Aquila Pomarina Research Articles

Prevalence and local transmission of haemosporidian (Haemosporida) parasites in nestlings of birds of prey (Aves, Accipitriformes) in the temperate forests in Lithuania

Wild birds of prey (Accipitriformes) are infected with haemosporidian (Haemosporida) parasites worldwide, and it is known that these parasites can negatively affect their health. These birds are less studied due to their low densities in ecosystems, conservation status, and difficulty of accessing them in the wild. Therefore, in this study, we focused on nestlings of birds of prey that are accessible in their nests during late breeding stages in temperate forests in Lithuania. Investigating haemosporidian parasites in nestlings is crucial for understanding local parasite transmission. To identify the haemosporidian parasite species transmitted in Lithuania, we sampled nestlings of the white-tailed eagles (Haliaeetus albicilla), lesser spotted eagles (Clanga pomarina), and common buzzards (Buteo buteo) in 2019–2022. Blood samples were collected from the nestlings, and molecular methods were employed to sequence a fragment of the parasite's cytochrome b (cyt b) gene using specific primers (Plas1F/HaemNR3 and 3760F/HaemJR4). In addition to molecular techniques, microscopy was used to examine blood smears for the presence of parasites. Our results revealed that nestlings of birds of prey were infected only with Leucocytozoon spp., with an overall prevalence of 30.5%. The prevalence was similar between years, but it was significantly species-dependent. The common buzzard nestlings had the highest prevalence (80%), followed by the lesser spotted eagle (29.2%) and the white-tailed eagle (13.2%). A total of nine genetic lineages were identified, with five of them being novel. Our study demonstrates that Leucocytozoon parasites are actively transmitted to nestlings of birds of prey in Lithuania, with a high prevalence.

Molecular investigation of Haemoproteus and Plasmodium species of some raptors in Hatay province: new CytB lineages for raptors of Accipitriformes in Turkey.

Accipitriform raptors are significant indicators of biodiversity and environmental health. Currently, most of the studies on avian haemosporidian parasites are on passerine birds, and data on raptors is constricted, with similarities both around the world and in Turkey. This study aimed to investigate the presence of Haemoproteus and Plasmodium spp. in raptors by microscopy and nested PCR technique. The study material consisted of 47 accipitriform raptors (Buteo buteo: 14, Buteo rufinus: 7, Clanga pomarina: 8, Circaetus gallicus: 12, Milvus migrans: 6). The prevalence of haemosporidian infection was 12.8% (6/47, 1 from Buteo buteo, 4 from Clanga pomarina, 1 from Milvus migrans) microscopically and 14.9% (7/47) molecularly. One Circaetus gallicus, microscopically found to be negative, probably due to low parasitemia, was molecularly found to be positive. All PCR-positive amplicons were bidirectionally sequenced, and the identification of lineages of the isolates and phylogenetic analysis were performed using the MalAvi and GenBank databases. The study revealed H-MILANS02 lineage in Buteo buteo, H-MILANS02 and P-CIAE1 lineages in Clanga pomarina, P-GRW06 lineage in Circaetus gallicus, and P-RTSR1 lineage in Milvus migrans, respectively. While this study removes the uncertainty regarding the reporting of the H-MILANS02 lineage in Turkey, it is also the first report to reveal 3 different Plasmodium spp. CytB lineages in raptors. Moreover, the fact that the P-GRW06 lineage (Plasmodium elongatum) detected in passerine birds was detected in a raptor, Circaetus gallicus, draws attention to the need for further investigations on host-parasite interaction and gives clues about the host-shifting ability of this parasite.

Identification of the Greater Spotted Eagle Clanga clanga, Lesser Spotted Eagle Clanga pomarina and interspecific hybrids using the morphology of shed flight feathers

ABSTRACT Capsule Shed feathers can be used for the field identification of the Greater Spotted Eagle Clanga clanga and Lesser Spotted Eagle Clanga pomarina, but identification of hybrids is problematic. Aims To provide an easy method for distinguishing the shed flight feathers of the Greater Spotted Eagle, Lesser Spotted Eagle, and their hybrids. Methods We examined seven morphological characteristics and developed multinomial logistic regression models to aid in identification of feathers. Results The most informative feature was the relative feather length. Barring improved the identification of tail feathers, secondaries, and proximal primaries. Feathers of Lesser Spotted Eagles were significantly shorter and more barred than those of Greater Spotted Eagles. Feathers of hybrids were also highly barred but had an intermediate length. The length from the tip to notch, width of the notch, and specific colouration patterns were also included in the best models for specific feather types. The combination of these characteristics resulted in identification accuracies of 89–97% for Lesser Spotted Eagle feathers and 80–100% for Greater Spotted Eagle feathers. However, all F1-hybrids were incorrectly identified as Greater Spotted or Lesser Spotted Eagles. Conclusion Shed feathers could have potential for the non-invasive field identification of spotted eagle species at nest sites. However, the identification of hybrids based on feathers is difficult due to substantial morphological variation and overlap with parent species.

Trypanosomatids in Bloodsucking Diptera Insects (Ceratopogonidae and Simuliidae) Wild-Caught at Raptor Bird Nests in Temperate Forests

Trypanosomatids are a huge group of vertebrate, invertebrate and plant parasites that can cause severe illnesses in hosts. Although avian trypanosomes are widely spread throughout the world, information about their transmission and vector–host relationships is still scarce. This study aimed to investigate Trypanosoma prevalence in bloodsucking Diptera collected at tree-nesting raptor birds’ nests. Insects were collected in temperate forests of Eastern-Central Europe, in Lithuania, using UV light traps hung near common buzzard (Buteo buteo) and lesser spotted eagle (Clanga pomarina) nests at about 15 m height above the ground. A total of 1248 Culicoides (Ceratopogonidae) females and 3 blackflies (Simuliidae) were collected and tested for the presence of trypanosomatids using PCR-based methods. The blood of 85 nestlings, belonging to three different species (Buteo buteo, Clanga pomarina and Haliaeetus albicilla) was collected and tested using the same methods. We found that 11.1% of the investigated insects (one Simulium female and Culicoides biting midges belonging to five species) were infected with Trypanosoma parasites (Trypanosoma sp., T. bennetti group, T. avium) and monoxenous trypanosomatids (Crithidia sp., Obscuromonas sp.). Only one common buzzard nestling was found to be infected with Trypanosoma avium. The phylogenetic relationships of detected parasites were determined. Our findings supplement information on the ornithophilic behavior of Culicoides females, potential vector species of avian Trypanosoma, and produce some new information on the detection of monoxenous trypanosomatids (Crithidia sp. and Obscuromonas sp.) in Culicoides.

Тринадцать лет наблюдений за миграцией хищных птиц в Батуми: наблюдения и их значение для охраны пернатых хищников России

One of the most important autumn migration bottlenecks for birds of prey in the Western Palearctic is situated in South-Western Georgia, between the east coast of the Black Sea and the range of Lesser Caucasus. Every year from mid-August till October at least 1% of the world’s population of 10 raptor species passes through this corridor. Specifically, over one million raptors are recorded annually, including on average 528467 Honey Buzzards (Pernis apivorus), on average 163985 Black Kites (Milvus migrans), 304819 Steppe Buzzards (Buteo buteo vulpinus), and around 8000 Lesser Spotted Eagles (Aquila [Clanga] pomarina). The specifics of the landscape and relief makes the foothills of the Lesser Caucasus to the north of Batumi an ideal spot for counting raptor migration, and since 2008, an international team of volunteers, the Batumi Raptor Count, has monitored autumn raptor migration from two strategic vantage points. The count effort is focused on 7 priority species, including Honey Buzzard, Black Kite, Lesser Spotted Eagle, Booted Eagle (Hieraaetus pennatus), Marsh, Montagu’s and Pallid Harriers (Circus aeruginosus, C. pygargus, C. macrourus, respectively). In addition, 13 other diurnal raptor species and 10 non-raptor bird species are monitored at the BRC. Using the trektellen-app, BRC is able to record all data digitally in the field, and to provide daily updates of migration counts on its website. At the end of each season, the data is cleaned and made available through the Global Biodiversity Information Facility (GBIF). Protocols were developed to standardize count effort across years, thus allowing an accurate assessment of population trends in the priority species. Importantly, the BRC systematically records data on the age and sex of raptors, allowing to infer trends separately for different demographic groups. The standardized data collected from 2011 till 2019 revealed rather stable numbers for most priority species, but also a significant annual decrease in numbers of juvenile Montagu’s Harriers; a strong ongoing increase in numbers of both juvenile and adult Black Kites; and increase in numbers of adult Booted Eagles accompanied by a decrease in juvenile birds of this species. Based on GPS-tracking studies on a variety of species, it appears that the western border of the breeding area for the populations counted by BRC is most probably not too far away from the western border of Russia. At least in case of Spotted Eagles, individuals breeding in the Baltic States, Finland, and Germany tend to use the migration routes to the West from the Black Sea, and this is also the case for birds from Western Ukraine and Belarus. There is insufficient data available to define the eastern border for the populations migrating through Batumi. We do know that raptors tracked from the south of Siberia tend to migrate to the east from the Caspian Sea, although some Pallid Harriers tracked from Russia and Kazakhstan do migrate over the Caucasus. All considered, we assume that the vast majority of raptors observed in Batumi during autumn migration breed in Central European Russia up to the Ural Mountains. A comparison of Batumi counts with the breeding population size estimates in Russia and neighbouring countries suggests that a significant proportion of the Russian population of the Lesser Spotted Eagle and Honey Buzzard is passing through the Batumi bottleneck on migration. Trends in migration counts at Batumi are probably representative of changes in raptor breeding populations from European Russia and Western Kazakhstan. In addition to collecting the data on migration, the BRC supports the development of ecotourism in the area and combats the widespread poaching of migrating raptors in Georgia by implementing various educational programs in schools and higher education institutions in Georgia. The BRC would like to build stronger links with professional ornithologists and amateur birdwatchers from the breeding areas of the raptors that pass through Batumi each year, and cordially invites everyone to participate in its migration counts.

Миграция хищных птиц через Западный Кавказ в осенний период

Миграция хищных птиц через Западный Кавказ в осенний период

Numbers and distribution of eagles in the Czech Republic: reason for optimism

At present, four eagle species are regular breeders in the Czech Republic: White-Tailed Sea-Eagle (Haliaeetus albicilla), Eastern Imperial Eagle (Aquila heliaca), Lesser Spotted Eagle (Aquila [Clanga] pomarina), and Golden Eagle (Aquila chrysaetos). There is also a historical record of confirmed breeding of Greater Spotted Eagle (Aquila [Clanga] clanga) in 1847 in the region of Eastern Bohemia. At present, this species is only a rare visitor on autumn and spring passage. White-Tailed Sea Eagle (Haliaeetus albicilla) has re-colonized the country since the mid-1980s, after approx. one hundred years absence as a breeder. The recolonization started at two separate areas: South Bohemia, with birds coming mainly from German and Poland source population, and South Moravia, with birds coming from Pannonia, i.e. mainly from Hungary. Later the species occupied nearly the whole area of suitable habitats. The population is still increasing and currently reaches ca. 160–180 breeding pairs. Eastern Imperial Eagle (Aquila heliaca) has bred in the Check Republic for the first time in 1998 (there is one unconfirmed note about its breeding also in 1930s). Since then, the population is slowly growing, similarly as the whole Pannonian population (with source populations mainly in Hungary and Eastern Slovakia). So far, the breeding is limited to Pannonian region of the country (i.e. south-eastern part) but the first pairs have spread north and west during the last years. 23 territorial pairs were monitored in 2023. The Lesser Spotted Eagle (LSE, Aquila [Clanga] pomarina) was never an abundant species in the Czech Republic. Scarce population existed especially in submountainous regions and in the mountains throughout the CR. The last breeding pairs were documented at the end of 1980’s and the beginning of 1990’s in Šumava Mts. After more than 20 years, breeding of LSE was surprisingly confirmed in western Bohemia. Since 2012, one pair breeds there regularly. In 2018, a small new population was discovered in the north of Morava region and currently three pairs breed there. Since 2020, another pair breeds in eastern Bohemia. Presently, two pairs breed in this region but we presume that another 1–2 breeding pairs could be hiding in this region. Therefore, in 2023 we estimate the breeding population of the LSE in the Czech Republic as 6–8 pairs. Golden Eagle (Aquila chrysaetos) started to breed in Northern Moravia (NE part of the country) in 2013 (similarly as White-Tailed Sea Eagle after more than one hundred years of absence), partly as a result of re-introduction project carried out during 2006–2017 (27 birds originating from Slovakia were released). Along with the growing population size and range expansion in the neighbouring Slovakia, there are now min 5–6 occupied territories in Czech Republic. Osprey (Pandion haliaetus) is a regular passage migrant (both spring and autumn), with some birds oversummering and very rarely also wintering. Historical data about its regular breeding in 19th or even early 20th century are not fully confirmed. Several breeding attempts were recorded also during the last 20 years. These included nest building but the clutch was never laid. Short-Toed Snake Eagle (Circaetus gallicus) is a very rare visitor in the Czech Republic, but the number of observations seems to increase rapidly during the last 10 years. With the increasing population in Hungary and possibly also Slovakia, its breeding cannot be excluded in the near future.

Distribution, population status, habitats, and conservation of Lesser Spotted Eagle in Bulgaria

The Lesser Spotted Eagle (Aquila [Clanga] pomarina) is a territorial raptor, distributed from Baltic region to Anatolia and Caucasus. Bulgaria is a part of the southern limit of the species distribution range. Since 2014, intensive field research in Eastern and Central Bulgaria identified an abundant and stable population of the species. For the period 2014–2023, 167 different active nests were found, and more than 450 occupied territories were mapped in Eastern and Central Bulgaria. Thus, the current population estimate is at least 1,000 breeding pairs. About 60% of the breeding population of the Lesser Spotted Eagle was situated in SPAs, but only 2.3% was located within Nature reserves, indicating insufficient protection of the species. The increasing anthropogenic pressure, mainly in terms of dramatic alteration of the species foraging and breeding habitats, and the lack of efficient legal protection pose a serious risk to the future of the Lesser Spotted Eagle in this part of the species distribution range. Most of the nests were situated at the edge of a forest, 19% were found in tree lines along the rivers, and only 2% were situated in single trees. The habitats varied from small forests and grasslands and significant percent of arable land to forests, small patches of arable land, and shrubs (less than 1%), as well as typical mosaic landscape with patches of cultivated crops, grasslands, and forest areas. The major threats to the habitats include plowing of grasslands, overgrowth of grasslands, forest management gaps, disturbance, construction of wind farms and solar parks, natural fires. Analysis of prey (n=523) from collected food remains (n=45 nests) shows that the main prey is Voles (Arvicolinae), accounting for 42.64% of all prey, followed by the Northern White-breasted Hedgehog (Erinaceus roumanicus), 13%. A parallel survey of the diet using photo traps (n=24 nests) and examining 141,985 photographs identified 1,357 different prey items. The results demonstrate again the dominant role of Voles (36%) as a main food resource, but followed by lizards (Lacertidae), 30%. The main conservation activities undertaken for the species in Bulgaria include appling biodiversity-friendly forest practices, improving breeding and foraging habitats, satellite tracking, restoration of breeding habitats through forest planting, insulation of hazardous electric poles, implementation of educational programs with children and local communities.

The second egg in the lesser spotted eagle (Clanga pomarina) clutch as a nesting insurance

Abstract Over an interval of 16 days, two eggs were laid by the same lesser spotted eagle female in her nest in the west-central Slovakia in 2021. The first egg failed to hatch, and the female ate it on the 45th day after she had laid it. Thereafter, the chick hatched from the second egg and later successfully fledged. The case contributes toward explaining why the species lays a second egg, even though the younger hatched chick is almost always prone to siblicide. In this case, the second egg acts as a reserve or an insurance if the first egg should not hatch, enabling the parents to breed successfully.

Contrasting patterns of genetic diversity and lack of population structure in the lesser spotted eagleClanga pomarina(Aves: Accipitriformes) across its breeding range

AbstractCharacterizing the genetic diversity and structure of populations is essential for understanding their evolutionary history and planning species conservation. The lesser spotted eagle (Clanga pomarina) is a large migratory raptor with a relatively small breeding range concentrated in Eastern Europe. We evaluated the level of genetic diversity and population structuring by estimating the length diversity of 23 microsatellite markers in 306 individuals and sequencing 473 nucleotides from the mitochondrial pseudo-control region in 265 individuals across the distribution range. The microsatellite data suggested shallow differentiation between geographical regions and moderate genetic diversity across the range; no recent population bottlenecks were detected. Mitochondrial diversity was relatively low; however, high values were recorded at the southern edge of the distribution range. This, in combination with the star-like distribution of mitochondrial haplotypes, suggests the expansion of the European population from a single (Balkan) refugium during the late Pleistocene or early Holocene after the glacial population bottleneck. However, the Caucasian population may have survived in a separate refugium. We conclude that the lack of clear population structuring and ongoing gene flow across Europe support the treatment of the geographically restricted global population of the lesser spotted eagle as a single evolutionary and conservation unit.

Nest-platform, nest-tree, nest-site, home-range and landscape characteristics of the Lesser Spotted Eagle (Clanga pomarina) in relation to its breeding performance in East Carpathians

Habitat loss and fragmentation along with altered disturbance regimes cause raptor population declines, but processes, rates and interactions are seldom known. Knowledge gaps remain mainly in large forest-dwelling raptors that use habitats on several spatial scales. Our study focusses on breeding habitats and habitat-associated breeding performance of the Lesser Spotted Eagle (“eagle”) across five spatial scales in Laborecká vrchovina Mts (East Carpathians, Slovakia) during 2011–2016. We calculated two relative measures of breeding performance (breeding attempt index, BAI; nest productivity index, NPI) and related them to habitat characteristics sampled on the nest-platform, nest-tree, nest-site, home-range and landscape scale. We found that eagle‘s breeding performance was best explained by predictors on the home-range and landscape scale. BAI and NPI strongly and consistently increased with increasing distance of nest to the nearest felling site and with occurrence of the nest site on lower slope landforms. Former finding supported ample evidence that logging operations pose agrave threat to eagle’s reproduction, while the latter hinted at its strong preference or even specialization for forest edges, for notably old regional ecotones between montane forests and submontane non-forest formations show lower slope topography. On the nest-site scale, nest productivity (NPI) significantly and strongly increased with increasing percentage of Sessile Oak (Quercus petraea) and decreased with cosine of slope aspect in response to more open and accessible canopy structure resulting from oak appearance in beech-dominated forests and to contrasts in solar radiation, shade and similar north–south effects. On the nest-platform and nest-tree scale breeding performance marginally significantly increased with increasing relative nest height above ground and decreased in nests of natural origin (in BAI). It pointed to unrecognized relevance of relative nest height that may link nest-tree with nest-site scale and reflect atrade-off between nest accessibility and nest protective cover, and to greater nest placement diversity with possible greater vulnerability of natural nests. Differences in breeding performance measured by BAI vs NPI indicated that certain selection pressures may vary significantly during the breeding cycle, e.g., early vs late breeding failures and subsequent learning from negative experience. We recommended several management actions by our results, particularly to advance systematic eagle monitoring, to address multiple scales of its habitat use according to their relative importance, to increase the width of protection zones around nests and adopt new or strengthen existing landscape-scale measures and to follow sustainable forestry as apart of integrated landscape management instead of close-to-nature forestry.

Weak niche partitioning between closely related sympatric Greater (Clanga clanga) and Lesser Spotted Eagles (C. pomarina)

Species coexist only when occupying different ecological niches. We evaluated habitat and trophic niches in two recently diverged hybridizing avian apex predators, the declining Greater Spotted Eagle Clanga clanga (mainly found in contracting wetlands) and the more numerous Lesser Spotted Eagle Clanga pomarina (inhabiting mosaic farmlands). We tracked 24 Spotted Eagles, including interspecific hybrids, by GPS to estimate the home‐range size, land use composition and landscape structure in sympatric populations. In addition to information for landscape utilization, data for diet composition were evaluated. Home‐ranges of the two species were similar in size and open foraging habitats consisted mostly of agricultural landscape. However, landscape utilization of the Greater Spotted Eagle was largely driven by the composition of land‐use types, whereas the Lesser Spotted Eagle was mostly influenced by structural components of the landscape. Farmland‐dwelling voles accounted for the bulk of the diet in both species; however, subdominant prey classes differed. Hybrids exhibited intermediate or mixed features of home‐ranges and diets. Our results provide evidence for reduced niche partitioning and potential competition between the two Spotted Eagles, which may have been reinforced by anthropogenic habitat alteration. A closer examination of movement patterns revealed previously overlooked differences between closely related species with respect to landscape utilization strategies.

Web-based citizen science as a tool in conservation research: A case study of prey delivery by the Lesser Spotted Eagle.

Citizen science is increasingly contributing to ecology and conservation research, mostly by the extensive collection of field data. Although webcams attract numerous observers, they have been underused in this respect. We used prey delivery records deposited by citizen scientists in an internet forum linked to webcams to explore the diet composition and food provisioning in a forest-dwelling raptor of conservation concern, the Lesser Spotted Eagle (Clanga pomarina). Four pairs were studied throughout the breeding season. Most of the identified prey items were mammals (62.1%), followed by frogs (31.2%), birds (6.6%) and fish (0.1%). Among mammals, voles accounted for 84.6%, moles 12.1%, water voles 2.4% and weasels 0.4%. Frogs were the most frequently detected prey item in the spring, with a slight increase towards the end of the season, the proportion of mammals increased during the breeding season, and birds were hunted mostly in the middle of the breeding season. However, exact temporal patterns differed between nests. The food delivery rate of males increased over time but decreased somewhat before fledging the young. Females started hunting in mid-summer and their rapidly increasing effort compensated for a reduced male hunting intensity. The data collected by citizen scientists via webcams reflected the general patterns detected in earlier studies, supporting the reliability of crowd-sourced web-based data collection in avian foraging ecology.

Diet composition and food supply of the Lesser Spotted Eagle Clanga pomarina in the core area of its breeding range

ABSTRACT Capsule Small rodents and amphibians are both important prey items for the Lesser Spotted Eagle Clanga pomarina, and their proportions in the diet depend on their local availability, as well as the degree of involvement of the female in food provisioning to the nestlings, which increases towards the end of the breeding season. Aims To describe the diet composition and aspects of the food supply of the Lesser Spotted Eagle during the nesting period. Methods Cameras were installed at five nests of three pairs of the Lesser Spotted Eagle in eastern Latvia, to collect data on food items brought to the nests. Results Of 3109 identified prey items, small rodents (43.36%) and amphibians (44.81%) were the most important prey groups. The proportion of common (small rodents and amphibians) and uncommon (moles, birds and others) food items differed between nests and years. Among the common food items, the deficiency of small rodents in some years was compensated for by an increase in frogs and vice versa. Male eagles brought 66% of all food items to the nest. Females brought more amphibians and fewer rodents than did males. After hatching, the mean number of food items delivered to the nest was 6.9 per day. The main activity period of food delivery was between the 3rd to 7th hour after sunrise. Conclusion The alternative prey hypothesis explains the diet of the Lesser Spotted Eagle in our study area. Rodents and amphibians are food items of equal importance that can replace each other, depending on their availability. The increasing share of amphibians towards the end of the breeding season was mainly a result of an increasing proportion of prey items brought into the nest by females.

Future projection for forest management suggests a decrease in the availability of nesting habitats for a mature-forest-nesting raptor

The demand for timber, bioenergy feedstock and other forest products, leading to intensified forest harvesting, is expected to increase in the coming decades in European Union. A reduction in the delivery of forest ecosystem services and, specifically, biodiversity, including the provision of habitats for mature-forest-dwelling raptors, has been attributed to the intensification of forest exploitation. Therefore, in order to adopt adequate conservation measures to create a timely buffer against the consequences of increased harvesting, it is critically important to understand how the availability of nesting habitats for protected species will fluctuate in the future landscape.In this study, using the LandSim tool, we modelled the dynamics of the forests and nesting habitat availability for the forest-nesting raptor, the lesser spotted eagle Clanga pomarina, for the next 50 years in eastern Lithuania, Central Europe. Our findings indicate that the share of forests available for final harvesting is expected to increase rapidly in the coming decades due to a large amount of forest stands reaching a mature age, if current forest management practices, despite them being considered as relatively conservative, are continued. As a consequence, the availability of nesting habitats will constantly decrease in nesting territories, as well as elsewhere in the landscape, in the coming decades. We suggest that species conservation strategies should not only incorporate directly targeted measures to protect nest sites from destruction and disturbance, but also, at the very least, preserve a sufficient amount of nesting habitats in areas inhabited by eagle pairs and, at best, at the landscape scale.

The Greater and Lesser Spotted Eagles in the Center of European Russia

This article presents new data on the number and distribution of the Greater and Lesser Spotted Eagles (Aquila clanga and A. pomarina) in 9 regions located in the central part of European Russia. The area under surveys is 415,900 km2. The results of surveys carried out in the Nizhny Novgorod region (76,900 km2) in 2014-2020 allow us to characterize the level of underestimation of the Greater Spotted Eagle in the region in previous periods, as well as estimate the degree of knowledge of the species in adjacent regions and calculate the probable number of the Greater Spotted Eagle in the study area (about 500 breeding pairs). In the central part of the Russian Plain, the important areas for the Great Spotted Eagle have been identified, which are very significant for the species conservation. The activities to protect the Greater Spotted Eagle are discussed. They should combine the establishment of protected areas and regulation of nature management aimed at the conservation of breeding habitats. The Lesser Spotted Eagle expanding its home range rapidly to the east has been shown. The relevance, great theoretical and practical significance of the study of the Lesser Spotted Eagle population, developing in the center of European Russia has been demonstrated.

Nest-Platform, Nest-Tree, Nest-Site, Home-Range and Landscape Characteristics of the Lesser Spotted Eagle (Clanga Pomarina) in Relation to its Breeding Performance in East Carpathians

Nest-Platform, Nest-Tree, Nest-Site, Home-Range and Landscape Characteristics of the Lesser Spotted Eagle (Clanga Pomarina) in Relation to its Breeding Performance in East Carpathians

Age of maturity and exceptionally distant natal dispersal of over 500 km by a male lesser spotted eagle Clanga pomarina

Abstract According to previous studies using colour rings, lesser spotted eagles Clanga pomarina have established breeding territories up to 249 km from their natal site. A colour-ringed lesser spotted eagle nestling from NE Poland settled 540 km further west in NE Germany. This male was discovered at the age of six and nested there for several years. This finding is all the more remarkable because the bird was a male, which in large eagles typically settle nearer to their natal sites than females. They apparently reproduce successfully for the first time later than females, normally at the age of five.

Sex‐, landscape‐ and climate‐dependent patterns of home‐range size – a macroscale study on an avian generalist predator

Animal home‐ranges are expressions of the biology and ecology of a species, and their size is often considered to be a proxy for habitat quality. Understanding the factors affecting variation in home‐range size may aid prediction of the impact of local or global environmental change on studied populations. To this end, we established an international collaborative programme to gather GPS telemetry data on the Lesser Spotted Eagle Clanga pomarina across a large part of its range. The breeding season home‐ranges of 58 individuals from Estonia, Lithuania, Poland, Hungary and Romania were estimated using autocorrelated kernel density estimation. Differences in home‐range size were analysed using linear mixed‐effects models incorporating global (latitude, longitude, climate) and local (habitat heterogeneity, land cover, topography, human disturbance) variables. Home‐range was significantly affected by habitat heterogeneity, vegetation cover and human disturbance, and also by climate, increasing with greater temperature seasonality. A quadratic relationship between home‐range and Shannon diversity index, found in males, suggests that Eagles use less space in the least and most diverse habitats. Home‐ranges were also smaller close to human settlements, but range size was positively correlated with human population density. The first result reflects the positive influence of agricultural management on prey availability, whereas the second reflects negative impacts of disturbance and loss of foraging space. Home‐ranges of male Eagles were relatively consistent in size and were more linked to environmental conditions compared with those of females. Female home‐ranges were significantly more variable in size and showed less distinctive patterns of relationship with the tested predictors. Sex‐dependent variation in home‐range may result from the different roles of males and females in breeding activities and territoriality limitations of males. The latter factor both limited and increased the home‐range size in different individuals.

Movement patterns of an avian generalist predator indicate functional heterogeneity in agricultural landscape

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. 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. 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. 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. 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.