The global spread of convergent Klebsiella pneumoniae, which combines multidrug resistance with hypervirulence, poses a major clinical threat, but its environmental dissemination remains poorly understood. Here, we show that wild migratory gulls along the Georgian Black Sea coast harbor clinically important, convergent isolates belonging to internationally dominant clonal lineages. We identify 33 carbapenem-resistant K. pneumoniae, predominantly globally disseminated high-risk clones (ST307 and ST395) carrying the blaNDM-5 carbapenemase gene. Ten isolates represent convergent pathotypes with hypervirulence markers, and four exhibit resistance to the last-resort antibiotic cefiderocol. Long-read sequencing reveals mosaic plasmids that co-encode resistance and virulence determinants. In addition, GPS telemetry shows that these gulls frequently use anthropogenic sites, including wastewater treatment plants and landfills. These findings indicate that migratory birds are carriers of critically resistant pathogens, highlighting the role of human-impacted environments in their broader dissemination across One Health interfaces.

Highly pathogenic avian influenza (HPAI) H5N1 viruses of clade 2.3.4.4b have caused widespread mortality in wild and domestic birds globally. Colonial breeding seabirds have been severely affected across Europe, the Americas and Antarctica since 2021. Despite extensive outbreaks, most reports have been limited to morbidity and mortality, while less is known on behavioural effects of infection. We monitored six colonies of black-headed gulls (Chroicocephalus ridibundus) throughout an outbreak during the 2023 breeding season (confirmed as H5N1 clade 2.3.4.4b, EA-2022-BB genotype), combining field observations, global positioning system (GPS)-tracking, virological and serological analyses to assess the epidemiological and behavioural impacts of the disease. Die-offs were observed in five of the colonies, resulting in more than 90% chick mortality and substantial adult losses. Serological analyses of samples taken 1- and 2-years post-outbreak revealed high neutralizing antibody titres against HPAI viruses in surviving individuals. Movement data from GPS-tagged birds confirmed a high adult mortality in affected colonies, reduced daily speed and earlier onset of migration. Our findings emphasize the severity of HPAI in seabirds with effects not only on direct mortality but also on behaviour. Integrating mortality, behavioural and immunological information is therefore crucial to improve surveillance and mitigation strategies for future wildlife disease events.

Environmental antimicrobial resistance (AMR) surveillance has expanded substantially across aquatic systems, wildlife, and other ecological compartments. While these efforts have improved our understanding of resistant bacteria and resistance determinants, translating surveillance outputs into meaningful interpretation, risk assessment, and operational decision-making remains challenging. We argue that the next challenge for environmental AMR surveillance is to develop purpose-driven and context-aware frameworks that align surveillance objectives, environmental context, and methodological design and enable interpretation and action across One Health systems.

Successful conservation and management actions to safeguard migratory huntable waterbirds require knowledge of their spatio-temporal distributions and migration patterns throughout the annual cycle. Such actions are challenging, because migration patterns within a population can vary, for example, due to migratory barriers and sex-specific factors. We studied individual migratory patterns of East Atlantic flyway Eurasian wigeon (Mareca penelope), using GPS-tracking data from birds caught during spring in central and northern Europe. We found complex migratory patterns and differences in the spring migration of wigeon captured in central and northern Europe. These wigeon migrated south and north of the Baltic Sea, respectively, despite the Baltic Sea presenting no barrier to the population. Wigeon captured in central Europe moved northeast towards northern Russia, differing from movements of the birds captured in northern Europe, which were more varied and tended to migrate toward the northeast and northwest. Autumn migration orientation of birds from both capture areas was towards the southwest, resulting in Scandinavian breeding birds undertaking loop migration. Moult migrating males moved further during the summer than females, reducing migratory connectivity among males and reflecting sex-specific differences in the migratory behaviour of Eurasian wigeon. Our results confirm that individual migratory patterns of Eurasian wigeon show more diversity than expected from ring recovery data, suggesting that successful management at flyway-population level needs more detailed information to support management planning.

Avian influenza viruses (AIV) pose a major zoonotic threat with pandemic potential. Waterbirds facilitate AIV spillovers into farm animals and humans through exposure and virus reassortment. Here, we propose waterbird activity entropy (WAE), an indicator of waterbird activity intensity based on monthly distributions of 779 species worldwide. WAE demonstrated high explanative power (AUC = 0.87 ± 0.001) for global avian influenza cases, particularly for H5N1, revealing the potential of WAE for identifying AIV exposure hotspots which cover 14% of global land area. Notably, the AIV exposure hotspots in the USA, EU, China, and India contain 52% of the globally exposed human population, 41% cattle, and 51% poultry. Despite reporting <1% of global cases, sub-Saharan Africa contains >300 Mha of hotspots area (15% globally), highlighting considerable surveillance gaps. This WAE-based framework enhances AIV risk assessment by incorporating waterbird residency time, offering critical insights for anticipating AIV emergence and improving surveillance.

Wild waterfowl and shorebirds are the primary reservoir of influenza A viruses in nature. The role of wild birds from other taxonomic groups remains insufficiently studied or is a subject of debate. This applies in particular to Passeriformes, the most diverse avian order, accounting for approximately 60% of the global bird population, where the role in circulation of influenza A viruses is underexplored. We used serological, virological, and PCR-based methods to survey avian influenza viruses in Passeriformes birds (65 species, 20 families) in Ukraine over a 20-year period, 2004-2025. Antibodies to influenza viruses were detected in serum and egg yolk of seven passerine species, with average seroprevalence 1.24% in sera and 8.94% in yolk samples. Seroprevalence varied across species, ranging from 1.96 to 27.2%. Virological screening resulted in the isolation of two viruses from Fieldfares (Turdus pilaris) of the subtypes H1N1 and H7N1. The overall infection rate based on virus isolation was 0.15%, while local infection rate in Fieldfares reached 11.1%. According to PCR results, 41 positive samples were detected, representing 3.61% of all tested birds (ranging from 1.42-9.1%), and by location ranged from 6.25-9.1%. Sequencing and phylogenetic analyses of H1N1 (Fieldfare), H7N1 (Fieldfare), H3N8 (Great Tit Parus major) influenza viruses confirmed them as Eurasian lineage low pathogenic avian influenza viruses and with close relatedness to viruses of the same subtypes circulating among wild waterfowl.

GPS telemetry has become the norm for the tracking of large-bodied bird species, whereas management and conservation of populations often rely on low-tech methods such as capture-mark-resighting (CMR). Direct evaluations of the comparability of the respective outcome from these methods remain rare despite being crucial for comparative studies and management decisions. Here, we investigated whether GPS tracking and CMR lead to same conclusions about seasonal migration and year-round space use. We chose greylag geese (Anser anser) as a study species, for which a long record of both coded neckband reports and GPS tracking are available, and whose management relies on CMR data. Our data set was comprised of neckband reports and GPS tracks collected for birds from five capture sites in Sweden (n = 665 neckband birds; n = 156 GPS collar birds). We evaluated the similarity of movement metrics and year-round space use derived from continuous-time movement models and auto-correlated kernel density estimators. We further quantified overlap of spatial range estimates between tracking methods for the breeding period and the wintering season. We approximated spatial observation bias by contrasting range estimates estimated with and without the use of a debiasing algorithm. We found that estimates of space use derived from CMR and GPS tracking were in general agreement: average year-round space use for most individuals was similar even if means among tracking methods differed among all individuals per method (CMR: 5.07×10^5 km^2 ; GPS: 1.76×10^5 km^2 ), and mean overlap of range estimates for summer and winter did not differ depending on whether the comparison was with the same, or differing tracking methods. Movement metrics differed considerably between methods whenever the CMR data captured behaviour at a different temporal scale than GPS (position velocity autocorrelation), and else in agreement with GPS tracking (periodicity). Our study suggests that the historical and current use of coded neckband data for greylag goose management decisions is appropriate regarding space use of migratory greylag geese in Europe. Understanding whether the existing reporter network can capture changes to the migratory behaviour of greylag geese including short-stopping of migration will however require additional in-depth analyses.

Avian influenza viruses are predominantly associated with waterfowl and shorebirds, and are rarely detected in other avian hosts in nature. In 2021, an H1N1 virus was isolated from a Fieldfare Turdus pilaris in Zaporizhzhia Oblast, Ukraine. A phylogenetic analysis revealed that all eight gene segments belonged to the Eurasian low-pathogenic avian influenza lineages. The highest nucleotide identity of the HA gene was observed with viruses detected in Georgia, Sweden, and Ukraine (99.11%), while the NA gene showed the greatest identity to viruses from Western Europe (99.14–99.57%). Genetic analysis of the HA cleavage site showed a sequence (PSIQSR↓GLF) that contained a single basic amino acid. No deletions were detected in the stalk region of NA gene, and no specific mutations in PB2 protein were found. However, several amino acid substitutions were identified in the HA gene (D204E, S207T, and D239G) that may affect the binding affinity to specific antibodies. The occurrence of this virus in a wild, seemingly healthy thrush indicate that additional surveillance in poorly studied ecological groups such as Passeriformes is warranted.

Animal movements contribute to the spread of infectious diseases and are driven in part by environmental conditions. We investigated the links among the environment, animal movement, and infectious disease dynamics in waterfowl, which are among the primary wildlife hosts of avian influenza viruses. By combining telemetry data on 4606 individuals from 26 waterfowl species with data on land cover, weather, and vegetation, we found that waterfowl moved less in areas of higher land cover heterogeneity and higher human population density. Moreover, predicted waterfowl movement distances were weakly but positively correlated with distances between detections of H5N1 highly pathogenic avian influenza in wild waterfowl, suggesting that environmental conditions might contribute to the spread of this disease via their effects on bird movements. By considering wildlife movements alongside other drivers of infectious disease dynamics, such as livestock production and human mobility, we move closer to predicting outbreaks and informing interventions.

Global products of land use and land cover (LULC) provide maps with a consistent classification, thereby allowing for comparisons of resource and habitat use of species over large spatial scales. While global LULCs tend to be evaluated extensively, the distribution ranges of species can extend into remote areas that are hard to access for ground truthing. It is unclear how adequate global LULCs are for mapping habitat of long-distance migrants throughout their entire range. Here, we investigated whether different global LULCs could successfully capture the known preferences of a migratory wetland specialist, the Eurasian wigeon (Mareca penelope), along the East Atlantic flyway. We evaluated how well five different global LULC products captured known wigeon habitat preferences using remote tracking data, and tested whether a further classification based on wetland expert knowledge can improve on their performance. We found that average performance of global LULC products varied greatly, with ESA WorldCover performing best with a 94% correspondence to wigeon habitat. All products performed best in the Tundra biome, and worse in Boreal as well as Temperate forests. In the latter areas, our wetland expert LULC classification provided improved results by explicitly considering small and temporary wetlands, and wetlands underneath vegetation. Overall, habitat use of habitat specialists can inform us about habitat types that are currently not considered in large-scale LULC maps. We suggest LULC mapping methods integrate information from tracking of wetland specialists for a better detection of small and temporary wetlands on a global scale.

Sindbis virus (SINV) is a zoonotic arbovirus transmitted by mosquitoes and maintained by wild birds with an expanding distribution globally. Despite its importance, surveillance efforts are low or lacking in many areas, especially in Africa. Our study aimed to highlight the epidemiology of SINV in wild birds in a West African country - Nigeria - with implications for human health. Blood samples were collected from wild resident Afrotropical and migrant Palearctic birds over two years. RT-qPCR was used to detect SINV RNA positive samples, followed by confirmatory conventional PCR and Sanger sequencing targeting the non-structural protein gene. Three out of 504 samples (0.6%; 95% CI: 0.12-1.73%) were positive for SINV, all from individuals of a single species, the African Thrush (Turdus pelios). We successfully generated the whole genome sequence of one sample. Phylogenetic analysis revealed it was closely related to strains from Algeria, Spain and Kenya in the SINV-I genotype. The study suggests that SINV is enzootic in the region and that the African Thrush may be a putative reservoir species.

In recent decades, interest has grown in how increasing populations of herbivorous geese and swans (Anseriformes: Anatidae: Anserinae) affect macrophyte communities in wetlands, especially because many waterbodies are simultaneously subjected to stressors like eutrophication and biodiversity declines. Here, we review the literature on methods applied in grazing experiments that have been conducted in aquatic ecosystems. We also investigate and how different macrophyte characteristics may respond to waterfowl herbivory. Results indicate that both research methodology and responses of macrophytes differ widely among studies. While most experimental studies on grazing pressure employ a ‘paired plot design’ with exclosures and open control plots, the structure, size, and placement of plots vary among studies. Commonly sampled macrophyte variables are biomass (of either above- or below-ground plant parts), density, height, plant cover, and community composition. The literature provides support that geese and swans significantly affect several of these variables, but the outcome depends on additional factors, e.g., waterfowl density, water depth, and timing (within or between seasons/years). Because of the persisting conservation threats to aquatic ecosystems, more knowledge is needed about potential direct and indirect consequences of waterfowl herbivory in these environments.

Wild passerine birds may serve as environmental reservoirs and as vectors for the long-distance dispersal of microorganisms and resistance determinants. However, there is no much knowledge on pathogenic bacteria in wild birds in Iran. The present study aimed to analyze antibiotic resistance in wild passerine birds collected from the northeast region of Iran as the rich breeding bird fauna with a special focus on Escherichia coli virulence, integron, and phylogenetic groups. A total of 326 isolates were collected and identified from the cloaca of wild birds using a swab. The results showed a high percentage of resistance to tetracycline (45.8%) and ampicillin (26.7%). The resistance genes, tet(A), tet(B), tet(M), and tet(L) were detected in tetracycline-resistant isolates, while the blaTEM gene was the most prevalent in ampicillin-resistant isolates (38.6%). Out of the 129 E. coli isolates examined, 99 isolates were found to have virulence gene, with the highest prevalence of the fimbriae (fimH) gene (22.4%). Additionally, the E. coli strains were most often classified into phylogenetic groups B1 (48.8%) followed by B2 (19.3%). Also, the highest average frequency of class 1 integron was detected among our isolates. Results indicated that wild birds are reservoirs of multidrug resistance and virulence genes that may have the potential to be transferred to other organisms, including humans.

Humans are radically altering global ecology, and one of the most apparent human-induced effects is urbanization, where high-density human habitats disrupt long-established ecotones. Changes to these transitional areas between organisms, especially enhanced contact among humans and wild animals, provide new opportunities for the spread of zoonotic pathogens. This poses a serious threat to global public health, but little is known about how habitat disruption impacts cross-species pathogen spread. Here, we investigated variation in the zoonotic enteric pathogen Campylobacter jejuni. The ubiquity of C. jejuni in wild bird gut micro- biomes makes it an ideal organism for understanding how host behavior and ecology influence pathogen transition and spread. We analyzed 700 C. jejuni isolate genomes from 30 bird species in eight countries using a scalable generalized linear model approach. Comparing multiple behavioral and ecological traits showed that proximity to human habitation promotes lineage diversity and is associated with antimicrobial-resistant (AMR) strains in natural populations. Specifically, wild birds from urban areas harbored up to three times more C. jejuni genotypes and AMR genes. This study provides novel methodology and much-needed quantitative evidence linking urbanization to gene pool spread and zoonoses.

Migratory birds play a dual role as potential reservoirs of tick-borne pathogens, and potential dispersers of pathogen-containing ticks during their migratory journeys. Ixodes ricinus, a prevalent tick species in Northern and Western Europe, serves as a primary vector for Anaplasma phagocytophilum—a bacterium with implications for human and animal health. There is limited information available regarding A. phagocytophilum in birds. Our investigation focused on A. phagocytophilum prevalence in ticks collected from migratory birds in southeastern Sweden. The identification of ticks involved both molecular analyses for species determination and morphological classification to ascertain the developmental stage. The presence of A. phagocytophilum was determined using real-time PCR. Of the 1115 ticks analyzed from 4601 birds, 0.9% (n = 10), including I. ricinus and Ixodes frontalis, tested positive for A. phagocytophilum. Notably, common blackbirds (Turdus merula) yielded the highest number of A. phagocytophilum-infected ticks. The findings suggest that A. phagocytophilum is present in a small proportion of ticks infesting migratory birds in southeastern Sweden. Consequently, the role of birds as hosts for ticks infected with A. phagocytophilum appears to be low, suggesting that birds seem to play a minor indirect role in the geographic dispersal of A. phagocytophilum.

Objectives The recent detection and expansion of West Nile virus (WNV) and Usutu virus (USUV) in the Netherlands, Germany, and Austria point to the likelihood of the viruses spreading to northern Europe. Migratory birds and ornithophilic mosquitoes may spread these viruses to new areas. We sampled birds during the spring and autumn bird migration of 2021 in southern Sweden to investigate the risk of the introduction of mosquito-borne zoonotic avian viruses like WNV and (USUV). Methods We collected blood samples from 1775 birds comprising 59 species and determined the seroprevalence of WNV using a competitive ELISA. WNV and USUV belong to the Japanese encephalitis serocomplex and antibodies against both viruses are detected in the WNV ELISA. Focus forming assays or fluorescence-based neutralization assays were performed to verify ELISA results and to differentiate between antibodies against WNV and USUV. Results We found 9 (0.51%) samples to be WNV-antibody positive. Cross-neutralization experiments with WNV and USUV confirmed that 7 (0.41%) had WNV-neutralizing antibodies and 2 (0.11%) had USUV-neutralizing antibodies. Interestingly, the two samples had neutralizing antibodies of both viruses. All samples but one with anti-flavivirus antibodies came from long-distance migrants wintering in sub-Saharan Africa. Antibodies were detected in samples taken during spring and autumn and only in adult birds. Conclusion The findings show that migratory birds in Sweden have been exposed to WNV and USUV.

Outbreaks of avian influenza in poultry and humans are a global public health concern. Aquatic birds are the primary natural reservoir of avian influenza viruses (AIVs), and strikingly, AIVs mainly cause asymptomatic or mild infection in these species.