Turdus Merula Research Articles

Usutu Virus Africa 3 Lineage, Luxembourg, 2020.

We detected Usutu virus in a dead Eurasian blackbird (Turdus merula) in Luxembourg in September 2020. The strain clustered within the Africa 3.1 lineage identified in Western Europe since 2016. Our results suggest maintenance of the virus in Europe despite little reporting during 2019–2020, rather than a new introduction.

Physiological stress responses to nonmimetic model brood parasite eggs: Leukocyte profiles and heat-shock protein Hsp70 levels.

Obligate avian brood parasites lay their eggs in the nest of other bird species, known as hosts. Brood parasitism often imposes severe fitness costs on hosts, selecting for the evolution of effective antiparasitic defences, such as recognition and rejection of brood parasite eggs. Glucocorticoids have been recently found to mediate host physiological and behavioral adjustments in response to brood parasite eggs; however, it remains unclear whether brood parasitism triggers a general response involving multiple physiological elements. In this study, we experimentally investigated whether a salient brood parasitic stimulus (the presence of a nonmimetic model egg in the nest) causes physiological adjustments in adult Eurasian blackbirds (Turdus merula) at immune (leukocyte profiles) and cellular (heat-shock protein Hsp70 synthesis) level. Also, we explored whether these physiological changes are mediated by variations in corticosterone (CORT) levels. We found that experimental brood parasitism caused an increase in heterophils and a decrease in lymphocytes, leading to higher heterophils and lymphocytes ratios in parasitized birds. Nevertheless, we did not find tradeoffs between immune function and CORT levels. Hsp70 synthesis was not affected by our experimental manipulation. Our findings provide evidence that brood parasite eggs trigger a general stress response in egg-rejecter hosts, including changes in cellular immune profiles.

Heterospecific eavesdropping of jays (Garrulus glandarius) on blackbird (Turdus merula) mobbing calls

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.

Usutu virus in blackbirds (Turdus merula) with clinical signs, a case study from northern Italy

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.

The Interferon Response Dampens the Usutu Virus Infection-Associated Increase in Glycolysis.

The mosquito-borne Usutu virus (USUV) is a zoonotic flavivirus and an emerging pathogen. So far therapeutical options or vaccines are not available in human and veterinary medicine. The bioenergetic profile based on extracellular flux analysis revealed an USUV infection-associated significant increase in basal and stressed glycolysis on Vero and with a tendency for basal glycolysis on the avian cell line TME-R derived from Eurasian blackbirds. On both cell lines this was accompanied by a significant drop in the metabolic potential of glycolysis. Moreover, glycolysis contributed to production of virus progeny, as inhibition of glycolysis with 2-deoxy-D-glucose reduced virus yield on Vero by one log10 step. Additionally, the increase in glycolysis observed on Vero cells after USUV infection was lost after the addition of exogenous type I interferon (IFN) β. To further explore the contribution of the IFN response pathway to the impact of USUV on cellular metabolism, USUV infection was characterized on human A549 respiratory cells with a knockout of the type I IFN receptor, either solely or together with the receptor of type III IFN. Notably, only the double knockout of types I and III IFN receptor increased permissiveness to USUV and supported viral replication together with an alteration of the glycolytic activity, namely an increase in basal glycolysis to an extent that a further increase after injection of metabolic stressors during extracellular flux analysis was not noted. This study provides evidence for glycolysis as a possible target for therapeutic intervention of USUV replication. Moreover, presented data highlight type I and type III IFN system as a determinant for human host cell permissiveness and for the infection-associated impact on glycolysis.

Characterization of the Immunopathology of Usutu Virus-Associated Encephalitis: A Pilot Study in Naturally Infected Eurasian Blackbirds (Turdus Merula)

Characterization of the Immunopathology of Usutu Virus-Associated Encephalitis: A Pilot Study in Naturally Infected Eurasian Blackbirds (Turdus Merula)

Opportunistic myiasis of nestling common blackbirds by Lucilia silvarum.

Previously, the Marsh greenbottle blowfly, Lucilia silvarum Meigen (Diptera: Calliphoridae), has been implicated in myiasis of anurans but not of mammals or birds. This report describes an incident of opportunistic myiasis of nestling common blackbirds, Turdus merula (Passeriformes: Turdidae), by L. silvarum larvae in association with an infestation by the hematophagous maggot Neottiophilum praeustum (Diptera: Piophilidae).

Functional explanation of extreme hatching asynchrony: Male Manipulation Hypothesis.

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.

Սև կեռնեխների (Turdus Merula Linnaeus, 1758) բնադրման էկոլոգիան Ստեփանակերտ քաղաքի պայմաններում

The ecology of nesting common blackbirds in the territory of Stepanakert city, Artsakh are presented. Although common blackbirds are considered typical forest birds, due to their high ecological flexibility, they easily adapt to urban areas. Through observations, we found out that common blackbirds use about 23 species of plants and artificial structures for nesting in different parts of the city. Nests are built at an average height of 0,5-7 m from the ground, and both natural and anthropogenic materials are used as building materials.

ОСОБЕННОСТИ ГНЕЗДОВАНИЯ ЧЕРНОГО ДРОЗДА (TURDUS MERULA) В УСЛОВИЯХ ГОРОДСКИХ ДРЕВЕСНЫХ НАСАЖДЕНИЙ Г. МИНСКА

Synurbic populations of birds are characterized by specific features that differ from those of wild populations of the same species, which is the result of adaptation to living in cities. The paper analyses some parameters of breeding of the Blackbird (Turdus merula) in two park in Minsk and compares them with the breeding biology of wild Blackbirds in natural habitats. During the years 2015-2017 and 2019-2021, 74 nests of urban Blackbird were obtained. For comparison, data on 245 nest of this species in natural landscapes were used.As a result, it was found that the nest selection in urban Blackbirds remains similar to wild Blackbirds in forests, and the differences are explained by the peculiarities of forestry activities carried out in urban parks. More than 74 % of all nests were built in the undergrowth layer, while most of the nests were located on the Norway spruce (59.72 %). A majority of urban Blackbirds started laying first eggs relatively later (from 21.04 to 10.05) than forest birds (from 11.04 to 30.04), which most likely results from the adaptation of birds to a significant recreational load from humans during the period when the trees have not come into leaf yet. Nevertheless, no differences were found in the average clutch size between urban (4.17 ± 0.72 eggs) and forest (4.51 ± 0.64 eggs) birds. The low breeding success of the Blackbird (39.4 %) in the urbanized area testifies to the fact that the homeostasis of the relatively high number of the urban Blackbird population in Minsk is most likely maintained due to the constant influx of individuals from local suburban forests.

Description and Molecular Characterization of Two Species of Avian Blood Parasites, with Remarks on Circadian Rhythms of Avian Haematozoa Infections.

Simple SummaryThe diversity of avian blood parasites is remarkable, and they are often found in co-infections, which is a challenge for wildlife parasitology research. Co-infections not only make parasite morphological and molecular identification difficult, but also might influence the infection dynamics and disease manifestation. This study investigated blood parasites infections in a Eurasian blackbird (Turdus merula) and a Song thrush (Turdus philomelos). A new Lankesterella species was found and described. The molecular characterization of this parasites as well as Splendidofilaria mavis, an avian filarioid nematode, was developed. As several blood infections were present in co-infection, we used this opportunity to investigate the daily changes in the parasite intensity seen in the blood of these birds. A peak of the Plasmodium matutinum parasitemia was seen during the daytime. Leucocytozoon spp. showed some parasitemia peaks close to the evening and night. Trypanosoma spp. and S. mavis parasitemia increased during the night. Data about daily variation of Haemoproteus, Lankesterella, and S. mavis parasites were obtained for the first time. No pattern in parasitemia dynamics was identified in Haemoproteus and Lankesterella infections.Avian blood parasites are remarkably diverse and frequently occur in co-infections, which predominate in wildlife. This makes wildlife pathogen research challenging, particularly if they belong to closely related groups, resulting in diagnostic problems and poor knowledge about such infections as well as the patterns of their co-occurrence and interactions. This is particularly true due to the periodicity (circadian rhythms) of parasitemia, which means that different parasitemia and parasite stages might be found throughout the day. We analysed blood samples from a Eurasian blackbird (Turdus merula) and a Song thrush (Turdus philomelos). This study aimed to describe a new avian Lankesterella species and molecularly characterize and redescribe Splendidofilaria mavis, a common avian filarioid nematode. Additionally, it was possible to investigate the circadian rhythms of the avian blood parasites belonging to Plasmodium, Haemoproteus, Leucocytozoon, and Trypanosoma, which occurred in co-infection in the same avian host individuals. Different circadian rhythms were seen in different parasites, with Plasmodium sp. peaks occurring at midday, Leucocytozoon spp. peaks mainly during the evening and night, and Trypanosoma spp. and microfilariae peaks at midnight. No periodicity was seen in Haemoproteus and Lankesterella species infections. The time of parasitemia peaks most likely coincides with the time of vectors’ activity, and this should be beneficial for transmission. Knowledge about the circadian rhythms is needed for better understanding patterns in host-parasite interactions and disease transmission.

A partial migrant relies upon a range-wide cue set but uses population-specific weighting for migratory timing

BackgroundMany birds species range over vast geographic regions and migrate seasonally between their breeding and overwintering sites. Deciding when to depart for migration is one of the most consequential life-history decisions an individual may make. However, it is still not fully understood which environmental cues are used to time the onset of migration and to what extent their relative importance differs across a range of migratory strategies. We focus on departure decisions of a songbird, the Eurasian blackbird Turdus merula, in which selected Russian and Polish populations are full migrants which travel relatively long-distances, whereas Finnish and German populations exhibit partial migration with shorter migration distances.MethodsWe used telemetry data from the four populations (610 individuals) to determine which environmental cues individuals from each population use to initiate their autumn migration.ResultsWhen departing, individuals in all populations selected nights with high atmospheric pressure and minimal cloud cover. Fully migratory populations departed earlier in autumn, at longer day length, at higher ambient temperatures, and during nights with higher relative atmospheric pressure and more supportive winds than partial migrants; however, they did not depart in higher synchrony. Thus, while all studied populations used the same environmental cues, they used population-specific and locally tuned thresholds to determine the day of departure.ConclusionsOur data support the idea that migratory timing is controlled by general, species-wide mechanisms, but fine-tuned thresholds in response to local conditions.

Analysis of avian Usutu virus infections in Germany from 2011 to 2018 with focus on dsRNA detection to demonstrate viral infections

Usutu virus (USUV) is a zoonotic arbovirus causing avian mass mortalities. The first outbreak in North-Western Germany occurred in 2018. This retrospective analysis focused on combining virological and pathological findings in birds and immunohistochemistry. 25 common blackbirds, one great grey owl, and one kingfisher collected from 2011 to 2018 and positive for USUV by qRT-PCR were investigated. Macroscopically, most USUV infected birds showed splenomegaly and hepatomegaly. Histopathological lesions included necrosis and lymphohistiocytic inflammation within spleen, Bursa fabricii, liver, heart, brain, lung and intestine. Immunohistochemistry revealed USUV antigen positive cells in heart, spleen, pancreas, lung, brain, proventriculus/gizzard, Bursa fabricii, kidney, intestine, skeletal muscle, and liver. Analysis of viral genome allocated the virus to Europe 3 or Africa 2 lineage. This study investigated whether immunohistochemical detection of double-stranded ribonucleic acid (dsRNA) serves as an alternative tool to detect viral intermediates. Tissue samples of six animals with confirmed USUV infection by qRT-PCR but lacking viral antigen in liver and spleen, were further examined immunohistochemically. Two animals exhibited a positive signal for dsRNA. This could indicate either an early state of infection without sufficient formation of virus translation products, occurrence of another concurrent virus infection or endogenous dsRNA not related to infectious pathogens and should be investigated in more detail in future studies.

Breeding birds of ‘Nomentum’ nature reserve (central Italy): a forest remnant landscape surrounded by an agro-urbanized matrix

We carried out a standardized breeding bird atlas of “Nomentum” nature reserve (central Italy), located in a fragmented hilly forest near a large urbanized area (Rome). In order to obtain data about local composition, occurrence, distribution and richness, we correlated data with environmental heterogeneity and vegetation structure variables. We recorded 58 species in 48 500x500 m-wide atlas units, with Parus major, Corvus cornix, Turdus merula, Sylvia atricapilla, Sylvia melanocephala, as the most occurring in frequency (> 80%). Although synanthropic species represent only slightly more than 20% in number and urban environments are relatively reduced in size, these species show a higher mean occurrence when compared to mosaic species, despite the fact that these last are higher in species number and mosaic habitats are widely diffused. Local urbanization may disrupt communities, facilitating opportunistic species linked to these environments (i.e. synantropic) and inducing a decline in mosaic species. Moreover, the homogenization induced by anthropization could, at least partially, explain the lack of correlation between habitat diversity and species richness, at local scale. Finally, tree density and diameter do not affect total bird richness at this spatial grain/scale. In this regard, further analyses could test for possible correlations between habitat variables and single ecological guilds.

A citizen science-based survey of avian mortality focusing on haemosporidian infections in wild passerine birds

BackgroundHaemosporidioses are common in birds and their manifestations range from subclinical infections to severe disease, depending on the involved parasite and bird species. Clinical haemosporidioses are often observed in non-adapted zoo or aviary birds, whereas in wild birds, particularly passerines, haemosporidian infections frequently seem to be asymptomatic. However, a recent study from Austria showed pathogenic haemosporidian infections in common blackbirds due to high parasite burdens of Plasmodium matutinum LINN1, a common parasite in this bird species, suggesting that virulent infections also occur in natural hosts. Based on these findings, the present study aimed to explore whether and to what extent other native bird species are possibly affected by pathogenic haemosporidian lineages, contributing to avian morbidity.MethodsCarcasses of passerine birds and woodpeckers were collected during a citizen science-based survey for avian mortality in Austria, from June to October 2020. Tissue samples were taken and examined for haemosporidian parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon by nested PCR and sequencing the mitochondrial cytb barcode region, histology, and chromogenic in situ hybridization applying genus-specific probes.ResultsFrom over 160 dead bird reportings, 83 carcasses of 25 avian species were submitted for investigation. Overall haemosporidian infection rate was 31%, with finches and tits prevailing species counts and infections. Sequence analyses revealed 17 different haplotypes (4 Plasmodium, 4 Haemoproteus, 9 Leucocytozoon), including 4 novel Leucocytozoon lineages. Most infected birds presented low parasite burdens in the peripheral blood and tissues, ruling out a significant contribution of haemosporidian infections to morbidity or death of the examined birds. However, two great tits showed signs of avian malaria, suggesting pathogenic effects of the detected species Plasmodium relictum SGS1 and Plasmodium elongatum GRW06. Further, exo-erythrocytic tissue stages of several haemosporidian lineages are reported.ConclusionsWhile suggesting generally little contribution of haemosporidian infections to mortality of the investigated bird species, the findings indicate a possible role of certain haemosporidian lineages in overall clinical manifestation, either as main causes or as concurrent disease agents. Further, the study presents new data on exo-erythrocytic stages of previously reported lineages and shows how citizen science can be used in the field of haemosporidian research.Graphic abstract

Days to visit an offshore island: effect of weather conditions on arrival fuel load and potential flight range for common blackbirds Turdus merula migrating over the North Sea

BackgroundCrossing open water instead of following the coast(line) is one way for landbirds to continue migration. However, depending on prevailing weather and the birds’ physiological conditions, it is also a risky choice. To date, the question remains as to which interplay between environmental and physiological conditions force landbirds to stop on remote islands. We hypothesise that unfavourable winds affect lean birds with low energy resources, while poor visibility affects all birds regardless of their fuel loads.MethodsTo test this hypothesis, we caught 1312 common blackbirds Turdus merula stopping over on Helgoland during autumn and spring migration. Arrival fuel load was measured using quantitative magnetic resonance technology. Weather parameters (wind and relative humidity as a proxy for visibility) were interpolated for the night before arrival. Further, we calculated whether caught individuals would have successfully crossed the North Sea instead of landing on Helgoland, depending on wind conditions.ResultsBoth wind and relative humidity the night before arrival were correlated with arrival fuel load. After nights with strong headwinds, birds caught the following day were mostly lean, most of which would not have managed to cross the sea if they had not stopped on Helgoland. In contrast, fat birds that could have successfully travelled on were caught mainly after nights with high relative humidity (≥ 80%). Furthermore, the rate of presumably successful flights was lower due to wind: although only 9% of all blackbirds captured on Helgoland had insufficient fuel loads to allow safe onward migration in still air, real wind conditions would have prevented 30% of birds from successfully crossing the sea during autumn and 21% during spring migration.ConclusionsWe were able to decipher how physiological condition, wind and relative humidity partially force blackbirds to stop on a remote island. Adverse winds tend to affect lean birds with low energy resources, while poor visibility can affect blackbirds, regardless of whether the arrival fuel load was sufficient for onward flight. Our findings will help to understand different migratory strategies and explain further questions like migration timing.

Low prolactin allows blackbird mums to dispose of imposter cuckoo eggs

The urge to protect offspring is strong and primeval. In many species, parents of vulnerable and defenceless young nurture and care devotedly for their charges until the youngsters are capable of forging their own path. But how do bird parents manage to overwhelm this driving instinct when faced with a cuckoo in the nest? ‘Blackbirds remove parasitic eggs from their nests by grasping them in their beaks and flying away with them’, says Francisco Ruiz-Raya from the Universidad de Vigo, Spain. Knowing that prolactin is one of the key hormones behind parenting, Ruiz-Raya, Juan Diego Ibáñez-Álamo and Manuel Soler, both from the Universidad de Granada, Spain, wondered whether a decline in the hormone might allow female Eurasian blackbirds (Turdus merula) to make the decision to despatch imposter eggs.Heading to the Lecrin valley, near Granada, in spring, Ruiz-Raya went in search of blackbird nests containing eggs. Then, he captured soon-to-be blackbird mums and gently implanted a tiny biodegradable pellet in their backs, to temporarily reduce the amount of prolactin hormone circulating in their blood. Once the pellets were in place, Ruiz-Raya cunningly sneaked a blackbird egg disguised as a cuckoo egg into the nests and waited to see how the mothers responded to the fraudulent eggs. In addition, Charline Parenteau and Olivier Chastel from Centre d'Études Biologiques de Chizé, France, measured the amount of hormone in the birds' blood.Impressively, the duped mums with lower prolactin levels caught on that there was an intruder in the nest far faster than mums whose prolactin levels continued rising over the course of incubation. The mother birds with less prolactin began dislodging the charlatan eggs within 12 h of the imposter's arrival, in contrast to normal blackbird mums, which only began to turn out the interlopers after 2.5 days. The mothers with lower prolactin levels were also far more efficient at disposing of the uninvited guests, evicting 75% of Ruiz-Raya's egg frauds from the nests, while the mothers with regular levels of prolactin only discarded 25%.A fall in prolactin seems to help blackbird mothers override their instincts and toss out an egg that isn't their own. But why might mothers experience a drop in prolactin while incubating their young? The team suspects that blackbird mums that are aware of cuckoos touring the vicinity become stressed and may suffer a prolactin dip, which could be sufficient to allow them to eject egg imposters that pose a threat to their progeny.

Prolactin mediates behavioural rejection responses to avian brood parasitism.

Adaptations resulting from co-evolutionary interactions between avian brood parasites and their hosts have been extensively studied, yet the physiological mechanisms underlying antiparasitic host defences remain little known. Prolactin, one of the main hormones involved in the regulation of avian parental behaviour, might play a key role in the orchestration of the host responses to avian brood parasitism. Given the positive association between prolactin and parental behaviour during incubation, decreasing prolactin levels are expected to facilitate egg-rejection decisions. We tested this prediction by implanting Eurasian blackbird (Turdus merula) females with an inhibitor of prolactin secretion, bromocriptine mesylate, to experimentally decrease their plasma prolactin levels. Bromocriptine mesylate-implanted individuals ejected mimetic model eggs at higher rates, and showed shorter latency to egg ejection, than placebo-treated birds. To our knowledge, this is the first experimental evidence that behavioural host defences against avian brood parasitism are mediated by prolactin.

Morishitium polonicum as a Cause of Severe Respiratory Disease in Eurasian Blackbirds (Turdus merula) in Central Italy.

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.

Blood Toxic Elements and Effects on Plasma Vitamins and Carotenoids in Two Wild Bird Species: Turdus merula and Columba livia

Birds have historically suffered adverse effects by toxic elements, such as As, Pb, Hg, and Cd. However, reports on exposure to a wide range of elements, including rare earth elements and other minor elements of emerging concern, and the potential consequences for wildlife are still scarce. This study evaluates blood concentrations of 50 elements and their related effects on lutein and vitamin levels in the Eurasian blackbird (Turdus merula) and wild rock pigeon (Columba livia), inhabiting different scenarios of contaminant exposure. Blood concentrations of As, Cd, and Pb (and Mn in T. merula) were increased in both species captured in the mining area, compared to the control site. T. merula also showed increased As, Cd, and Pb concentrations in blood in the agricultural–urban area, as compared to the control area, together with the highest Hg levels, which could be related to agricultural practices and industrial activities. Decreases of 33 and 38% in the plasma retinol levels in T. merula inhabiting the mining and the agricultural–urban areas, respectively, as compared to the control site, were associated with increased Pb, As, and Cd exposure. This could be due to a metal-driven suppressive effect in retinol metabolism and/or its over-use for coping with metal-related oxidative stress.