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ABSTRACT During an intensive study of the urban population of the blackbird Turdus merula in Szczecin (1997–2023), four cases of surrogate copulation were observed in the blackbird and three in the fieldfare Turdus pilaris. In three cases, birds (blackbirds twice and fieldfare once) try to copulate with fledglings of their own species, and in all other cases, the birds try to copulate with moss and sticks. In three cases copulation, attempts were done by adult birds (two blackbirds and one fieldfare), and in four cases, it was a fledgling.

The presence of Borrelia burgdorferi sensu lato (the agent of Lyme disease) in Ixodes ricinus ticks removed from wild birds and questing ticks was investigated. A total of 345 ticks from 75 infested birds belonging to 10 species and 274 questing ticks collected from the surrounding vegetation were examined by PCR for Borrelia burgdorferi s. l. Pathogen DNA was found in 8.1% (28/345) of the bird-feeding ticks - 10.9% (11/101) in larvae and 7.0% (17/244) in nymphs. Prevalence of infection was 9.4% in ticks from the Eurasian blackbird (Turdus merula), 4.0% in ticks from the song thrush (T. philomelos) and 16.6% from the European robin (Erithacus rubecula). Detection of infected larvae (13.3%) collected from the Eurasian blackbird suggests that this species might contribute to the transmission to the vector I. ricinus. The overall prevalence of B. burgdorferi in the questing nymphs was 10.6%. This is the first report of B. burgdorferi s. l. infection in I. ricinus from wild birds in Bulgaria. [ABSTRACT FROM AUTHOR]

Nest reuse is often observed in large- and medium-sized birds, including hole-nesters, while in smaller passerines building open-cup nests it is rarely recorded. In this note we report a case of multiple nest reuse, observed in a residential garden in Poland. The nest was located on the wall of a farm building partly overgrown by Boston Ivy at the height of 2.3 m. The nest was occupied eight times between 2007 and 2023 by three bird species: Grey and Pied Wagtails and Common Blackbirds. The nest was built by Grey Wagtails in 2007, but in 2009 it was reconstructed considerably by blackbirds. The Blackbird cup with mud lining survived until 2023 and contained all other nests. We suggest that the most plausible reason for multiple nest reuse was the high quality of this nest site. However, we also found that the nest was used during warm, dry springs but avoided when weather conditions at the beginning of the breeding season were adverse. We hypothesize that cold and wet springs – thought to be associated with high costs of reproduction – may have influenced birds' decision not to reuse the nest. To our knowledge, this is the longest case of nest reuse reported for passerines building open-cup nests. [ABSTRACT FROM AUTHOR]

Mitochondrial genome is a very useful marker for determining the phylogenetic relationships. Hence in this study, the complete mitochondrial genome of Turdus merula was sequenced, described, and analyzed with Sanger sequencing technology. The complete mitochondrial genome of T. merula was 16,734 bp in length and encoded 37 genes, including 13 protein-coding genes, 22 tRNAs, 2 rRNA gene fragments, a control region (D-loop region) and gene arrangement was identical to that of other Passeriformes mitogenomes. The overall base composition included A, 29.34%; C, 32.50%; G, 14.82% and T, 23.34%. The motifs obtained by sequence comparison, "ATGAACCTAA" between ATP8 and ATP6, and "ATGCTAA" between ND4L and ND4, and "CAAGAAAGG" between COXI and tRNASer(UCN) were highly conservative in Passeriformes species. The monophyly of Passeriformes is divided into four major clades: Musicicapoidea, Sylvioidea, Passeroidea, and Corvoidea. The phylogeny analyses of Passerida was conducted with the clear support of dividing the group into three superfamilies: the Muscicapoidea, the Sylvioidea, and the Passeroidea, and Passeroidea is a sister taxon for Muscicapoidea and Sylvioidea, which are closely related to each other. We suggest that the genus Paradoxornis will be classified as family Sylviidae, while these two species (Luscinia cyanura and Monticola gularis) are placed in the family Muscicapidae. Moreover, Turdidae formed a sister group with Muscicapidae, which indicates that they are closely related and form the superfamily Muscicapoidea together with the Sturnidae families. The relationships between some species of the order Passeriformes may remain difficult to resolve despite an effort to collect additional characters for phylogenetic analysis. Current research of avian phylogeny should focus on adding molecular markers and taxa samples and use both effectively to reconstruct a better resolution for disputed species. [ABSTRACT FROM AUTHOR]

AbstractWe studied extra-pair paternity in a socially monogamous bird, the European Blackbird (Turdus merula). The research was conducted in an urban park in Poland. We obtained genetic samples from 36 broods (123 nestlings) of 21 unique pairs. The proportion of broods with some extra-pair nestlings was 17.1% (6 broods), and overall, 13.1% (16 nestlings) of all nestlings were sired by extra-pair males. In one brood (2.8% of all the investigated broods), we found one egg laid by a female which did not have her own territory in the study area (brood parasitism). These figures are relatively low compared to other closely related passerines. We suggest that mate guarding in the studied population may effectively prevent females from engaging in extra-pair activity, and in the case of females, divorce and serial polygamy are better strategies for enhancing the genetic quality and genetic diversity of their offspring than infidelity.

The use of wild animals in research is complicated due to the capture and housing conditions, as well as to legal aspects, making it difficult to develop in vivo and in vitro models for the study of pathologies that affect these species. Here we validate an in vitro model of tendon-derived mesenchymal cells (TDSC) from Eurasian blackbird (Turdus merula) cadaveric samples. Through the expression of surface markers and the ability to differentiate into multiple lineages, the nature of the cells was confirmed. We then evaluated Mesenchymal Stem Cells (MSCs) as an infection model for the Usutu Flavivirus. To this aim, blackbird TDSCs were compared to Vero E6 cells, commonly used in Flavivirus studies. Both cells showed permissiveness to USUV infection as confirmed by immunocytochemistry. Moreover, TDSCs exhibited replication kinetics similar to, although slightly lower than, Vero E6, confirming these cells as a pertinent study model for the study of the pathogenesis of USUV. In this work, we isolated and characterized tendon-derived mesenchymal stem cells, which represent an interesting and convenient in vitro model for the study of wildlife species in laboratories. [ABSTRACT FROM AUTHOR]

We studied extra-pair paternity in a socially monogamous bird, the European Blackbird (Turdus merula). The research was conducted in an urban park in Poland. We obtained genetic samples from 36 broods (123 nestlings) of 21 unique pairs. The proportion of broods with some extra-pair nestlings was 17.1% (6 broods), and overall, 13.1% (16 nestlings) of all nestlings were sired by extra-pair males. In one brood (2.8% of all the investigated broods), we found one egg laid by a female which did not have her own territory in the study area (brood parasitism). These figures are relatively low compared to other closely related passerines. We suggest that mate guarding in the studied population may effectively prevent females from engaging in extra-pair activity, and in the case of females, divorce and serial polygamy are better strategies for enhancing the genetic quality and genetic diversity of their offspring than infidelity. [ABSTRACT FROM AUTHOR]

Blackbird Turdus merula is a model species for studying the impact of environmental factors on the form and structure of nests. In the middle of XX, this species began to expand its range into the artificial forests of the Ukrainian steppe zone. This expansion may have led to changes in bird behaviour, including changes in nest construction choices (e.g., nest shape, size, location and building materials). In this study, we investigated Blackbird nest diversity (i. e., size, volume, and composition) in the park of Simferopol (a city in Crimea, South Ukraine) and in an artificial forest located nearby. We found a significant inverse relationship between nest placement height and external nest diameter. External nest depth was greater in the forest than in the park. This difference reflects the variation in plant life form between the sites. More specifically, nests in trees have significantly greater external depth than the nests located on shrubs. Most nests in both urban and suburban localities contained natural and anthropogenic materials; there was no significant difference in component types between sites. In general, the anthropogenic materials played a decorative role and also served as camouflage. [ABSTRACT FROM AUTHOR]

Dichlorodiphenyltrichloroethane (DDT) is a pesticide that was commonly used for decades worldwide. The use of DDT was banned in the 1970s and 1980s in Europe because of its high toxicity and persistence in the environment, bioaccumulation in living organisms and biomagnification through food webs. However, monitoring using both invasive and non‐invasive methods has routinely reported the occurrence of DDT metabolites such as dichlorodiphenyldichloroethylene (DDE) in wild birds, providing valuable information about the exposure to pesticides and potential differences between species and over time. Here, we analysed the relative proportion of DDE in the uropygial gland secretions of European Blackbirds Turdus merula from two localities in southern Spain. Given the negative effects of this pollutant on animal immunity, we also tested for associations between the prevalence of haemosporidians and the relative proportion of DDE in their secretions. Relative proportions of DDE varied between sampling sites and were higher in females than in males, regardless of their age. In spite of the potential immunosuppressive effect of DDE, haemosporidian infection was not associated with DDE presence. [ABSTRACT FROM AUTHOR]

Resumen Igual que es posible trazar una historia de los cantos de las aves, de su recepción por y su relación con los seres humanos, también se puede especular sobre si esos cantos pueden funcionar como historia, viva, sonora, en qué grado y modos, así como en qué diferiría esa historia aviar de la humana o si podría enriquecerla. Muchas aves, después de todo, transmiten y aprenden sus cantos unas de otras, construyen sobre ellos y los complican, recogiendo otros sonidos que asumen e incorporan, sonidos humanos incluidos. Crean así paisajes sonoros que no siempre quedan de fondo: en ocasiones, reclaman su relevancia y toman el primer plano, en la historia y como historia.

Brood reduction is a frequent outcome in asynchronously hatching birds. In these species, first-hatched nestlings get a disproportionately larger share of the food delivered by parents, often leading the youngest nestling to starve to death soon after hatching. However, we still do not know the proximate mechanisms of such brood reduction. Starvation of the smallest nestling may be the outcome of scramble competition among nestmates (due to brood size hierarchies) or, alternatively, be caused by parents that ignore the persistent begging from their smallest nestling. To determine whether parents or scramble competition among siblings induces brood reduction, we used a cross-fostering approach to experimentally create asynchronous Eurasian blackbird, Turdus merula , broods. Then, we assessed food allocation by parents in two different situations: when sibling competition was allowed and when competition was prevented by physically separating nestlings with wooden barriers placed within the nest. We found that smaller nestlings experimentally introduced into blackbird nests received less food than their larger nestmates regardless of whether scramble competition among nestlings was allowed or not. Males preferentially fed larger nestlings regardless of the competitive context, while females showed no feeding differences. Our results suggest that nestlings may exert limited control over parental food allocation. • The smallest nestling usually starves in asynchronously hatched broods. • This can be due to nestling control, parental control or both. • Smaller nestlings received less food regardless of the competitive situation. • Parents actively ignore the smallest nestling. [ABSTRACT FROM AUTHOR]

Usutu virus (USUV) is an emerging zoonotic arbovirus in Europe, where it primarily impacts Eurasian blackbirds (Turdus merula). For mosquito‐borne viruses to persist in temperate areas, transovarial transmission in vectors or overwintering in either hosts or diapausing vectors must occur to facilitate autochthonous transmission. We undertook surveillance of hosts and vectors in 2021 to elucidate whether USUV had overwintered in the United Kingdom (UK) following its initial detection there in 2020. From 175 dead bird submissions, we detected 1 case of USUV infection, in a blackbird, from which a full USUV genome was derived. Using a molecular clock analysis, we demonstrate that the 2021 detection shared a most recent common ancestor with the 2020 Greater London, UK, USUV sequence. In addition, we identified USUV‐specific neutralizing antibodies in 10 out of 86 serum samples taken from captive birds at the index site, demonstrating in situ cryptic infection and potential sustained transmission. However, from 4966 mosquitoes, we detected no USUV RNA suggesting that prevalence in the vector community was absent or low during sampling. Combined, these results suggest that USUV overwintered in the UK, thus providing empirical evidence for the continued northward expansion of this vector‐borne viral disease. Currently, our detection indicates geographically restricted virus persistence. Further detections over time will be required to demonstrate long‐term establishment. It remains unclear whether the UK, and by extension other high‐latitude regions, can support endemic USUV infection. [ABSTRACT FROM AUTHOR]

Hatching asynchrony in birds is considered an adaptation to facilitate brood reduction because under conditions of food scarcity, the smallest nestling usually dies soon after hatching, thereby minimizing parental effort. However, in species with extreme hatching asynchrony, the last hatchlings paradoxically experience a very low probability of survival and death can take so long that it can hardly be considered an adaptation. Here, we propose and experimentally tested a new adaptive hypothesis explaining the brood reduction paradox, namely the “Male Manipulation Hypothesis”. Our hypothesis suggests that by inducing asynchronous hatching, females increase the feeding requirements of the brood, which will induce males to increase provisioning effort. In addition, females may extend the period of male manipulation by feeding the smallest nestling just enough to sustain life. Our study showed that male common blackbirds (Turdus merula) increased their effort (i.e., number of food items per hour) in experimental asynchronous broods compared to synchronous broods, while females reduced their contribution, as predicted by the hypothesis. [ABSTRACT FROM AUTHOR]

Abstract Background Land-use change is one of the main drivers of the global erosion of biodiversity. In that context, it is crucial to understand how landscape characteristics drive the presence of rare endangered species. Nevertheless, it is also important to study common species in multiple habitats, because they represent a large proportion of biodiversity and are essential to maintain ecological functions. Interestingly, some habitats, as farmlands with permanent crops (e.g. vineyards), have been overlooked in the literature. Methods In this study, we investigated the distribution of a widespread and common bird species, the Common Blackbird (Turdus merula), within and between the three main habitats of our study area (rural Western France). We specifically focused on (1) woodlands, (2) farmlands with a high vineyard coverage, and (3) moderately urbanized areas. Specifically, we aimed to assess the beneficial and detrimental effects of these habitats and their fine-scale composition on the presence of a common bird species, relying on a survey by point counts (nearly 100 locations). We studied the effects of habitats and gradients of fine-scale habitat composition on blackbird presence using logistic regression analyses. Results Blackbirds were present in all studied habitats. However, their presence varied between habitats, being lower in vineyards than in woodlands and cities. In woodlands and cities, fine-scale analyses did not reveal any component driving the species’ presence. However, we found that shrub and tree vegetation cover had a significant positive effect on blackbird presence in vineyards. Conclusions Our results are in agreement with the definition of a generalist species. Interestingly, species distribution varied between habitats. The high presence of blackbirds in urban areas suggests that medium-sized cities, despite their artificialization, do not constrain the settlement of this former forest specialist and that green spaces may allow blackbirds to thrive in medium-sized cities. On the contrary, we found an impoverished presence of blackbirds in vineyards and a positive effect of vegetation on their presence in these landscapes. This suggests that permanent crops, and more generally farmlands, may impose important constraints to common species. Future studies should examine how to enhance biodiversity through agricultural management policies, especially in vineyards.

Heterospecifics eavesdrop on mobbing calls and respond with appropriate behavior, but the functional aspects are less studied. Here, I studied whether jays (Garrulus glandarius) eavesdrop on blackbird (Turdus merula) mobbing calls in comparison to blackbird song. Furthermore, it was studied whether jays provided with extra information about predators differ in their response. Three different experimental designs were carried out: (1) control playback of blackbird song to control for the species' presence, (2) experimental playback of different mobbing events of blackbirds towards different predators, (3) experimental playback similar to (2) but combined with different predator models. In the combined experiments, mobbing calls were tied to the respective visual stimuli. Comparing the experiments with and without predator presentation, a similar number of jays occurred during the playback-only experiment (n = 7) and the playback combined with model presentation (n = 6). However, during the playback-only experiment, jays approached the speaker closer and stayed for longer time in the nearer surrounding. These results show that jays need extra information to make an informed decision. [ABSTRACT FROM AUTHOR]

Usutu virus (USUV) is a mosquito-borne virus belonging to the family Flaviviridae, genus Flavivirus. Natural transmission cycle of USUV involves mosquitoes and birds, so humans and other mammals are considered incidental hosts. In this study, USUV infection was diagnosed in all wild blackbirds, collected from July to September 2018 in a wildlife recovery center in the province of Bologna, in the Emilia-Romagna region, northern Italy. All blackbirds showed neurological clinical signs, such as overturning, pedaling, and incoordination. Moreover, the subjects died shortly after arriving at the hospitalization center. Virological investigations were performed by real-time PCR on frozen samples of the spleen, kidney, myocardium, and brain for the detection of Usutu (USUV) and West Nile (WNV) viruses. The small and large intestine were used as a matrix for the detection of Newcastle disease virus (NDV). All 56 subjects with neurological clinical signs were positive for USUV, only one subject (1.8%) tested positive for WNV, and no subject was positive for NDV. The most represented age class was class 1 J (58.9%), followed by class 3 (25.0%), and lastly from class 4 (16.1%). Most of the blackbirds before dying were in good (51.8%) and fair (39.3%) nutritional status, while only five subjects (8.9%) were cachectic. The USUV genomes detected in the blackbirds of this study fall within the sub-clade already called EU2 that has been detected since 2009 in the Emilia-Romagna region. Neurological clinical signs in USUV-affected blackbirds are still widely discussed and there are few works in the literature. Although our results require further studies, we believe them to be useful for understanding the clinical signs of Usutu virus in blackbirds, helping to increase the knowledge of this zoonotic agent in wild species and to understand its effect on the ecosystem. The goal of this study was to report—in the context of the regional passive surveillance program—the detection of USUV RNA in its most important amplifying host, the common blackbird, when showing clinical signs before death. [ABSTRACT FROM AUTHOR]

Abstract Birds have been observed to have dietary preferences for unsaturated fatty acids during migration. Polyunsaturated fatty acids (PUFAs) may increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative damage in migratory individuals. To shed light on this potential constraint, we analyzed plasma fatty acid (FA) composition and estimated the unsaturation index as a proxy for susceptibility to lipid peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stopover site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ω‐3 PUFA α‐linolenic acid, suggesting a dietary and/or storage preference for these FAs in migrants. Interestingly, the FA unsaturation index did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate without simultaneously increasing the susceptibility of the substrate to lipid peroxidation. In summary, our results are in line with the hypothesis that increased exercise performance during migration might be constrained by oxidative stress, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs.

Blackbird Turdus merula is a model species for studying the impact of environmental factors on the form and structure of nests. In the middle of XX, this species began to expand its range into the artificial forests of the Ukrainian steppe zone. This expansion may have led to changes in bird behaviour, including changes in nest construction choices (e.g., nest shape, size, location and building materials). In this study, we investigated Blackbird nest diversity (i.e, size, volume, and composition) in the park of Simferopol (a city in Crimea, South Ukraine) and in an artificial forest located nearby. We found a significant inverse relationship between nest placement height and external nest diameter. External nest depth was greater in the forest than in the park. This difference reflects the variation in plant life form between the sites. More specifically, nests in trees have significantly greater external depth than the nests located on shrubs. Most nests in both urban and suburban localities contained natural and anthropogenic materials; there was no significant difference in component types between sites. In general, the anthropogenic materials played a decorative role and also served as camouflage.

Two Eurasian Blackbirds (Turdus merula) from central Italy were found with severe cyclocoelid trematodosis associated with airsacculitis. The birds were submitted with severe respiratory distress; one died shortly after hospitalization, while the second bird was euthanized. At necropsy, a massive presence of cyclocoelid flukes was observed in the coelomic cavity and air sacs of both birds. The air sacs were diffusely opaque, thickened, and covered by scant fibrinous exudate mixed with numerous parasites. Histologically, the air sacs showed diffuse and severe oedema with fibrinous exudate. Diffuse mononucleated and heterophilic infiltration mixed with multiple granulomas contained degenerated trematodes. Morishitium polonicum was identified using morphologic keys and molecular analysis of extracted DNA. Infections caused by M. polonicum are poorly documented in blackbirds and the findings in these birds support the pathogenic role of this trematode as a potential cause of death in blackbirds in Italy. Extended epidemiologic surveys are required to properly assess the potential importance of M. polonicum as a life-threatening pathogen in Blackbird populations. [ABSTRACT FROM AUTHOR]

The uropygial gland of birds produces an oily secretion with different functions, mainly related to plumage protection. In addition, the volatile compounds of this secretion may act as chemical signals that provide information to conspecifics, but it is also possible that those compounds may further attract hematophagous insect vectors such as those responsible for avian malaria transmission. Individual characteristics such as sex and age are usually associated with variation in the composition of the uropygial secretion. Different studies have shown that mosquitoes are more attracted towards birds infected by avian malaria parasites. However, whether the individual infection status by these parasites may lead to differences in the composition of this secretion remains poorly known. We used gas chromatography–mass spectrometry (GC–MS) to characterise the chemical composition of the volatile lipophilic fraction of the uropygial gland secretions of wild European blackbirds and compare its composition in an urban and a forest locality according to their age, sex and infection status by blood parasites. We found differences in the composition of the secretion between age classes and also between sexes within adult birds. However, no differences were found in the chemical composition of the uropygial gland secretion of birds according to their infection status by blood‐parasites and habitat type. These results suggest that haemosporidian infection does not alter the composition of the volatile fraction of uropygial gland secretions in infected birds. [ABSTRACT FROM AUTHOR]

This study was conducted in order to determine the effects of seasonal and daily temperatures on the levels of plasma thyroid hormone (T3 and T4) of Eurasian Blackbird (Turdus merula) among the different seasons. During the field studies carried out in Sankum Sinop between 2017-2018, 48 T merula were caught with mist nets, ringed and blood samples were taken for hormone analysis. It was found that thyroid hormone levels were affected by seasonal temperatures as a result of hormone analysis. According to our results plasma T3 and T4 hormone concentrations were changed in both morning and afternoon groups in autumn, winter, spring and summer seasons, and this situation was closely related to the reproductive period or moulting of T merula while that seasonal varying temperatures affect the amount of these hormones. The dramatic temperature differences both seasonally and during the day were important factors in changing hormone levels. [ABSTRACT FROM AUTHOR]

Background: Land-use change is one of the main drivers of the global erosion of biodiversity. In that context, it is crucial to understand how landscape characteristics drive the presence of rare endangered species. Nevertheless, it is also important to study common species in multiple habitats, because they represent a large proportion of biodiversity and are essential to maintain ecological functions. Interestingly, some habitats, as farmlands with permanent crops (e.g. vineyards), have been overlooked in the literature. Methods: In this study, we investigated the distribution of a widespread and common bird species, the Common Blackbird (Turdus merula), within and between the three main habitats of our study area (rural Western France). We specifically focused on (1) woodlands, (2) farmlands with a high vineyard coverage, and (3) moderately urbanized areas. Specifically, we aimed to assess the beneficial and detrimental effects of these habitats and their fine-scale composition on the presence of a common bird species, relying on a survey by point counts (nearly 100 locations). We studied the effects of habitats and gradients of fine-scale habitat composition on blackbird presence using logistic regression analyses. Results: Blackbirds were present in all studied habitats. However, their presence varied between habitats, being lower in vineyards than in woodlands and cities. In woodlands and cities, fine-scale analyses did not reveal any component driving the species’ presence. However, we found that shrub and tree vegetation cover had a significant positive effect on blackbird presence in vineyards. Conclusions: Our results are in agreement with the definition of a generalist species. Interestingly, species distribution varied between habitats. The high presence of blackbirds in urban areas suggests that medium-sized cities, despite their artificialization, do not constrain the settlement of this former forest specialist and that green spaces may allow blackbirds to thrive in medium-sized cities. On the contrary, we found an impoverished presence of blackbirds in vineyards and a positive effect of vegetation on their presence in these landscapes. This suggests that permanent crops, and more generally farmlands, may impose important constraints to common species. Future studies should examine how to enhance biodiversity through agricultural management policies, especially in vineyards. [ABSTRACT FROM AUTHOR]

Birds have been observed to have dietary preferences for unsaturated fatty acids during migration. Polyunsaturated fatty acids (PUFAs) may increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative damage in migratory individuals. To shed light on this potential constraint, we analyzed plasma fatty acid (FA) composition and estimated the unsaturation index as a proxy for susceptibility to lipid peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stopover site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ω‐3 PUFA α‐linolenic acid, suggesting a dietary and/or storage preference for these FAs in migrants. Interestingly, the FA unsaturation index did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate without simultaneously increasing the susceptibility of the substrate to lipid peroxidation. In summary, our results are in line with the hypothesis that increased exercise performance during migration might be constrained by oxidative stress, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs. [ABSTRACT FROM AUTHOR]

Blackbird Turdus merula is a model species for studying the impact of environmental factors on the form and structure of nests. In the middle of XX, this species began to expand its range into the artificial forests of the Ukrainian steppe zone. Th is expansion may have led to changes in bird behaviour, including changes in nest construction choices (e.g., nest shape, size, location and building materials). In this study, we investigated Blackbird nest diversity (i. e., size, volume, and composition) in the park of Simferopol (a city in Crimea, South Ukraine) and in an artificial forest located nearby. We found a significant inverse relationship between nest placement height and external nest diameter. External nest depth was greater in the forest than in the park. This difference reflects the variation in plant life form between the sites. More specifically, nests in trees have significantly greater external depth than the nests located on shrubs. Most nests in both urban and suburban localities contained natural and anthropogenic materials; there was no significant difference in component types between sites. In general, the anthropogenic materials played a decorative role and also served as camouflage. [ABSTRACT FROM AUTHOR]

Abstract Background Nests are composed of and built with different materials that are handled in specific ways. These materials must initially have been used de novo before commonly being incorporated into nests. Plastic and plastic bags were invented in the 1950s, and they are widely distributed in the environment. Birds started picking up plastic from plastic used to cover farm produce such as silage, potatoes, beets and other crops for use in their nests in the 1960s. Methods I recorded the frequency of such plastic use by the Blackbird (Turdus merula) in nests in Denmark, starting in 1966, followed by a peak in use in the 1970s and a subsequent decline. Results Nests with plastic were initially built earlier in the season than those without plastic, indicating an association between innovation and early reproduction. Plastic use was subsequently selected against because nests with plastic suffered from higher rates of predation than nests without plastic, probably because nests with plastic were easier to locate. However, the elevated risk of nest predation only applied to outdoor nests, but not to nests inside buildings, probably because visually searching nest predators such as corvids do not enter buildings. Conclusions These findings show that the dynamics of nest material use depend on the benefits of innovation and the fitness costs of nest predation.

[This paper indicates, by describing their predatory behaviors, seven species of birds observed to catch Cydalima perspectalis larvae; moth infestations widespread in the Far East and accidentally introduced to Europe in 2006, larvae that cause considerable damage to the box tree, Buxus sp., removing all leaves from the area. The observations were made in Piedmont (NW Italy) in 2016 in relation to the Blackbird, Turdus merula and Great tit, Parus major; and in the Holland (Noord Brabant) in 2017 in relation to Oystercatcher, Haematopus ostralegus; Great tit, Parus major; Blue tit, Cyanistes caeruleus; Magpie, Pica pica; Starling, Sturnus vulgaris; House sparrow, Passer domesticus.] [Article in Italian]

Aims: To determine the presence of infection and co-infection of Plasmodium lineages in introduced birds at translocation sites for the North Island saddleback (Philesturnus rufusater), to investigate their role as Plasmodium spp. reservoirs. Methods: Blood samples were collected from introduced bird species, with a special focus on blackbirds (Turdus merula) and song thrushes (Turdus philomelos), at six locations in the North Island of New Zealand that were the origin, or translocation sites, for North Island saddleback. Where available, blood smears were examined, and blood samples were tested using nested PCR with subsequent sequence analysis, for the presence of Plasmodium spp. Results: Of the 55 samples tested using PCR analysis, 39 (71%) were positive for Plasmodium spp., and 28/40 (62%) blood smears were positive for Plasmodium spp. Overall, 31 blood samples were from blackbirds with 28/31 (90%) samples positive for Plasmodium spp. Six distinct avian Plasmodium lineages were identified, including three cosmopolitan lineages; Plasmodium vaughani SYAT05 was detected in 16 samples, Plasmodium matutinum Linn1 in 10 samples and Plasmodium elongatum GRW6 in eight samples. Mixed infections with more than one lineage were detected in 12 samples. Samples from two Australian magpies (Gymnorhina tibicen) were positive for Plasmodium. sp. lineage MYNA02, previously not identified in New Zealand. Conclusions and clinical relevance: This is the first report from New Zealand in which specific Plasmodium spp. mixed infections have been found in introduced birds. Co-infections with several cosmopolitan Plasmodium lineages were identified, as well as the first report in New Zealand of an exotic avian Plasmodium sp. lineage, in Australian magpies. Whilst the role of introduced birds in maintaining and spreading pathogenic avian malaria in New Zealand is unclear, there is a potential infection risk to native birds, especially where distributions overlap. [ABSTRACT FROM AUTHOR]

Macro-anatomical importance of ossa cranii is increasing since the bones that make up the head skeleton in birds have the greatest diversity in the vertebrate group. Within this scope, macro-anatomical examination of the neurocranium in blackbird will contribute to the elimination of the lack of information in this area. In this research, regardless of gender, skulls of seven male and five female adult blackbirds were examined macro-anatomically by maceration. Images of materials examined were taken from different angles under 50 mm classical magnifying glass. It is determined that blackbirds have no suturas between their skull bones and have aegithognath type skull structure. It was observed that neurocranium is composed of occipital, sphenoid, parietal, frontal and temporal bone; also, ethmoid bone was included in the splanchnocranium part by the pressure of orbita. It was found that the triangular sphenoid bone forms a large part of the ventral part of the cavum cranii. As a result; It was concluded that the data obtained in this study will contribute to the lack of information in this field and it may be a source that will be used in taxonomy for the researchers working in the systematic area. [ABSTRACT FROM AUTHOR]

Even though much has been published in recent years on the factors affecting the lifespan and lifetime reproductive success of birds, there are still gaps in our knowledge. Here, we present the results of a long-term study of European blackbirds which examined the effect of natal conditions on lifespan and lifetime reproductive success (expressed by the number of fledglings) of 152 nestlings (72 males and 80 females) ringed in the Stefan Żeromski Park in Szczecin (NW Poland). We have complete information regarding parental age, family brood (first-egg laying date, clutch size, and hatching sequence), bird size, lifetime reproductive success, pair density and weather conditions during the natal year. For males, total fledgling production was the smaller, the later the laying date of the family brood, but increased with mean daily precipitation and pair density in the natal year. In the case of females, we did not find any significant relationships between their lifetime reproductive success and the above parameters. Male lifespan increased with mean daily precipitation and bird density, but only pair density had a positive effect on female lifespan. We suggest that for females, genetic factors could be more important for their reproductive success than for males. In addition, a blackbird's lifespan depends strongly on environmental factors. [ABSTRACT FROM AUTHOR]

Necropsy of two free-ranging common blackbirds (Turdus merula) found dead in central Italy revealed the presence of a high number of cyclocoelid flukes in the coelomatic cavity. Cyclocoelid flukes primarily infect avian respiratory system. Histologically, air sac walls were covered with a fibrinous exudate containing degenerate heterophils, many trematodes and some colonies of Gram-positive cocci. The superficial bronchi and parabronchi were markedly distended, and the adjacent pulmonary parenchyma was congested and collapsed. Trematodes, surrounded by a mild suppurative to pyogranulomatous inflammatory reaction, were also observed on the pericardial, intestinal, kidney and hepatic serosal surfaces. The death of the two examined birds was likely due to the high parasite load and associated severe lesions. At parasitological examination, flukes showed a tongue-shaped elongate body, tapered anteriorly and rounded posteriorly, of 2,088–2,314 μm in width and 8,268–11,830 μm in length. The mouth was slightly oval and sub-terminal, with a small oral sucker. The oval pharynx measured 250–309 μm, and the two caeca joined posteriorly. Two large (550–702 μm × 450–520 μm) globular testes were situated obliquely to each other, whereas an oval (250 × 300 μm in mean) or round (about 334 μm in diameter) intertesticular ovary was placed in a longitudinal straight line with the testes. The ootype was about 110 μm in diameter, while the brown-yellow eggs measured 131.5 × 73.9 μm in mean. The genital pore was post-pharyngeal, while the symmetrically arranged vitelline glands were not confluent posteriorly. Morphoflogical diagnosis led to the identification of Morishitium polonicum , a cyclocoelid fluke species that typically inhabits the air sacs of blackbirds. The morphological diagnosis was corroborated by molecular phylogenetic analysis of the mitochondrial (CO1, ND1) DNA loci. The present study provides the first report of pathological lesions and death caused by M. polonicum in birds. Image 1 • Necropsy revealed a high fluke load in the coelom of two deceased common blackbirds. • Based on morphology, the air sac trematode Morishitium polonicum was identified. • Morphological diagnosis was confirmed by molecular analysis. • Blackbird death was likely caused by the high parasite load and severe lesions. • This is the first report of M. polonicum as a cause of death in Turdus merula. [ABSTRACT FROM AUTHOR]

Several functions have been proposed to explain eggshell colouration in birds. Eggshell colour may, for instance, signal female egg investment and hence the quality of the female and/or the egg. Such a covariation between eggshell colour and egg quality is supported by several studies, but what is related to eggshell colour is not necessarily consistent between populations, species or egg compounds. In this study, we examined several maternally derived egg compounds; namely yolk mass, egg white lysozyme and pH, yolk testosterone, oestrogens and eggshell colour and we determined the abundance of cultivable bacteria on the eggshell surface of blackbirds' eggs Turdus merula. Based on that, we examined whether there is an association between eggshell colour parameters derived via spectrophotometric analyses and eggshell spot size and any of the investigated egg parameters. Our results suggest that two eggshell colour components derived by a principle component analyses and eggshell spot size covary with different egg parameters. We found that eggs containing more UV, yellow and red chroma in their eggshells contain heavier yolks. In contrast more bluish, greener and brighter eggs have to face higher loads of bacteria i.p. haemolytic bacteria and bacteria originating from the urogenital tract of the female. No other egg compound investigated seemed to be reflected in any eggshell colour parameter. Our data do not support an antibacterial function of eggshell colour as the abundance of bacteria originating from the female urogenital tract is negatively related to eggshell colouration. Furthermore, we found a positive but weak association between egg spot size and egg white lysozyme levels. Possible functional implications of our results are discussed. [ABSTRACT FROM AUTHOR]

The ornithophilic tick species Ixodes frontalis (Panzer) is spatially distributed in Europe, Asia and northern Africa. It can serve as a carrier of different bacteria and viruses, but little is known of its actual vector competence. In addition, adult females of this species are associated with the avian "tick-related syndrome" (TRS). Like most ornithophilic tick species, I. frontalis is usually collected from bird nests or directly from their hosts. Reports of I. frontalis being collected with the flagging method are scarce. In Germany, the species is considered as very rare. In the few reports that are available, the majority of ticks has been discovered on migrating birds. Therefore, knowledge of the actual distribution of this species in Germany was strictly limited. In this study, we report the finding of 1084 individuals of I. frontalis collected with the flagging method in urban areas and gardens in several regions of Germany. Furthermore, the species was discovered on 35 dead Eurasian blackbirds (Turdus merula) from all over Germany. Finally, we report of five new possible cases of TRS, three in free-ranging birds and two in captive birds, including a Harris's hawk (Parabuteo unicinctus) kept for falconry. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to investigate viscerocranium bones in black-bird (Turdus merula) bird macro-anatomically. In this research, regardless of gender, skulls of seven male and five female adult blackbirds were examined macro-anatomically by maceration. Splanchnocranium bones constituted of lacrimal, nasal, incisive, maxilla, zygomatic, palatine, vomer, quadratum, mandible and hyoid bones. Ethmoid bone was included in the splanchnocranium part by the pressure of orbita. Lacrimal bone was found to be oval and blunt ended. It was seen that nasal bone determines dorsal and lateral borders of the cavum nasi and also nostrils are formed at the end of fusion of extensions constituted together with intermaxillae and nasal bone. It was determined that proc. palatinus of maxilla bone contribute to the shape of palate. Zygomatic bone was also a thin, long, rod-shaped bone formed by the fusion of os jugale and os quadratatojugale, while os vomer was present as a nucleus in this region. It was seen that the mandibula shaped the skeleton of the lower jaw and this bone is formed by incorporating os angulare, os articulare, os supraangulare, os complamentare, os oparculare and os dentale bones. It was observed that the basihyoideum forming the body of the os hyoid bone was rod shaped. It was concluded that data obtained in this study would contribute to the lack of information in this area and it might be a source for systematic field researchers to use in taxonomy. [ABSTRACT FROM AUTHOR]

Usutu virus (USUV, Flaviviridae) was first reported in Europe in Austria in 2001, where it caused wild bird (mainly blackbird) mortality until 2005. Since 2006 no further USUV cases were diagnosed in the country. However, the virus emerged in other European countries (Hungary, Italy, Switzerland, Spain, Germany and the Czech Republic) between 2005 and 2011. In 2016, widespread USUV-associated wild bird mortality was observed in Germany, France, Belgium and the Netherlands. In this study, we report the results of passive monitoring for USUV in Austria and Hungary between 2010 and 2016. In Hungary, USUV caused sporadic cases of wild bird mortality between 2010 and 2015 (altogether 18 diagnosed cases), whereas in summer and autumn 2016 the number of cases considerably increased to 12 (ten blackbirds, one Eurasian jay and one starling). In Austria, USUV was identified in two blackbirds in 2016. Phylogenetic analyses of coding-complete genomes and partial regions of the NS5 protein gene revealed that USUVs from Hungary between 2010 and 2015 are closely related to the virus that emerged in Austria in 2001 and in Hungary in 2005, while one Hungarian sequence from 2015 and all sequences from Hungary and Austria from 2016 clustered together with USUV sequences reported from Italy between 2009 and 2010. The results of the study indicate continuous USUV circulation in the region and exchange of USUV strains between Italy, Austria and Hungary.Emerging Microbes & Infections (2017) 6, e85; doi:10.1038/emi.2017.72; published online 11 October 2017

During two successive years (2013–2014), we studied the breeding ecology of the European Blackbird Turdus merula in Guelma province, north-east of Algeria. The study was carried out in orange orchards of the region. We investigated nest placement in the orange trees and determined the factors of reproductive failure at this study area. Nests were placed at low height (mean ± SD = 1.42 ± 0.04 m) and located near the trunk (mean ± SD = 0.61 ± 0.04 m). The breeding season occurred between mid-May and mid-June and the peak of egg laying took place during the first half of May. The mean clutch size was 2.96 ± 0.05, density of breeding pairs was 0.83 ± 0.30 p/ha. The breeding success reported in the present study was higher than that recorded in other studies. Predation was the leading cause of nest failure of the population under investigation. The present study shows that the orange orchards appear to be the preferred breeding area for Blackbird population.

This paper describes a trematode isolated from the air sacs of a common blackbird (Turdus merula) by the authors in Qaemshahr city, Mazandaran province, north of Iran. The specimens were in the best form to make whole-mounts for species identification. The identified species was Morishitium vagum (Morishita 1924) Witenberg 1928, belonging to the family Cyclocoelidae Stossich 1902, according to morphologic and morphometric characters, as explained in references. This is the first report of a species belonging to the family Cyclocoelidae in Iran, and the first report of this type-species isolated from Turdus merula in the world.

Bird ring‐recovery data have been widely used to estimate demographic parameters such as survival probabilities since the mid‐20th century. However, while the total number of birds ringed each year is usually known, historical information on age at ringing is often not available. A standard ring‐recovery model, for which information on age at ringing is required, cannot be used when historical data are incomplete. We develop a new model to estimate age‐dependent survival probabilities from such historical data when age at ringing is not recorded; we call this the historical data model. This new model provides an extension to the model of Robinson, 2010, Ibis, 152, 651–795 by estimating the proportion of the ringed birds marked as juveniles as an additional parameter. We conduct a simulation study to examine the performance of the historical data model and compare it with other models including the standard and conditional ring‐recovery models. Simulation studies show that the approach of Robinson, 2010, Ibis, 152, 651–795 can cause bias in parameter estimates. In contrast, the historical data model yields similar parameter estimates to the standard model. Parameter redundancy results show that the newly developed historical data model is comparable to the standard ring‐recovery model, in terms of which parameters can be estimated, and has fewer identifiability issues than the conditional model. We illustrate the new proposed model using Blackbird and Sandwich Tern data. The new historical data model allows us to make full use of historical data and estimate the same parameters as the standard model with incomplete data, and in doing so, detect potential changes in demographic parameters further back in time. A method to estimate age‐specific survival of fledged birds when age at ringing is known only for birds later recovered. [ABSTRACT FROM AUTHOR]

Through this study, it was investigated whether the biometry of Turdus merula, the biometry of which was not studied in a detailed manner in Turkey, shows differences depending on sex and seasons. The wing, tail length and weight of T. merula caught in Kızılırmak Delta during spring and autumn ringing periods between 2002 and 2009 were measured. During the eight year ringing season, 423 T. merula in spring and 421 in autumn were caught and ringed and biometric measurements were taken. Both wing length and tail length average of the T. m. aterrimus overlap with the samples of the North West Anatolia whereas it is longer than the samples of the North East Anatolia. Regardless of the season, the mean wing length of both the females and the males overlap with the lengths of the T. m. aterrimus. The mean of the wing, tail length and weight of the samples caught in Kızılırmak Delta overlap with T. m. aterrimus subspecies. This study aimed to identify the taxonomy among T. merula subspecies was first and the most detailed study on biometrics in terms of sample size in Kızılırmak Delta in Turkey. [ABSTRACT FROM AUTHOR]

Usutu virus (USUV) is an African mosquito-borne flavivirus belonging to the Japanese encephalitis virus serocomplex. USUV is closely related to Murray Valley encephalitis virus, Japanese encephalitis virus, and West Nile virus. USUV was discovered in South Africa in 1959. In Europe, the first true demonstration of circulation of USUV was reported in Austria in 2001 with a significant die-off of Eurasian blackbirds. In the subsequent years, USUV expanded to neighboring countries, including Italy, Germany, Spain, Hungary, Switzerland, Poland, England, Czech Republic, Greece, and Belgium, where it caused unusual mortality in birds. In 2009, the first two human cases of USUV infection in Europe have been reported in Italy, causing meningoencephalitis in immunocompromised patients. This review describes USUV in terms of its life cycle, USUV surveillance from Africa to Europe, human cases, its cellular tropism and pathogenesis, its genetic relationship with other flaviviruses, genetic diversity among USUV strains, its diagnosis, and a discussion of the potential future threat to Asian countries.

To evolve and to be maintained, seasonal migration, despite its risks, has to yield fitness benefits compared with year-round residency. Empirical data supporting this prediction have remained elusive in the bird literature. To test fitness related benefits of migration, we studied a partial migratory population of European blackbirds (Turdus merula) over 7 years. Using a combination of capture-mark-recapture and radio telemetry, we compared survival probabilities between migrants and residents estimated by multi-event survival models, showing that migrant blackbirds had 16% higher probability to survive the winter compared to residents. A subsequent modelling exercise revealed that residents should have 61.25% higher breeding success than migrants, to outweigh the survival costs of residency. Our results support theoretical models that migration should confer survival benefits to evolve, and thus provide empirical evidence to understand the evolution and maintenance of migration.

Adoption behavior is well-known in birds, but the majority of adoption studies concern the nestling phase of birds' lives, whereas fledgling adoption is a much less well-known phenomenon, especially in passerines. During 17 years of observations, we collected data on the fate of 238 broods of European Blackbirds Turdus merula. In 171 cases fledglings were fed only by their own parents, in 24 cases the fledglings were given to adoption, while in 43 cases at least one fledgling was cared for by foster parents. Our analyses suggest that fledgling adoption in Blackbirds occurred under conditions that are consistent with the predictions of 2 hypotheses that explain the adoption phenomenon in birds. First, adoptions involved young fledglings of roughly the same age as the foster parents' offspring and in the context of a short distance between the biological parents and foster parents' nests: this gave rise to errors in foster parents recognizing their own young--in line with the Reproductive Error Hypothesis. Second, adoptions also occurred in instances where the distance between nests and the age difference between the adopted and the foster parents' own fledglings was twice as great compared to the conditions suggesting erroneous adoption. The longer distance between nests and the bigger age difference are in line with the Intergeneration Conflict Hypothesis. [ABSTRACT FROM AUTHOR]

The distribution of Turdus merula in the steppe zone of Ukraine is studied. The expansion of its range occurred in the steppe zone in artificial forestations, many of which have been established as early as the second half of the 19th century. However, the Blackbird expansion in the steppe zone of the Left-bank and Right-bank Ukraine started only in the middle of the 20th century, and in the Crimean steppe zone only to the end of the 20th century. Now, the southern border of this species' range in the Left-bank Ukraine is almost at the northern coasts of the Black and Azov seas. In the Right-bank Ukraine its range is already at the seashore. In the Crimean steppe zone, the range expanded to the North of the forests of mountainous Crimea. The Blackbird populations farthest from the mountainous forests are found in artificial forest plantings at the northern and eastern borders of the peninsula. The species is absent from the western and north-western steppes of the Crimea. [ABSTRACT FROM AUTHOR]

Background: Nests are composed of and built with different materials that are handled in specific ways. These materials must initially have been used de novo before commonly being incorporated into nests. Plastic and plastic bags were invented in the 1950s, and they are widely distributed in the environment. Birds started picking up plastic from plastic used to cover farm produce such as silage, potatoes, beets and other crops for use in their nests in the 1960s. Methods: I recorded the frequency of such plastic use by the Blackbird (Turdus merula) in nests in Denmark, starting in 1966, followed by a peak in use in the 1970s and a subsequent decline. Results: Nests with plastic were initially built earlier in the season than those without plastic, indicating an association between innovation and early reproduction. Plastic use was subsequently selected against because nests with plastic suffered from higher rates of predation than nests without plastic, probably because nests with plastic were easier to locate. However, the elevated risk of nest predation only applied to outdoor nests, but not to nests inside buildings, probably because visually searching nest predators such as corvids do not enter buildings. Conclusions: These findings show that the dynamics of nest material use depend on the benefits of innovation and the fitness costs of nest predation. [ABSTRACT FROM AUTHOR]

Seasonal migration is a widespread phenomenon, which is found in many different lineages of animals. This spectacular behaviour allows animals to avoid seasonally adverse environmental conditions to exploit more favourable habitats. Migration has been intensively studied in birds, which display astonishing variation in migration strategies, thus providing a powerful system for studying the ecological and evolutionary processes that shape migratory behaviour. Despite intensive research, the genetic basis of migration remains largely unknown. Here, we used state-of-the-art radio-tracking technology to characterize the migratory behaviour of a partially migratory population of European blackbirds ( Turdus merula) in southern Germany. We compared gene expression of resident and migrant individuals using high-throughput transcriptomics in blood samples. Analyses of sequence variation revealed a nonsignificant genetic structure between blackbirds differing by their migratory phenotype. We detected only four differentially expressed genes between migrants and residents, which might be associated with hyperphagia, moulting and enhanced DNA replication and transcription. The most pronounced changes in gene expression occurred between migratory birds depending on when, in relation to their date of departure, blood was collected. Overall, the differentially expressed genes detected in this analysis may play crucial roles in determining the decision to migrate, or in controlling the physiological processes required for the onset of migration. These results provide new insights into, and testable hypotheses for, the molecular mechanisms controlling the migratory phenotype and its underlying physiological mechanisms in blackbirds and other migratory bird species. [ABSTRACT FROM AUTHOR]

Several studies have found that adult birds of altricial species adjust their parental care behaviour (i.e. nest visits) in response to the current risk of predation for their offspring. However, no experimental study has so far investigated whether there are sex differences in these passive anti-predator responses during the nestling period. Differences between males and females could arise because of several factors, including (1) probability of detection, (2) confidence in parenthood, and (3) different parental care behaviour associated with each sex. To test whether these anti-predator passive responses involve sex differences, we experimentally manipulated the perceived risk of nest predation of adult Common Blackbirds ( Turdus merula), a sexually dimorphic species with a relatively high extra-pair paternity level. Our results showed that nest predation significantly reduced adult visits to the nest, but not differentially between males and females, which does not support our predictions. Our findings suggest (1) that sex differences in predator-induced behaviour could depend on the type of response (active vs. passive anti-predator strategies); (2) the potential existence of a minimum threshold in detectability between males and females for these behavioural changes to occur; and (3) the contrasting and opposite effects of several factors that might impede the selection of sex differences in these types of parental care behaviour. [ABSTRACT FROM AUTHOR]