Strix Aluco Research Articles

Ecosystem specific accumulation of organohalogenated compounds: A comparison between adjacent freshwater and terrestrial avian predators

Insight into processes determining the exposure of organohalogenated contaminants (OHCs) in wildlife might be gained from comparing predators in different ecosystems. This study compared two avian predator species with similar food chain lengths: the goldeneye duck (Bucephala clangula) and the tawny owl (Strix aluco) breeding in adjacent freshwater- and terrestrial ecosystems in central Norway. We measured lipophilic organochlorines (OCs) and protein-bound perfluorinated substances (PFASs) in eggs of the two species over 21 years (1999–2019). Across years, the proportional distribution of OCs (∼90% of the ΣOHC load) relative to PFASs (∼10%) was similar in the two species. Moreover, ΣOC concentrations were similar between the species, but PFAS compounds were 2–12 times higher in the goldeneyes than in tawny owls. OC-pesticides dominated in tawny owls (∼60% of ΣOC), whereas persistent polychlorinated biphenyl (PCBs) congeners were the main OC components in goldeneyes (∼70% of ΣOC). The lipid-normalized concentrations of most OC-pesticides and the less persistent PCB101 declined significantly in both species. Hexachlorobenzene (HCB), p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE), and more persistent PCBs decreased in tawny owls, while they tended to increase in goldeneyes. The increase in HCB was particulary robust. Among the PFASs, contrasted temporal trends were found across the species for four out of 11 compounds: PFOS declined while most perfluorocarboxylic acids (PFCAs) increased in tawny owls. In contrast, most PFASs were stable in goldeneyes. Moreover, there was no annual covariance between the OHC exposure in the two species: i.e., high concentrations in one species in a given year did not translate into high concentrations in the other. Hence, the two avian predators in adjacent ecosystems seem to be subject to different processes determining the OHC exposure, probably related to variation in diet and climate, long-range transport of different contaminants, and emissions of pollution locally.

Dormice (Gliridae) in the diet of predators in Eurasia: a review

Dormice are widely distributed through Eurasia and Africa, but their abundance varies considerably. In many regions, dormice are rare, and their role in ecosystems is considered to be unimportant. The aim of this study was to evaluate the significance of dormice in the diet of predators in the Palaearctic (excluding Japan). A total of 540 sources, containing information on dormice in the diet of predators was analysed. Countries of Southern and Central Europe had the largest numbers of target sources. Dormice were recorded in the diet of 57 predator species: 21 mammals, 13 owls, 18 diurnal birds and 5 reptiles. Owls hunting in the forests, particularly the Tawny Owl (Strix aluco), are the main dormouse predators. The highest proportion of dormice in the diet of predators was recorded in the Mediterranean region, where Edible Dormice (Glis glis) are abundant and some other dormouse species are sympatric. In particular periods, dormice may be an alternative prey for predators such as Tawny Owl and even Lynx (Lynx lynx). It was supposed previously that predation was an important cause of high winter mortality in dormice, but analysis of publications showed that dormice were rather seldom recorded in the winter diet of predators. Thus, the exact impact of predators on winter mortality of dormice remains unclear. The role of dormice in the diet of predators depends on dormouse abundance. In areas where dormice are rare, it is trivial. However, predators catching even individual females, may have a significant impact on dormouse reproductive success.

Causes, temporal trends, and the effects of urbanization on admissions of wild raptors to rehabilitation centers in England and Wales.

Data from wildlife rehabilitation centers (WRCs) can provide on‐the‐ground records of causes of raptor morbidity and mortality, allowing threat patterns to be explored throughout time and space. We provide an overview of native raptor admissions to four WRCs in England and Wales, quantifying the main causes of morbidity and mortality, trends over time, and associations between threats and urbanization between 2001 and 2019. Throughout the study period, 14 raptor species were admitted totalling 3305 admission records. The Common Buzzard (Buteo buteo; 31%) and Tawny Owl (Strix aluco; 29%) were most numerous. Relative to the proportion of breeding individuals in Britain and Ireland, Peregrine Falcons (Falco peregrinus), Little Owls (Athene noctua), and Western Barn Owls (Tyto alba) were over‐represented in the admissions data by 103%, 73%, and 69%, respectively. Contrastingly Northern Long‐eared Owls (Asio otus), Western Marsh Harriers (Circus aeruginosus), and Merlin (Falco columbarius) were under‐represented by 187%, 163%, and 126%, respectively. Across all species, vehicle collisions were the most frequent anthropogenic admission cause (22%), and orphaned young birds (10%) were most frequent natural cause. Mortality rate was highest for infection/parasite admissions (90%), whereas orphaned birds experienced lowest mortality rates (16%). For one WRC, there was a decline in admissions over the study period. Red Kite (Milvus milvus) admissions increased over time, whereas Common Buzzard and Common Kestrel admissions declined. There were significant declines in the relative proportion of persecution and metabolic admissions and an increase in orphaned birds. Urban areas were positively associated with persecution, building collisions, and unknown trauma admissions, whereas vehicle collisions were associated with more rural areas. Many threats persist for raptors in England and Wales, however, have not changed substantially over the past two decades. Threats associated with urban areas, such as building collisions, may increase over time in line with human population growth and subsequent urban expansion.

Heritability and Parental Effects in Telomere Length in a Color Polymorphic Long-Lived Bird.

AbstractRelative telomere length (RTL), an indicator of senescence, has been shown to be heritable but can also be affected by environmental factors, such as parental effects. Investigating heritability as well as parental effects and rearing environment can help us to understand the factors affecting offspring telomeres. Moreover, how phenotypic parental traits linked with fitness can impact offspring RTL is still unclear. A phenotypic marker closely associated with physiological traits and fitness is melanin-based color polymorphism, which in tawny owl (Strix aluco) is highly heritable and strongly associated with adult telomere shortening and survival. We studied narrow-sense heritability (h2) of RTL, as well as the impact of parental age and color morph and their interaction on offspring RTL. Offspring RTL at fledging was strongly positively correlated with both mother RTL and father RTL at breeding. Offspring RTL was also negatively associated with father age, suggesting that older fathers sired offspring with shorter telomeres. Parental color morph did not explain offspring RTL, and there were no interactive effects of parental morph and age, despite previously documented morph-specific senescence patterns. Our results suggest that RTL is highly heritable and affected by paternal age but not related to color polymorphism. This suggests that either morph-specific telomere shortening as an adult does not result in significantly shorter telomeres in their gametes, or that parents compensate morph-specific senescence via parental care. Morph-specific patterns of telomere dynamics in polymorphic species may thus emerge from different life history strategies adopted in adulthood.

Mercury speciation in Scottish raptors reveals high proportions of inorganic mercury in Scottish golden eagles (Aquila chrysaetos): Potential occurrence of mercury selenide nanoparticles

Knowledge of the uptake and fate of mercury (Hg) compounds in biota is important in understanding the global cycling of Hg and its transfer pathways through food chains. In this study, we analysed total mercury (T-Hg) and methylmercury (MeHg) concentrations in 117 livers of Scottish birds of prey that were found across Scotland and submitted for post-mortem examination through the Raptor Health Scotland project between 2009 and 2019. Statistical comparisons focussed on six species (barn owl, Tyto alba; Eurasian common buzzard, Buteo buteo; golden eagle, Aquila chrysaetos; hen harrier, Circus cyaneus; Eurasian sparrowhawk, Accipiter nisus; and tawny owl, Strix aluco) and showed that golden eagles had a statistically lower fraction of MeHg compared to other raptor species. Further investigation using stable carbon and stable nitrogen isotope ratio measurements carried out for the golden eagles (n = 15) indicated that the increased presence of inorganic mercury (iHg) correlated with a marine influence on the primarily terrestrial diet. Additional bioimaging (n = 1) with laser ablation – inductively coupled plasma – mass spectrometry indicated the co-location of Hg and selenium (Se) within the liver tissue and transmission electron microscopy showed evidence of nanoparticles within the range of 10–20 nm. Further analysis using single particle – inductively coupled plasma – mass spectrometry (n = 4) confirmed the presence of Hg nanoparticles. Together, the evidence suggests the presence of mercury selenide (HgSe) nanoparticles in the liver of some golden eagles that, to our knowledge, has never been directly observed in terrestrial birds of prey. This study points to two alternative hypotheses: these golden eagles may be efficient at breaking down MeHg and form HgSe nanoparticles as a detoxification mechanism (as previously observed in cetaceans), or some golden eagles with elevated iHg may have accumulated these nanoparticles by foraging on stranded cetaceans or seabirds.

In Its Southern Edge of Distribution, the Tawny Owl (Strix aluco) Is More Sensitive to Extreme Temperatures Than to Rural Development

Populations at the warm edge of distribution are more genetically diverse, and at the same time are more susceptible to climate change. Between 1987–1996, we studied Tawny Owls in Israel, the species’ global southern edge of distribution and a country undergoing a rapid land cover transformation for over a century. To assess the potential impacts of land cover transformation, we modelled the species’ most suitable habitat and climate and analyzed how climate and habitat affected the nesting success and prey selection. Moreover, we monitored Tawny Owl juveniles’ survival and ontogeny from eggs to dietary independent young, to find out whether the Israeli population is a sink. While the species distribution model correctly predicted the Tawny Owl’s densest areas of occurrence, it failed to predict its occurrence in adjacent regions. The model also predicted that areas included in the species’ historical range remained suitable habitats. The number of fledglings increased with precipitation and in rural settings but was adversely affected by extreme temperatures. While voles dominated the diet in all habitats, the Tawny Owl’s diet is considerably more variable than other Israeli owls. Our results suggest that the Tawny Owl can adapt to rural-agricultural environments, but is susceptible to climate change.

Detection and Molecular Characterization of a Novel Species of Circovirus in a Tawny Owl (Strix aluco) in Southern Italy.

Simple SummaryThe genus Circovirus groups some of the smallest viruses capable of autonomous replication, including some notable swine and avian pathogens. Among domestic and wild birds, circoviruses are often associated with immunosuppression and integumental disorders, but, despite their relevance, nothing is known about their circulation in birds of prey. By conducting molecular analyses on samples from birds of prey recovered by a wildlife rescue centre in Italy, we identified a new viral species in the spleen of a tawny owl (Strix aluco). However, there is contrasting evidence regarding its definitive host. On one hand, the virus was discovered to be phylogenetically closer to mammalian rather than avian circoviruses, which allows speculations on its host being a micromammal preyed by the tawny owl, rather than the bird itself. On the other hand, its detection in the spleen, a lymphoid organ in which other avian circoviruses are often detected, supports the tawny owl being its actual host, perhaps following a spillover event associated with predation. Adding to the growing number of circoviruses found in recent years in a diverse range of hosts, this discovery represents another step forward in the characterization of this genus of remarkable veterinary importance.Thanks to recent developments in molecular methods, many new species have been discovered within the genus Circovirus, which comprises viruses of veterinary relevance found in a broad range of hosts. In particular, several circoviruses are known to infect birds, often causing immunosuppression and feathering disorders. Nonetheless, nothing is known about their circulation in birds of prey. In this study, samples from 61 birds of prey representing ten different species, recovered by a wildlife rescue centre in Southern Italy, were taken at necropsy and analysed by PCR with pan-Circovirus primers. Only one sample, collected from a tawny owl (Strix aluco), tested positive. Its genome, sequenced by primer walking, displays the typical features of circoviruses. Based on demarcation criteria, the detected strain qualifies as a novel species, which was named “tawny owl-associated circovirus” (ToCV). Phylogenetically, ToCV clustered with mammalian rather than avian circoviruses, and its closeness to a rodent circovirus suggests that its host may have been a micromammal eaten by the tawny owl. On the other hand, its detection in the spleen fits with the tropism of other avian circoviruses. Little can be therefore said on its biology and pathogenicity, and further efforts are needed to better characterize its epidemiology.

Cold winters have morph-specific effects on natal dispersal distance in a wild raptor.

Dispersal is a key process with crucial implications in spatial distribution, density, and genetic structure of species’ populations. Dispersal strategies can vary according to both individual and environmental features, but putative phenotype-by-environment interactions have rarely been accounted for. Melanin-based color polymorphism is a phenotypic trait associated with specific behavioral and physiological profiles and is, therefore, a good candidate trait to study dispersal tactics in different environments. Here, using a 40 years dataset of a population of color polymorphic tawny owls (Strix aluco), we investigated natal dispersal distance of recruiting gray and pheomelanic reddish-brown (hereafter brown) color morphs in relation to post-fledging winter temperature and individual characteristics. Because morphs are differently sensitive to cold winters, we predicted that morphs’ natal dispersal distances vary according to winter conditions. Winter temperature did not affect the proportion of brown (or gray) among recruits. We found that dispersal distances correlate with winter temperature in an opposite manner in the two morphs. Although the gray morph undertakes larger movements in harsher conditions, likely because it copes better with winter severity, the brown morph disperses shorter distances when winters are harsher. We discuss this morph-specific natal dispersal pattern in the context of competition for territories between morphs and in terms of costs and benefits of these alternative strategies. Our results stress the importance of considering the interaction between phenotype and environment to fully disentangle dispersal movement patterns and provide further evidence that climate affects the behavior and local distribution of this species.

My home is your home: Nest boxes for birds and mammals provide habitats for diverse insect communities

Abstract Cavity‐bearing trees are important nesting sites for many birds and mammals but have become rare due to anthropogenic modification of natural environments. Nest boxes are often used to compensate for the loss of these microhabitats. Nest boxes contain amounts of organic debris exploited by a variety of organisms, mainly insects. We studied the largely unexplored group of nest‐dwelling insects by rearing them from plant detritus and animal remains accumulated in nest boxes of six bird and two mammal species, distributed in forest, farmland and urban environments in Poland. We recorded 119 species representing eight insect orders. Nest substrates composed of plant detritus and animal remains supported similar insect species richness but differed significantly in terms of the insect community composition. Nests of Falco tinnunculus and Tyto alba and also Parus spp. and Strix aluco had very similar insect communities. The structural compositions of insect communities were also similar in nests of Parus spp. and Sturnus vulgaris, and of F. tinnunculus and S. aluco. Flies and earwigs were associated with nests of Parus spp. and Sciurus vulgaris and were more abundant in forests and urban environments, whereas wasps preferred S. aluco nests in forests. Our study shows that nest boxes may serve as replacement habitats for a variety of nest‐associated insects. Therefore, we suggest a more flexible approach to nest boxes maintenance and management, for example, less frequent cleaning or providing more than one nest box in a given place to enhance conservation of nest‐associated insects.

Importance of melanin‐based colouration and environment in shaping intracellular glutathione levels in nestling and adult tawny owls Strix aluco

Resources allocated in reproduction are traded off against those invested in self‐maintenance such as antioxidant response. Glutathione (GSH) is an intracellular antioxidant defence that scavenges reactive oxygen species, the deleterious byproducts of oxygen consumption. Given the role of intracellular GSH in pheomelanogenesis, a trade‐off in GSH allocation between resistance in oxidative stress and melanin production may take place. To investigate how intracellular GSH is regulated in differently coloured individuals at the time of reproduction (in adults) and of intense melanogenesis (in nestlings), we measured the total pool of GSH produced (tGSH), consumed (oxGSH) and available (redGSH) in adult tawny owls and their offspring which were cross‐fostered between randomly chosen nests. Our goal was to describe potential correlations between resistance in oxidative stress and colour morphs in natural conditions. Nestling GSH levels were correlated with GSH levels in their genetic and foster parents suggesting that producing GSH is genetically and environmentally determined (although the effect of the foster nest seemed stronger). This species shows continuous variation in pheomelanin reddish colouration, which is associated with life‐history strategies. Based on the hypothesis of GSH dependence of pheomelanism, we expected a greater amount of oxGSH in dark compared to light pheomelanic nestlings, which was not the case. In contrast, light melanic breeding adults had higher levels of tGSH and redGSH than dark breeders probably because of a higher investment in antioxidant capacity. The link between pheomelanism and GSH may therefore be due to the fact that differently colored individuals have different life‐history strategies rather than because the production of pheomelanin pigments requires GSH.

Differential responses of coexisting owls to annual small mammal population fluctuations in temperate mixed forest

Montane temperate forests in central and southern Europe host diverse small mammal assemblages, but the fluctuations in these assemblages in correlation with owl predators are still poorly explored. The key questions of our study were how coexisting owls responded to different prey fluctuations and whether any particular small mammal species governed predator–prey co‐dynamics. We conducted a long‐term study (2004–2020) in low‐elevation (300–1100 m above sea level) mixed Beech and Silver Fir forest in the northern Dinaric Alps (central Slovenia). Monitoring data on the main small mammal groups – mice Muridae, voles Cricetidae, dormice Gliridae and shrews Soricidae – and three owl species – the Ural Owl Strix uralensis, Tawny Owl Strix aluco and Boreal Owl Aegolius funereus – were collected annually. To find relationships between prey and predator populations, we used two types of supervised machine learning approaches and addressed three predictive modelling tasks of multi‐target regression. The dominant species in the small mammal assemblage, the Yellow‐necked Mouse Apodemus flavicollis, had a key role in determining predator populations and their breeding performance. We noted higher sensitivity to small mammal fluctuations in boreal zone owl species (Boreal Owl and Ural Owl), which reach their southern distribution limit in the Dinaric Alps, whereas the temperate zone species (Tawny Owl) seemed to be less affected. In years of prey shortage, the Boreal Owl was found to presumably abandon its territories, the Ural Owl suppressed breeding and the Tawny Owl sustained breeding activity by shifting prey selection. Low‐elevation forests appeared to be suboptimal habitat for the competitive subordinate Boreal Owl, which may exploit occasional outbreaks of small mammal populations in these habitats even in the presence of larger competitors. Whether low‐elevation forests can play a role in maintaining threatened and cold‐adapted Boreal Owl populations in central and southern Europe in the face of recent ecosystem changes due to climate and environmental changes remains an open scientific question.

Colonization of Urban Habitats: Tawny Owl Abundance Is Conditioned by Urbanization Structure.

Simple SummaryAlteration of natural habitats due to urbanization is an increasing concern worldwide. Some species, including owls, can exploit this novel environment, although the consequences at the population level have not been described. In this study, we analyze the effect of different urban variables on tawny owl (Strix aluco) population abundance. At the local scale, forest and urban cover, as well as the clumpiness index, affected tawny owl abundance. At the landscape scale, its abundance decreased in complex-shaped urban patches and when distance between them was greater. Urban habitats do not substitute natural habitats in terms of abundance, but the species can easily colonize patchy urban habitats.Natural habitats are being altered and destroyed worldwide due to urbanization, leading to a decrease in species abundance and richness. Nevertheless, some species, including tawny owls, have successfully colonized this novel habitat. Consequences at the population level have not been described; thus, our main objective was to describe the effects that urban structure have on the tawny owl population at local and landscape levels. Data were obtained from 527 survey points over 7 months in a large-scale owl survey in the Basque Country (northern Spain) in 2018. At the local scale, the interaction between forest and urban cover affected tawny owl abundance, the optimum being in medium forested areas. The interaction between urban cover and clumpiness index (urban patch distribution) showed a generally negative effect. At the landscape scale, its abundance decreased in complex-shaped urban patches and when distance between them was greater. In conclusion, at the local scale, when a minimal forest structure is present in urbanized areas, the species can exploit it. At the landscape scale, it prefers smaller urban towns to cities. Thinking ahead, the current tendency toward “green capitals” should benefit tawny owl populations.

Landscape Configuration Influences Species Occupancy over Multiple Spatial Scales: A Case Study on Tawny Owl

ABSTRACT Landscape configuration can influence the distribution of species across multiple spatial scales. The primary factors related to this process are connectivity, the size and position of habitat patches, and edge effects. These factors together determine the overall fragmentation of a landscape, which in turn influences species occurrence. Although some species show a negative response to fragmentation, others benefit from it. Potential effects may act over multiple spatial scales, possibly with contrasting effects on species occurrence. We chose the Tawny Owl (Strix aluco), a ubiquitous and generalist species, to study the influence of fragmentation on species occurrence and to identify relevant landscape metrics, using multi-scale hierarchical modelling. Between 2016 and 2018, we recorded Tawny Owls on 64 sampling sites located in a forested landscape. We used a space-for-time substitution in the framework of occupancy modelling to assess Tawny Owl responses to landscape fragmentation. We found that the Tawny Owl is widespread in the study area. Its distribution across the landscape (larger spatial scale) was related to a heterogeneous configuration of forest patches, while high connectivity of coniferous forest influenced its occurrence at a smaller spatial scale (sites). Overall, the Tawny Owl prefers landscapes with well-connected forest patches and an uneven patch distribution in the surrounding area.

Herpesvirus Infection in a Breeding Population of Two Coexisting Strix Owls.

Simple SummaryAlthough infection with herpesvirus in owls has commonly been described as a highly lethal disease, there is very little information about the presence of herpesvirus and its potential impact in living owls in wild populations. Our study detected herpesvirus in a breeding population of Ural owls, which showed no clinical signs of illness nor productivity deviances (i.e., in clutch and brood size). Herpesvirus was detected in Ural owl adults and chicks, but not in a young tawny owl (despite the fact that they were in same nest and in persistent contact). Furthermore, herpesviruses were also detected in yellow-necked mice as both owls’ main prey. However, comparison of the herpesviruses detected showed that different herpesviruses are present in the owls and mice. The results of this study show that herpesvirus may be present in a Ural owl breeding population without any consequences on health and breeding performance. However, in the case of tawny owls, it seems that they are not susceptible to infection, which could be related to their polymorphism. It seems that small rodents are not a source of herpesvirus infection in owls and that the probable herpesvirus transmission pathway takes place intraspecifically, mostly from adults to young.Birds are a frequent host of a large variety of herpesviruses, and infections in them may go unnoticed or may result in fatal disease. In wild breeding populations of owls, there is very limited information about the presence, impact, and potential transmission of herpesvirus. The herpesvirus partial DNA polymerase gene was detected using polymerase chain reaction in oropharyngeal swabs of 16 out of 170 owls examined that were captured in or near nest boxes. Herpesvirus was detected in Ural owls (Strix uralensis), in both adults and young, but not in tawny owls (Strix aluco). In yellow-necked mice (Apodemus flavicollis), as the main prey of tawny owls and Ural owls in the area, herpesvirus was detected in the organs of 2 out of 40 mice captured at the same locations as the owls. Phylogenetic analysis showed that the herpesvirus sequences detected in the Ural owls differed from the herpesvirus sequences detected in the yellow-necked mice. The results indicate that herpesvirus infection exists in the breeding wild Ural owl population. However, herpesvirus-infected owls did not show any clinical or productivity deviances and, based on a phylogenetic comparison of detected herpesvirus sequences and sequences obtained from Genbank database, it seems that mice and other rodents are not the source of owl infections. The most probable transmission pathway is intraspecific, especially from adults to their chicks, but the origin of herpesvirus in owls remains to be investigated.

The effect of environmental variables on owl distribution in Central Europe: A case study from the Czech Republic

Species distributional data from atlas projects collected by volunteers and professionals play an essential role in ecology and biodiversity conservation. Atlas data primarily allow evaluating longitudinal and latitudinal gradients in species distribution. However, the effects of additional factors such as elevation and associated climatic conditions and landscape structure are rarely assessed. We used the original data from the Atlas of birds breeding in the Czech Republic in terms of the presence and absence (0/1) of breeding occurrence of seven owl species in 604 mapping quadrates (each quadrate 12.0 × 11.1 km in size) to assess the effect of elevation (reaching from 100 to 1100 m a.s.l.) and temperature on the distributional patterns of the owls. Using a multivariate spatial analysis with latitude and longitude as space predictors and landscape structure as covariates, we found that elevation and temperature significantly affected owl distribution; the model explained 94.8% of the variability (p = 0.002). Only the boreal owl (Aegolius funereus) showed a clear preference for the highest elevation, and simultaneously, boreal and pygmy (Glaucidium passerinum) owls preferred the coldest environments. Eagle owl (Bubo bubo) and tawny owl (Strix aluco) most often occupied low and middle elevation of moderate temperatures. Barn owl (Tyto alba) and long-eared owl (Asio otus) inhabited the warmest areas in low elevations. Finally, little owl (Athene noctua) most often occurred in the lowest elevations of intermediate temperatures. We have documented that the elevation and associated climate conditions can work as an effective predictor to assess distributional preferences of owl species based on atlas data. The findings can be helpful when the management of owls' habitats is considered and implemented. For example, the results of our case study suggest that the boreal owl can be susceptible to global warming and intensive logging at high elevations.

Predisposing Anatomical Factors of Humeral Fractures in Birds of Prey: A Preliminary Tomographic Comparative Study.

The aim of this study was to identify possible predisposing anatomical factors associated with humeral fractures in birds of prey through comparison of specific anatomical features in different raptor species. An anatomical study of bone features in birds of prey was performed on 3 male subjects from 5 different species. The selected species included in this investigation were 3 diurnal species (the common buzzard [Buteo buteo], the peregrine falcon [Falco peregrinus], and the European honey-buzzard [Pernis apivorus]) and 2 nocturnal species (the barn owl [Tyto alba] and the tawny owl [Strix aluco]). Humeral bone samples were tomographically analyzed with a micro-macro-focus computed tomographic machine. Specific humeral anatomical points were selected (foramen pneumaticum and tuberculum dorsale for the proximal humerus; corpus humeri for the diaphyseal humerus; and above the condylus dorsalis for the distal humerus) to measure foramen pneumaticum diameter (in millimeters), cortical thickness (in millimeters), and trabeculae number and sizes (in millimeters). Apparent density, measured with the Hounsfield unit, was used to assess the degree of bone resistance. Statistical analysis was performed with a Spearman's correlation, and significance was set at P < .05. The differences among the observed bone volumes were highly significant (P = .00). Trabeculae number and the humeral anatomical point measurements showed differences in all 5 avian species investigated. However, those differences were not significant, except at the condylus dorsalis; in which, a significant interspecies difference (P = .002) was recorded. Trabecular size, cortical thickness, bone density, and diameter of the foramen pneumaticum were all different in all raptor species; however, these variations were not significant. The study confirms the existence of humeral bone volume differences between diurnal and nocturnal species. Furthermore, the data suggest that the humeri of peregrine falcons and European honey-buzzards may be stronger than the humeri of common buzzards, tawny owls, and barn owls.

Raptor wing morphing with flight speed.

In gliding flight, birds morph their wings and tails to control their flight trajectory and speed. Using high-resolution videogrammetry, we reconstructed accurate and detailed three-dimensional geometries of gliding flights for three raptors (barn owl, Tyto alba; tawny owl, Strix aluco, and goshawk, Accipiter gentilis). Wing shapes were highly repeatable and shoulder actuation was a key component of reconfiguring the overall planform and controlling angle of attack. The three birds shared common spanwise patterns of wing twist, an inverse relationship between twist and peak camber, and held their wings depressed below their shoulder in an anhedral configuration. With increased speed, all three birds tended to reduce camber throughout the wing, and their wings bent in a saddle-shape pattern. A number of morphing features suggest that the coordinated movements of the wing and tail support efficient flight, and that the tail may act to modulate wing camber through indirect aeroelastic control.

Rediscovery of the Type Specimens of Strix aluco volhyniae Dunajewski, 1948

This paper reports the rediscovery of the type specimens (holotype and paratype) of Strix aluco volhyniaeDunajewski, 1948, a junior synonym of Strix aluco aluco Linnaeus, 1758. Previously thought to have been destroyed during the Second World War, the types were found in the collection of the Museum and Institute of Zoology of the Polish Academy of Sciences. Additionally, this paper provides support for the availability of the name Strix aluco volhyniae, which was initially proposed as a new race.

First report of Trichinella pseudospiralis in a wolf (Canis lupus italicus).

Within the genus Trichinella, Trichinella pseudospiralis is the only recognized non-encapsulated species known to infect mammals and birds. In October 2020, larvae recovered from muscle tissues of a wolf (Canis lupus italicus) originating from Molise Region, Central Italy, were molecularly confirmed as those of Trichinella britovi and T. pseudospiralis. This is the first detection of T. pseudospiralis from a wolf. In Italy, this zoonotic nematode was detected in a red fox (Vulpes vulpes), three birds (Strix aluco, Athene noctua, Milvus milvus) and five wild boars (Sus scrofa), and was also identified as the etiological agent of a human outbreak of trichinellosis in 2015. Since T. pseudospiralis is rarely reported from carnivore mammals in comparison to the encapsulated species frequently detected in these hosts, this finding opens the question of the role of carnivores as reservoirs for this parasite.

Lice, Flies, Mites, and Ticks on Raptors (Accipitriformes, Falconiformes and Strigiformes) in Rescue Centers in Central Italy

This study aims to assess the occurrence of external arthropods on deceased raptors in rescue centers in Tuscany, central Italy. The examined diurnal raptors include 17 common buzzards (Buteo buteo), two European honey buzzards (Pernis apivorus), seven sparrowhawks (Accipiter nisus), six common kestrels (Falco tinnunculus), a western osprey (Pandion haliaetus), and a peregrine falcon (Falco peregrinus). Nocturnal raptors included seven barn owls (Tyto alba), ten tawny owls (Strix aluco), 22 little owls (Athene noctua) and two scops owls (Otus scops). The skin and the feathers of each animal were examined, and arthropods were collected, fixed, and microscopically identified. In 48 out of the 75 examined birds (64%), at least a single arthropod species was found. Identified arthropods included chewing lice (Degeeriella fulva, D. rufa, Colpocephalum turbinatum, C. apivorus, Nosopon lucidum, N. clayae, Craspedorrhyncus platystomus, Laemobothrion tinnunculi, Kurodaia subpachygaster, Strigiphilus cursitans), hippoboscid flies (Ornithomya avicularia), chigger and feather mites (Kramerella lunulata, K. lyra, Kramerella sp., Glaucalges attenuatus, Hieracolichus nisi, Hieracolichus sp., Neotrombicula autumnalis) and ticks (Haemaphysalis sp.). Most of the identified mite, fly and tick species are the first records in raptors in Italy. Moreover, this study presents the first record of Hieracolichus sp. and N. autumnalis mites in P. haliaetus and F. tinnunculus, respectively.