Mercury and rare earth elements (REEs) show different spatial trends in feathers of Kentish plover (Charadrius alexandrinus) breeding along the Adriatic Sea coast, Italy.

Feather analysis is an ethical and effective method for assessing the exposure of wild birds to environmental contamination due to trace elements and organic pollutants. We used feather to monitor the exposure to three toxic and non-essential metals (Hg, Cd, and Pb) and rare earth elements (REEs) of Kentish plover (Charadrius alexandrinus) breeding in different coastal areas (Veneto, Emilia-Romagna, Marche, Abruzzo, and Apulia) along the Italian coast of the Adriatic Sea. Feathers (n = 113) were collected from April to June. Feather concentrations evidenced a significant exposure to Hg (13.05 ± 1.71 mg kg-1 dw) and REEs (447.3 ± 52.8 ng g-1 dw) in the Kentish plover breeding in Veneto (n = 21) compared to the other coastal areas, with several individuals showing Hg concentrations above the adverse effect (5 mg kg-1 dw) and high-risk (9.14 mg kg-1 dw) thresholds reported for birds. Higher REE concentrations compared to Marche (n = 29), Abruzzo (n = 11) and Apulia (n = 13) were also reported for birds breeding in Emilia-Romagna (474.9 ± 41.9 ng g-1 dw; n = 29). The exposure to Cd and Pb was low in all the coastal areas, and only a few samples (n = 6 and n = 4 for Cd and Pb, respectively) exceeded the adverse effect thresholds (0.1 and 4 mg kg-1 for Cd and Pb, respectively). A significant sex-related difference was observed for REE-concentrations, with females showing higher concentration than males. These data highlight the need to monitor the exposure of the Kentish plover to Hg and REEs, especially in the northern basin of the Adriatic Sea, since these elements might negatively affect species' reproductive success and threaten its conservation.

The effects of cities on quail (Coturnix coturnix) migration: a disturbing story of population connectivity, health, and ecography.

The increasing impact of human activities on ecosystems is provoking a profound and dangerous effect, particularly in wildlife. Examining the historical migration patterns of quail (Coturnix coturnix) offers a compelling case study to demonstrate the repercussions of human actions on biodiversity. Urbanization trends, where people gravitate toward mega-urban areas, amplify this effect. The proliferation of artificial urban ecosystems extends its influence across every biome, as human reliance on infrastructure and food sources alters ecological dynamics extensively. We examine European quail migrations pre- and post-World War II and in the present day. Our study concentrates on the Italian peninsula, investigating the historical and contemporary recovery of ringed quail populations. To comprehend changes in quail migration, we utilize trajectory analysis, open statistical data, and linear generalized models. We found that while human population and economic growth have shown a linear increase, quail recovery rates exhibit a U-shaped trajectory, and cereal and legume production displays an inverse U-shaped pattern. Generalized linear models have unveiled the significant influence of several key factors-time periods, cereal and legume production, and human demographics-on quail recovery rates. These factors closely correlate with the levels of urbanization observed across these timeframes. These insights underscore the profound impact of expanding human populations and the rise of mega-urbanization on ecosystem dynamics and services. As our planet becomes more urbanized, the pressure on ecosystems intensifies, highlighting the urgent need for concerted efforts directed toward conserving and revitalizing ecosystem integrity. Simultaneously, manage the needs and demands of burgeoning mega-urban areas. Achieving this balance is pivotal to ensuring sustainable coexistence between urban improvement and the preservation of our natural environment.

Avian Haemosporidians Infecting Short- and Long-Distance Migratory Old World Flycatcher Species and the Variation in Parasitaemia After Endurance Flights.

PURPOSE: Avian haemosporidians are widespread parasites, occurring in many bird families and causing pathologies ranging from rather benign infections to highly virulent diseases. The state of knowledge about lineage-specific intensities of haemosporidian infection (i.e., parasitaemia) is mainly based on infection experiments conducted under laboratory conditions. The levels and range of parasitaemia in natural host-parasite associations as well as their influencing factor remain largely unexplored. METHODS: Thus, we explored the parasitaemia of four songbird species (i.e., European Robins, Black and Common Redstarts and Whinchats) during migration by screening individuals upon landing on an insular passage site after extensive endurance flights to (1) describe their natural host-parasite associations, (2) quantify parasitaemia and (3) explore potential host- and parasite-related factors influencing parasitaemia. RESULTS: We found 68% of Whinchats to be infected with haemosporidians, which is more frequent than any other of the studied host species (30-34%). Furthermore, we confirmed that parasitaemia of Haemoproteus infections was higher than average Plasmodium infections. Median parasitaemia levels were rather low (parasite cells in 0.01% of hosts' red blood cells) and varied largely among the different parasite lineages. However, we found four individuals hosting infections with parasitaemia higher than typical chronic infections. CONCLUSIONS: Based on the known transmission areas of the respective lineages, we argue that these higher intensity infections might be relapses of consisting infections rather than acute phases of recent primary infections.

Modelling the timing of migration of a partial migrant bird using ringing and observation data: a case study with the Song Thrush in Italy.

BACKGROUND: The study of the timing of migration is fundamental to the understanding of the ecology of many bird species and their response to climate change, and it has important conservation and management implications e.g., for assessing the hunting seasons according to the EU Directive 2009/147/EC (Birds Directive). METHODS: We developed a new method for the analysis of ringing data (both first capture and re-encounters) and citizen science observations, to assess the timing of pre- and post-nuptial migration of birds. This method was tested on the Song Thrush Turdus philomelos, using i) the Bird Ringing Database hosted by the ISPRA Italian Ringing Centre from the whole Italian peninsula, the three closest large islands (Sicily, Sardinia and Corsica), and Canton Ticino (Switzerland) and ii) the eBird data for the same study area. RESULTS: The results from both datasets consistently showed that pre-nuptial migration starts during the first 10-day period of January (Jan 1) in some central and southern areas of the Italian peninsula, in central Sicily, southern Sardinia, and Corsica. The onset of migration occurs on Jan 2 in the rest of central and southern Italy, Sicily and Sardinia, and western Liguria, while it starts later in the north-eastern Alps, up to Mar 3. The end of post-nuptial migration is more synchronous, occurring on Nov 1 across most of Italy, slightly earlier (Oct 3) in northern Italy and later (Nov 2) in Sicily. The uncertainty of the estimated dates was < 2 days in most cases. CONCLUSION: This method represents a novel and valuable tool for the analyses of the timing of migration using ringing and citizen science data and provides an important contribution to the Key Concepts Document of the EU Birds Directive, where migration timings are considered and used to define the hunting period of birds.

Tick Species Diversity and Molecular Identification of Spotted Fever Group Rickettsiae Collected from Migratory Birds Arriving from Africa.

The role of migratory birds in the spread of ticks and tick-borne pathogens along their routes from Africa to Europe is increasingly emerging. Wild birds can host several tick species, often infected by bacteria responsible for zoonoses. The aim of the study is to assess the possible introduction of exotic ticks carried by migratory birds into Italy from Africa and to detect the presence of Rickettsia species and Coxiella burnetii they may harbor. During a two-year survey, we collected ticks from migratory birds captured during their short stop-over on Ventotene Island. Specimens were first identified by morphology or sequencing molecular targets when needed, and then tested by real-time PCR for the presence of selected pathogens. A total of 91% of the collection consisted of sub-Saharan ticks, more than 50% of which were infected by Rickettsia species belonging to the spotted fever group, mainly represented by R. aeschlimannii. In contrast, the suspected C. burnetii detected in two soft ticks were confirmed as Coxiella-like endosymbionts and not the pathogen. Although there are still gaps in the knowledge of this dispersal process, our findings confirm the role of migratory birds in the spread of ticks and tick-borne pathogens, suggesting the need for a continuous surveillance to monitor the potential emergence of new diseases in Europe.

Weather, sex and body condition affect post-fledging migration behaviour of the greater flamingo Phoenicopterus roseus.

BACKGROUND: Understanding which intrinsic and extrinsic factors dictate decision-making processes such as leaving the natal area or not (migratory vs resident strategy), departure time, and non-breeding destination are key-issues in movement ecology. This is particularly relevant for a partially migratory meta-population in which only some individuals migrate. METHODS: We investigated these decision making-processes for 40 juvenile greater flamingos Phoenicopterus roseus fledged in three Mediterranean colonies and equipped with GPS-GSM devices. RESULTS: Contrary to the body size and the dominance hypotheses, juveniles in better body condition were more likely to migrate than those in worse conditions, which opted for a residence strategy. Flamingo probability of departure was not associated with an increase in local wind intensity, but rather with the presence of tailwinds with departure limited to night-time mostly when the wind direction aligned with the migratory destination. Moreover, a positive interaction between tailwind speed and migration distance suggested that juveniles opted for stronger winds when initiating long-distance journeys. In contrast to previous studies, the prevailing seasonal winds were only partially aligned with the migratory destination, suggesting that other factors (e.g., adults experience in mix-aged flocks, availability of suitable foraging areas en route, density-dependence processes) may be responsible for the distribution observed at the end of the first migratory movement. We found potential evidence of sex-biased timing of migration with females departing on average 10 days later and flying ca. 10 km/h faster than males. Female flight speed, but not male one, was positively influenced by tailwinds, a pattern most likely explained by sexual differences in mechanical power requirements for flight (males being ca. 20% larger than females). Furthermore, juveniles considerably reduced their flight speeds after 400 km from departure, highlighting a physiological threshold, potentially linked to mortality risks when performing long-distance non-stop movements. CONCLUSION: These results suggest that not only intrinsic factors such as individual conditions and sex, but also extrinsic factors like weather, play critical roles in triggering migratory behaviour in a partially migratory metapopulation. Furthermore, social factors, including conspecific experience, should be taken into consideration when evaluating the adaptive processes underlying migration phenology, flight performance, and final destination selection.

Reconstructing migratory network nodes to improve environmental management and conservation decisions: A case study of the common quail Coturnix coturnix as a biosensor.

Public health risks are related to environmental management practices, and are essential to the understanding of ecosystem dynamics. The expansion of urbanized areas affects migratory bird networks and can impact the population sizes of migratory species and, in parallel, increase the risk of diseases carried by migratory species spreading into urban areas. Taking the European population of the common quail as a case study, we reconstructed its migratory network between Europe and the Maghreb using quail recoveries from the Italian Bird Ringing Scheme. We showed that soils at the central European migratory node have been degraded through urbanization and reforestation, decreasing the number of successful migrations over this area. Conceptual models incorporating the One Health approach, natural and social capital, landscape infrastructure, and ecosystem services could explain the relationships between climate warming and extensively developed, intensively developed, and urbanized ecosystems. Failed migratory flights of quail over central Europe highlight not only the problems of infrastructure design and their impact on ecosystems services, but also on One Health parameters. The damage to migratory network nodes presents a global threat to biodiversity and can increase the spread of diseases. To address this challenge we propose: i) improvements in land quality; ii) transboundary migration monitoring programmes; and iii) management plans for migratory birds - the overall aim being to optimize infrastructures to improve the quality of human life. Lessons drawn from a better understanding of the migratory networks of quail in relation to different ecosystems provide useful tools to improve infrastructure management and political decision making processes.

Active breeding seabirds prospect alternative breeding colonies.

Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Prospecting in active breeders occurred in 85.7% of studied species, across 61.3% of sampled populations. Prospecting was more common in populations with frequent inter-annual changes of breeding sites and among females. These results contradict theoretical models which predict that prospecting is expected to evolve in relatively predictable and stable environments. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and understand the consequences of prospecting on fitness at the individual and population level.

Direct and Indirect Role of Migratory Birds in Spreading CCHFV and WNV: A Multidisciplinary Study on Three Stop-Over Islands in Italy.

The annual movements of migratory birds can contribute to the spread of African ticks and tick-borne pathogens of potential public health concern across Europe. The aim of the study was to investigate their role in the possible introduction of African ticks and tick-borne pathogens into European countries during spring migration. A total of 2344 ticks were collected during three spring seasons from 1079 birds captured on three Italian stop-over islands during their northbound migration. Once identified, each tick was tested by RT-PCR for the presence of Crimean-Congo hemorrhagic fever (CCHFV), West Nile (WNV), and Usutu (USUV) viruses. Moreover, carcasses of birds found dead were collected and tested for the possible presence of WNV and USUV. Results confirmed a higher contribution of trans-Saharan migrants compared to intra-Palearctic ones and the prevalence of African tick species in the sample. CCHFV was detected for the second time in Italy in a Hyalomma rufipes, and WNV was found in two ticks of the same genus, all carried by trans-Saharan birds. WNV lineage 1 was also found in the organs of a Garden warbler. These results confirm the role of migratory birds in carrying African ticks, as well as viruses of zoonotic importance, from Africa into Europe.

The hidden cost of following currents: Microplastic ingestion in a planktivorous seabird.

Microplastics are increasingly pervasive pollutants, particularly abundant in the neuston where they drift with currents. We assessed dietary microplastic ingestion in the Mediterranean storm petrel (Hydrobates pelagicus melitensis), a small pelagic seabird that forages on plankton and inhabit the Mediterranean sea, one of the most polluted seas worldwide. We collected spontaneous regurgitates from 30 chick-rearing individuals and used GPS tracking data from 7 additional individuals to locate foraging areas. Birds foraged in pelagic areas characterized by water stirring and mixing, and regurgitates from 14 individuals (i.e. 45 %) contained microplastics. Fibers were the dominant shape (56 %), with polyester, polyethylene and nylon being the most frequent polymers. Our findings highlight the potential sensitivity of this species of conservation interest to plastic pollution and suggest that storm petrel regurgitates can be a valuable matrix to investigate microplastic ingestion in planktonic foragers, providing a characterization of spatio-temporal patterns of microplastic exposure in pelagic environments.

Short- and long-distance avian migrants differ in exercise endurance but not aerobic capacity.

BACKGROUND: Migratory birds differ markedly in their migration strategies, particularly those performing short- versus long-distance migrations. In preparation for migration, all birds undergo physiological and morphological modifications including enlargement of fat stores and pectoral muscles to fuel and power their flights, as well as cardiovascular and biochemical adjustments that improve lipid and oxygen delivery and uptake by flight muscles. While the magnitude of these changes varies in relation to migration strategy, the consequence of these variations on aerobic performance is unknown. We tested whether the aerobic performance of four Old-world flycatcher species (Muscicapidae) varied according to migration strategy by comparing minimum resting metabolic rates (RMRmin), exercise-induced maximum metabolic rates (MMR), and exercise endurance times of short-distance and long-distance migratory birds. RESULTS: As expected, RMRmin did not vary between short-distance and long-distance migrants but differed between the species within a migration strategy and between sexes. Unexpectedly, MMR did not vary with migration strategy, but MMR and blood haemoglobin content were positively related among the birds tested. Exercise endurance times differed substantially between migration strategies with long-distance migrants sustaining exercise for > 60% longer than short-distance migrants. Blood haemoglobin content had a significant positive effect on endurance among all birds examined. CONCLUSIONS: The lack of difference in RMRmin and MMR between long- and short-distance migrants during this stage of migration suggests that the attributes favouring the greater aerobic endurance of long-distance migrants did not come at the expense of increased maintenance costs or require greater aerobic capacity.

Hernia de hiato paraesofágica derecha asociada a situs inversus completo / Right paraesophageal hiatus hernia associated with complete situs inversus

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Analysis of movement recursions to detect reproductive events and estimate their fate in central place foragers.

BACKGROUND: Recursive movement patterns have been used to detect behavioral structure within individual movement trajectories in the context of foraging ecology, home-ranging behavior, and predator avoidance. Some animals exhibit movement recursions to locations that are tied to reproductive functions, including nests and dens; while existing literature recognizes that, no method is currently available to explicitly target different types of revisited locations. Moreover, the temporal persistence of recursive movements to a breeding location can carry information regarding the fate of breeding attempts, but it has never been used as a metric to quantify recursive movement patterns. Here, we introduce a method to locate breeding attempts and estimate their fate from GPS-tracking data of central place foragers. We tested the performance of our method in three bird species differing in breeding ecology (wood stork (Mycteria americana), lesser kestrel (Falco naumanni), Mediterranean gull (Ichthyaetus melanocephalus)) and implemented it in the R package 'nestR'. METHODS: We identified breeding sites based on the analysis of recursive movements within individual tracks. Using trajectories with known breeding attempts, we estimated a set of species-specific criteria for the identification of nest sites, which we further validated using non-reproductive individuals as controls. We then estimated individual nest survival as a binary measure of reproductive fate (success, corresponding to fledging of at least one chick, or failure) from nest-site revisitation histories during breeding attempts, using a Bayesian hierarchical modeling approach that accounted for temporally variable revisitation patterns, probability of visit detection, and missing data. RESULTS: Across the three species, positive predictive value of the nest-site detection algorithm varied between 87 and 100% and sensitivity between 88 and 92%, and we correctly estimated the fate of 86-100% breeding attempts. CONCLUSIONS: By providing a method to formally distinguish among revisited locations that serve different ecological functions and introducing a probabilistic framework to quantify temporal persistence of movement recursions, we demonstrated how the analysis of recursive movement patterns can be applied to estimate reproduction in central place foragers. Beyond avian species, the principles of our method can be applied to other central place foraging breeders such as denning mammals. Our method estimates a component of individual fitness from movement data and will help bridge the gap between movement behavior, environmental factors, and their fitness consequences.

Home, dirty home: effect of old nest material on nest-site selection and breeding performance in a cavity-nesting raptor.

The quality of a breeding site may have major fitness consequences. A fundamental step to understanding the process of nest-site selection is the identification of the information individuals use to choose high-quality nest sites. For secondary cavity-nesting bird species that do not add nest lining material, organic remains (faeces, pellets) accumulated inside nest cavities during previous breeding events may be a cue for high-quality nest-sites, as they contain information about past successful breeding and may improve thermal insulation of eggs during incubation. However, cavities in which breeding was successful might also contain more nest-dwelling ectoparasites than unoccupied cavities, offering an incentive for prospective parents to avoid them. We exposed breeding cavity-nesting lesser kestrels (Falco naumanni) to nestbox dyads consisting of a dirty (with a thick layer of organic substrate) and a clean nestbox (without organic material). Dirty nestboxes were strongly preferred, being occupied earlier and more frequently than clean ones. Hatching success in dirty nestboxes was significantly higher than in clean ones, suggesting a positive effect of organic nest material on incubation efficiency, while nestbox dirtiness did not significantly affect clutch and brood size. Nestlings from dirty nestboxes had significantly higher ectoparasite load than those from clean nestboxes soon after egg hatching, but this difference was not evident a few days later. Nest substrate did not significantly affect nestling growth. We concluded that nest substrate is a key driver of nest-site choice in lesser kestrels, although the adaptive value of such a strong preference appears elusive and may be context-dependent.

Spatial segregation of home ranges between neighbouring colonies in a diurnal raptor.

Enhancement of information transfer has been proposed as a key driver of the evolution of coloniality. Transfer of information on location of food resources implies that individuals from the same colony share foraging areas and that each colony can be associated to a specific foraging area. In colonial breeding vertebrates, colony-specific foraging areas are often spatially segregated, mitigating intercolony intraspecific competition. By means of simultaneous GPS tracking of lesser kestrels (Falco naumanni) from neighbouring colonies, we showed a clear segregation of space use between individuals from different colonies. Foraging birds from different neighbouring colonies had home ranges that were significantly more segregated in space than expected by chance. This was the case both between large and between small neighbouring colonies. To our knowledge, the lesser kestrel is the only terrestrial species where evidence of spatial segregation of home ranges between conspecifics from neighbouring colonies has been demonstrated. The observed spatial segregation pattern is consistent with the occurrence of public information transfer about foraging areas and with the avoidance of overexploited areas located between neighbouring colonies. Our findings support the idea that spatial segregation of exploited areas may be widespread among colonial avian taxa, irrespective of colony size.

Economic assessment of wild bird mortality induced by the use of lead gunshot in European wetlands.

In European wetlands, at least 40 bird species are exposed to the risk of lead poisoning caused by ingestion of spent lead gunshot. Adopting a methodology developed in North America, we estimated that about 700,000 individuals of 16 waterbird species die annually in the European Union (EU) (6.1% of the wintering population) and one million in whole Europe (7.0%) due to acute effects of lead poisoning. Furthermore, threefold more birds suffer sub-lethal effects. We assessed the economic loss due to this lead-induced mortality of these 16 species by calculating the costs of replacing lethally poisoned wild birds by releasing captive-bred ones. We assessed the cost of buying captive-bred waterbirds for release from market surveys and calculated how many captive-bred birds would have to be released to compensate for the loss, taking into account the high mortality rate of captive birds (72.7%) in the months following release into the wild. Following this approach, the annual cost of waterbird mortality induced by lead shot ingestion is estimated at 105 million euros per year in the EU countries and 142 million euros in the whole of Europe. An alternative method, based upon lost opportunities for hunting caused by deaths due to lead poisoning, gave similar results of 129 million euros per year in the EU countries and 185 million euros per year in the whole of Europe. For several reasons these figures should be regarded as conservative. Inclusion of deaths of species for which there were insufficient data and delayed deaths caused indirectly by lead poisoning and effects on reproduction would probably increase the estimated losses substantially. Nevertheless, our results suggest that the benefits of a restriction on the use of lead gunshot over wetlands could exceed the cost of adapting to non-lead ammunition.

Dietary flavonoids advance timing of moult but do not affect redox status of juvenile blackbirds (Turdus merula).

Flavonoids are the most abundant plant polyphenols, widely occurring in fruits and berries, and show a strong antioxidant activity in vitro Studies of avian species feeding on berries suggest that dietary flavonoids have health-promoting effects and may enhance the expression of melanin-based plumage traits. These effects are probably mediated by the antioxidant activity of flavonoids. However, the effect of dietary flavonoids on oxidative status has never been investigated in any bird species. We analysed the effects of dietary flavonoids on blood non-enzymatic antioxidants and protein oxidative damage of juvenile European blackbirds (Turdus merula). In addition, we analysed the effects of flavonoid-enriched diet on body condition and on the timing of moult from juvenile to adult plumage. Dietary flavonoids did not significantly affect redox status but significantly advanced the onset of moult, hastening plumage development. Moulting birds showed higher protein oxidative damage compared with those that had not yet started moulting. The probability of initiating moult after 40 days of dietary treatment was higher for birds with low circulating levels of oxidizing agents and high glutathione concentration. The metabolization of flavonoids could have altered their redox potential, resulting in no net effects on redox status. However, flavonoid consumption before and during moult may contribute to enhance plumage development. Moreover, our findings suggest that moulting feathers may result in redox imbalance. Given their effect on moult and growth of melanin-rich feathers, fruit flavonoids may have contributed to shape plant fruiting time in relation to fruit consumption preferences by birds.

Toward a resolution of a taxonomic enigma: first genetic analyses of Paradoxornis webbianus and Paradoxornis alphonsianus (Aves: Paradoxornithidae) from China and Italy.

Paradoxornis webbianus and Paradoxornis alphonsianus naturally occur in South-East Asia. Due to a recent introduction, a mixed population currently occurs in northern Italy. A preliminary phylogeographic analysis using samples from Italy and China found little genetic differentiation between the two taxa and revealed the existence of two molecular lineages, sympatric in some part of China, that do not correspond to the morphological classification. Possible taxonomic changes and preliminary inferences on the relationships between Chinese and the Italian populations and on the likely provenance of the founders introduced in Italy are also discussed.