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Simple Summary: Wild birds fly across countries and continents. They carry pathogens in their blood, and they might also carry infected parasites like ticks or lice. Their flight path spreads diseases over long distances. Some birds may carry pathogens that are not infectious to the birds themselves, only to humans, in which case they are reservoirs for these bacteria. Bacteria are often spread from reservoirs to humans by blood-sucking insects like ticks. These bacteria, especially the spiral-shaped Borrelia spirochetes, are usually not detected via direct blood investigation, like microscopy, because they are low in numbers, so concentration steps are necessary. In this research we investigated bacteria extracted from 36 blood samples collected in a wild bird hospital from wild birds that did not show specific symptoms for a Borrelia infection. Still, at least two thirds of the samples contained Borrelia (e.g., B. anserina, B. burgdorferi sensu lato). All five samples subjected to the specific investigation confirmed the presence of the human-pathogenic Borrelia burgdorferi, which proves that not only are ticks carried by wild birds but the blood of birds can also potentially transmit human diseases. Wild birds across the globe can carry the causative agent of avian borreliosis, Borrelia anserina, and that of human Lyme borreliosis, Borrelia burgdorferi sensu lato in the ticks attached to them. Currently, only limited proof exists for the presence of these pathogens in samples taken from living wild birds, carried by the birds as a reservoir, without symptoms. We investigated blood samples of large-bodied wild birds admitted to a bird hospital, where basic clinical symptoms were recorded. Thirty-six blood samples were collected from them, according to the DualDur kit methodology, and investigated using dark-field microscopy to search for spirochetes. Five of the samples were also investigated by immunofluorescence microscopy to identify Borrelia burgdorferi. Since the main reason for admittance to the hospital was a physical injury, no significant symptoms were observed regarding a current Borrelia infection. Out of the sixteen birds of prey, eleven (68%) were infected with spirochetes, and fifteen out of twenty storks (75%) were also infected with spirochetes, without major symptoms. All five samples investigated using immunofluorescence were confirmed to contain the human pathogenic Borrelia burgdorferi sensu lato. Thus, direct investigations of the blood of wild birds may show the asymptomatic prevalence of Borrelia in the wild bird population. [ABSTRACT FROM AUTHOR]

Simple Summary: The black stork is a large woodland bird. There has been a steady decline in its numbers in Europe in recent years. The safe development and independence of young individuals in the post-breeding period are crucial for the conservation of this species' population. This research uses GPS loggers to track young storks' use of space from the time of their first flight attempts until they finally leave the nest. During this period, the birds spend most of their time in an area less than 200 m away from the nest. They often rest outside the nest, with three-quarters of their resting places being within 500 m of the nest. Ensuring that the birds have peace and quiet during the nesting season in a zone 500 m from the nest is a good conservation strategy for this rare species. The black stork is a protected species in Poland, and its numbers have declined significantly in recent years. The protection of nesting sites during the period of growth and independence of young birds is crucial for the population. In 2022–2023, 34 young storks were equipped with GPS-GSM backpack loggers. On average, birds had left the nest by the 87th day of life. In the period between the first flight attempt and the final abandonment of the nest, the birds spent 82% of their time in a zone up to 200 m from the nest. During the period of independence, resting areas played an important spatial role, 75% of which were located within 500 m of the nest. As the young birds grew older, their area of activity gradually increased. Differences in nesting phenology were observed depending on the geographical location of the nest. A shorter migration route from the wintering grounds allowed for earlier breeding. As a result, the young birds begin to fledge earlier. The data collected confirm the validity of designating protective zones with 500 m radii around nests and the need to maintain them from the beginning of the breeding season in March until the end of August. [ABSTRACT FROM AUTHOR]

Simple Summary: Mites are one of the most diverse groups of invertebrates that inhabit a wide range of environments. The acarofauna, and in particular Oribatida, inhabiting the nests of the White Stork and the Black Stork has not been thoroughly explored so far. The material collected from White and Black Stork nests in Poland was analyzed. This study presents original data on species diversity, abundance, density, and the age structure of Oribatida mites inhabiting the nests of two stork species that breed in Poland. Of the mites, the most numerous group was Mesostigmata. The average number of Oribatida (80.2 individuals in 500 cm3) was several times higher in the Black Stork nests than in the White Stork nests. Also, the species diversity of oribatid mites was greater in the Black Stork nests (47 species). The species diversity of oribatid mites was also greater in the Black Stork nests. In addition, we noted the potential importance of White and Black Stork nests for mite dispersion and the evolution of interspecies interactions. The White Stork (Ciconia ciconia) and the Black Stork (Ciconia nigra) are well-known model organisms for the study of bird migration, as well as the selectivity of nesting sites and the choice of living environment. The former breeds mainly in open areas, while the latter inhabits forest areas. The acarofauna, and in particular Oribatida, inhabiting the nests of these species, has not been thoroughly explored so far. Therefore, we analyzed the material collected from 70 White Stork nests and 34 Black Stork nests in Poland, between Poznań and Rawicz, and in Kampinos National Park. Our research has increased the faunal and ecological knowledge of the mite fauna inhabiting the nests of large migratory bird species. Oribatida constituted 5–12% of the total mites identified in the nests of White and Black Storks. Their average number was several times higher in the Black Stork nests (80.2 individuals in 500 cm3). Also, the species diversity of moss mites was greater in the Black Stork nests (47 species). In total, the nests of the two stork species were inhabited by 62 moss mite species, with only 22 recorded in both the White and the Black Storks' nests. The most numerous species included Ramusella clavipectinata, R. fasciata, Oppiella subpectinata, Acrogalumna longipluma, and Scheloribates laevigatus. In addition, we found that juvenile oribatid mites accounted for 0.6% of all the mites in the White Stork nests, with tritonymphs having the largest share, while juveniles in the Black Stork nests comprised 1.4%, of which larvae and protonymphs had the largest share. Our research shows that the nests of large migratory birds provide living space for many mite species. In addition, we noted the potential importance of White and Black Stork nests for mite dispersion and the evolution of interspecies interactions. [ABSTRACT FROM AUTHOR]

Simple Summary: High levels of predation can reduce survival rates of young birds and affect overall population growth. Therefore, birds that are better adapted to avoid predators, such as through strategic nest positioning, camouflage, and loud alarm calls, have a greater chance of successfully fledging their young. This study examines how white storks adapt to potential human threats during their nesting season and shows the effects of factors such as age, reproductive stage, and presence of a mate on their nesting behavior. The results show that storks are able to adapt their defense strategies depending on the perceived value and level of threat to their current brood. In particular, during crucial breeding phases, storks tend to prolong their stay in the nest while accelerating their return, reflecting a delicate balance between immediate reproductive needs and future prospects. In addition, the influence of a mate leads to earlier departure from the nest, suggesting a possible sexual conflict and interplay between parental care priorities. These results provide a deeper understanding of the intricate decision-making mechanisms of white storks when faced with perceived threats during the breeding season. The study contributes to a more comprehensive understanding of avian behaviors in response to environmental challenges. Recognizing, assessing, and responding to threats is critical for survival in the wild. Birds, especially in their role as parents, must decide whether to flee or delay flight when threatened. This study examines how age, reproductive stage, and the presence of a mate influence flight initiation distance (FID) and nest recess duration in white storks. Analyzing the data with a generalized additive mixed model (GAMM), we found significant correlations between FID and age, reproductive stage, and presence of a mate. These results suggest that the trade-off between current and future reproduction shifts during critical breeding periods, such as incubation and nestling care. To increase breeding success, White Storks appear willing to take risks and extend their stay in the nest when offspring are most valuable and vulnerable. In the presence of a mate, individuals leave the nest earlier, suggesting possible sexual conflict over parental care. The duration of nest abandonment is consistent with FID, except for age. These results illustrate how parental age, brood value, vulnerability, and sexual dynamics influence white stork flight decisions in complex ways. Understanding these dynamics enriches our knowledge of bird behavior and adaptations to environmental challenges and highlights the complexity of parental decision making. [ABSTRACT FROM AUTHOR]

Simple Summary: Antimicrobial resistance (AMR) has become a major health challenge of the 21st century. Several studies confirm the potential role of wildlife as sentinel for pathogens surveillance. Moreover, the presence of AMR bacteria in the wildlife can be considered as a good indicator of anthropization level on the ecosystem. The fast increase in AMR worldwide has been enhanced by several factors as globalization and migration. The study of antimicrobial resistance in wild birds is of great importance, as they can travel hundreds of kilometers and disseminate pathogens and AMR across different regions or even continents. The aim of this study was to compare the level of AMR in three bird species: white stork (Ciconia ciconia), lesser black-backed gull (Larus fuscus) and black-headed gull (Chroicocephalus ridibundus). For the analysis, 17 antibiotics from the most representative classes were tested by disk-diffusion method. Results showed 63.2% of seagulls and 31.6% of white storks as carriers of antimicrobial-resistant Escherichia coli, and from all of them, 38.9% were considered multi-drug resistant. Betalactamics, quinolones and tetracyclines were the antibiotic classes with the highest rate of AMR. The presence of AMR bacteria in the human–animal–environmental interface is a clear example of the One Health medicine. Several studies evidence the presence of resistant bacteria in wildlife, which can be used as a good indicator of anthropization level on the ecosystem. The fast increase in AMR in the environment in the last decade has been led by several factors as globalization and migration. Migratory birds can travel hundreds of kilometers and disseminate pathogens and AMR through different regions or even continents. The aim of this study was to compare the level of AMR in three migratory bird species: Ciconia ciconia, Larus fuscus and Chroicocephalus ridibundus. For this purpose, commensal Escherichia coli has been considered a useful indicator for AMR studies. After E. coli isolation from individual cloacal swabs, antimicrobial susceptibility tests were performed by the disk-diffusion method, including 17 different antibiotics. A total of 63.2% of gulls had resistant strains, in contrast to 31.6% of white storks. Out of all the resistant strains, 38.9% were considered multi-drug resistant (50% of white storks and 30% of seagulls). The antibiotic classes with the highest rate of AMR were betalactamics, quinolones and tetracyclines, the most commonly used antibiotic in human and veterinary medicine in Spain. [ABSTRACT FROM AUTHOR]

Simple summary: Protocols were adjusted and established for biomarker assessment in two blood fractions: plasma and the post-mitochondrial fraction (S9). Basal biomarker values were determined in white stork (Ciconia ciconia) nestlings from Croatia, and biomarker responses in two different types of blood samples were compared. Novel fluorescence-based glutathione and reactive oxygen species detection was established providing the potential usage of blood for assessment of environmental impact at the molecular level. White stork (Ciconia ciconia) nestlings can provide quantitative information on the quality of the surrounding environment by indicating the presence of pollutants, as they depend on locally foraged food. This study represents the first comparison of biomarkers in two fractions of white stork nestling blood: plasma and S9 (the post-mitochondrial fraction). The aim of this study was to evaluate acetylcholinesterase (AChE), carboxylesterase (CES), glutathione S-transferase (GST), and glutathione reductase (GR), as well as to establish a novel fluorescence-based method for glutathione (GSH) and reactive oxygen species (ROS) detection in plasma and S9. Considering the enzymatic biomarkers, lower variability in plasma was detected only for AChE, as CES, GST, and GR had lower variability in S9. Enzyme activity was higher in plasma for AChE, CES, and GST, while GR had higher activity in S9. Regarding the fluorescence-based method, lower variability was detected in plasma for GSH and ROS, although higher GSH detection was reported in S9, and higher ROS was detected in plasma. The present study indicated valuable differences by successfully establishing protocols for biomarker measurement in plasma and S9 based on variability, enzyme activity, and fluorescence. For a better understanding of the environmental effects on nestlings' physiological condition, biomarkers can be measured in plasma and S9. [ABSTRACT FROM AUTHOR]