Avian Populations Research Articles

Molecular Screening and Characterization of Enteric Protozoan Parasites and Microsporidia in Wild Ducks from Portugal.

Enteric parasites pose significant threats to both human and veterinary health, ranking among the top causes of mortality worldwide. Wild migratory waterfowl, such as ducks, may serve as hosts and vectors for these parasites, facilitating their transmission across ecosystems. This study conducted a molecular screening of enteric parasites in three species of wild ducks of the genus Anas (A. acuta, A. platyrhynchos and A. crecca) from Portugal, targeting Blastocystis sp., Balantioides coli, Cryptosporidium spp., Encephalitozoon spp., and Enterocytozoon bieneusi. Fecal samples from 71 ducks were analyzed using PCR and sequencing techniques. The results revealed a 2.82% occurrence of Blastocystis sp. subtype 7 and Cryptosporidium baileyi, marking the first molecular detection of these pathogens in wild ducks in Portugal. While previous studies have documented these parasites in Anas spp. in other regions, this study contributes novel data specific to the Portuguese context. No evidence of Balantioides coli, Encephalitozoon spp. or Enterocytozoon bieneusi was found. These findings highlight the potential role of migratory ducks as vectors for zoonotic protozoa, emphasizing the need for enhanced surveillance of avian populations to mitigate cross-species transmission risks. Further research is warranted to understand the global public health implications associated with migratory waterfowl.

A comprehensive biochemical and epidemiological review of avian influenza: Mechanisms, pharmacology and emerging trends in treatment

Avian influenza viruses, particularly H5N1, H7N9, and H9N2, pose significant threats to avian and human populations through zoonotic transmission, as they have potential to change their genetic material through mutations. Symptoms of Avian Influenza ranges from mild to severe, mainly respiratory problems in both and muscle aches, fatigue in humans. This review highlights the molecular mechanisms by which the virus infects host cells, emphasizing the roles of hemagglutinin (HA) and neuraminidase (NA) in viral entry and release. Biochemical processes involved in viral replication, immune responses, and cytokine production are discussed, with a detailed examination of how antiviral drugs like neuraminidase and polymerase inhibitors disrupt these processes. Outbreak of AIV can cause mass culling results in massive economic loss, trade disruptions, and consumer reductions. The review also addresses the challenges posed by antiviral resistance and outlines novel therapeutic strategies, including combination therapies, vaccine advancements, and host-directed treatments. With an interdisciplinary “One Health” approach, this paper underscores the need for enhanced biosecurity, international cooperation, and continued research to mitigate the global impact of avian influenza.

Non-breeding conditions induce carry-over effects on survival of migratory birds.

Identifying the processes that limit populations is a foundational objective of ecology and an urgent need forconservation. For migratory animals, researchers must study individuals throughout their annual cycles to determine how environmental conditions limit demographic rates within each period of the annual cycleand also between periods through carry-over effects and seasonal interactions.1,2,3,4,5,6 Our poor understanding of the rates and causes of avian migration mortality7 hinders the identification of limiting factors and the reversal of widespread avian population declines.8,9 Here, we implement new methods to estimate apparent survival (hereafter survival) during migration directly from automated telemetry data10 in Kirtland's Warblers (Setophaga kirtlandii) and indirectly from mark-recapture data in Black-throated Blue Warblers (S.caerulescens). Previous experimental and observational studies of our focal species and other migratory songbirds have shown strong effects of Caribbean precipitation and habitat quality on food availability,11,12,13,14 body condition,12,13,14,15,16,17,18,19 migration timing,11,12,15,16,20,21,22,23 natal dispersal,24,25 range dynamics,26 reproductive success,20,22,27 and annual survival.18,19,20,23,28,29,30,31 Building on this research, we test the hypotheses that environmental conditions during the non-breeding period affect subsequent survival during spring migration and breeding. We found that reduced precipitation and environmental productivity in the non-breeding period strongly influenced survival in both species, primarily by reducing survival during spring migration. Our results indicate that climate-driven environmental conditions can carry over to affect survival in subsequent periods and thus likely play an important role in year-round population dynamics. These lethal carry-over effects may be widespread and are likely magnified by intensifying climate change.

The First Report of Sphaerirostris picae Infection in the Oriental Magpie (Pica serica) in Beijing, China.

Background: Sphaerirostris picae is a parasitic species known for its ability to infect and transmit between hosts in the gastrointestinal tracts of wild avian species. However, there is limited information on its presence and impact on urban avian populations, particularly in China. Materials and Methods: In this study, morphological observations were conducted to detect the presence of Sphaerirostris sp. within the intestinal tract of the Oriental Magpie (Pica serica) collected in Beijing, China. Further confirmation of the parasite's identity was achieved through phylogenetic analysis using COX1 gene sequencing to compare with previously documented Sphaerirostris picae isolates. Results: The morphological and molecular analyses confirmed the presence of Sphaerirostris picae in the Oriental Magpie. Phylogenetic analysis indicated a close relationship with known Sphaerirostris picae isolates. This represents the first reported case of Sphaerirostris picae infection in magpies from Beijing, China. Conclusion: The findings highlight the potential health hazards posed by Sphaerirostris picae to urban avian populations and public health. The study suggests that additional research and surveillance efforts are necessary to better understand the risks associated with this parasite and to develop effective mitigation strategies.

Genomic Diversity and Evolutionary Insights of Avian Paramyxovirus-1 in Avian Populations in Pakistan.

The virulent form of Avian paramyxovirus-1 (APMV-1), commonly known as Newcastle Disease Virus (NDV), is a pathogen with global implications for avian health, affecting both wild and domestic bird populations. In Pakistan, recurrent Newcastle Disease (caused by NDV) outbreaks have posed significant challenges to the poultry industry. Extensive surveillance in Pakistan over 20 years has demonstrated a dynamic genetic diversity among circulating APMV-1 strains, emphasizing the potential necessity for customized vaccination strategies and continuous surveillance. In this study, 13 APMV-1-positive isolates harboring four different APMV-1 genotypes circulating throughout Pakistan were identified. These included the highly virulent genotypes VII and XIII, genotype XXI, commonly associated with Columbiformes, and genotype II, hypothesized to have been detected following vaccination. These findings underscore the intricate interplay of mutational events and host-immune interactions shaping the evolving NDV landscape. This study advances our understanding of the evolutionary dynamics of APMV-1 in Pakistan, highlighting the need for tailored vaccination strategies and continuous surveillance to enable effective APMV-1 management in avian populations, further emphasizing the importance of globally coordinated strategies to tackle APMV-1, given its profound impact on wild and domestic birds.

Integrating adverse effects of triazole fungicides on reproduction and physiology of farmland birds

The extensive use of pesticides has been recognized as one of the major factors negatively impacting birds in agricultural habitats. One of the pesticide groups most used worldwide are triazole fungicides due to their effectiveness in controlling phytopathogenic fungi in cereals, vineyards and orchards. In the last decades, different experimental studies have reported important negative effects on the health and fitness of birds after exposure to triazoles. Birds can be exposed throughout the year through different routes, including oral uptake, dermal contact with treated surfaces and inhalation by overspray. Yet, the ingestion of treated or sprayed material is the principal route. The most alarming effect of triazoles, which can even occur several months after cessation of the exposure, is the decreasing reproductive outputs of birds, including delay in the onset of laying dates, reduced clutch size and hatching rate, and increased mortality of chicks. In order to synthesize the data and knowledge about the toxic effects of triazoles at different levels of biological organization, here we propose an dverse outcome pathway (AOP) on the mechanisms by which triazoles can affect avian reproduction and physiology. The reported effects highlight that the current risk assessment needs some improvements to avoid undesired effects on birds, especially long‐term effects that can influence stability and viability of avian populations from agricultural habitats.

Trait Variation and Spatiotemporal Dynamics across Avian Secondary Contact Zones.

A secondary contact zone (SCZ) is an area where incipient species or divergent populations may meet, mate, and hybridize. Due to the diverse patterns of interspecific hybridization, SCZs function as field labs for illuminating the on-going evolutionary processes of speciation and the establishment of reproductive isolation. Interspecific hybridization is widely present in avian populations, making them an ideal system for SCZ studies. This review exhaustively summarizes the variations in unique traits within avian SCZs (vocalization, plumage, beak, and migratory traits) and the various movement patterns of SCZs observed in previous publications. It also highlights several potential future research directions in the genomic era, such as the relationship between phenotypic and genomic differentiation in SCZs, the genomic basis of trait differentiation, SCZs shared by multiple species, and accurate predictive models for forecasting future movements under climate change and human disturbances. This review aims to provide a more comprehensive understanding of speciation processes and offers a theoretical foundation for species conservation.

Environmental conditions influence host-parasite interactions and host fitness in a migratory passerine.

The study of host-parasite co-evolution is a central topic in evolutionary ecology. However, research is still fragmented and the extent to which parasites influence host life history is debated. One reason for this incomplete picture is the frequent omission of environmental conditions in studies analyzing host-parasite dynamics, which may influence the exposure to or effects of parasitism. To contribute to elucidating the largely unresolved question of how environmental conditions are related to the prevalence and intensity of infestation and their impact on hosts, we took advantage of 25 years of monitoring of a breeding population of pied flycatchers, Ficedula hypoleuca, in a Mediterranean area of central Spain. We investigated the influence of temperature and precipitation during the nestling stage at a local scale on the intensity of blowfly (Protocalliphora azurea) parasitism during the nestling stage. In addition, we explored the mediating effect of extrinsic and intrinsic factors and blowfly parasitism on breeding success (production of fledglings) and offspring quality (nestling mass on day 13). The prevalence and intensity of blowfly parasitism were associated with different intrinsic (host breeding date, brood size) and extrinsic (breeding habitat, mean temperature) factors. Specifically, higher average temperatures during the nestling phase were associated with lower intensities of parasitism, which may be explained by changes in blowflies' activity or larval developmental success. In contrast, no relationship was found between the prevalence of parasitism and any of the environmental variables evaluated. Hosts that experienced high parasitism intensities in their broods produced more fledglings as temperature increased, suggesting that physiological responses to severe parasitism during nestling development might be enhanced in warmer conditions. The weight of fledglings was, however, unrelated to the interactive effect of parasitism intensity and environmental conditions. Overall, our results highlight the temperature dependence of parasite-host interactions and the importance of considering multiple fitness indicators and climate-mediated effects to understand their complex implications for avian fitness and population dynamics.

Microbiomes in Birds: A Review of Links to Health and Reproduction.

Microbiomes have emerged as a key component essential for maintaining the health of an organism. Additionally, the roles of microbiomes are multifaceted, some unique to specific body areas and organs while others, particularly the gut microbiome, having broader effects on the entire organism. Comparative literature is emerging that compares microbiomes across mammals and birds. Domestic poultry have been the most extensively studied relative to their role in production agriculture. These data have provided a great deal of information about the effects of diet and nutritional requirements relative to the gut microbiome, productivity, and resilience to diseases. Conversely, limited such research has been conducted on wild birds, despite them inhabiting a broad array of ecological niches and environments, providing a rich diversity in their adaptations to different habitats. Migratory birds and raptors are of particular interest. Migratory birds encounter a range of ecosystems and provide a link between allopatric populations. Raptors occupy high positions in the food chain, with potential exposure to biomagnification of environmental contaminants and pathogens. This review overviews our current understanding of the structure and function of avian microbiomes as related to avian health and reproduction in domestic and wild birds, highlighting knowledge gaps in need of further investigation for more effective conservation of rapidly declining avian populations.

Unraveling the genomic landscape of Campylorhynchus wrens along western Ecuador's precipitation gradient: Insights into hybridization, isolation by distance, and isolation by the environment.

Environmental gradients have the potential to influence genetic differentiation among populations ultimately leading to allopatric speciation. However, environmental gradients can also facilitate hybridization between closely related taxa. We investigated a putative hybrid zone in western Ecuador, involving two polytypic wren species (Aves: Troglodytidae), Campylorhynchus zonatus and C. fasciatus. Our study addressed two primary questions: (1) Is there evidence of population structure and genetic admixture between these taxa in western Ecuador? and (2) What are the relative contributions of isolation by distance and isolation by the environment to the observed genetic differentiation along the environmental gradient in this region? We analyzed 4409 single-nucleotide polymorphisms (SNPs) from 112 blood samples sequenced using ddRadSeq and a de novo assembly. The optimum number of genetic clusters ranged from 2 to 4, aligning with geographic origins, known phylogenetics, and physical or ecological constraints. We observed notable transitions in admixture proportions along the environmental gradient in western Ecuador between C. z. brevirostris and the northern and southern genetic clusters of C. f. pallescens. Genetic differentiation between the two C. f. pallescens populations could be attributed to an unreported potential physical barrier in central western Ecuador, where the proximity of the Andes to the coastline restricts lowland habitats, limiting dispersal and gene flow, especially among dry-habitat specialists. The observed admixture in C. f. pallescens suggests that this subspecies may be a hybrid between C. z. brevirostris and C. fasciatus, with varying degrees of admixture in western Ecuador and northwestern Peru. We found evidence of isolation by distance, while isolation by the environment was less pronounced but still significant for annual mean precipitation and precipitation seasonality. This study enhances our understanding of avian population genomics in tropical regions.

Commons are cared for: Coexistence between humans and wild birds on the island of Kihnu, Estonia

Abstract Local knowledge is an essential dimension of humanity's relationship with the environment. Investigating the interdependence between humans and wild birds holds value in fostering a mutually beneficial relationship with avian populations. Gathering bird eggs is a significant practice for Kihnu islanders in Estonia. There are very few studies of this age‐old, complex knowledge that assess the topic from the perspective of the local community. This paper investigates the reciprocity and the relationality between people and birds and the position of commons in the local community practice of bird semi‐domestication. Several methods (interviews, participant observation and literature study) were used in data collection. We obtained information on local knowledge concerning 58 bird taxa. Locals named at least 21 bird species from which they have collected eggs. While collecting eggs is a central activity, the relationship surrounding egg collection is far more intricate. Locals take care of nesting boxes in Common Merganser which birds reside, collecting only a few eggs from every box. These nesting boxes are also constructed for passerine birds. Furthermore, caring for birds influences the soundscape of Kihnu and significantly impacts the cultural bond between local communities and the birds. Kihnu islanders are mindful of the changes occurring in the bird population. The intimate relationship between local people and birds is challenged when traditional ways of life are restricted by stricter nature conservation norms (e.g. banning the collection of bird eggs and visiting islets). However, birdlife is very important in ensuring biocultural diversity. Therefore, this study proposes several important future perspectives in promoting the sustainable development of rural life: (1) the introduction of pluralistic nature protection, including the opinion of local communities in the management of natural resources; (2) the promotion of birds as a means of pest control; and (3) reinforcing the reciprocal coexistence of birds and humans on Kihnu. We advocate for community‐centred nature management which takes into consideration Local Ecological Knowledge and its attached expertise, shared responsibility and benefits, sustainable development trajectories and local community‐based governance systems. Read the free Plain Language Summary for this article on the Journal blog.

Severe Avian Influenza A H5N1 Clade 2.3.4.4b Virus Infection in a Human with Continuation of SARS-CoV-2 Viral RNAs

Background. Since 2020, global attention has heightened towards epidemics caused by avian influenza A H5N1 virus of clade 2.3.4.4b in birds and mammals. This study presents the epidemiological history, clinical manifestations, and prognosis of a unique case infected with avian influenza A H5N1 clade 2.3.4.4b, along with the continuation of SARS-CoV-2 viral RNAs, in Eastern China. Methods. We collected and analysed the patient’s clinical, epidemiological, and virological data. Both sputum and bronchoalveolar lavage fluid (BALF) samples were subjected to real-time RT-PCR to test for respiratory pathogens of interests, including SARS-CoV-2 and influenza virus. Influenza virus isolation and propagation were performed on embryonated eggs. Serological tests were used to determine the presence of SARS-CoV-2 antibodies. Phylogenetic analysis was constructed to explore viral evolution and origin of A/H5N1 virus. Results. A 53-year-old female farmer with chronic bronchiectasis was hospitalized with severe pneumonia. Real-time RT-PCR revealed the presence of avian influenza A H5N1 and SARS-CoV-2 in BALF and sputum samples. Sequence analyses classified the human isolate as clade 2.3.4.4b of avian influenza A H5N1. The amino acid motif GlnSerGly at residues 226–228 of the haemagglutinin protein indicated avian-like receptor binding preference. Epidemiological investigation established that the patient had exposure to sick or dead poultry 3 days before illness onset, while no cases of human-to-human H5N1 virus transmission were identified in 31 close contacts. Conclusion. We presented that the clade 2.3.4.4b H5N1 avian influenza virus has the potential to cross-infect humans with serious symptoms, especially in individuals already affected by COVID-19. It is indeed crucial to closely monitor the virus’s evolution in both avian populations and humans. Continued research and surveillance efforts are vital to monitor any potential changes in the virus, as well as to inform public health policies and interventions.

Roads reduce breeding occupancy and productivity in barn owls

AbstractUrbanization and expanding road networks threaten some avian populations through habitat loss and degradation. Barn owls (Tyto alba) have been particularly affected through roadway mortality, loss of grassland, and conversion or destruction of nesting sites. To combat declines and bolster reproduction, and as part of integrated pest management to reduce crop damage, some land managers provide supplemental owl nesting sites via the installation of nest boxes. If nearby habitat and land cover characteristics are not considered when placing boxes, such as major roads or other anthropogenic features, owls could be attracted to locations that could hinder populations further. We investigated the effects of roads and urban areas on barn owl breeding occupancy and productivity to provide information to help guide the placement of nest boxes. We monitored >300 nest boxes over the 2020 and 2021 breeding seasons in southwestern Idaho, USA, where substantial roadway mortality of barn owls occurs. Barn owls occupied >60% of nest boxes, but the likelihood of breeding occupancy decreased with increasing proximity of nest boxes to roads. Boxes 500 m from roads had a predicted probability of occupancy of over 0.9, which was nearly double that of boxes within 100 m. Proximity to roads also was associated with reduced productivity such that boxes within 100 m of roads were predicted to produce approximately 1 fewer fledgling than those 500 m away. There was no evidence that the proportion of urban area surrounding nest boxes substantially influenced breeding occupancy or productivity. Thus, land managers can consider placing nest boxes for barn owls farther from roads when possible as a potential tactic to increase the probability of breeding occupancy and to foster higher productivity.

Seasonal migration directs and facilitates gene flow in the Broad-tailed and Lucifer Sheartail Hummingbirds

Gene flow, the movement of genes between populations, profoundly influences genetic and phenotypic homogeneity among populations. This study investigates gene flow patterns in two migratory hummingbird species, Selasphorus platycercus and Calothorax lucifer, shedding light on the intricate interplay between migration, resource availability, and genetic diversity. Using previously published information on microsatellites, we examine the genetic makeup and the movement of genes within populations. Selasphorus platycercus displays distinct genetic groups which can be associated with its migratory behaviour. Gene flow analysis suggests a higher level of connectivity among populations sharing winter ranges. In contrast, Calothorax lucifer populations exhibit genetic divergence despite overlapping winter ranges, possibly due to environmental niche adaptation and limited reproductive opportunities for dispersing individuals. While geographical distance does not explain genetic differentiation in these species, environmental niche similarities appear to facilitate gene flow. This study underscores the significance of migratory routes, resource availability, and niche adaptation in shaping gene flow dynamics in hummingbirds. Understanding these dynamics is crucial for the conservation and management of these unique avian populations.

Feathered diplomacy: when birds become main factors of research design and geography on Vigur Island

Vigur Island, situated in Iceland’s Westfjords, is renowned for its diverse avian species, such as Atlantic Puffins and Black Guillemots, and its marine inhabitants including Harbour and Grey Seals. Despite its openness to tourism, the island is a subject of ongoing conservation efforts. This opinion paper argues for a more holistic approach to research on the island, highlighting the complex interplay between human activity and the island’s ecosystem. It critiques the current, often narrow, research methodologies that fail to fully account for the intricate relationships between species and their environment. The paper calls for a re-evaluation of habitat classification to incorporate the significant impact of avian populations and stresses the importance of adhering to Icelandic laws that mandate minimal disturbance to wildlife. With seasonal closures and careful management practices like eiderdown collection, Vigur Island serves as a model for balancing human interests with ecological integrity. This opinion advocates for adaptable, comprehensive research strategies that, while illustrated through the case of Vigur, should be applied universally, urging scientists to embrace broader perspectives in environmental studies globally.

Avifaunal diversity of Moharli Lake, near Tadoba Andhari Tiger Reserve, Chandrapur (Maharashtra)

Lakes and their basins are major repositories of biodiversity. Monitoring the basin and their respective water bodies requires an assessment of avifaunal diversity, as birds are a health indicator of the ecosystem. The present investigation focused on the avifauna diversity of Moharli Lake and its environs. Moharli Lake is located a short distance from the Tadoba Andhari Tiger Reserve (TATR) in the Chandrapur district of Maharashtra. Serving as one of the primary entrances to TATR, the Moharli gate overlooks this perennial freshwater lake. Abundant in nutrients, the lake supports a diverse avian population, including migratory bird species. The lake and its environs were surveyed nightly throughout the study duration, spanning from June 2014 to April 2015. The birds were classified into five distinct groups based on their habitat. A total of 81 species, representing 67 genera across 31 families within 13 orders, were documented and classified according to their status and occurrence, including migratory species. The presence of birds was meticulously documented alongside their dietary inclinations and feeding behaviors. The diverse bird community within the study area indicates a conducive habitat for both breeding and sustenance. A comprehensive analysis of avifaunal diversity in this region will aid in formulating conservation strategies for the future.

Avian Haemosporidian Infection in Wildlife Rehabilitation Centres of Portugal: Causes, Consequences, and Genetic Diversity.

In the last decade, over 40% of bird species in Europe have experienced poor and bad conservation status, with more than 30% of bird species in mainland Portugal threatened with extinction. Along with anthropogenic factors, parasites and pathogens such as avian haemosporidians have been suggested to be responsible for these avian population declines. Wildlife rehabilitation centres play an essential role in species conservation and preservation. Moreover, animals admitted for rehabilitation can provide valuable information regarding transmission and pathogenicity of many diseases that affect wild birds that are rarely sampled in nature. However, reports of haemosporidians in captive birds are still limited. Here, we explored the prevalence and genetic diversity of avian haemosporidians in 89 birds from 29 species admitted to rehabilitation centres in Portugal, showing an overall infection prevalence of 30.3%. The prevalence of infection was higher in Strigiformes and in birds admitted to rehabilitation centres due to debilitating diseases. Remarkably, 30% of the infected bird species have not been found to harbour malaria parasites in preceding studies. We detected 15 different haemosporidian lineages infecting a third of bird species sampled. Notably, 2 out of these 15 detected haemosporidian lineages have not been obtained previously in other studies. Furthermore, we also identified nine new host-parasite interactions representing new host records for these haemosporidian parasites. Finally, our results revealed that birds infected with haemosporidians require longer rehabilitation treatments, which increase the economic costs for rehabilitation and may impair their survival prospects. These findings emphasise the importance of integrating haemosporidian infection considerations into rehabilitation protocols, highlighting the challenges posed by these infections in avian conservation and rehabilitation, including economic and logistical demands.

Highly pathogenic avian influenza A(H5N1) virus of clade 2.3.4.4b isolated from a human case in Chile causes fatal disease and transmits between co-housed ferrets

ABSTRACT Clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses have caused large outbreaks within avian populations on five continents, with concurrent spillover into a variety of mammalian species. Mutations associated with mammalian adaptation have been sporadically identified in avian isolates, and more frequently among mammalian isolates following infection. Reports of human infection with A(H5N1) viruses following contact with infected wildlife have been reported on multiple continents, highlighting the need for pandemic risk assessment of these viruses. In this study, the pathogenicity and transmissibility of A/Chile/25945/2023 HPAI A(H5N1) virus, a novel reassortant with four gene segments (PB1, PB2, NP, MP) from North American lineage, isolated from a severe human case in Chile, was evaluated in vitro and using the ferret model. This virus possessed a high capacity to cause fatal disease, characterized by high morbidity and extrapulmonary spread in virus-inoculated ferrets. The virus was capable of transmission to naïve contacts in a direct contact setting, with contact animals similarly exhibiting severe disease, but did not exhibit productive transmission in respiratory droplet or fomite transmission models. Our results indicate that the virus would need to acquire an airborne transmissible phenotype in mammals to potentially cause a pandemic. Nonetheless, this work warrants continuous monitoring of mammalian adaptations in avian viruses, especially in strains isolated from humans, to aid pandemic preparedness efforts.

Mitigating neglected zoonotic infections: A One Health approach on avian influenza in humans and animals

Avian influenza viruses pose a great challenge to both animal and human health. This viral disease, mainly affecting chickens and birds, poses a substantial zoonotic threat, particularly with the highly pathogenic avian influenza strain. The avian population is a key vector for viral transmission and fosters genetic changes and reassortment events that amplify the infectivity besides broadening the spectrum of host species. Infected animals shed viral particles into the environment, contributing to the widespread dissemination of the viral disease and perpetuating the persistence of viral strains. Given these factors, it is imperative to strengthen monitoring and prevention measures to curb the spread of the virus. Implementing vaccination and testing programs within the animal population, along with stringent biosecurity measures in agricultural environments, including adequate hygiene practices, controlled access to farms, and the separation of different animal species, could effectively mitigate the prevalence of circulating viruses. The measures not only reduce the risk of environmental spread but also mitigate the risk of viral transmission to humans through the One Health approach.

Considerations for a threatened seabird: The impact of shoreline avian predators on at‐sea marbled murrelets

AbstractWe tested the influence of on‐shore avian predators on the at‐sea distribution and abundance of marbled murrelets (Brachyramphus marmoratus) during their breeding season in Haida Gwaii, British Columbia, Canada. We conducted a field experiment using deterrent predator decoy kites that mimicked flying bald eagles (Haliaeetus leucocephalus). In the summers of 2018 and 2019, we conducted at‐sea surveys of murrelet distributions along inshore and offshore transects with and without kites flying, and tallied real eagles along the shoreline and fish schools encountered. Kites negatively influenced overall murrelet counts (estimate = −1.19, 95% CI = −1.88 to −0.51), but we did not detect inshore to offshore movements within the study site. Our results indicate murrelet movement out of the study area in response to the kites. Overall murrelet counts were also lower when real eagle counts were higher (estimate = −0.22, 95% CI = −0.35 to −0.09). When kites were flying, a higher proportion of the murrelets remaining along inshore transects were found between rather than adjacent to kite locations (estimate = −1.61, 95% CI = −2.67 to −0.54), indicating avoidance of kites. Since avian predator populations have steadily increased in the past 30 years throughout the murrelet's breeding range, these avoidance effects could create a negative bias in long‐term shoreline count trends. Our findings highlight the importance of considering non‐lethal predator effects on murrelets when conducting at‐sea censuses and constructing conservation plans.