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Abstract Understanding relationships between infection and wildlife movement patterns is important for predicting pathogen spread, especially for multispecies pathogens and those that can spread to humans and domestic animals, such as avian influenza viruses (AIVs). Although infection with low pathogenic AIVs is generally considered asymptomatic in wild birds, prior work has shown that influenza‐infected birds occasionally delay migration and/or reduce local movements relative to their uninfected counterparts. However, most observational research to date has focused on a few species in northern Europe; given that influenza viruses are widespread globally and outbreaks of highly pathogenic strains are increasingly common, it is important to explore influenza–movement relationships across more species and regions. Here, we used telemetry data to investigate relationships between influenza infection and movement behavior in 165 individuals from four species of North American waterfowl that overwinter in California, USA. We studied both large‐scale migratory and local overwintering movements and found that relationships between influenza infection and movement patterns varied among species. Northern pintails (Anas acuta) with antibodies to avian influenza, indicating prior infection, made migratory stopovers that averaged 12 days longer than those with no influenza antibodies. In contrast, greater white‐fronted geese (Anser albifrons) with antibodies to avian influenza made migratory stopovers that averaged 15 days shorter than those with no antibodies. Canvasbacks (Aythya valisineria) that were actively infected with influenza upon capture in the winter delayed spring migration by an average of 28 days relative to birds that were uninfected at the time of capture. At the local scale, northern pintails and canvasbacks that were actively infected with influenza used areas that were 7.6 and 4.9 times smaller than those of uninfected ducks, respectively, during the period of presumed active influenza infection. We found no evidence for an influence of active influenza infection on local movements of mallards (Anas platyrhynchos). These results suggest that avian influenza can influence waterfowl movements and illustrate that the relationships between avian influenza infection and wild bird movements are context‐ and species‐dependent. More generally, understanding and predicting the spread of multihost pathogens requires studying multiple taxa across space and time.

Botulism in wild birds is a widespread and potentially lethal disease raising major conservation issues. Botulism is also of public health concern. Due to the action of botulinum neurotoxins, mostly produced by Clostridium botulinum, botulism can affect wild birds, livestock, and humans. This study is part of a project aimed at improving our understanding of the pathogenesis of botulism in wild avifauna, which is still poorly understood. Indeed, the prevalence and dynamics of C. botulinum in the digestive tract or in bird tissue, whether as intermittent carriage related to environmental contamination or as part of the normal avian microbiota, is still unknown. In this study, we specifically addressed the presence of a healthy carrier status of wild birds, and its role in outbreaks. To answer this question, we monitored the estimated prevalence of C. botulinum in wild birds through samples from banded and swabbed birds as well as from hunted bird organs. Our results do not support the hypothesis of a healthy carriage outside of outbreaks, which raises the question of the bioavailability of the bacterium and toxin in the environment. Finally, the gene encoding botulinum neurotoxin type E was detected in keel muscle from a hunted bird, showing that recommendations on the consumption of wild bird meat are needed following a botulism outbreak.

Body mass in overwintering waterfowl is an important fitness attribute as it affects winter survival, timing of spring migration, and subsequent reproductive success. Recent research in Europe and the western United States indicates body mass of mallards (Anas platyrhynchos) has increased from the late 1960s to early 2000s. The underlying mechanism is currently unknown; however, researchers hypothesize that increases are due to a more benign winter climate, increased food availability through natural and artificial flooding, introgression of wild mallard populations by game-farm mallards, or shifting of wintering distributions northward. Further investigation of factors related to winter mallard body mass increases and whether this phenomenon is occurring in other major flyways could increase understanding of intrinsic and extrinsic variables influencing waterfowl fitness. Here, we analyzed mallard body mass in the Lower Mississippi Alluvial Valley from 1979 to 2021 to determine sources of temporal variation. We measured hunter-harvested mallards from private hunting clubs, public hunting areas, and duck-plucking businesses. Mallard body mass increased by approximately 6% among all age-sex classes from 1979 to 2021. Average mallard mass increased by about 1.5% per decade but varied substantially among years. Within years, body mass was related to rainfall and river gage height; mallards had greater mass after periods of increased rainfall or river flooding, likely due to increased food availability. Mallard body mass had a marginal negative relationship with severe cold weather (derived using a weather severity index [WSI]). While body mass increased after wet periods within years, there was no relationship of mallard body mass with wet vs dry years, low vs high flood years, or hot vs cold years. Additionally, there was no detectable change in rainfall, river discharge, or temperature from 1979 to 2021. This indicates that rainfall and river height may influence mallard body mass within years, but may not be the primary factor responsible for mass increases over time. Our research confirms changes in mallard body mass are widespread and within-season precipitation and flooding account for much of the observed annual variation. Future research investigating specific mechanisms, such as introgression of game-farm mallard DNA and climate change, may clarify their contribution to mallard body mass change over time.

The study investigated the necessity of improvement of the technical, financial and human resources in the veterinary sector, the need for strengthening the control on the prevention and eradication measures on avian influenza and the update in the legislation. A sociological survey was carried out through an anonymous written questionnaire with open and closed questions. More than one-third (36.67%) of the respondents in the study assessed the activities of the competent authorities in Bul-garia for eradication of the avian flu outbreaks as “Very good”. For 43.33% one of the main reasons for spreading the disease appeared to be the misinformation and non-declaration of the infection by the farmers, the illegal import and low biosecurity level. For more effective management of the future avian flu outbreaks, more than half of the respondents (56.67%) recommended improvement of the control measures. Of them, 20% proposed stricter control on the eradication at the farms; another 13.33% of the respondents stated the necessity of legislative amendments regarding the zoonotic character of the disease.

Studies on brood desertion in birds have been mainly conducted on species with biparental care, and less often on uniparental species. Females of many duck species remain with their ducklings, unassisted by males, during variable periods of time before the chicks can fledge. In this paper, we examined factors that influence brood desertion by female red-crested pochards (Netta rufina), common pochards (Aythya ferina) and white-headed ducks (Oxyura leucocephala) during a 10-year period in lakes in southern Spain that experienced interannual variations in water levels. At an interspecific level, we found that brood desertion was less frequent in the species that nested earlier (red-crested pochard), while it was more frequent in the species that nested later (white-headed duck). Larger (older) ducklings were deserted more frequently than smaller ones in the three species. However, an interaction between flooding conditions in wetlands and species identity on brood desertion, after accounting for chick age, suggests that there were variations between the ducklings of the three species in their requirements for maternal care, conditioned by environmental conditions. Therefore, our study indicates that environmental conditions may affect parental care. A longer duration of brood attendance by female ducks may buffer against adverse effects of environmental conditions. [ABSTRACT FROM AUTHOR]

To assess the pharmacokinetic profile of ivermectin in Biłgorajska geese (Anser anser domesticus) after single I/V or oral administration, in order to compare these routes of administration and assess oral bioavailability. Ten healthy male geese were used in a single-dose, two-phase study with a 3-month washout period between phases. In the first phase, all geese were given 0.2 mg/kg I/V ivermectin, while in the second phase they were treated orally with the same dosage. Blood samples were collected at selected time points up to 480 hours after each administration. Samples were purified using protein precipitation and drug concentration was quantified using HPLC. The analytical method was validated on blank goose plasma and was characterised by an optimal linearity and a limit of quantification of 0.025 μg/mL. The pharmacokinetic analysis was carried out using a non-compartmental approach. The drug was quantifiable up to 240 hours after I/V administration, while after oral treatment it was quantifiable up to 144 hours in most of the geese. The elimination half-life of ivermectin was approximately 3.8 (95% CI = 1.98–7.92; p = 0.027) times higher after I/V administration compared to oral administration. Moreover, the area under the curve from zero to the last detectable timepoint was 6.4 (95% CI = 4.65–8.74; p < 0.001) hours greater after I/V than oral administration. This difference led to a bioavailability of 20.38 (SD 5.92) %. Following oral administration in geese, ivermectin has a bioavailability of approximately 20%. Further research on the action of ivermectin in the gastrointestinal tract is required along with assessment of tissue residues to allow calculation of withdrawal time to ensure consumer safety. AUC: Area under the concentration-time curve; AUClast: Area under the curve from zero to the last detectable timepoint; AUMC: Area under the first moment curve; Cmax: Maximum concentration; Tmax: Time at maximum plasma concentration [ABSTRACT FROM AUTHOR]

The Caohai Lake wetland is one of the most important wetlands in China and is also one of the most important overwintering areas for waterfowl. However, the spatiotemporal changes in the waterfowl habitat's suitability and its response patterns to human activities are still unclear. Understanding these patterns is key to plateau wetland biodiversity conservation. In this study, remote sensing, the geographic information system, and global positioning system (3S) technology were employed, and the water source status, disturbance, shelter, and food availability were used as evaluation factors for waterfowl habitat selection. A suitability evaluation model was constructed to evaluate the spatiotemporal characteristics of the Caohai Lake wetland habitat's suitability in 2000, 2010, and 2022, and to evaluate the response mechanisms of the waterfowl toward human activities. The results show the following: (1) there were frequent changes in the suitability grade of the study area from 2000 to 2022, and there was an overall trend toward improvement as the areas of suitable regions continuously increased. This was due to the continuous improvements in water source status, food availability, and shelter. (2) Human disturbances gradually increased from 2000 to 2022, and the human disturbance index was negatively correlated with the waterfowl habitat suitability. (3) There were significant spatial differences in the suitable waterfowl habitats. The marshlands near the banks of the lake were the regions with optimum and good suitability, while the areas of poor suitability and unsuitable regions were the deep-water areas, roads, and residential areas with high human disturbance, along with the regions near these areas. It is vital to further decrease human disturbances, in order to increase the habitat suitability of the study area. [ABSTRACT FROM AUTHOR]

Precision poultry farming technologies include the analysis of images of poultry flocks using cameras. In large-scale waterfowl farming, these can be used to determine the individual weight of poultry flocks. In our research in a real farming environment, we investigated the cameras fixed to the metal support structure of the barn, located above the suspended bird scales. Camera images of the bird on the weighing cell, taken from a top view, were matched to the weight data measured by the scale. The algorithm was trained on training data sets from a part of the database, and the results were validated with the other part of the database (Training: 60% Validation: 20% Testing: 20%). Three data science models were compared, and the random forest method achieved the highest accuracy and reliability. Our results show that the random forest method gave the most reliable results for determining the individual weights of birds. We found that the housing environment had a strong influence on the applicability of the data collection and processing technology. We have presented that by analyzing carefully collected images, it is possible to determine the individual weights of birds and thus provide valuable information on it. [ABSTRACT FROM AUTHOR]

Duck plague virus (DPV) belongs to the alphaherpesvirinae and causes high morbidity and mortality in waterfowl. UL47 is a large abundant structural protein in DPV, which means that UL47 protein plays an important role in virus replication. US3 protein, as a viral protein kinase in alphaherpes viruses, has been reported to be critical for DPV virion assembly. In this study, we over-expressed UL47 and US3 proteins and found that DPV UL47 protein was a phosphorylated substrate of US3 protein, which interacted and co-localized with US3 protein in the cytoplasm. US3-regulated phosphorylation of UL47 was important for the cytoplasmic localization of UL47 because non-phosphorylated UL47 was localized in the nucleus. The six sites of UL47 at Thr29, Ser30, Ser42, Thr47, Ser161, and Thr775 were identified as the phosphorylation targets of US3 protein. In vivo, UL47 phosphorylation was also detected but not in ΔUS3-infected cells. US3 protein promoted the cytoplasmic localization of UL47 at the late stage of infection, and the lack of US3 protein caused a delay in UL47 translocation to the cytoplasm. These results enhance our understanding of the functions of US3 during DPV infection and provide some references for DPV assembly. [ABSTRACT FROM AUTHOR]

Simple Summary: Waterfowl parvoviruses are highly contagious lethal pathogens that cause economic loss in the duck production industry. In Vietnam, information is limited on epidemiological and genetic characterization of the viral genome. This study investigated epidemiological characteristics and the further genetic characterization of the viral genome in ducks farmed in northern Vietnam. The results revealed that waterfowl parvovirus was circulating among ducks at a moderately positive rate. The viral strains were clustered with another novel goose parvovirus from China. In total, 130 tissue-pooled samples collected from ducks in some provinces/cities in north Vietnam were examined for waterfowl parvovirus genome identification. Twenty-six (20%) samples were positive for the parvovirus infection, based on polymerase chain reaction analysis. Of the 38 farms tested, 14 (36.84%) were positive for the waterfowl parvovirus genome. The rate of the parvovirus genome detection in ducks aged 2–4 weeks (37.04%) was significantly (p < 0.05) higher than that at ages <2 weeks (9.09%) and >4 weeks (16.30%). The positive rate on medium-scale farms (9.36%) was significantly (p < 0.05) lower than for small-scale (31.03%) and large-scale (29.73%) farms. The lengths of the four Vietnamese waterfowl parvovirus genomes identified were 4750 nucleotides. Among the four Vietnamese parvovirus genomes, nucleotide identities were from 99.29% to 99.87%. Phylogenetic analysis of the near-complete genomes indicated that the waterfowl circulating in northern Vietnam belonged to the novel goose parvovirus (NGPV) group. The Vietnamese NGPV group was closely related to the Chinese group. Recombination analysis suggested that the Vietnam/VNUA-26/2021 strain was generated by a recombination event. One positive selection site of the capsid protein was detected. [ABSTRACT FROM AUTHOR]

Salmonella enterica is a widespread foodborne pathogen with concerning antimicrobial resistance (AMR). Waterfowl are a major source of Salmonella transmission, but there are few systematic studies on Salmonella prevalence in waterfowl species. In this study, 126 Salmonella isolates (65 collected in 2018– 2020 and 61 collected in 2002–2005) were obtained from waterfowl samples in Sichuan, China. Their serotypes, pulsed-field gel electrophoresis (PFGE) types, and phenotypic and genotypic AMR profiles were systematically examined. The isolates were distributed in 7 serotypes, including serovars Enteritidis (46.0%), Potsdam (27.8%), Montevideo (7.9%), Cerro (6.3%), Typhimurium (4.8%), Kottbus (4.0%) and Apeyeme (3.2%). Their PFGE characteristics were diverse; all isolates were distributed in four groups (cutoff value: 60.0%) and 20 clusters (cutoff value: 80.0%). Moreover, all isolates were multidrug resistant, and high rates of AMR to lincomycin (100.0%), rifampicin (100.0%), sulfadiazine (93.7%), erythromycin (89.7%), ciprofloxacin (81.0%), and gentamicin (75.4%) were observed. Finally, 49 isolates were subjected to whole-genome sequencing, and a wide variety of AMR genes were found, including multiple efflux pump genes and specific resistance genes. Interestingly, the tet(A)/tet(B) and catII resistance genes were detected in only isolates obtained in the first collection period, while the gyrA (S83F, D87N and D87G) and gyrB (E466D) mutations were detected at higher frequencies in the isolates obtained in the second collection period, supporting the findings that isolates from different periods exhibited different patterns of resistance to tetracycline, chloramphenicol and nalidixic acid. In addition, various incompatible plasmid replicon fragments were detected, including Col440I, Col440II, IncFIB, IncFII, IncX1, IncX9, IncI1-I and IncI2, which may contribute to the horizontal transmission of AMR genes and provide competitive advantages. In summary, we demonstrated that the Salmonella isolates prevalent in Sichuan waterfowl farms exhibited diverse serotypes, multiple AMR phenotypes and genotypes, and AMR changes over time, indicating their potential risks to public health. [ABSTRACT FROM AUTHOR]

The present study was carried out to determine the biodiversity of gastrointestinal helminths in migratory waterfowl-ducks and geese in various wetlands of Kashmir. For this purpose, 93 dead migratory waterfowl (Mallards, Gadwall, Common Teal, Northern Pintail, Northern Shoveler, and Graylag Geese) were collected from various sites for necroscopic examination. The overall prevalence of helminthiasis recorded was 43.01% percent. The gastrointestinal helminths isolated were Notocotylus attenuates (15.05%), Paryphostomum radiatum (5.37%), Capillaria anatis (11.82%), and Epomidostomum anattinum (8.60%) and Hymenolepis abortive (2.15%). Prevalence with respect to host and sex was also recorded during the present study. [ABSTRACT FROM AUTHOR]

Despite the propensity of waterfowl species to readily accumulate anthropogenic contaminants within polluted environments, few studies have examined bioaccumulation rates over time when entering such a contaminated site. We examined mercury (Hg) and radiocesium (137Cs) bioaccumulation over time in two waterfowl species released into a wetland system containing legacy contamination on the US Department of Energy's Savannah River Site in South Carolina. Released birds were collected at select time intervals over an exposure period of 94 days. We quantified total Hg concentrations in blood, muscle, and liver tissues, and 137Cs activity in whole‐body and muscle tissues. The relationship between the contaminant burdens of different body tissue types was examined over time. Likely a result of microhabitat selection, mallards in our study readily accumulated both Hg and 137Cs at consistent rates over time within our study system, while ring‐neck ducks did not. The findings demonstrated that whole blood can be used as a robust, nondestructive sampling alternative to estimate Hg burdens within muscle and liver, and whole‐body 137Cs activity is a good predictor of muscle burdens. Understanding such bioaccumulation information in waterfowl is useful for the assessment of the potential health risk in wildlife, as well as being important for human risk assessment toward the consumption of popular game species. Environ Toxicol Chem 2022;41:2479–2487. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations, influenza infection, influenza antibodies and body condition in 749 individuals from 11 species of wild ducks overwintering in California. We found that the odds of prior influenza infection increased more than fivefold across the observed range of blood mercury concentrations, while accounting for species, age, sex and date. Influenza infection prevalence was also higher in species with higher average mercury concentrations. We detected no relationship between influenza infection and body fat content. This positive relationship between influenza prevalence and mercury concentrations in migratory waterfowl suggests that immunotoxic effects of mercury contamination could promote the spread of avian influenza along migratory flyways, especially if influenza has minimal effects on bird health and mobility. More generally, these results show that the effects of environmental contamination could extend beyond the geographical area of contamination itself by altering the prevalence of infectious diseases in highly mobile hosts. [ABSTRACT FROM AUTHOR]

Global climate change is increasing the frequency and severity of extreme climatic events (ECEs) which may be especially detrimental during late‐winter when many species are surviving on scarce resources. However, monitoring animal populations relative to ECEs is logistically challenging. Crowd‐sourced datasets may provide opportunity to monitor species' responses to short‐term chance phenomena such as ECEs. We used 14 years of eBird—a global citizen science initiative—to examine distribution changes for seven wintering waterfowl species across North America in response to recent extreme winter polar vortex disruptions. To validate inferences from eBird, we compared eBird distribution changes against locational data from 362 GPS‐tagged Mallards (Anas platyrhynchos) in the Mississippi Flyway. Distributional shifts between eBird and GPS‐tagged Mallards were similar following an ECE in February 2021. In general, the ECE affected continental waterfowl population distributions; however, responses were variable across species and flyways. Waterfowl distributions tended to stay near wintering latitudes or moved north at lesser distances compared with non‐ECE years, suggesting preparedness for spring migration was a stronger "pull" than extreme weather was a "push" pressure. Surprisingly, larger‐bodied waterfowl with grubbing foraging strategies (i.e., geese) delayed their northward range shift during ECE years, whereas smaller‐bodied ducks were less affected. Lastly, wetland obligate species shifted southward during ECE years. Collectively, these results suggest specialized foraging strategies likely related to resource limitations, but not body size, necessitate movement from extreme late‐winter weather in waterfowl. Our results demonstrate eBird's potential to monitor population‐level effects of weather events, especially severe ECEs. eBird and other crowd‐sourced datasets can be valuable to identify species which are adaptable or vulnerable to ECEs and thus, begin to inform conservation policy and management to combat negative effects of global climate change. [ABSTRACT FROM AUTHOR]

The premise of Williams et al. (2021), however, does imply an important distinction between waterfowl conservation and bobwhite conservation; population objectives exist for some waterfowl species at flyway and continental scales but not for bobwhites. We argue throughout that federal policy and coordination alone would not have prevented the major problems facing bobwhite conservation today; however, federal collaboration with states, non-governmental organizations (NGO), landowners, and hunters is encouraged to enhance bobwhite conservation in the future. Bobwhites are not waterfowl. We do believe that the bobwhite community would benefit from more research involving decision science, conservation planning, ecosystem services, and human dimensions, among other topics, to improve conservation design but no more so than waterfowl conservation. [Extracted from the article]

Previous studies and efforts to prevent and manage avian influenza (AI) outbreaks have mainly focused on the wintering season. However, outbreaks of AI have been reported in the summer, including the breeding season of waterfowl. Additionally, the spatial distribution of waterfowl can easily change during the annual cycle due to their life‐cycle traits and the presence of both migrants and residents in the population. Thus, we assessed the spatiotemporal variation in AI exposure risk in poultry due to spatial distribution changes in three duck species included in both major residents and wintering migrants in South Korea, the mandarin, mallard and spot‐billed duck, during wintering (October–March), breeding (April–June) and whole annual seasons. To estimate seasonal ecological niche variations among the three duck species, we applied pairwise ecological niche analysis using the Pianka index. Subsequently, seasonal distribution models were projected by overlaying the monthly ranges estimated by the maximum entropy model. Finally, we overlaid each seasonal distribution range onto a poultry distribution map of South Korea. We found that the mandarin had less niche overlap with the mallard and spot‐billed duck during the wintering season than during the breeding season, whereas the mallard had less niche overlap with the mandarin and spot‐billed duck during the breeding season than during the wintering season. Breeding and annual distribution ranges of the mandarin and spot‐billed duck, but not the mallard, were similar or even wider than their wintering ranges. Similarly, the mandarin and spot‐billed duck showed more extensive overlap proportions between poultry and their distributional ranges during both the breeding and annual seasons than during the wintering season. These results suggest that potential AI exposure in poultry can occur more widely in the summer than in winter, depending on sympatry with the host duck species. Future studies considering the population density and variable pathogenicity of AI are required. [ABSTRACT FROM AUTHOR]

A fusogenic virus was isolated from a flock of breeder Pekin ducks in 2019, Hungary. The affected flock experienced a marked decrease in egg production. Histopathological lesions were seen in the oviduct and in the lungs of birds sent for diagnostic investigation. The fusogenic agent was characterized as an orthoreovirus by viral metagenomics. The assembled viral genome was composed of 10 genomic segments and was 23,433 nucleotides (nt) in length. The study strain, designated Reo/HUN/DuckDV/2019, shared low‐to‐medium gene‐wise sequence identity with avian orthoreovirus strains from galliform and anseriform birds (nt, 38.90%–72.33%) as well as with representative strains of neoavian orthoreoviruses (nt, 40.07%–68.23%). On the contrary, the study strain shared 86.48%–95.01% pairwise nt sequence identities with recent German and Chinese reovirus isolates, D2533/6 and Ych, respectively. Phylogenetic analysis clustered all three unusual waterfowl pathogens on a monophyletic branch, indicating a common evolutionary origin of Reo/HUN/DuckDV/2019 with these enigmatic orthoreoviruses described over the past few years. The finding that a candidate new orthoreovirus species, tentatively called Avian orthoreovirus B, was isolated in recent years in Europe and Asia in moribund ducks seems an alarming sign that needs to be better evaluated by extending laboratory diagnosis of viral pathogens in countries where the waterfowl industry is important. [ABSTRACT FROM AUTHOR]

Avian influenza viruses (AIV) are a worldwide threat to animal and human health. As wild waterfowl circulate and spread these viruses around the world, investigations of AIV prevalence in wild populations are critical for understanding pathogen transmission, as well as predicting disease outbreaks in domestic animals and humans. Surveillance efforts in this study have isolated H4N6 for the first time in Israel from a faecal sample of a wild mallard (Anas platyrhynchos). Phylogenetic analyses of the HA and NA genes revealed that this strain is closely related to isolates from Europe and Asia. This Eurasian origin, together with Israel serving as an important migratory bottleneck of the mid Palearctic‐African flyway, suggests a potential introduction of this strain by migratory birds. Additional phylogenetic analysis of the isolate's internal genes (PB1, PB2, PA, NP, M and NS) revealed high levels of phylogenetic relatedness with other AIV subtypes, indicating previous reassortment events. High reassortment rates are characteristic for H4N6 viruses, which, together with this subtype's ability to infect pigs and adaptability to the human receptor binding domain, raises the concern that it would potentially become zoonotic in the future. These results emphasize the importance of continuous AIV monitoring in migratory birds. [ABSTRACT FROM AUTHOR]

Outbreaks of short beak dwarf syndrome caused by novel goose parvovirus (NGPV) have been prevalent in China since 2015, resulting in a high mortality rate of ducks. Herein we evaluated differences between two NGPV strains: Muscovy duck‐origin (AH190917‐RP: MD17) and Cherry Valley duck‐origin (JS191021‐RP: CVD21) NGPV. Both of them showed certain level of pathogenicity to primary duck embryo fibroblasts, Cherry Valley duck embryos and ducklings. CVD21 showed comparatively stronger pathogenicity than MD17. Only CVD21 caused obvious cytopathic effect (CPE), characterized by cell shedding; further, the virus titer of MD17 and CVD21 was 102.571 ELD50 (i.e. median embryo lethal dose)/0.2 ml and 106.156ELD50/0.2 ml, respectively, and the mortality rate of CVD21‐ and MD17‐infected Cherry Valley ducklings was 100% and 80%, respectively. In addition, CVD21 had a greater influence on the growth and development of ducklings. Furthermore, we found that MD17 could infect Muscovy duck embryos and produce lesions similar to Cherry Valley duck embryos, but it could not infect Muscovy duck embryo fibroblasts (MDEFs,) and Muscovy ducklings. MDV21 had no infection to MDEFs, Muscovy duck embryo and Muscovy ducklings. We then sequenced the complete genome of the two isolates to enable genomic characterization. The complete genome of MD17 and CVD21 was 5046 and 5050 nucleotides in length, respectively. Nucleotide alignment, amino acid analysis and phylogenetic tree analysis revealed that MD17 showed higher homology to goose parvovirus (GPV), while CVD21 demonstrated stronger similarity with NGPV. Moreover, the two isolates shared 95.8% homology, with encoded proteins showing multiple amino acid variations. Our findings indicate that Muscovy ducks seem to have played a crucial role in the evolution of GPV to NGPV. We believe that our data should serve as a foundation for further studying the genetic evolution of waterfowl parvoviruses and their pathogenic mechanisms. [ABSTRACT FROM AUTHOR]

Zoonotic diseases are of considerable concern to the human population and viruses such as avian influenza (AIV) threaten food security, wildlife conservation and human health. Wild waterfowl and the natural wetlands they use are known AIV reservoirs, with birds capable of virus transmission to domestic poultry populations. While infection risk models have linked migration routes and AIV outbreaks, there is a limited understanding of wild waterfowl presence on commercial livestock facilities, and movement patterns linked to natural wetlands. We documented 11 wild waterfowl (three Anatidae species) in or near eight commercial livestock facilities in Washington and California with GPS telemetry data. Wild ducks used dairy and beef cattle feed lots and facility retention ponds during both day and night suggesting use for roosting and foraging. Two individuals (single locations) were observed inside poultry facility boundaries while using nearby wetlands. Ducks demonstrated high site fidelity, returning to the same areas of habitats (at livestock facilities and nearby wetlands), across months or years, showed strong connectivity with surrounding wetlands, and arrived from wetlands up to 1251 km away in the week prior. Telemetry data provides substantial advantages over observational data, allowing assessment of individual movement behaviour and wetland connectivity that has significant implications for outbreak management. Telemetry improves our understanding of risk factors for waterfowl–livestock virus transmission and helps identify factors associated with coincident space use at the wild waterfowl–domestic livestock interface. Our research suggests that even relatively small or isolated natural and artificial water or food sources in/near facilities increases the likelihood of attracting waterfowl, which has important consequences for managers attempting to minimize or prevent AIV outbreaks. Use and interpretation of telemetry data, especially in near‐real‐time, could provide key information for reducing virus transmission risk between waterfowl and livestock, improving protective barriers between wild and domestic species, and abating outbreaks. [ABSTRACT FROM AUTHOR]

Scientific support invited by Indigenous peoples and local communities (IPLC) to assist with customary environmental management can improve conservation and community livelihoods. For example, demographic models can help to understand how alternative wildlife management strategies affect population dynamics and harvest sustainability. We developed a demographic model to assist Ngāi Tahu, the southern-most Māori tribe in Aotearoa/New Zealand, in customary management of a culturally important population of Black Swans (kakī anau, Cygnus atratus). We used recent demographic data, including results of an experimental egg harvest study, to inform tangata tiaki (Ngāi Tahu environmental guardians) about how customary egg harvest and background pressure from sport hunting of swans aged = 1 year differentially affect population growth. We also assessed how sport hunting of swans affects the sustainability of customary egg harvest. Estimated population growth (1.018 or presently growing 1.8% annually; 95% CI: 0.808-1.241) was most sensitive to changes in adult and subadult survival, followed by juvenile (first-year) survival, breeding propensity, and nest hatching success. Uncertainty in population growth was almost entirely attributable to uncertainty in swan survival rates after hatching. Sustainable population-level rates of egg harvest varied from none to more than half of all eggs, depending on small changes in adult and subadult survival. Population sensitivity to adult and subadult survival suggests that limiting and monitoring their mortality are crucial to population and egg harvest sustainability, whereas contemporary government-mandated species management, through Fish and Game New Zealand, allows adult and subadult mortality from sport hunting, with little record of offtake. Recognizing the rights and interests of Ngāi Tahu, and monitoring swan mortality more closely, could improve Ngāi Tahu abilities to practice customary harvest, enhance population and environmental monitoring, and, when appropriate, control swan numbers in a culturally appropriate and less wasteful way. The model we present could aid decision making and communication between Ngāi Tahu and New Zealand's Crown government within a potential future co-management arrangement. Demographic models can be useful tools for supporting customary environmental management, but developing, maintaining, and implementing these tools requires support for adaptive policies and management arrangements that recognize IPLC rights to the environment and decision making. [ABSTRACT FROM AUTHOR]

Ondatra zibethicus (Common Muskrat) are often considered herbivores; however, they also eat animal matter, especially mussels, which comprise a considerable part of their diet in some populations. Common Muskrats also feed on crayfish (Astacoidea), although such behavior is poorly documented. On 21 April 2022, we observed a Common Muskrat repeatedly catching crayfish (Cambaridae) and carrying them to its den. The site in the Coldwater River National Wildlife Refuge, Quitman County, MS, consisted of a ditch with a water-control structure on the edge of a waterfowl impoundment being dewatered. The consumption of crayfish by a Common Muskrat during a time when vegetation was presumably less available has important ramifications for the management of both species. [ABSTRACT FROM AUTHOR]

Several Mycoplasma species can form biofilm, facilitating their survival in the environment, and shielding them from therapeutic agents. The aim of this study was to examine the biofilm-forming ability and its potential effects on environmental survival and antibiotic resistance in Mycoplasma anserisalpingitidis, the clinically and economically most important waterfowl Mycoplasma species. The biofilm-forming ability of 32 M. anserisalpingitidis strains was examined by crystal violet assay. Biofilms and planktonic cultures of the selected strains were exposed to a temperature of 50 °C (20 and 30 min), to desiccation at room temperature (16 and 24 h), or to various concentrations of eight different antibiotics. Crystal violet staining revealed great diversity in the biofilm-forming ability of the 32 tested M. anserisalpingitidis strains, with positive staining in more than half of them. Biofilms were found to be more resistant to heat and desiccation than planktonic cultures, while no correlation was shown between biofilm formation and antibiotic susceptibility. Our results indicate that M. anserisalpingitidis biofilms may contribute to the persistence of the organisms in the environment, which should be taken into account for proper management. Antibiotic susceptibility was not affected by biofilm formation; however, it is important to note that correlations were examined only in vitro. [ABSTRACT FROM AUTHOR]

Large-scale changes in the ranges and abundance of a large number of species of both southern and northern origin have occurred in the Baltic region under the development of the warm phase of the climate in recent decades. Moreover, changes are far from being synchronous in different species of these groups. An increase in the population of the Caspian Tern Hydroprogne caspia and its active settlement in the northeast direction were observed in the first half of the 20th century. In recent decades, there has been, on the contrary, a general downward trend in the number. The article discusses in detail the history of the invasion of the species in the eastern part of the Gulf of Finland, the spatial distribution, and features of the habitat confinement of nesting birds. It is shown that, unlike other southern invaders of the region, the Caspian Tern has remained a rare species over the past 30–40 years with a tendency to strong population fluctuations. This is probably caused by the lack of a reserve of birds in the nearest breeding areas. It is shown that the Caspian Tern, which is a stenobiont species, usually nests on open sandy biotopes. Inhabiting the Gulf of Finland, it has mastered reproduction in a fundamentally different landscape, on selga massive-crystalline rocks. [ABSTRACT FROM AUTHOR]

Although waterfowl are less susceptible to Newcastle disease (ND) virus (NDV) infection compared with chickens and turkeys, lethal ND in waterfowl has been sporadically reported. Factors underlying the high pathogenicity of certain NDV strains in waterfowl remain unclear. In ducks, the NDV 9a5b isolate shows low pathogenicity while the d5a20b isolate shows high pathogenicity. This study aimed to identify the definitive lesions that led to the lethal virulence of d5a20b by comparing the histopathology of 9a5b- or d5a20b-inoculated ducks in order to elucidate lesions related to the enhanced pathogenicity of certain NDV strains in ducks. Herein, 7-day-old ducks were intranasally inoculated with either 9a5b or d5a20b NDV strains. The neurological signs were more severe in the d5a20b-inoculated group than in the 9a5b-inoculated group. Ducks in the d5a20b-inoculated group exhibited more severe lymphoid depletion in immune organs than those in the 9a5b-inoculated group, which may have caused an immunosuppressive state in the d5a20b-inoculated ducks. Ducks in the d5a20b-inoculated group had more severe nonsuppurative encephalitis with increased NDV nucleoprotein than those in the 9a5b-inoculated group. Additionally, pancreatic necrosis, with intralesional NDV nucleoprotein, was more severe in the d5a20b-inoculated group than in the 9a5b-inoculated group. Our results showed that the immune organs, brain, and pancreas were significant targets of the NDV d5a20b infection in ducks., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Avian migration is a global phenomenon that transcends geographical boundaries. These migratory birds serve as unwitting carriers of diverse Gammacoronaviruses (γ-CoVs) and Deltacoronaviruses (δ-CoVs). While recombination events have been documented among γ-CoVs in avian species and β-CoVs in mammals, evidence for recombination between CoVs of distinct genera remains limited. This minireview examines the prevalence of CoVs in both domestic waterfowl (ducks and geese) and wild bird populations inhabiting various regions. We investigate the dissemination patterns of γ-CoVs and δ-CoVs among these populations, highlighting their shared characteristics. Furthermore, the review explores the intricate web of cross-species transmission of δ-CoVs from wild birds to mammals, with a particular focus on pigs. Understanding the distinct features of CoVs harbored by waterfowl and wild birds and their potential for cross-species transmission is crucial for preparedness and response to future CoV epidemics., Competing Interests: The authors declare no conflict of interest.

1. Erysipelas in geese and ducks is an infectious disease causing considerable economic losses in the poultry sector in Poland. The aim of this study was to determine the distribution of erysipelas cases in age groups of geese and in periods of the calendar year and to assess macroscopic lesions in birds infected with Erysipelothrix rhusiopathiae .2. The study used 286 geese and 16 ducks delivered to the laboratory for diagnosis in the years 2019-2021. The birds came from 99 different farms. E. rhusiopathiae from clinical samples were cultured on Columbia blood agar and identified by real-time PCR. Pathological lesions were characterised during anatomopathological examination.3. Distribution of erysipelas cases in age groups of geese and periods of the calendar year differed significantly from the assumed even distribution. Most cases were noted in August and September in birds aged between 11 and 13 weeks. Necropsy of birds infected with E. rhusiopathiae showed anatomopathological lesions characteristic of generalised infection, affecting multiple organs.4. The uneven distribution of erysipelas cases in geese in different age groups and periods of the calendar year suggested that both the age of the birds and climatic conditions are predisposing factors for infection.

Habitat preferences of invasive predators determine where and for which prey species they pose a threat upon. This is crucial information for the conservation of endangered prey species because invasive predators pose additional predation on top of that caused by natural predators. In large parts of Europe, the most common invasive mesopredator is the raccoon dog (Nyctereutes procyonoides). To understand the risk that the raccoon dog poses for wetland-associated species, we collected information about its habitat preferences near these habitats. We used data on 24 GPS-collared raccoon dogs from three landscape types in Finland, to study their spatial and temporal habitat preferences. We first determined their home ranges, within which we then examined habitat use and preferences. Raccoon dogs showed generalist habitat use, which was evident in their wide range of used habitats. However, in spring and summer, during the breeding seasons of waterfowl and amphibians, they preferred wetlands and peatlands. They also preferred shorelines and the edges of forests and agricultural fields. During autumn and winter, raccoon dogs did not prefer wetlands. These findings support the conclusion that the raccoon dog's habitat preferences pose a particular threat to wetland-associated species, such as nesting waterfowl and amphibians. The species' habitat preferences coupled with high numbers of this invasive mesopredator pose additional predation for endangered wetland-associated species on top of that of native predators., (© 2024. The Author(s).)

Abstract Tropical cyclones are the most powerful storms on earth, causing catastrophic damage to human lives and infrastructure. Hurricanes also cause wildlife mortality when they make landfall, but the severity of these effects is difficult to quantify because data collection is either logistically impossible or deprioritized in the wake of human tragedy. On August 27, 2020, Hurricane Laura made landfall in southwestern Louisiana with maximum sustained winds of 241 kph (150 mph), making it one of the most powerful storms to strike the mainland United States. Hurricane Laura passed directly over the core breeding range of the western Gulf Coast population of Mottled Duck (Anas fulvigula), during a time when many adult birds were undergoing a simultaneous wing feather molt and were flightless. We used GPS‐GSM telemetry data to evaluate survival rates of adult female Mottled Ducks in late summer 2020 (bracketing August 27 by one month on either side) relative to the same period in 2018 and 2019. Mortality was lower in 2018 (12 out of 29; 41%) and 2019 (8 out of 28; 29%) than in 2020 (12 out of 18; 67%), and 7 out of 12 mortalities documented in 2020 occurred when Hurricane Laura made landfall. Survival analyses in program MARK confirmed lower survival probability in 2020, but there was overlap in 85% confidence intervals in all years. This single storm resulted in the death of ~40% of all marked birds in our sample, suggesting that hurricanes have the potential to influence population demographics. In addition, Hurricane Laura resulted in widespread habitat loss and degradation that has reduced available nesting habitat in 2021, and possibly for years to come. The acute and chronic effects of hurricanes may exacerbate Mottled Duck population declines, which may worsen in the face of increasingly frequent and more severe tropical storms.

Abstract Background The long-term monitoring of demographic changes in waterbird populations remains limited, but such information can be valuable for conservationists and waterbird managers. Biased sex ratios can indicate differences in survival rates between sexes. In particular, differences in the sex ratios of fledged juveniles and adults can provide insight into the development of male bias among populations. Methods In this study, we used data from individual birds captured over a 57-year period to assess the extent, and temporal variability in male bias in nine populations of ducks wintering in the United Kingdom: Gadwall (Mareca strepera), Northern Mallard (Anas platyrhynchos), Northern Pintail (Anas acuta), Common Pochard (Aythya ferina), Common Shelduck (Tadorna tadorna), Northern Shoveler (Spatula clypeata), Eurasian Teal (Anas crecca), Tufted Duck (Aythya fuligula), and Eurasian Wigeon (Mareca penelope). Results Overall, eight of these populations were significantly male-biased and adults were more male-biased than first-winter juveniles for all nine populations. The increased male bias among adults is consistent with the hypothesis that factors such as higher mortality of reproductive-age females during the breeding season is a major cause of male bias in duck populations. However, such predation cannot explain the male bias detected in first-winter juveniles in four of the populations. The temporal trends in male bias differed between adults and first-winter juveniles in Northern Mallard, Northern Pintail, Common Pochard, Common Shelduck, Eurasian Teal, Tufted Duck, and Eurasian Wigeon. Over the study period we found increased male bias among adult Northern Mallard, Northern Pintail, Common Pochard, Common Shelduck, and Tufted Duck as well as both adult and first-winter juvenile Northern Shoveler. Conclusions We provide evidence that among wintering duck populations, sex ratios are typically male-biased, with adults exhibiting stronger male-biased sex ratios than first-winter juveniles. Improved monitoring of sex ratios of wintering waterbirds would help to increase our understanding of changes in waterbird demography, population structure, and observed population trends; our study shows that birds caught during ringing projects can be a valuable source of such data.

Abstract Identifying migration routes and fall stopover sites of Cinnamon Teal (Spatula cyanoptera septentrionalium) can provide a spatial guide to management and conservation efforts, and address vulnerabilities in wetland networks that support migratory waterbirds. Using high spatiotemporal resolution GPS‐GSM transmitters, we analyzed 61 fall migration tracks across western North America during our three‐year study (2017–2019). We marked Cinnamon Teal primarily during spring/summer in important breeding and molting regions across seven states (California, Oregon, Washington, Idaho, Utah, Colorado, and Nevada). We assessed fall migration routes and timing, detected 186 fall stopover sites, and identified specific North American ecoregions where sites were located. We classified underlying land cover for each stopover site and measured habitat selection for 12 land cover types within each ecoregion. Cinnamon Teal selected a variety of flooded habitats including natural, riparian, tidal, and managed wetlands; wet agriculture (including irrigation ditches, flooded fields, and stock ponds); wastewater sites; and golf and urban ponds. Wet agriculture was the most used habitat type (29.8% of stopover locations), and over 72% of stopover locations were on private land. Relatively scarce habitats such as wastewater ponds, tidal marsh, and golf and urban ponds were highly selected in specific ecoregions. In contrast, dry non‐habitat across all ecoregions, and dry agriculture in the Cold Deserts and Mediterranean California ecoregions, was consistently avoided. Resources used by Cinnamon Teal often reflected wetland availability across the west and emphasize their adaptability to dynamic resource conditions in arid landscapes. Our results provide much needed information on spatial and temporal resource use by Cinnamon Teal during migration and indicate important wetland habitats for migrating waterfowl in the western United States.

Abstract Globally, outbreaks of Avian Influenza Virus (AIV) in poultry continue to burden economies and endanger human, livestock and wildlife health. Wild waterbirds are often identified as possible sources for poultry infection. Therefore, it is important to understand the ecological and environmental factors that directly influence infection dynamics in wild birds, as these factors may thereby indirectly affect outbreaks in poultry. In Australia, where large parts of the country experience erratic rainfall patterns, intense rainfalls lead to wild waterfowl breeding events at temporary wetlands and increased proportions of immunologically naïve juvenile birds. It is hypothesized that after breeding, when the temporary wetlands dry, increasing densities of immunologically naïve waterbirds returning to permanent water bodies might strongly contribute to AIV prevalence in wild waterfowl in Australia. Since rainfall has been implicated as an important environmental driver in AIV dynamics in wild waterbirds in southeast Australia and wild waterbirds are identified globally to have a role in virus spillover into poultry, we hypothesise that rainfall events have an indirect effect on AIV outbreaks in poultry in southeast Australia. In this study we investigated this hypothesis by examining the correlation between the timing of AIV outbreaks in poultry in and near the Murray-Darling basin in relation to temporal patterns in regional rainfall since 1970. Our findings support our hypothesis and suggest that the risk of AIV outbreaks in poultry increases after a period of high rainfall, with peak AIV risk two years after the onset of the high-rainfall period. This is presumably triggered by increased rates of waterbird breeding and consequent higher proportions of immunologically naïve juvenile waterbirds entering the population directly after major rainfall events, which subsequently aggregate near permanent water bodies when the landscape dries out.

ABSTRACT: Botulism is generally a fatal disease caused by ingestion of neurotoxins produced by Clostridium botulinum. The present study describes the epidemiological, clinical, and laboratory aspects of a type C botulism outbreak in free-living aquatic birds residing in an urban park in Quirinópolis, Goiás, Brazil. Among a population of approximately 80 waterfowl, a total of 30 birds, including ducks (Cairina moschata), teals (Anas platyrhynchos), and geese (Anser cygnoides), died within 10 days. Of these, six birds showed signs of flaccid paralysis of the pelvic limbs, eyelids, neck, and wings. To confirm the suspicion of botulism, four lake water samples, two samples of the feed consumed by the birds, and samples of serum, intestinal content, stomach content, and liver tissue from two teals that died after presenting clinical signs were analyzed. Using bioassay and neutralization with homologous antitoxin in mice, it was possible to detect the presence of botulinum toxin type C in a water sample and in the intestinal content of one of the necropsied teals. Additionally, the presence of C. botulinum type C was identified in the lake water using polymerase chain reaction. Based on the clinical signs and laboratory results, a diagnosis of botulism caused by botulinum toxin type C was confirmed with probable transmission by lake water.

ABSTRACT: The study aimed to assess the goose hatching egg features in four reproductive seasons from 3 stages of laying. Three hundred sixty eggs were used in the study from geese in the first, second, third, and fourth laying season. From each group, 90 eggs were analyzed (30 eggs from the beginning, the peak, and the end of the laying cycle). The structure of the egg and morphological and physical features of the yolk, albumen, and eggshell were analyzed. It was shown that the weight and structure of eggs increased, but the shape index was lower in 2-yr-old geese, as well Haugh's units decreased. The yolk share was lower in the first year, but albumen and eggshell were higher than in other groups. The eggshell whiteness was higher in the first year than in the second, and third. The pores’ quantity was higher in the first year in the blunt and equatorial parts, but the total number in the egg was the highest in the fourth year. The yolk, albumen, and eggshell' density increased with the age. Changes in laying periods were inversely proportional to the changes shown depending on the layers’ age. Geese's age and laying period impact the eggs’ features. Based on the egg quality features, the incubation conditions could be adapted, as well as it can be treated as an indicator of the effectiveness of hatching and goslings quality. Research has shown that the biological value of hatching eggs changes with the age of the geese and the laying period.

Habitat availability determines the distribution of migratory waterfowl along their flyway, which further influences the transmission and spatial spread of avian influenza viruses (AIVs). The extensive habitat loss in the East Asian-Australasian Flyway (EAAF) may have potentially altered the virus spread and transmission, but those consequences are rarely studied. We constructed 6 fall migration networks that differed in their level of habitat loss, wherein an increase in habitat loss resulted in smaller networks with fewer sites and links. We integrated an agent-based model and a susceptible-infected-recovered model to simulate waterfowl migration and AIV transmission. We found that extensive habitat loss in the EAAF can 1) relocate the outbreaks northwards, responding to the distribution changes of wintering waterfowl geese, 2) increase the outbreak risk in remaining sites due to larger goose congregations, and 3) facilitate AIV transmission in the migratory population. In addition, our modeling output was in line with the predictions from the concept of "migratory escape", i.e., the migration allows the geese to "escape" from the location where infection risk is high, affecting the pattern of infection prevalence in the waterfowl population. Our modeling shed light on the potential consequences of habitat loss in spreading and transmitting AIV at the flyway scale and suggested the driving mechanisms behind these effects, indicating the importance of conservation in changing spatial and temporal patterns of AIV outbreaks. Author summary: What are the possible consequences of extensive habitat loss on the spread and transmission of avian influenza viruses (AIVs)? We used a logistic regression model to select the suitable habitats of Greater white-fronted goose Anser albifrons in the East Asian-Australasian Flyway, which has extensive habitat loss and seasonal passing waterfowl population. We treated these habitats as sites to construct 6 fall migration networks by removing sites in order of habitat loss (i.e., site removal). We then simulated geese migration in these networks and explored the impacts of habitat loss on AIV spread and transmission. We found that extensive habitat loss can cause relocation of the geese and outbreaks and promote the AIV spread and transmission. Our modeling outputs also suggested a "migratory escape" pattern for changing the spatial and temporal pattern of infection prevalence in the population. Overall, our study showed that habitat loss can affect AIV spread and transmission, suggesting the importance of habitat conservation in changing the spatial and temporal pattern of disease prevalence. [ABSTRACT FROM AUTHOR]

Gut microbiota plays a vital role in maintaining the health and immunity of wild birds. However, less is known about the comparison of fecal microbiota between different ecological groups of wild birds, particularly in the Yellow River National Wetland in Baotou, China, an important transit point for birds migrating all over the East Asia-Australian and Central Asian flyways. In this study, we characterized the fecal microbiota and potential microbial function in nine bird species of raptors, waders, and waterfowl using 16S rRNA gene amplicon sequencing to reveal the microbiota differences and interaction patterns. The results indicated that there was no significant difference in α-diversity, but a significant difference in β-diversity between the three groups of birds. The fecal bacterial microbiota was dominated by Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes in all groups of birds. Furthermore, we identified five bacterial genera that were significantly higher in raptors, five genera that were significantly higher in waders, and two genera that were more abundant in waterfowl. The bacterial co-occurrence network results revealed 15 and 26 key genera in raptors and waterfowls, respectively. The microbial network in waterfowl exhibited a stronger correlation pattern than that in raptors. PICRUSt2 predictions indicated that fecal bacterial function was significantly enriched in the antibiotic biosynthesis pathway in all three groups. Metabolic pathways related to cell motility (bacterial chemotaxis and flagellar assembly) were significantly more abundant in raptors than in waders, whereas waders were enriched in lipid metabolism (synthesis and degradation of ketone bodies and fatty acid biosynthesis). The fecal microbiota in waterfowl harbored more abundant vitamin B6 metabolism, RNA polymerase, and tyrosine and tryptophan biosynthesis. This comparative study revealed the microbial community structure, microbial co-occurrence patterns, and potential functions, providing a better understanding of the ecology and conservation of wild birds. Future studies may focus on unraveling metagenomic functions and dynamics along with the migration routine or different seasons by metagenomics or metatranscriptomics. [ABSTRACT FROM AUTHOR]

Waterfowl parvovirus, duck enteritis virus and goose astrovirus have become serious pathogens in waterfowl farming. Co-infections occasionally occur, and as a result, it is much harder to rapidly and simultaneously identify several pathogens using conventional PCR. According to the characteristics of the goose parvovirus (GPV) and muscovy duck parvovirus (MDPV) genome sequences, a universal PCR primer was designed using Rep1 as the target gene. The specific detection primers were designed based on the specific conserved regions of UL54 of the duck enteritis virus (DEV) gene and ORF1a of the goose astrovirus (GAstV) gene. The PCR reaction system and conditions were optimized, and the optimal annealing temperature was found to be 56.2 ℃. The volume ratio of the GPV–MDPV, GAstV and DEV primers (20 μM) was 1:4:5. The established multiplex PCR detection method can simultaneously detect GPV, MDPV, DEV and GAstV within one reaction, and be negative for duck Tembusu virus, muscovy duck reovirus, duck hepatitis A virus type 3 and duck circovirus. The method with excellent sensitivity, specificity and repeatability was successfully applied to clinical samples, it is a useful platform for identifing co-infections of GPV, MDPV, DEV and GAstV in waterfowl. [ABSTRACT FROM AUTHOR]

There is limited data regarding the nesting ecology of boreal ducks and their response to industrial development, despite this region being an important North American breeding area. We investigated how landcover and oil and gas development affect third‐order nest‐site selection of boreal ducks. We located duck nests in Alberta's western boreal forest between 2016 and 2018. We used multiscale analysis to identify how scale affects the selection of a resource using generalized linear mixed‐effects models and determined what scale‐optimized combination of landscape features were most important in describing where ducks nest. We located 136 nests of six species of upland nesting ducks between 2016 and 2018. The magnitude, direction, and best spatial scale varied by resource. For landcover, ducks selected nest‐sites associated with mineral wetlands (300 m) and open water (300 m). Ducks avoided greater densities of seismic lines (300 m) and pipelines (2500 m) but selected nest‐sites associated with borrow pits (300 m) and roads (1000 m). We used our models to predict important duck nesting habitat in the boreal forest, which can support conservation and management decisions. We recommend conservation actions target the conservation of mineral wetlands and associated habitats within this working landscape. Further research is necessary to understand the adaptive consequences of nest‐site selection and how industrial development influences important nest predators. [ABSTRACT FROM AUTHOR]

Adult survival is a key driver of waterfowl population growth and is subject to temporal and spatial variation. Mottled ducks (Anas fulvigula) are native to the Gulf Coast and peninsular Florida, USA, and have suffered population declines over the past decade, especially in Texas and Louisiana, USA. Although the cause of this decline is not well understood, previous research concluded variation in survival contributed to nearly a third of variation in the species' population growth rate. We used global positioning system‐groupe spécial mobile (GPS‐GSM) transmitters to study temporal and spatial variation in survival of adult female western Gulf Coast mottled ducks in southwestern Louisiana, 2017–2020. We evaluated weekly survival models parameterized with combinations of hunted and non‐hunted periods, biological seasons, and landcover types that were used by mottled ducks. There were 3 competitive survival models, and all contained 4 parameters that parsed the annual cycle into the non‐hunted period, first part of the general waterfowl season, and second part of the waterfowl season, and included the proportion of GPS locations in agricultural lands. Weekly survival was 0.979 during the first part of the general waterfowl hunting season, and 0.996 during the second part of the general waterfowl season. Daily survival rate increased with an increasing proportion of locations logged in agricultural lands. Annual survival rates were similar to other waterfowl that are not experiencing population declines, which suggests survival is not limiting population growth of mottled ducks along the western Gulf Coast. Managers should ensure the availability of refuge areas where hunting is prohibited during the first part of the general waterfowl season, when mottled ducks are at an increased risk of mortality, in addition to the targeted conservation of agricultural lands that provide cover and forage. [ABSTRACT FROM AUTHOR]

The management of sustainable harvest of animal populations is of great ecological and conservation importance. Development of formal quantitative tools to estimate and mitigate the impacts of harvest on animal populations has positively impacted conservation efforts.The vast majority of existing harvest models, however, do not simultaneously estimate ecological and harvest impacts on demographic parameters and population trends. Given that the impacts of ecological drivers are often equal to or greater than the effects of harvest, and can covary with harvest, this disconnect has the potential to lead to flawed inference.In this study, we used Bayesian hierarchical models and a 43‐year capture–mark–recovery dataset from 404,241 female mallards Anas platyrhynchos released in the North American midcontinent to estimate mallard demographic parameters. Furthermore, we model the dynamics of waterfowl hunters and habitat, and the direct and indirect effects of anthropogenic and ecological processes on mallard demographic parameters.We demonstrate that density dependence, habitat conditions and harvest can simultaneously impact demographic parameters of female mallards, and discuss implications for existing and future harvest management models.Our results demonstrate the importance of controlling for multicollinearity among demographic drivers in harvest management models, and provide evidence for multiple mechanisms that lead to partial compensation of mallard harvest. We provide a novel model structure to assess these relationships that may allow for improved inference and prediction in future iterations of harvest management models across taxa. [ABSTRACT FROM AUTHOR]