Migratory Waterfowl Research Articles

Incorporating drivers of global change throughout the annual cycle in species distribution models for migratory birds: a gap in ecological forecasting

Understanding the consequences of global change for migratory birds is complex as individuals are exposed to diverse conditions and experiences that interact across their annual cycle. Species distribution models (SDMs) can serve as a powerful tool that help us understand how species distributions respond to global change. However, SDMs applied to migratory birds may fail to capture the effects of seasonal variability on species distributional changes, likely due to a lack of appropriate modeling frameworks and limited data availability that hamper the inclusion of events and conditions throughout the annual cycle. Here, we review patterns in the migratory bird SDM literature over the last two decades using a vote counting approach, and provide a framework for migratory bird SDMs moving forward. We found evidence that species distribution models applied to migratory birds (1) typically incorporate data from only one season of the full annual cycle and do not account for seasonal interactions, (2) are focused on terrestrial species in North America and Europe, (3) tend to model the distributions of obligate migratory species, especially songbirds and waterfowl, and (4) largely lack biologically relevant threat layers. To improve our ability to forecast how species cope with global change, we recommend a Bayesian modeling framework where existing knowledge about a species’ migratory connectivity, threats, and/or other biologically relevant factors can be specified via model priors. Full annual cycle species distribution models are important tools for improving forecasts of migratory bird distributions in response to global change.

Comparative analysis of PB2 residue 627E/K/V in H5 subtypes of avian influenza viruses isolated from birds and mammals.

Avian influenza viruses (AIVs) are naturally found in wild birds, primarily in migratory waterfowl. Although species barriers exist, many AIVs have demonstrated the ability to jump from bird species to mammalian species. A key contributor to this jump is the adaption of the viral RNA polymerase complex to a new host for efficient replication of its RNA genome. The AIV PB2 gene appears to be essential in this conversion, as key residues have been discovered at amino acid position 627 that interact with the host cellular protein, acidic nuclear phosphoprotein 32 family member A (ANP32A). In particular, the conversion of glutamic acid (E) to lysine (K) is frequently observed at this position following isolation in mammals. The focus of this report was to compare the distribution of PB2 627 residues from different lineages and origins of H5 AIV, determine the prevalence between historical and contemporary sequences, and investigate the ratio of amino acids in avian vs. mammalian AIV sequences. Results demonstrate a low prevalence of E627K in H5 non-Goose/Guangdong/1996-lineage (Gs/GD) AIV samples, with a low number of mammalian sequences in general. In contrast, the H5-Gs/GD lineage sequences had an increased prevalence of the E627K mutation and contained more mammalian sequences. An approximate 40% conversion of E to K was observed in human sequences of H5 AIV, suggesting a non-exclusive requirement. Taken together, these results expand our understanding of the distribution of these residues within different subtypes of AIV and aid in our knowledge of PB2 mutations in different species.

Sixty-years of community-science data suggest earlier fall migration and short-stopping of waterfowl in North America

Abstract Worldwide, migratory phenology and movement of many bird species is shifting in response to anthropogenic climate and habitat changes. However, due to variation among species and a shortage of analyses, changes in waterfowl migration, particularly in the fall, are not well understood. Fall migration phenology and movement patterns dictate waterfowl hunting success and satisfaction, with cascading implications on economies and support for habitat management and securement. Using 60 years of band recovery data for waterfowl banded in the Canadian Prairie Pothole Region (PPR), we evaluated whether fall migration timing and/or distribution changed in Mallard (Anas platyrhynchos), Northern Pintail (A. acuta), and Blue-winged Teal (Spatula discors) between 1960 and 2019. We found that in the Midcontinent Flyways, Mallards and Blue-winged Teal migrated faster in more recent time periods, whereas Northern Pintail began fall migration earlier. In the Pacific Flyway, Mallards began fall migration earlier. Both Mallards and Northern Pintails showed evidence of short-stopping in the Midcontinent Flyways. Indeed, the Mallard and Northern Pintail distribution of band recovery data shifted 180 and 226 km north, respectively, from 1960 to 2019. Conversely, Blue-winged Teal recovery distributions were consistent across years. Mallards and Northern Pintails also exhibited an increased proportion of band recoveries in the Pacific Flyway in recent decades. We provide clear evidence that the timing and routes of fall migration have shifted over the past 6 decades, but these phenological and spatial shifts differ among species. We suggest that using community-science data collected by hunters themselves to explain one of the group’s major concerns (changes in duck abundance at traditional hunting grounds), within the environmental lens of climate change, may help lead to further engagement and two-way dialogue to support effective waterfowl management for these culturally and ecologically important species.

Detection of H5N1 High Pathogenicity Avian Influenza Viruses in Four Raptors and Two Geese in Japan in the Fall of 2022.

In the fall of 2022, high pathogenicity avian influenza viruses (HPAIVs) were detected from raptors and geese in Japan, a month earlier than in past years, indicating a shift in detection patterns. In this study, we conducted a phylogenetic analysis on H5N1 HPAIVs detected from six wild birds during the 2022/2023 season to determine their genetic origins. Our findings revealed that these HPAIVs belong to the G2 group within clade 2.3.4.4b, with all isolates classified into three subgroups: G2b, G2d, and G2c. The genetic background of the G2b virus (a peregrine falcon-derived strain) and G2d viruses (two raptors and two geese-derived strains) were the same as those detected in Japan in the 2021/2022 season. Since no HPAI cases were reported in Japan during the summer of 2022, it is probable that migratory birds reintroduced the G2b and G2d viruses. Conversely, the G2c virus (a raptor-derived strain) was first recognized in Japan in the fall of 2022. This strain might share a common ancestor with HPAIVs from Asia and West Siberia observed in the 2021/2022 season. The early migration of waterfowl to Japan in the fall of 2022 could have facilitated the early invasion of HPAIVs.

Research Note: A recombinant duck-derived H6N2 subtype avian influenza virus can replicate and shed in young chickens and cause disease

The H6N2 subtype avian influenza virus (AIV) is commonly detected in the migratory waterfowl reservoirs. Previously, H6N2 AIV was believed to be nonpathogenic to young chickens and could not infect or shed in their respiratory tract under experimental conditions. However, in present study, a highly recombinant strain of duck-derived H6N2 AIV was discovered and isolated for pathogenicity tests. The results revealed that H6N2 could induce seroconversion in chickens and high morbidity of over 86.7%, along with evident upper respiratory tract hemorrhage. Moreover, 5 substitutions were detected in the upper respiratory tract shedding reisolated virus, with a high viral load in the target organs of infected chickens. In contrast, ducks failed to exhibit any symptoms, pathological lesions, or viral shedding, while demonstrated seroconversion and high viral load in the livers. These findings indicate that H6N2 AIV could also show pathogenicity to chickens under experimental conditions, thereby effectively replicating and shedding in chickens. Therefore, the study provides further elucidations on the pathogenicity of H6N2 AIV.

Genome sequence of a Sobemovirus from the feces of Northern Pintail (Anas acuta).

Northern pintail (Anas acuta) is a migratory waterfowl that can transmit various viruses. The genome sequence of a Sobemovirus was determined using metagenomic sequencing from the feces of northern pintail (Anas acuta) in Xinjiang, northwest China. The virus possesses a linear RNA molecule of 4177bp and is most closely related to isolates SoMV-WA (GenBank accession no. HM163159.1) and ATCC PV-109 (GenBank accession no. GQ845002.2), with a nucleotide identity of 86.7%. The virus encodes four open reading frames (ORF) coding for four proteins, and phylogenetic analysis of capsid protein and RNA-dependent RNA polymerase (RdRp) showed that the strain was clustered into the species Sowbane Mosaic Virus (SoMV). The amino acid sequence identity of capsid protein was 89.6-90.9% to other isolates of SoMV, but 17.6-31.4% similar to other strains in the genus Sobemovirus, indicating a strain of Sowbane Mosaic Virus. This is the first report of SoMV in the feces of wild birds and in China, and it suggested that northern pintail likely plays an alternative role in the transmission of SoMV.

Lake Atotonilco: A First Approach to Determining the Minimum Lake Level Necessary to Sustain Its Biodiversity

Lake Atotonilco is a shallow saline water body located in the central-west portion of Mexico. The lake is in the low plain of an endorheic watershed. It is shallow, with a large area of surrounding wetlands and serves as a refuge for dozens of native and migratory waterfowl. Its extremely flat morphometric features coupled with the precipitation and runoff regime from the watershed cause significant changes in the lake surface area and storage volume throughout the year. In recent years, the lake has behaved as an intermittent lake, remaining practically dry in June, and reaching its highest storage volume in October. An ecological water volume that the lake must maintain to support its biodiversity was estimated. This minimum lake storage volume can only be achieved if public policies are implemented to rationalize the use of water resources in the basin and to protect the few forest areas that remain in the watershed. Key Words: ecological minimum volume, endorheic watershed, lake bathymetry, playa lake.

Epidemiology and phylodynamics of multiple clades of H5N1 circulating in domestic duck farms in different production systems in Bangladesh.

Waterfowl are considered to be natural reservoirs of the avian influenza virus (AIV). However, the dynamics of transmission and evolutionary patterns of AIV and its subtypes within duck farms in Bangladesh remain poorly documented. Hence, a cross-sectional study was conducted in nine districts of Bangladesh between 2019 and 2021, to determine the prevalence of AIV and its subtypes H5 and H9, as well as to identify risk factors and the phylodynamics of H5N1 clades circulating in domestic duck farms. The oropharyngeal and cloacal swab samples were tested for the AIV Matrix gene (M-gene) followed by H5, H7, and H9 subtypes using rRT-PCR. The exploratory analysis was performed to estimate AIV and its subtype prevalence in different production systems, and multivariable logistic regression model was used to identify the risk factors that influence AIV infection in ducks. Bayesian phylogenetic analysis was conducted to generate a maximum clade credibility (MCC) tree and the maximum likelihood method to determine the phylogenetic relationships of the H5N1 viruses isolated from ducks. AIV was detected in 40% (95% CI: 33.0-48.1) of the duck farms. The prevalence of AIV was highest in nomadic ducks (39.8%; 95% CI: 32.9-47.1), followed by commercial ducks (24.6%; 95% CI: 14.5-37.3) and backyard ducks (14.4%; 95% CI: 10.5-19.2). The H5 prevalence was also highest in nomadic ducks (19.4%; 95% CI: 14.0-25.7). The multivariable logistic regression model revealed that ducks from nomadic farms (AOR: 2.4; 95% CI: 1.45-3.93), juvenile (AOR: 2.2; 95% CI: 1.37-3.61), and sick ducks (AOR: 11.59; 95% CI: 4.82-32.44) had a higher risk of AIV. Similarly, the likelihood of H5 detection was higher in sick ducks (AOR: 40.8; 95% CI: 16.3-115.3). Bayesian phylogenetic analysis revealed that H5N1 viruses in ducks belong to two distinct clades, 2.3.2.1a, and 2.3.4.4b. The clade 2.3.2.1a (reassorted) has been evolving silently since 2015 and forming at least nine subgroups based on >90% posterior probability. Notably, clade 2.3.4.4b was introduced in ducks in Bangladesh by the end of the year 2020, which was genetically similar to viruses detected in wild birds in Japan, China, and Africa, indicating migration-associated transmission of an emerging panzootic clade. We recommend continuing AIV surveillance in the duck production system and preventing the intermingling of domestic ducks with migratory waterfowl in wetlands.

Newly emerged genotypes of highly pathogenic H5N8 avian influenza viruses in Kagoshima prefecture, Japan during winter 2020/21.

During the 2020/21 winter season, 29 and 10 H5N8 high pathogenicity avian influenza viruses (HPAIVs) were isolated from environmental water and wild birds, respectively, in Kagoshima prefecture, Japan. Furthermore, seven subtypes of low pathogenicity avian influenza viruses (LPAIVs) were also isolated; H1N1, H2N9, H3N2, H3N6, H3N8, H4N6, and H6N6 subtypes. While the H5 hemagglutinin (HA) genes of the G1 cluster were isolated throughout the winter season, those of the G2 cluster were also detected in late winter, suggesting that H5 HPAIVs possessing H5 HA genes from the two different clusters were individually introduced into Kagoshima prefecture. Intriguingly, genetic constellations revealed that the H5N8 HPAIVs could be classified into six genotypes, including four previously reported genotypes (E1, E2, E3, and E7), and two new genotypes (tentatively named E8 and E9). The PB1 and PA gene segments of genotypes E8 and E9 shared high similarity with those of LPAIVs, whereas the remaining gene segments were close to those of genotype E1. Furthermore, LPAIVs whose PA gene segment was close to that of genotype E9 were isolated from the environmental water. Overall, we revealed that various HPAIV genotypes circulated in Kagoshima prefecture during the 2020/21 winter season. This study highlights the importance of monitoring both HPAIV and LPAIV to better understand AIV ecology in migratory waterfowl populations.

Morphological and molecular identification of <i>Neomoliniella longicorpa</i> gen. et sp. nov. (Digenea: Echinostomatidae) from the Eurasian coot <i>Fulica atra</i> (Aves: Rallidae): a taxonomic evaluation

The purpose of the research is the morphological and molecular identification of trematodes found in the intestines of migratory waterfowl with subsequent taxonomic evaluation.Materials and methods. Mature specimens of trematodes were collected from the intestines of waterfowl (Fulica atra and Aythya ferina) shot during the ecological-faunistic monitoring in the southern part of the Primorsky krai. Preliminary morphological analyze revealed that trematodes belong to the Echinostomatidae family. The whole-mounts of worms from F. atra were prepared using standard methods with alum carmine. Divergent domains of 28S ribosomal RNA gene were sequenced and used to determine systematic position and relationships of discovered species of echinostome by reconstructing Bayesian and Maximum likelihood trees.Results and discussion. Trematodes found in the coots' intestine, should be described as Neomoliniella longicorpa in the new genus Neomoliniella gen. et sp. nov., which is reliably confirmed by morphological and genetics data. Another cryptic echinostomatid species sister to Neomoliniella gen. nov., and probably representing the separate unknown genus, was demonstrated only on the phylogenetic reconstructions and confirmed by large genetic distances. Currently, this taxon is indicated as Echinostomatidae gen. sp. and more evidence is needed for its validation. We also report about the first detection of Echinostoma paraulum from A. ferina in the south of the Russian Far East. The biology, morphology of each life cycle stage of newly described species of worms should be investigated to test not only their scientific but also medical significance. For the first time in the history of the group, dichotomous keys for eight families of the superfamilyEchinostomatoidea and, to date, the largest of all previously known for the family Echinostomatidae identification chart – dichotomous keys for the identification of 27 Palearctic genera were compiled.

Migratory geese allow plants to disperse to cooler latitudes across the ocean

AbstractAimHow plants can disperse in response to global change is a critical question, yet major knowledge gaps persist about long‐distance dispersal (LDD) mechanisms. We studied the potential a migratory waterfowl has for LDD of flowering plants via gut passage of seeds (endozoochory), comparing spring and autumn migration.LocationUnited Kingdom and Iceland.TaxonPink‐footed Goose (Anser brachyrhynchus, Baillon) and Angiosperma.MethodsWe studied endozoochory by Pink‐footed geese migrating within and between the UK and Iceland by faecal sampling and GPS tracking. We collected 614 faecal samples from 14 areas in the UK and one in Iceland. Using GPS tracks to and from these areas, we estimated how far seeds can be dispersed by Pink‐footed geese, and where to or from.ResultsWe recorded 5507 intact seeds of 35 species (27 terrestrial) from 15 plant families, with lower seed abundance per dropping when birds were migrating northwards in the UK during spring than upon their arrival in autumn. Species richness of plant seeds was highest in Iceland and in autumn. Only four plant species dispersed had an “endozoochory syndrome”. GPS movements showed that seeds retained in guts for up to 24 h can be readily dispersed in both directions between the UK and Iceland, with maximum distances exceeding 2000 km, as well as between UK localities separated by 100 s of km. Movements northwards of ≤400 km were even recorded in autumn. While at stopover sites, daily movements between roost and feeding sites often exceed 20 km.Main ConclusionsPink‐footed geese are LDD vectors for plants previously assumed to lack an LDD mechanism. Spring migration is not the only period when geese move plants to cooler latitudes. The pink‐footed goose can allow terrestrial and aquatic plants to cross the ocean and to keep pace with climate change.

FOOD CONTENTS ANALYSIS OF WATERFOWL PASSING THROUGH INDUS THE RIVER AT TAUNSA, SOUTH PUNJAB, PAKISTAN

A study was carried out to assess the food composition of migratory waterfowl in Bet Makwal Kalan, near the Head Taunsa Barrage, along the River Indus passage. Migratory water birds are thought to be important components in dispersal of total living entity especially seeds due to their proclivity for extensive relocations. They might be found in large numbers in the muddy sections. Migratory water birds are important components of total plant dispersal due to their proclivity for making extensive migrations. A sum of 459 gizzard samples was collected, during their Fall migration, relating to 10 Waterfowl species i.e. Northern Pintail (n=56), Eurasian Wigeon (n=17), Garganay (n=07), Mallard (n=02), Northern Shoveler (n=22), Common Teal (n=129), Gadwall (n=158), Tufted Duck (n=04), Common Pochard (n=29) and Ferruginous Duck (n=34). During their winter migration, the Waterfowl species picked plants over animals as their primary source of sustenance when travelling through Taunsa. Food research revealed that all 10 species of birds consumed large amounts of seeds. Out of ten duck species, two plant species (Naias marina and Potamogeton pusillus) consistently ranked among the top seeds ingested by six of the duck species (Eurasian Wigeon, Garganey, Mallard, Gadwall, Tufted Duck, and Common Pochard). Whereas the Northern Pintail, Northern Shoveler, Common Teal, and Ferruginous Duck have been found to consume large amounts of seeds from Potamogeton pectinatus and Poligonum spp. It was determined that molluscans and crustaceans residues were found to be well-represented in the gizzard samples of ducks. The recent study also highlighted that various vegetations play vital role in wetland ecosystems as a basic wild food provider. A larger population of migrating Waterfowl yield better findings for this study, which is currently being undertaken.

Surveillance of avian influenza viruses from 2014 to 2018 in South Korea

Surveillance of influenza A viruses (IAVs) among migratory waterfowl is a first step in understanding the ecology, biology, and pathogenicity of IAVs. As part of the nationwide surveillance effort for IAVs in fowl in South Korea, we collected environmental fecal samples in different migratory bird stopover sites in South Korea during the winter seasons within November 2014 through January 2018. We collected a total of 6758 fecal samples, 75 of which were positive for IAV (1.11% positivity). Prevalence of IAVs varied per site and per year. Based on sequencing, the most prevalent hemagglutinin (HA) subtypes were H1, H6, and H5, and the most prevalent neuraminidase (NA) subtypes were N1, N3, and N2. Phylogenetic analyses showed that the genes we isolated clustered with reported isolates collected from other locations along the East Asian-Australasian Flyway. All the H5 and H7 isolates collected in this study were of low pathogenicity. None of the N1 and N2 genes carried amino acid markers of resistance against NA inhibitors. The winter 2016–2017 subset were primarily borne by migratory geese (Anser spp.). These results suggest that majority of the IAVs circulating among migratory wild fowl in South Korea in 2014–2018 were of low pathogenicity.

Semantic Segmentation with Multispectral Satellite Images of Waterfowl Habitat


 
 
 Migratory waterfowl (i.e., ducks, geese, and swans) management relies on landscape bioenergetic models to inform on-the-ground habitat conditions and conservation practices. Therefore, conservation planners rely on accurate predictions of wetland habitats for waterfowl at regional scales. Unharvested flooded corn is a popular management tool on public and private lands that greatly increases landscape-level energy compared to other wetlands; thus, landscape bioenergetic models are particularly sensitive to these habitat features. Despite their importance to conservation planning and implementation, the abundance and distribution of unharvested flooded corn fields across North America is unknown. Furthermore, training data is difficult to collect and accurate predictions are challenging given their unique attributes and discreteness at landscape-level lens. Advances in multispectral imagery and deep learning algorithms may enable continuous and autonomous detection of these habitat features. Therefore, we conducted modeling experiments using training data of unharvested flooded corn fields in West Tennessee and multispectral imagery collected from Sentinel-2 satellite missions. We performed several experiments using individual band combination composites and/or vegetation indices to identify optimal bands using MRUNET architectures. We subsequently used 3 ensemble models of important individual networks. We found the use of multispectral bands was necessary and although the CIR composite and OSAVI index improved precision, the 12-band composite increased recall, the metric we were most interested in. Moreover, all ensembles exhibited poor performance. Here, we present results of our initial modeling experiments and suggest future modeling exercises including temporal image and vegetation index stacking using multi-modal and/or recurrent neural network architectures.
 
 

Shallow water habitat management influences soil CO2 efflux from agricultural fields in the Lower Mississippi River Basin (LMRB), USA

AbstractTemporary winter flooding is a common practice for enhancing wildlife habitat in the Lower Mississippi River Basin (LMRB) and other migratory waterfowl flyways in North America. This practice also facilitates nutrient retention and reuse of rainwater‐ or drainage‐water. This study examines the consequence of five different water management approaches on soil carbon dioxide (CO2) efflux and corn (Zea mays L.) residue decomposition, from October 11, 2021, through January 31, 2022. Management treatments included (i) control (CT) or no flooding; (ii) passive (P) rainfall capture; (iii) fall (F) pumping of leftover irrigation water; (iv) winter (W) flooding with leftover irrigation water; and (v) fall–winter (FW) flooding. The fall–winter flood field (FW) had reduced daily soil CO2 efflux for 4 out of 12 observations and increased soil pH and residue decomposition compared to the control field. The winter flood field (W) had reduced CO2 efflux on December 8 and January 21, and FW had lower efflux on December 8, December 14, December 21, and January 13, than the control field (CT). Soil temperature was positively associated with soil CO2 efflux in all fields except control. Results are consistent with the hypothesis that flood‐timing and ‐duration had strong connections with soil carbon dynamics in LMRB row croplands during fallow periods.

Helminth fauna of migratory waterfowl ducks and geese in Hokersar wetland of Kashmir, India

Helminth fauna of migratory waterfowl ducks and geese in Hokersar wetland of Kashmir, India

Surveillance and Phylogenetic Characterisation of Avian Influenza Viruses Isolated from Wild Waterfowl in Zambia in 2015, 2020, and 2021

In recent years, the southern African region has experienced repeated incursions of highly pathogenic avian influenza viruses (HPAIVs), with wild migratory birds being implicated in the spread. To understand the profile of avian influenza viruses (AIVs) circulating in Zambia, we surveyed wild waterfowl for AIVs and phylogenetically characterised the isolates detected in 2015, 2020, and 2021. A total of 2,851 faecal samples of wild waterfowl were collected from Lochinvar National Park in the Southern Province of Zambia. During the study period, 85 (3.0%) low pathogenicity AIVs belonging to various subtypes were isolated, with H2N9, H8N4, and H10N8 being reported for the first time in avian species in Africa. The majority of the isolates were detected from glossy ibis (order Pelecaniformes) making it the first report of AIV from these birds in Zambia. Phylogenetic analysis of all eight gene segments of the 30 full genomes obtained in this study revealed that all the isolates belonged to the Eurasian lineage with their closest relatives being viruses isolated from wild and/or domestic birds in Bangladesh, Belgium, Egypt, Georgia, Mongolia, the Netherlands, and South Africa. Additionally, the Zambian viruses were grouped into distinct clusters based on the year of isolation. While no notifiable AIVs of the H5 or H7 subtypes were detected in wild birds in Zambia, viral internal protein genes of some viruses were closely related to H7 low pathogenicity AIVs. This study shows that periodically, a considerable diversity of AIV subtypes are introduced into the Zambian ecosystem by wild migratory waterfowl. The findings highlight the importance of continuous surveillance and monitoring of AIVs in wild waterfowl, including birds traditionally not considered to be major AIV reservoirs, for a better understanding of the eco-epidemiology and evolutionary dynamics of AIVs in Africa.

Spatial and Temporal Variations in Waterfowl Assemblage Structures in Mongolian Lakes and the Changes Linked to the Gradient of Lake Surface Areas

Lakes and wetlands provide top-priority hotspots that play a key role in maintaining and protecting threatened and migratory waterfowl. Identifying seasonal and spatial variations in aquatic bird communities and their responses to environmental factors is vital conservation efforts. However, there is a lack of information on waterfowl in Mongolian lakes and their associated wetlands. The purpose of this study was to investigate the spatial–seasonal changes in waterfowl assemblage structures in Mongolian lakes, as well as to determine how they respond to various environmental factors (lake surface area, elevation, and geographical distribution). Statistical analyses were performed using seasonal data (May, July, and September) for 28 waterfowl collected from 54 lakes across the country between 2016 and 2018. Seasonal heterogeneity in species richness and abundance was observed in lakes in each geographical region (Eastern, Central, and Western Mongolia). The composition of waterfowl in the lake was also relatively similar between May and September compared to July. This was due to the overlapping migration seasons in spring and autumn. Regionally, the number of waterfowl was much higher in the Eastern Mongolian lakes, followed by Central Mongolian lakes and then Western Mongolian lakes. This is likely due to differences in habitat availability and water levels between the regions. Eastern Mongolian lakes tend to have more wetlands and shallow water habitats, while Central and Western Mongolian lakes tend to have deeper open-water habitats. These differences in habitat types could contribute to the observed differences in waterfowl abundance among the regions. Additionally, some small lakes and the group of small lakes supported a greater abundance and diversity of waterfowl compared to some medium-sized and large lakes, suggesting that they are important for conservation. Indices of diversity (H’) and species dominance (D’) showed positive and negative correlations with lake surface area, respectively. Perhaps the increased surface area of the lake decreases the habitat overlap for designated waterfowl due to habitat heterogeneity. Accordingly, the indices (H’ and EH) increased as the waterfowl species composition became relatively equivalent in large lakes. Overall, spatial variations among the lakes were primarily attributable to the individual features of the lakes (shallowness, small lake groupings, and surface area), and seasonal variation in the lakes depended majorly on the compositional changes of the waterfowl due to migration.

Tabusintac Bay (New Brunswick, Canada): an important spring migratory stopover for Atlantic Brant (<i>Branta bernicla hrota</i>)

Atlantic Brant (Branta bernicla hrota) is an Arctic-breeding migratory waterfowl that relies heavily on Common Eelgrass (Zostera marina) for food during migration and overwintering. Although the abundance of Atlantic Brant along the coasts of the Maritime provinces has declined drastically over the past decades, some flocks continue to migrate through the area in spring. Here, we present field observations of Atlantic Brant spring staging in the Tabusintac Bay, New Brunswick, Canada. We surveyed the Tabusintac Bay seven times between 26 May and 6 June 2018. We observed a maximum daily count of 1259 individuals, which is comparable to high counts from the 1970s. These spring surveys indicate the continuing importance of Tabusintac Bay to Atlantic Brant for spring staging. There is a pressing need to increase monitoring and research in the region and to preserve or enhance the quality of the area for spring staging brant.

Intestinal Microbiota of Anser fabalis Wintering in Two Lakes in the Middle and Lower Yangtze River Floodplain.

The intestinal microbiota of migratory birds participate in the life activities of the host and are affected by external environmental factors. The difference in habitat environment provides diversity in external environmental selection pressure for the same overwintering waterfowl, which may be reflected in their intestinal microbiota. Caizi lake and Shengjin Lake in the Middle and Lower Yangtze River Floodplain are the main habitats for migratory waterfowl in winter, especially the Anser fabalis (A. fabalis). It is important to explore the changes in intestinal microbiota composition and function of A. fabalis in the early overwintering period to clarify the effect of habitat size and protection status on intestinal microbiota. In this study, the composition and structural characteristics of the intestinal microbiota of A. fabalis in Shengjin Lake (SL) and Caizi Lake (CL) were preliminarily explored in order to obtain data for the migratory birds. In both SL and CL groups, 16S rRNA amplicon sequencing analysis showed that Firmicutes was the dominant bacterial phylum, but the relative abundance showed significant differences. Lactobacillus was the most abundant genus in both SL and CL groups. At the species level, the abundance of L. aviaries was the highest, with a relative abundance in both SL and CL groups of more than 34%. When comparing the average relative abundance of the 15 most abundant genera, it was found that Subdoligranulum, Exiguobacterium, and Terrisporobacter had higher abundances in the intestinal microbiota of CL A. fabalis, while Streptococcus and Rothia had higher abundances in the intestinal microbiota of SL A. fabalis. There was only a positive correlation between Bacteroidota and Proteobacteria in the intestinal microbiota flora of SL A. fabalis, and the species were closely related. At the same time, there were positive and negative correlations between Firmicutes and Actinomycetes. However, CL is mainly associated with a positive correlation between Firmicutes and Actinomycetes, and there are also a small number of connections between Firmicutes. PICRUSt1 prediction analysis revealed that the Clusters of Orthologous Groups (COG) functions of SL and CL involve energy production and transformation, amino acid transport and metabolism, carbohydrate transport and metabolism, and transcription. Understanding the changes in intestinal microbiota in Aves during the overwintering period is of great importance to explore the adaptation mechanism of migratory Aves to the overwintering environment. This work provides basic data for an A. fabalis intestinal microbiota study.