Exposure of the animals to owl feces led to significant reductions in both duration of feeding and amount of food consumed, while some defensive behavioral responses (e.g., freezing and rearing) were more significant in the exposed animals than in the control. Serum levels of adrenocorticotropic hormone and corticosterone in plateau zokors exposed to owl feces were significantly higher compared with the control. The hypothalamic corticotropin-releasing factor and c-fos mRNA expression levels of plateau zokors exposed to 1, 3, and 6 g owl feces increased significantly, concomitant with the amount of eagle owl feces presented. Owl feces induced various behavioral, hormonal, and hypothalamic gene expression changes in plateau zokors exposed to them. Some behavioral and gene expression (but not hormonal) responses appeared to be threshold dependent. Significance statement: Predator odors supersede other signals and can provide comprehensive information to prey during life-threatening events. The plateau zokor is a typical subterranean rodent living in dark and enclosed subterranean habitats. Owing to this special habitat, zokors may be able to recognize ground predator odors and respond defensively. We investigated changes in behavior, hormones, and the hypothalamic corticotropin-releasing factor and c-fos mRNA expression levels of the plateau zokor when exposed to different amounts of eagle owl feces. We believe that our study makes a significant contribution to the literature because our results support the predation risk allocation hypothesis, showing that eagle owl feces inhibit foraging and induce various anti-predatory behavioral and neuroendocrine responses in plateau zokors. [ABSTRACT FROM AUTHOR]

Many apex predator populations are recolonizing old areas and dispersing to new ones, with potential consequences for their prey species and for livestock. An increasing population of the White-tailed Eagle (Haliaeetus albicilla) has settled north of the Arctic Circle in northern Finland, mainly at two big water reservoirs but also in areas with mainly terrestrial habitat. We examined nesting habitat preferences and prey use of White-tailed Eagles in this environment, where reindeer husbandry is a traditional livelihood and concerns are rising that the growing White-tailed Eagle population poses a threat to reindeer calves. Lakes, peat bogs, and marshlands were preferred habitats in the nesting territories. Fish constituted 64.3% of the identified prey items, with birds accounting for 28.5% and mammals 7.2%. The nesting territory habitat within a 10 km radius and the latitude influenced the prey composition at both the group and species level. The occurrence of reindeer calves as prey increased with latitude but was not associated with any habitat. Knowledge of the diet and territory preferences can be used to predict future dispersal and local prey use of this species. Nesting White-tailed Eagles do not seem to pose a threat to traditional reindeer herding, but further research is needed regarding non-breeding sub-adults and whether the White-tailed Eagles actually kill reindeer calves or simply exploit their carcasses. [ABSTRACT FROM AUTHOR]

This work is aimed at determining the onset of breeding of the White-tailed Eagle and the reasons that affect its breeding phenology in the central part of the Volga–Kama region (Republic of Tatarstan, together with the adjacent areas of the republics of Chuvashia and Udmurtia, as well as Samara and Ulyanovsk oblasts). In the Republic of Tatarstan, the bulk of data were obtained in 2011–2016; in Ulyanovsk and Samara oblasts, in 2012; in the Republic of Chuvashia, in 2013, 2015, 2016; and in Udmurtia, in 2016. An analysis of the onset of breeding was carried out on the basis of photo records of the White-tailed Eagle nests with nestlings primarily at ages of 30–60 days and some younger than 30 days, in 2011–2016. The age of nestlings was determined by the photo tables comparing the degree of development of their plumage. When establishing the date of the first egg laying, the age of the elder (or the only) nestling and the incubation time, which amounts to 37 days, were taken into account. In total, 119 cases of breeding were analyzed. For additional control of calculations concerning the earliest periods of breeding, at the beginning of the breeding season, on February 23, 2015, distant observations of a group of 16 nests were carried out using optical devices along the upper reaches of the Kuibyshev reservoir. More precise data on the dates of egg laying were also obtained using a surveillance camera at an eagle nest in the Volga–Kama Biosphere Nature Reserve. According to the results of calculations, the period of the first egg laying extends from February 22 to April 11 (n = 119). Most of the clutches (70.6%, n = 84) are laid in the period from February 22 to March 15, and the maximum occurs in the first five days of March (26.05%, n = 31). A comparison with previously published data shows that, on average, the eagles start breeding half a month earlier than they did in the 20th century. In our opinion, the shift towards earlier breeding dates is primarily caused by the presence of artificial food supply at local wintering sites and increased species numbers in the Volga–Kama region. The White-tailed Eagle's status in the region partially changed from the migrating breeder to resident breeder. The distances from the breeding territories to the wintering grounds with abundant of forage shortened significantly. The influence of climate warming on the time of egg-laying cannot be excluded either. [ABSTRACT FROM AUTHOR]

Collision risk of soaring birds is partly associated with updrafts to which they are attracted. To identify the risk-enhancing landscape features, a micrositing tool was developed to model orographic and thermal updraft velocities from high-resolution remote sensing data. The tool was applied to the island of Hitra, and validated using GPS-tracked white-tailed eagles (Haliaeetus albicilla). Resource selection functions predicted that eagles preferred ridges with high orographic uplift, especially at flight altitudes within the rotor-swept zone (40–110 m). Flight activity was negatively associated with the widely distributed areas with high thermal uplift at lower flight altitudes (<110 m). Both the existing wind-power plant and planned extension are placed at locations rendering maximum orographic updraft velocities around the minimum sink rate for white-tailed eagles (0.75 m/s) but slightly higher thermal updraft velocities. The tool can contribute to improve micrositing of wind turbines to reduce the environmental impacts, especially for soaring raptors. [ABSTRACT FROM AUTHOR]

Sexual selection and non-random mating are considered, among others, determinant mechanisms for the maintenance of genetic colour polymorphism in some bird species. We analyse the mechanisms, which, in parallel with Mendelian inheritance, may be acting in the maintenance and evolution of the morph ratio in a two-morph raptor species, using observational data of successful breeding individuals and their offspring from long-term studies conducted in three Spanish populations. Our results showed that the dark offspring produced in breeding events involving mixed-morph adult pairs far exceeds the expected value under the Hardy–Weinberg equilibrium, especially in the case of pairs formed by a light male and a dark female. In addition, the low number of dark eaglets born from pairs formed by light individuals (indistinctly homozygous or heterozygous) indicates that the number of breeding events of heterozygous (both the male and female) light morph pairs, was much lower than expected. As the plausible existence of a transmission ratio distortion phenomenon in heterozygous light morph males does not, alone, explain the disproportionate number of dark eaglets observed, our results suggest that one or two selective mating phenomena may be occurring in this polymorphic system. The first one could be a disassortative mating process whereby heterozygous light males preferentially mate with dark females, based on the imprint of the colour morph of their mother. The second phenomenon would only affect light morph individuals, which would preferentially mate with heterozygous individuals of the opposite sex, selected according to secondary sexual characteristics or behavioural traits that are unknown at the moment. [ABSTRACT FROM AUTHOR]

Several studies on wind turbine collision mortality in raptors suggest a bias towards adult birds, while sex-biased mortality has not yet been documented. We compared collision mortality in relation to all known causes of mortality and in relation to demographic data for the German population of the White-tailed Eagle and found collision mortality to be sex biased but not age biased. We suggest that these contrasting results may in part be explained by the lack of baseline data about the demographic structure of surveyed populations in previous studies. Our results stress the importance of baseline data for inferring demographic consequences of wind turbine collision mortality. [ABSTRACT FROM AUTHOR]

Context: Biodiversity is closely related to landscape heterogeneity, but both are difficult to evaluate directly. Apex predators, such as raptors, are potential surrogate indicators of diversity, but previous studies using a correlative approach have been heavily criticised. Objectives: We evaluated whether space use by a generalist avian predator, the lesser spotted eagle Clanga pomarina, is an effective indicator of functional landscape heterogeneity and evaluate mechanisms driving this relationship. Methods: We used GPS-tracking of eagles over eight breeding seasons along with precise field mapping data for broad and detailed land-use types from Estonia, Eastern Europe. We analysed the effects of various landscape metrics and composition on movement patterns of eagles. Results: Activity centres of eagles were associated with configurational heterogeneity, as evidenced by their foraging on the edges of small complex patches more often than expected at random. The eagles also avoided roads (disturbance) and preferred forest edges (ecotones with abundant prey and perch sites). The importance of compositional heterogeneity was revealed by preferences for specific land-use types (e.g. spring-sown but not autumn-sown wheat); preferred crops changed over time. The model including only general land-use classes was outperformed by the model based on a detailed classification. Conclusions: Movement ecology provides an opportunity to biomonitor the heterogeneity of landscapes and adds a functional perspective to earlier raptor-biodiversity correlation studies. This suggests that in addition to GPS-tracking, large quantities of opportunistic observations by citizen scientists can be used to evaluate biodiversity across landscapes. [ABSTRACT FROM AUTHOR]

The Spanish Imperial Eagle (Aquila adalberti) disappeared from Africa as a breeding species in the 1960s coincident with a general decline of their populations in the Iberian Peninsula. Because of a combination of successful conservation actions and a general change in human attitudes, the Spanish Imperial Eagle population has been increasing in Iberia from 103 pairs in 1980 to more than 500 breeding pairs in 2018. As a consequence, the number of juveniles that cross the Strait of Gibraltar into Africa has increased recently. Abundance and distribution of potential prey should affect young eagles' behaviour and could be a limiting factor for a potential re-colonization of previous North-African populations. Additionally, determination of temporary settlement areas is crucial from a conservation point of view. Conservation actions in these areas, particularly reduction of juvenile mortality, are a priority to facilitate future reestablishment of breeding populations of the species in North Africa. Here we report on the dispersal movements of juvenile Spanish Imperial Eagles marked with GPS-GSM transmitters in Andalusia (southern Spain), some of which crossed the Strait of Gibraltar into north-western Africa, an area that does not have populations of the eagle's main prey, the European rabbit. We analysed the differences in dispersal patterns and temporary settlement behaviour in the two study areas. We found that dispersal movements were greater, temporary settlement areas were larger, and individuals stayed longer in areas and moved greater distances among them in Africa than in Iberia. We believe that our results are best explained by applying the Marginal Value Theorem, which predicts that individuals will leave a foraging area when the availability of prey drops to similar levels of those of the surrounding environment. We suggest that the increase in the records of the species in Africa could lead to a recolonization of the species in Africa based on birds coming from the "source" Iberian population, but only if the Iberian population continues to increase. We recommend that conservation measures must be established in these temporary settlement areas in Africa. [ABSTRACT FROM AUTHOR]

Collision with wind turbines is a conservation concern for eagles with population abundance implications. The development of acoustic alerting technologies to deter eagles from entering hazardous air spaces is a potentially significant mitigation strategy to diminish associated morbidity and mortality risks. As a prelude to the engineering of deterrence technologies, auditory function was assessed in bald eagles (Haliaeetus leucocephalus), as well as in red-tailed hawks (Buteo jamaicensis). Auditory brainstem responses (ABRs) to a comprehensive battery of clicks and tone bursts varying in level and frequency were acquired to evaluate response thresholds, as well as suprathreshold response characteristics of wave I of the ABR, which represents the compound potential of the VIII cranial nerve. Sensitivity curves exhibited an asymmetric convex shape similar to those of other avian species, response latencies decreased exponentially with increasing stimulus level and response amplitudes grew with level in an orderly manner. Both species were responsive to a frequency band at least four octaves wide, with a most sensitive frequency of 2 kHz, and a high-frequency limit of approximately 5.7 kHz in bald eagles and 8 kHz in red-tailed hawks. Findings reported here provide a framework within which acoustic alerting signals might be developed. [ABSTRACT FROM AUTHOR]

Table 4 Dispersal characteristics of 35 young white-tailed eagles tracked during the first year of life (individuals with a lost signal or that died before March 31 are marked in italic). [Extracted from the article]

During the post-fledging dependence period, young raptors are particularly vulnerable as they are still developing flying, hunting and social skills, and collecting spatial environmental information required for emancipation. We studied the use of space during this critical period by the highly threatened Spanish Imperial Eagle Aquila adalberti, using high temporal and spatial resolution tracking devices. Ten juveniles from four different nests were tracked throughout their dependence period with GPS/GSM tags. This period lasted until a median age of 137 days (93–153). Juveniles remained within a stable home range with a median of 232 ha, but when 90–100 days old began making exploratory movements that became more frequent and extensive with the approach of emancipation. These movements had a median of 22.2 km and were usually completed within the same day, but this exploratory behaviour proved to be quite plastic, as one movement was 1291 km long and lasted 4.5 days. Moreover, three individuals that were apparently forced to emancipate particularly early seem to have virtually skipped the exploratory phase. The length of the movements varied among years within the same nest, and those of females were about twice those of males. Most movements were towards the NW, and the outgoing flight was usually against the wind. This behaviour may keep animals from flying so far from the nest that they are then unable to return. The high spatial and time resolution provided by GPS tracking resulted in data that highlight the conservation importance of the nest site until well after fledging. Measures to minimize nest disturbance should thus be extended until early October. Moreover, data show that so much of the activity of the still inexperienced juveniles is concentrated in the small pre-emancipation range that is critical to protecting its habitats and eliminating all anthropogenic sources of mortality. [ABSTRACT FROM AUTHOR]

Mesopredators frequently suffer lethal and/or non-lethal negative effects when breeding in sympatry with more powerful apex predators. The recent recovery of the White-tailed Eagle Haliaeetus albicilla (WTE) population throughout its range indicates the return of the largest predator of the raptor communities there. In this study, we assess the importance of habitat overlap and spatial distribution to the reproduction of the Lesser Spotted Eagle Clanga pomarina (LSE), a species that breeds sympatrically in areas of high WTE density near the Baltic Sea, but is three times smaller than the latter. Fewer water bodies surround the nesting sites of the LSE, and it uses agricultural areas and transitional habitats more frequently than the WTE. The same breeding territories are faithfully occupied by the LSE annually, irrespective of the distance between these and those of the WTE. We found that the breeding success of the LSE was not affected by the proximity or breeding output of the nearest pair of WTEs, nor was this affected by the number of WTE pairs present within a 3-km radius of nests. Our data suggest that the smaller LSE coexists with an abundant top predator without any obvious adverse effects on its population dynamics. [ABSTRACT FROM AUTHOR]

The Crowned Solitary Eagle ( Buteogallus coronatus) is one of the rarest and most severely threatened birds of prey in the Neotropical region. We studied levels of neutral genetic diversity, population structure, and the demographic history of the species using 55 contemporary samples covering a large fraction of the species range, which were genotyped at 17 microsatellite loci. Our results indicated genetic homogeneity across the sampled regions, which may be explained by a high dispersal capability of Crowned Solitary Eagles resulting in high gene flow or relatively recent population expansion. Further demographic tests revealed that the species has experienced a recent demographic reduction, but inbreeding was not detected. The existing connectivity between geographically separated populations may have buffered the negative effects of the demographic bottleneck. Alternatively, the demographic reduction may be too recent to detect a genetic signature due to the long generation time of the species. Potential conservation strategies, including the possibility of translocations of individuals, are discussed. [ABSTRACT FROM AUTHOR]

The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors' economic niche and potential for human-wildlife conflict. The crowned eagle ( Stephanoaetus coronatus) is one of Africa's apex predators and a population is present within the urban greenspace mosaic of Durban and Pietermaritzburg, KwaZulu-Natal, South Africa. In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets. Time-lapse cameras were positioned at urban nest sites ( n = 11) to identify the prey composition during breeding, particularly in regards to taxa with human associations. The numerical proportion of avian prey, particularly hadeda ibis ( Bostricia hagedash) pulli, was several times greater than any previous diet description. The methodology used and the abundance of hadeda ibis in these urban environments are potential contributing factors. Rock hyrax ( Procavia capensis) was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys ( Chlorocebus pygerythrus). It was found that domestic stock comprised 6 % of the identifiable prey. Contrary to popular belief, no dogs ( Canis familiaris) and few cats ( Felis domesticus) were delivered to the nest by breeding eagles in this study. The negative consequences of small proportions of pet losses should be considered against the majority of wildlife prey consumed, which also have various wildlife conflict interactions. Juvenile and sub-adult eagles are most frequently identified at in situ attacks of pets, particularly toy dog breeds. Further research on juvenile dispersal and winter diet will provide insights on the ecological impacts of eagle management strategies in the region. [ABSTRACT FROM AUTHOR]

We conducted a retrospective analysis to evaluate demographic and pathologic characteristics in 484 bald eagles ( Haliaeetus leucocephalus) and 68 golden eagles ( Aquila chrysaetos) diagnosed with lead poisoning at the U.S. Geological Survey National Wildlife Health Center. As part of our analysis, we compared characteristics of lead poisoned eagles with those that died of other causes. Odds of lead poisoning were greater for bald eagles versus golden eagles, females versus males, adults versus juveniles, and eagles from the Mississippi and Central flyways versus the Atlantic and Pacific flyways. In addition to spatial, species, and demographic associations, we detected a distinct temporal trend in the collection date of lead poisoned bald eagle carcasses. These carcasses were found at greater frequency in late autumn and winter than spring and summer. Lesions in lead poisoned birds included emaciation, evidence of bile stasis, myocardial degeneration and necrosis, and renal tubular nephrosis and necrosis. Ingested lead ammunition or fragments were found in 14.2 % of bald eagles and 11.8 % of golden eagles. The overall mean liver lead concentration (wet weight basis) for eagles diagnosed with lead poisoning was 28.9 ± 0.69 SE mg/kg in bald eagles and 19.4 ± 1.84 SE mg/kg in golden eagles. In eagles diagnosed with collision trauma, electrocution, poisoning (other than lead), emaciation, infectious disease, trapping death, other, and undetermined causes, average liver lead concentrations were low (<1 mg/kg) and did not differ among causes of mortality. Thus, based on our data, we found no evidence that lead exposure of eagles predisposed them to other causes of mortality. [ABSTRACT FROM AUTHOR]

The Spanish imperial eagle ( Aquila adalberti) is found only in the Iberian Peninsula and is considered one of the most threatened birds of prey in Europe. Here we analyze lead concentrations in bones (n = 84), livers (n = 15), primary feathers (n = 69), secondary feathers (n = 71) and blood feathers (n = 14) of 85 individuals collected between 1997 and 2008 in central Spain. Three birds (3.6%) had bone lead concentration > 20 μg/g and all livers were within background lead concentration. Bone lead concentrations increased with the age of the birds and were correlated with lead concentration in rachis of secondary feathers. Spatial aggregation of elevated bone lead concentration was found in some areas of Montes de Toledo. Lead concentrations in feathers were positively associated with the density of large game animals in the area where birds were found dead or injured. Discontinuous lead exposure in eagles was evidenced by differences in lead concentration in longitudinal portions of the rachis of feathers. [ABSTRACT FROM AUTHOR]

Haematological and serum biochemical values were estimated in blood samples collected from 21 apparently adult golden eagles ( Aquila chrysaetos) of both sexes. The mean values of red blood cells, packed cell volume, haemoglobin, white blood cells, heterophils, lymphocytes, monocytes and eosinophils were 1.63 ± 0.11 × 1012/l, 0.47 ± 0.009 l/l, 91.73 ± 1.52 g/l, 24.31 ± 1.97 × 109/l, 4.40 ± 0.22 × 109/l, 16.81 ± 0.65 × 109/l, 0.99 ± 0.19 × 109/l and 2.10 ± 0.30 × 109/l, respectively. The leucocytes had 69.14%, 4.09%, 18.12% and 8.65% lymphocytes, monocytes, heterophils and eosinophils, respectively. The results of serum biochemistry in the golden eagle indicated that the concentrations of glucose, total protein, albumin, total globulin, cholesterol, triglyceride, uric acid, blood urea nitrogen, creatinine, calcium, phosphorous, aspartate aminotransferase, alanine aminotransferase, creatine kinase, lactate dehydrogenase and alkaline phosphatase were 16.42 ± 0.73 mmol/l, 49.76 ± 1.35 g/l, 20.46 ± 0.79 g/l, 29.30 ± 1.47 g/l, 2.14 ± 0.09 mmol/l, 2.04 ± 0.08 mmol/l, 457.67 ± 97.46 μmol/l, 2.74 ± 0.17 mmol/l, 53.27 ± 3.87 μmol/l, 2.37 ± 0.24 mmol/l, 1.73 ± 0.08 mmol/l, 293.24 ± 18.96 IU/l, 28.21 ± 2.36 IU/l, 411.29 ± 58.37 IU/l, 1,209.89 ± 21.73 IU/l and 67.31 ± 5.29 IU/l, respectively. There were no significant differences between haematological and serum biochemical parameters of male and female golden eagles ( P > 0.05). [ABSTRACT FROM AUTHOR]

Aerial surveys of Caspian seals on the winter ice field in Kazakhstan territorial waters were carried out in February 2005 and 2006 to assess the annual pup production for the species and natural predation on newborn pups. Estimated pup production was 21 063 in 2005 and 16 905 in 2006 (including an estimated figure for pups born in Russian territory in each year). The breeding population size of approximately 20 000 females is much less than published estimates from the late 1980s. Eagles were the principal natural predators of pups. Commercial icebreaker routes passed through areas of dense pup concentrations in 2006, although not in 2005. Our findings have important implications for the development of conservation strategies for the species. Natural mortality, loss to predators, and, more important, the current hunting quota substantially exceed the recruitment of the Caspian seal population. Anthropogenic sources of mortality should be managed to avoid further declines in the species. [ABSTRACT FROM AUTHOR]

Some non-human primates produce acoustically distinct alarm calls to different predators, such as eagles or leopards. Recipients respond to these calls as if they have seen the actual predator, which has led to the notion of functionally referential alarm calls. However, in a previous study with free-ranging putty-nosed monkeys ( Cercopithecus nictitans martini), we demonstrated that callers produced two acoustically distinct alarm calls to eagle shrieks and leopard growls, but both alarm calls were given to both predators. We can think of two basic explanations for this surprising result, a methodological and theoretical one. Firstly, acoustic predator models may not always be suitable to test alarm call behaviour in primates, sometimes causing uncharacteristic behaviour. Secondly, referential alarm calling may not be a universal feature of primate alarm call systems. Considering the methodological and theoretical importance of these possibilities, we conducted a follow-up study using life-sized leopard, eagle, and human models on the same population and compared the resulting vocal responses to those given to acoustic predator models. We compared the alarm call series given to each of these predator model types and found a considerable degree of consistency suggesting that the mode of presentation did not affect anti-predator calling strategies. However, evidence for audience effects on calling behaviour was inconclusive. While it appears that predator class is reliably encoded by different call series types irrespective of the mode of presentation, observations of these same call series given in non-predatory contexts indicate that predator class is unlikely to be the relevant organising principle underlying the alarm-calling behaviour in this species. We conclude by offering an alternative, non-referential, account of the alarm-calling system exhibited by this species. [ABSTRACT FROM AUTHOR]

The Bonelli's eagle (BE) is considered by the European Union as a high-priority species for conservation in the Valencian Community (East of Spain). However, in 2006 the European Union opened a legal procedure against the Spanish Kingdom, accused of lacking of an adequate network of special protected areas (SPAs) to preserve the BE in the region. Here we evaluate whether important bird areas (IBAs) and SPAs network is enough to preserve this species, on the basis of a thorough analysis of habitat preferences. A GAP analysis is performed to conduct a revision of current SPAs and BirdLife proposed IBAs. Our results suggest that the current network of SPAs becomes insufficient to protect the BE. The IBAs network, although improves the current network of SPAs, increasing the percentage of BE potential habitat included, also results inadequate. We propose a new SPAs network according to the potential suitable habitat for the species. Given the trade-off between financial investment and the conservation of biodiversity, we propose to maximize the surface of potential habitat included in the protected network minimizing the surface of the region that would be necessary to protect, thus avoiding an unnecessary expense and otherwise unrealistic results. [ABSTRACT FROM AUTHOR]

We examined the patterns of habitat use of six radio-tagged booted eagles (Hieraaetus pennatus) in a Special Protection Area (SPA) in southeastern Spain. Variable percentages of radio locations (20.8-72.0 %) and home range areas (45.2-81.3 %) lay outside the SPA limits. A model selection procedure showed that habitat use was mainly influenced by habitat type and the distance to the nest. Edges and open lands were the most selected habitat types at long distances, while the probability of forest use strongly decreased with the distance. We conclude that effective conservation strategies for this species should encourage not only the protection of the forest nesting habitats, but also the traditional agricultural practices of the surrounding agroecosystems. [ABSTRACT FROM AUTHOR]

The present study focused on analyzing samples of bones, livers and kidneys of European white-tailed eagles ( Haliaëtus albicilla) and lesser-spotted eagle ( Aquila pomarina). Bone samples were collected for both species, from 7 and 2 individuals, respectively, whereas liver and kidney samples for white-tailed eagle species only, 2 and 1 individuals, respectively. The samples were analyzed for the presence of gamma-emitters and then for 90Sr, 238Pu, 239+240Pu and 241Am. The applied radiochemical method is presented. Activity concentration in ashen bones (600 °C) for 90Sr ranged from 4.6±1.2 to 31.0±2.5 Bq/kg, for 239+240Pu from <1.7 to 21±4 mBq/kg, for 238Pu from <2.7 to 6.5±1.3 mBq/kg and for 241Am from <1.2 to 6.5±4.4 mBq/kg. Relatively high 239+240Pu activity concentration of 78±9 mBq/kg (for fresh weight) was recorded in a single kidney sample. The liver samples showed activities of magnitude at least one order lower. No clear correlations were found between the activities of different radionuclides. [ABSTRACT FROM AUTHOR]

This paper presents the levels of lead found in the feathers of adult and blood of nestlings of booted eagle (Hieraaetus pennatus), European buzzard (Buteo buteo), and gos- hawk (Accipiter gentilis) sampled in the 1999 and 2000 breeding seasons in a Mediterranean forest of the Province of Murcia (Southeastern Spain) located far from potential sources of metal contamination. Levels of δ-aminolevulinic acid dehydratase activity (δ-ALAD) in blood were also measured in the nestlings. Lead concentrations ranged from 1.1 to 11.21 µg/dl in blood of nestlings and from 0.35 to 1.66 mg/kg d.w. in the feathers of their parents. A significant relationship was found between blood δ-ALAD and lead (ρ = -568), showing a negative correlation with blood lead levels even at lead concentrations below 5 µg/dl. This fact suggests the usefulness of this enzymatic biomarker for low lead exposure in forest raptors. There were also positive relationships between the lead concentrations in blood of nestlings and those in feathers of their parents (ρ = 0.817), suggesting the usefulness of feathers for biomonitoring environmental exposure to lead. [ABSTRACT FROM AUTHOR]

Investigates possible causes of territory desertion among Bonelli's eagles Hieraaetus fasciatus in Murcia (southeastern Spain): low demographic parameters, low habitat quality and competition with Golden eagles Aquila chrysaetos. Surveying of a Bonelli's eagle population; Comparison of abandoned and occupied territories to find differences in demographic parameters (flight rate, productivity and mortality) or habitat characteristics; Mortality that was significantly higher in abandoned territories; Abandoned territories that also had larger areas of forest and extensive agriculture, while occupied territories had more shrublands; Competition with Golden eagles that was not a determinant of territorial abandonment but interacted with human persecution of the species; Management implications that are discussed.