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The Eurasian eagle-owl (Bubo bubo) is distributed throughout Asia and Europe and contains approximately twelve subspecies. Three subspecies, B. b. kiautschensis, B. b. ussuriensis, and B. b. tibetanus, are separately distributed in the refugia and plateau habitats of China. However, the genetics of these subspecies and populations have not been studied. Genetic differences were investigated among 32 individuals from six populations of these three B. bubo subspecies based on the mitochondrial genome. Low genetic diversity but high haplotype diversity was observed in these subspecies. The phylogenetic relationship of three B. bubo subspecies distributed in China was proven to be coordinated with geographic and environmental gradients. This study provides the first detailed insights into the mitochondrial genetic diversity of three Eurasian eagle-owl subspecies distributed in China and demonstrates the utility of the mitochondrial genome in intraspecific genetic population analyses of these eagle-owls.

Adenoviruses have been reported to infect a variety of birds. Here, we isolated a novel adenovirus from the liver of a dead owl chick (Bengal eagle owl; Bubo bengalensis) at a raptor-breeding facility in Japan and determined the complete genome sequence of the virus. We performed necropsies on the dead owl chicks and found that they had enlarged livers, pericardial edema, and focal necrosis of the liver tissue. Transmission electron microscopy of the liver tissue revealed a virus-like structure, appearing as paracrystalline arrays in the nucleus, and immunohistochemical staining with anti-adenovirus antibodies showed positive reactions in hepatocytes and other cells. Attempts to isolate the virus from homogenized liver tissue of a dead owl chick showed a cytopathic effect on chicken-derived cultured cells after multiple blind passages. Further, we determined the complete genome sequence of this virus and performed phylogenetic analysis, revealing that this adenovirus belongs to the genus Aviadenovirus, forming a cluster with fowl and turkey aviadenoviruses. The amino acid sequence divergence between the DNA polymerase of this virus and its closest known adenovirus relative is approximately 29%, implying that this virus can be assigned to a new species in the genus Aviadenovirus. Based on our data, this novel owl adenovirus is a likely cause of fatal infections in owls, which may threaten wild and captive owl populations. Further, this virus is unique among raptor adenoviruses in that it infects chicken-derived cultured cells, raising the importance of further investigations to evaluate interspecies transmission of this virus.

To contribute to have a better understanding of the symbolic or not use of certain items by Neanderthals, this work presents new evidence of the deliberate removal of raptor claws occurred in Mediterranean Europe during the recent phases of the Mousterian. Rio Secco Cave in the north-east of Italy and Mandrin Cave in the Middle Rhône valley have recently produced two golden eagle pedal phalanges from contexts not younger than 49.1-48.0 ky cal BP at Rio Secco and dated around 50.0 ky cal BP at Mandrin. The bones show cut-marks located on the proximal end ascribable to the cutting of the tendons and the incision of the cortical organic tissues. Also supported by an experimental removal of large raptor claws, our reconstruction explains that the deliberate detachment occurred without damaging the claw, in a way comparable at a general level with other Mousterian contexts across Europe. After excluding that these specimens met the nutritional requirements for human subsistence, we discuss the possible implications these findings perform in our current knowledge of the European Middle Palaeolithic context.

We determined the population density and number of Eurasian Eagle-Owl in one of the regions of Russia (Republic of Mordovia). The work was carried out over sixteen years (2009 2024). The studies were conducted using methods of direction finding of vocalizing birds with subsequent search for nests and with the use of digital voice recorders. The Eurasian Eagle-Owl reliably lives in 16 out of 22 districts (72.7%). During our research, we built more than 60 artificial nests, in which Eurasian Eagle-Owls subsequently settled. In total, during the research period, 89 Eurasian Eagle-Owl habitats (of which 38 in four stationary sites), 125 nesting cases, and 214 chicks were identified. Over the entire period, the birds laid 282 eggs. Productivity for couples was 76%. The most successful years in terms of the number of eggs and chicks in nests were 2014, 2018, 2022, 2023. The density of the Eurasian Eagle-Owl population ranges from 3.1 to 5 pairs per 100 km . The total population density in the open spaces of the region can reach 583 habitats. The presence of a large number of ravines with stands determines the high population density of Eurasian Eagle-Owl in Mordovia. Making artificial nesting boxes in ravines improves the suitability of breeding sites and promotes better survival of young individuals.

Despite the fact that investigations of home range behaviour have exponentially evolved on theoretical, analytical and technological grounds, the factors that shape animal home range behaviour still represent an unsolved question and a challenging field of research. However, home range studies have recently begun to be approached under a new integrated conceptual framework, considering home range behaviour as the result of the simultaneous influences of temporal, spatial and individual-level processes, with potential consequences at the population level. Following an integrated approach, we studied the influence of both external and internal factors on variations in the home range behaviour of 34 radiotagged eagle owl (Bubo bubo) breeders. Home range behaviour was characterised through complementary analysis of space use, movement patterns and rhythms of activity at multiple spatio-temporal scales. The effects of the different phases of the biological cycle became considerably evident at the level of movement patterns, with males travelling longer distances than females during incubation and nestling periods. Both external (i.e. habitat structure and composition) and internal (i.e. sex and health state) factors explained a substantial amount of the variation in home range behaviour. At the broader temporal scale, home range and core area size were negatively correlated with landscape heterogeneity. Males showed (1) smaller home range and core area sizes, (2) more complex home range internal structure and (3) higher rates of movement. The better the physiological condition of the individuals, the simpler the internal home range structure. Finally, inter- and intra-individual effects contributed to shaping space use and movement patterns during the biological cycle. Because of the plurality of behavioural and ecological processes simultaneously involved in home range behaviour, we claim that an integrative approach is required for adequate investigation of its temporal and spatial variation.

In current ornithological literature, there is a general consensus that the eagle owl (Bubo bubo) is a breeder of rocky habitats in Slovakia, especially on cliffs and quarry walls, but little research to date has concentrated on cases of ground-nesting in the lowland areas of the country. This study provides an overview of the documented cases of eagle owls breeding in lowland forests, a relatively unusual method of breeding for this species. The authors also report a recent case of an eagle owl breeding on the ground in a floodplain forest at the small settlement of Sedín near the forest edge in the western part of the Danube Lowlands. The nest was located in a shallow basin at the base of a large white poplar (Populus alba) tree, just 3 m from an oxbow lake. The site was visited three times between 12 April and 12 May 2024, and three young birds were observed in the nest, all of which likely fledged successfully. Prey remains from the nest were analysed and the results are presented here together with those of five other eagle owl nests from the lowlands of Slovakia and the Czech Republic. In the nest near Sedín, the common hamster (Cricetus cricetus) was the predominant prey species, in contrast to a location near Vojčice in the East Slovak Lowlands in which the brown rat (Rattus norvegicus) predominated or nest sites in Southern Moravia and the Třeboňsko region of the Czech Republic where larger birds were the main prey.

We recorded vocal interaction in the natural environment of an Eurasian Eagle-Owl with canines Gray Wolves , Red Foxes and domestic dogs . Vocalization was recorded using Olympus digital voice recorders. The calls of the male Eurasian Eagle-Owl were recorded by us in the frequency range of 200–420 Hz. The howl of a Gray Wolf was recorded in the frequency range from 300 to 1,100 Hz. Red Fox barking was recorded in the frequency range from 750 to 1,000 Hz. Barking of domestic dogs was recorded in the frequency range from 250 to 1,500 Hz. The vocalization of the Eurasian Eagle-Owl had an independent character inherent in the biology of the species. The Eurasian Eagle-Owl, with its cries, involuntarily provoked the entry of canines into joint vocal interaction, which can be explained by the high social activity of the latter. Co-vocalizations of the Eurasian Eagle-Owl and canines were noted in winter, spring and autumn, but mainly in spring (50%). The increased use of autonomous voice recorders, which record spontaneous vocalizations emitted by animals over long periods, will allow us to better document and study the importance of such interspecific interactions.

Each predator hunts and consumes its prey in a particular way. Consequently, the traces left by predators on bones might vary according to the manner in which the prey are processed. For this reason, prey size has been proposed as a key issue that affects the damage inflicted on bones. The Eagle Owl ( Bubo bubo ) is one of the main potential predators of small prey found in archaeological sites. However, detailed taphonomic research describing bone accumulations produced by this nocturnal raptor is still scarce. The aim of the present work is to describe a modern accumulation of pellets originated by the Eagle Owl from this perspective, with a specific focus on birds. Particular attention is paid to prey size to evaluate the real significance of this variable when assessing bone damage. The results confirm that bone alterations reflect how prey was ingested, as the bones show greater damage with increasing prey size. This finding emphasises the complexity of characterising archaeological accumulations, as the alterations will vary according to prey size. In addition, bone architecture—or other aspects that cannot be controlled—may hinder accurate diagnosis and should be taken into account.

The El Salt site (Alcoi, Alicante, Spain) is one of the latest Neanderthal sites in the south-eastern Iberian Peninsula. The disappearance of this human group is controversial and needs detailed studies from different research areas. Taphonomy is essential to establish how representative is a fossil assemblage of the past living organisms that produced it and to interpret the formation process of the fossil site. In the case of El Salt, we have analyzed the micromammal assemblages of Units X and V, which contain fossils of Neanderthals and/or evidence of their activity. In contrast with previous identifications of the little owl (Athene noctua), our detailed taphonomic study shown here allows us to conclude that the main predator involved in the production of the micromammal assemblages was the European eagle owl (Bubo bubo). This is an opportunistic predator whose feeding preferences and behavior reflect the abundance of local micromammalian species, which can therefore provide a representation of past ecosystems near El Salt. The taphonomic information provided by this study also indicates the absence of transport and reworking processes, and reinforces previous paleoecological interpretations, suggesting an increase of aridity at the top of El Salt sequence that coincided with the local disappearance of Neanderthals.

Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n = 610), Strigiformes (n = 260), Ciconiiformes (n = 156), Gruiformes (n = 21), and other orders (n = 32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1:25) were found in 282 (26.1%, IC95%:23.5–28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) “vulnerable” Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN “near threatened” red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild birds in Spain, most likely related to their feeding behaviour.