Variations in sexual size dimorphism (SSD) have important consequences for animal ecology, behavior, population dynamics, and the evolution of life-history traits, and can be explained by many intraspecific and interpopulation hypotheses. Urbanization is an important factor that affects anuran phenotypic characteristics (including morphology), but how it impacts anuran SSD has been explored less widely. In this study, we aimed to investigate the differences in SSD in two dominant amphibian species populations; that is, the Hong Kong rice-paddy frog (Fejervarya multistriata) and Beijing gold-striped pond frog (Pelophylax plancyi), across an urban-rural gradient in Shanghai (including urban, suburban, and rural areas). We also tested whether these variations in SSD supported Rensch's rule or not. Our results showed that in both sexes, the snout-vent length (SVL) in F. multistriata was higher in urban areas compared with suburban and rural areas. In addition, only male P. plancyi exhibited a higher SVL in urban areas compared with those in rural areas. Furthermore, we found that the SSD in SVL was significantly higher for urban populations than suburban and rural populations of F. multistriata. All SSD results in terms of SVL, head width, forelimb length, and hindlimb length in these two frog species supported the inverse Rensch's rule based on reduced major axis regression. Moreover, the size scaling rates in these two frog species were higher in urban and suburban populations than rural populations. Thus, we concluded that urbanization shapes SSD in these two anurans according to the inverse of Rensch's rule, and that variations in morphological characteristics, SSD, and size scaling rates differed between these two anuran species regarded as an "urban-associated species" (P. plancyi) and "urban-sensitive species" (F. multistriata).

Land reclamation is a widely adopted method for managing land shortage and promoting coastal economic development globally. However, its impacts on biodiversity vary based on distinct reclamation histories and land use management strategies in different regions. This study aims to examine the effects of reclamation history and land use types at different spatial scales on anuran communities in coastal reclaimed land, which are an important taxon in the coastal ecosystem. We used visual and acoustic encounter methods to survey anurans in 2016 and 2017 across 20 1-km radius coastal land reclamation landscapes with different reclamation histories (10, 20, and 60 y after reclamation) in Nanhui Dongtan of Shanghai, an important coastal land reclamation region along the Yangtze River Estuary. Landscape variables (farmlands, woodlands, and impermeable surface covers, and the landscape Shannon diversity index) at four different spatial scales (250 m, 500 m, 750 m and 1000 m) and water salinity in each landscape were measured. Our findings reveal differences in anuran communities between study sites with 10, 20, and 60 years of reclamation history. Abundances of the ornamented pygmy frog (Microhyla fissipes) and Beijing gold-striped pond frog (Pelophylax plancyi) in landscapes with a 10year reclamation history were significantly lower compared to those with histories of 20 and 60 years. Zhoushan toad (Bufo gargarizans) abundance was significantly negatively related to farmland cover at the 1000 m scale and impermeable surface cover at the 250 m scale; Hong Kong rice-paddy frog (Fejervarya multistriata) abundance was significantly positively related to farmland cover at the 1000 m scale; ornamented pygmy frog abundance was positively related to farmland cover at the 1000 m scale; and Beijing gold-striped pond frog abundance was significantly positively and negatively related to the landscape Shannon diversity index at the 1000 m scale and to water salinity, respectively. Amphibians quickly migrated and colonized coastal reclaimed land from older natural lands. However, two anuran species with specific habitat requirements tended to avoid areas with shorter reclamation histories. The single-species models revealed different responses to various land uses at the various scales, which indicated that land use management was important to amphibian conservation in coastal reclamation regions.

Ongoing wind energy developments play a key role in mitigating the global effects of climate change and the energy crisis; however, they have complex ecological consequences for many flying animals. The Yellow Sea coast is considered as an ecological bottleneck for migratory waterbirds along the East Asian-Australasian flyway (EAAF), and is also an important wind farm base in China. However, the effects of large-scale onshore wind farms along the EAAF on multidimensional waterbird diversity, and how to mitigate these effects, remain unclear. Here we examined how wind farms and their surrounding landscapes affected multidimensional waterbird diversity along the Yellow Sea coast. Taxonomic, functional, and phylogenetic diversity of the waterbird assemblages, and mean pairwise distances and nearest taxon distances with null models were quantified in relation to 4 different wind turbine densities. We also measured 6 landscape variables. Multi-dimensional waterbird diversity (taxonomic, functional, and phylogenetic diversity) significantly decreased with increasing wind turbine density. Functional and phylogenetic structures tended to be clustered in waterbird communities, and environmental filtering drove waterbird community assemblages. Furthermore, waterbird diversity was regulated by a combination of wind turbine density and landscape variables, with edge density of aquaculture ponds, in addition to wind turbine density, having the greatest independent contribution to waterbird diversity. These results suggest that attempts to mitigate the impact of wind farms on waterbird diversity could involve the landscape transformation of wind farm regions, for example, by including high-edge-density aquaculture ponds (i.e., industrial ponds) around wind farms, instead of traditional low-edge-density aquaculture ponds.

警戒行为是动物对外界风险的一种行为反应,可以提前探测或避开风险以提高生存率,发生警戒行为时动物距外界干扰源的距离则定义为警戒距离.快速城市化发展引起的栖息地改变和人为干扰会对动物的警戒距离产生影响.本研究以饰纹姬蛙(Microhyla fissipes)为研究对象,于2020和2021年的5至7月沿上海市城市化梯度,即市区-近郊-郊区,设置22个研究样点,其中,市区3个、近郊10个、郊区9个,共测量100只饰纹姬蛙的警戒距离,包含市区15只、近郊51只及郊区34只,并基于2km半径景观中不透水表面(包括建筑和道路)占比定义各研究样点的城市化指数,同时获取各研究样点所在区域的人口密度以定义人类活动强度,探究城市化梯度上两栖动物警戒距离变化与城市化发展引起的栖息地与人类活动强度改变之间的关系.研究结果表明,饰纹姬蛙的警戒距离与城市化指数呈显著负相关,与人口密度也呈负相关,但不显著.本研究认为,两栖动物会通过改变警戒距离适应栖息地城市化过程,研究结果有利于理解两栖类行为对城市化的响应机制.

Urbanization leads to globally decline of amphibian biodiversity. Amphibians change their phenotypic characteristics, especially morphological traits, to adapt to urbanization. To examine the effects of urbanization on the morphological traits of the gold-striped pond frog（Pelophylax plancyi） and rice-paddy frog（Fejervarya multistriata） in Shanghai, China, we collected 170 individuals of adult P. plancyi and 305 individuals of adult F. multistriata from 38 sampling sites along an urbanization gradient between April and August in 2020 and 2021. We mea-sured five morphological traits: snout-vent length, body mass, head width, forelimb length, and hindlimb length. The urbanization index of each sampling site was evaluated based on the area proportions of buildings, roads, and woodlands, to represent the urbanization level. The snout-vent length in both male and female P. plancyi was positively correlated with the urbanization index. The snout-vent length, head width, and hindlimb length in male F. multistriata, and body mass and hindlimb length in female F. multistriata were positively correlated with the urbanization index. Our results indicate that the responses of the morphological traits to urbanization were stronger in F. multistriata than P. plancyi in Shanghai.

Coastlines with extensive estuaries and broad tidal flats are acutely vulnerable to coastal development. The tidal wetlands of the Yellow Sea are globally important for waterbirds, yet river mouths have disproportionately been developed as industrial ports, fishing ports, or have become abandoned fishing ports, with the type of management strategies depending on biophysical attributes and regional economic drivers. However, river mouths also support extensive upper tidal flat ecosystems, in contrast to many open coastal regions of the Yellow Sea, where reclamation has excised many of the upper tidal flats and dramatically reduced the time that tidal flats are available for foraging and roosting waterbirds each day. However, the extent to which waterbirds disproportionately occurs in river mouths compared to the open coast in the region remains unclear. We used a paired survey design to quantify the waterbird communities and habitat attributes (i.e., areas of upper tidal flats, Spartina alterniflora, and human activity) of 15 river mouths and 15 otherwise similar adjacent open coasts areas along the Yellow Sea coast. Waterbird species richness and abundance were higher in river mouths than open coasts. Among river mouths, the most species rich waterbird communities occurred in fishing ports and the most species poor in industrial ports. Notably, upper tidal flats were absent in many of the open coast regions, which had been subject to reclamation. Our results suggest that river mouths, especially those river mouths currently used as fishing ports, are probably of crucial importance for waterbird conservation on the Jiangsu coast due to their larger areas of upper tidal flats. Our work highlights the need to ensure that the tidal flats in river mouth systems are effectively protected to promote the completion of the annual cycle of migratory waterbirds.

Co-infection of SARS-CoV-2 and influenza viruses has been reported worldwide in humans. Wild birds are natural reservoir hosts for coronaviruses (CoVs) and avian influenza viruses (AIVs). It is unknown whether co-infection with these two types of viruses occurs in wild birds. In this study, the prevalence of co-infection with CoV and AIV in wild birds in Shanghai, China during 2020-2021 was investigated by detecting these viruses in cloacal, tracheal, and faecal samples. Results showed that the overall rate of samples positive for both CoV and AIV was 3.3% (82/2510; 95% confidence interval [CI]: 2.6%-4.0%), and that was mainly from Anseriformes. In CoV-positive samples, 38.9% (82/211; 95% CI: 32.5%-45.6%) of them had both CoVs and AIVs, whereas only 26.9% (82/305; 95% CI: 22.2%-32.1%) of AIV-positive samples had both CoVs and AIVs. These results suggest that CoV infection in wild birds renders them more susceptible to AIV infection. Phylogenetic analysis based on partial RNA-dependent RNA polymerase (RdRp) gene sequences of CoVs revealed that gamma-CoVs mainly cluster with duck CoVs and that delta-CoVs are more diversified and cluster with those of various wild birds. Continual surveillance is necessity to monitor the transmission and evolution of co-infection of these two types of viruses in their natural hosts.

Millions of migratory waterfowl winter in the coastal wetlands in Shanghai City, among which Eastern Spot-billed Ducks and Mallards are among the most common species and are sensitive to infection with avian influenza virus. However, information on the migration behaviors of these two species in Northeast Asia is lacking. Therefore, GPS transmitters were used to track the migration of 13 Eastern Spot-billed Ducks and eight Mallards wintering in Shanghai during 2017-2020. Mallards covered a (mean +/- standard deviation) migration distance of 1,663.69 +/- 1,063.33 km, with wider variation than Eastern Spot-billed Ducks (1,639.24 +/- 642.72 km), though the difference was not significant. Both species ended their northward migrations in Northeast Asia encircling the Yellow Sea, mainly in northeastern China. The dynamic Brownian bridge movement model confirmed that multiple stopover sites mainly located in the Korean Peninsula along the Yellow Sea coastline were crucial nodes for maintaining the stability and function of the migration network. This study confirmed the close relationships between habitats in the Korean Peninsula and China, indicating the importance of habitat conservation in related countries to the stability of the migration network. The results of this study additionally highlight the relationships between migration behaviors and outbreaks of avian influenza virus in Northeast Asia.

Abstract Although wind power is a promising source of renewable energy, previous studies have focused on uncovering species and abundance decreases caused by wind farms. However, very few studies focus on collision risk of onshore wind farms in relation to birds’ movements which are the important indicators for balancing wind energy development and biodiversity conservation. Here, birds’ movement were recorded by combining 15 ducks’ satellite tracking and six field surveys to assess collision risks in Yangtze River Mouth, the wintering site for migratory waterbirds along the East Asian–Australasian Flyway. It is found that distances between ducks’ locations and nearest wind turbines in middle and later wintering periods were significantly higher than during early period. Besides, ducks inside wind farm tended to fly outside turbine rotor height range (45–135 m: between lowest and highest points the rotor tips) within 300 m from the dyke where the turbines were located, thus decreasing their collision risk. Ducks also tended to fly below the minimum rotor tip height (< 45 m) when the turbines were rotating. These results suggest that ducks adopt behavioural avoidance strategies in response to wind farms, and turning off turbines to reduce collision risks may be unnecessary.

盐度和种间作用是影响湿地植物群落构建的关键因子.然而,已有研究主要集中于植物成体阶段,我们对生活史早期更新阶段的种间相互作用了解十分有限.崇明东滩国家级自然保护区是位于长江口的重要湿地,外来入侵植物互花米草对优势土著物种海三棱藨草的竞争排斥对当地生态系统造成了严重的负面影响.通过受控实验探讨了盐度及种间作用对海三棱藨草和互花米草种子萌发及生长的影响,以深入了解更新过程在盐沼湿地植物群落构建中的作用.结果表明,在培养皿中盐度对海三棱藨草的萌发有显著抑制作用,互花米草的萌发率受盐度影响不显著但萌发进程被延迟.混种处理对两者的萌发存在一定促进效应,且其作用强度受到盐度的调控.海三棱藨草与互花米草种子在萌发阶段的相互促进并非是通过化感作用实现的,可能是由于萌发过程对盐分的吸收减弱了盐胁迫的影响.盆栽条件下,两物种混种时的萌发及生长表现(高度、地上生物量)较单种时有所下降,但差异不显著.种间竞争受环境胁迫程度及生活史阶段的影响,竞争作用在胁迫较弱的淡水环境及生活史后期更强.盐沼湿地植物群落在形成早期受到盐度等环境因子的影响较大,不同植物对盐胁迫的响应是影响种群建成的主导因素,后期种间竞争的重要性不断增加,最终决定了植物群落的整体格局.

Urbanization has a significant influence on amphibian communities, populations, and individuals because of habitat loss, degradation of habitat quality, and habitat fragmentation. Advertisement calls of anurans are used for communication and play an important role in reproduction; however, how anthropogenic noise and habitat change caused by urbanization affect anuran advertisement calls is less well known. In this study, we examined changes in the advertisement calls of two frog species, the ornamented pygmy frog (Microhyla fissipes) and rice frog (Fejervarya multistriata), during the breeding season along an urban–rural gradient in Shanghai, China. We used the percentage of impervious area (including buildings and roads) in each 2 km-radius landscape to represent the urbanization index of 34 study sites. We then measured five advertisement call parameters (call duration, call interval, call rate, pulse rate, and dominant frequency) of these two species (100 males of F. multistriata and 89 males of M. fissipes) in each study site from May to July in 2020 and 2021. We explored how the urbanization index and other variables (air temperature, snout–vent length and calling situation (one frog species calling, or two frog species calling together)) in each study site affected these call parameters. The results showed that the dominant frequency of M. fissipes was significantly negatively related to urbanization index, and call duration and call interval were significantly negatively related to air temperature; furthermore, call rate and pulse rate were significantly positively related to air temperature, and call duration was also significantly positively related to snout–vent length. For F. multistriata, pulse rate was significantly negatively related to urbanization index, snout–vent length, and situation (two frog species calling together), but significantly positively related to air temperature; by contrast, call interval was significantly positively related to snout–vent length. We suggested that these two frog species had different responses to urbanization, which could help us to better understand the change of anuran breeding behaviors and reproductive life-history strategies in the face of rapid urbanization.

The use of wind turbines for energy generation has complex impacts on ecosystems, especially for flying wildlife. Given the importance of birds in many ecosystems and food webs, they are often used as ecological indicators to evaluate the direct (e.g., collision mortality) and indirect (e.g., habitat degradation and loss, low food available) impact of wind farms. To test the effect of wind farms on the nest distribution of magpie (Pica pica), a common bird species in agroforestry systems on Chongming Island, China, the differences in magpie nest density variables and character variables were compared between quadrats inside and outside a wind farm. The relationship between magpie nest character variables and density variables in each quadrat was also examined and the impacts of landscape variables on magpie nest density variables were clarified in each quadrat. From March to December 2019, nest density variables (including total and in-use nest density) were recorded in quadrats inside and outside a wind farm in an agroforestry system on Chongming Island, Shanghai. Three nest character variables and five landscape variables were also recorded in each quadrat. The total nest density and nesting height in the quadrats outside were significantly higher than those inside the wind farm. There was a significant negative correlation between the average nest size in the quadrats and the total nest density, and a significant positive correlation between the average nesting height in the quadrats and both nest density variables. Moreover, farmland shelterbelt network cover and the distance to the nearest wind turbine were significantly positively related to the total nest density, whereas the farmland shelterbelt network cover was significantly positively related to the in-use nest density. These results indicate a negative effect of wind turbines on the nest density of magpies, which could be addressed by the provision of more farmland shelterbelt networks inside the wind farms located in agroforestry systems on Chongming Island, China.

In late 2020, we detected 32 highly pathogenic avian influenza A(H5N8) viruses in migratory ducks in Shanghai, China. Phylogenetic analysis of 5 representative isolates identified 2 sublineages of clade 2.3.4.4b. Each sublineage formed separate clusters with isolates from East Asia and Europe.

H7N7 avian influenza virus (AIV) can divided into low-pathogenic AIV and high-pathogenic AIV groups. It has been shown to infect humans and animals. Its prevalence state in wild birds in China remains largely unclear. In this study, a new strain of H7N7 AIV, designated CM1216, isolated from wild birds in Shanghai, China, was characterized. Phylogenetic and nucleotide sequence analyses of CM1216 revealed that HA, NA, PB1, NP, and M genes shared the highest nucleotide identity with the Japan H7 subtype AIV circulated in 2019; the PB2 and PA genes shared the highest nucleotide identity with the Korea H7 subtype AIV circulated in wild birds in 2018, while NS gene of CM1216 was 98.93% identical to that of the duck AIV circulating in Bangladesh, and they all belong to the Eurasian lineage. A Bayesian phylogenetic reconstruction of the 2 surface genes of CM1216 showed that multiple reassortments might have occurred in 2015. Mutations were found in HA (A135 T, T136S, and T160 A [H3 numbering]), M1 (N30D and T215 A), NS1 (P42S and D97 E), PB2 (R389 K), and PA (N383D) proteins; these mutations have been shown to be related to mammalian adaptation and changes in virulence of AIVs. Infection studies demonstrated that CM1216 could infect mice and cause symptoms characteristic of influenza virus infection and proliferate in the lungs without prior adaption. This study demonstrates the need for routine surveillance of AIVs in wild birds and detection of their evolution to become a virus with high pathogenicity and ability to infect humans.

本研究使用GPS卫星跟踪技术,以本地区最常见的斑嘴鸭(Anas poecilorhyncha)(5只)和绿头鸭(A.platyrhynchos)(4只)为研究对象,研究了冬季斑嘴鸭和绿头鸭在浦东的栖息地空间利用特征.利用固定核空间法(FKE)测得越冬季个体的平均活动范围为(15.073 士 25.390)km2,没有明显的种间差异.两种鸭属鸟类的主要栖息地类型为滩涂、沟渠、农田和内陆水体,观测到的利用率分别为38.45％、32.46％、19.88％和8.85％,滩涂和沟渠是最主要的栖息地类型且昼、夜均利用.农田是研究区域主要的栖息地类型,是鸭属鸟类冬季重要的取食地,但只有部分个体使用,且多在夜间.所有监测个体均在夜间保持较高的活动强度,且活动高峰出现在清晨与黄昏.本研究比较系统地揭示了上海地区冬季斑嘴鸭和绿头鸭的栖息地利用和活动节律、活动范围等时空特征,为高度城市化地区的鸟类保护和管理提供了基础资料.

Wind energy development has complex ecological consequences for many bird species. Previous environmental impact assessments (EIAs) for avian taxa mainly focused on the direct and indirect impacts of wind farm, such as collision mortality, flight changes, and habitat displacement. Their impact on waterbird behavior is less studied, especially foraging behaviors, which determine their energy budget and, thus, their reproduction and survival. In this study, we examined the effect of wind farms and the surrounding landscape on the abundance and energy budget-related behaviors of little egrets (Egretta garzetta), a dominant resident waterbird species near wind farms along the East China coast, from June to October 2019. Three egret behavioral categories were recorded, i.e., rest, locomotion, and foraging, and three foraging subcategories, i.e., stand-and-wait, walk slowly, and walk quickly. We also measured the distance to the wind farm and five landscape variables (aquaculture pond edge, ditch, marsh grassland, marsh open water, and river) within each quadrat. We found no significant effect of the distance to the wind farm on the abundance of little egrets, although their abundance was positively and negatively related to the aquaculture pond edge and marsh open water, respectively. The distance to the wind farm was positively correlated with stand-and-wait foraging. In addition, the river was negatively correlated with locomotion. Marsh open water was negatively correlated with walk slowly foraging. Therefore, the abundance of little egrets in Chongming Dongtan was not affected by the wind farm, although the wind farm resulted in changes to some of their behavior. Overall, the effect of this wind farm on little egrets was limited. We suggest aquaculture ponds mainly inhabited by egrets as alternatives for coastal wind farm development. We also highlight the behavioral evaluation of waterbirds as a complementary technique for EIAs of wind farm developments.

城市化在全球范围内快速扩张,已经成为影响物种进化的重要力量.两栖动物的迁移能力较弱,城市化导致两栖类被完全或部分的隔离,丢失更多的遗传多样性.本研究对上海市的金线侧褶蛙(Pelophylax plancyi)的mtDNA Cyt b部分序列进行分析,共扩增出235条序列,获得61个单倍型.研究表明城市区域遗传多样性较低,上海市的金线侧褶蛙分化程度处于中低的水平(Max FST=0.296;Min FST=0.004),各种群之间遗传分化有限.黄浦江及其支流可能作为水上扩散通道,有助于基因交流,各城市公园之间的遗传分化差异并不显著;而长江阻碍了种群之间的交流,城市公园和郊区,以及岛屿种群之间的遗传分化显著.此外,单倍型网络和系统发育分析表明,上海的金线侧褶蛙并没有对应城市化程度形成相应的单系.

Abstract Understanding the mechanisms of how urbanization influences the evolution of native species is vital for urban wildlife ecology and conservation in the Anthropocene. With thousands of years of agriculture‐dominated historical urbanization followed by 40 years of intensive and rapid urbanization, Shanghai provides an ideal environment to study how the two‐stage urbanization process influences the evolution of indigenous wildlife, especially of anuran species. Therefore, in this study, we used mitochondrial Cyt‐b gene, microsatellite (SSR), and single nucleotide polymorphism (SNP) data to evaluate the demographic history and genetic structure of the eastern golden frog (Pelophylax plancyi), by sampling 407 individuals from 15 local populations across Shanghai, China. All local populations experienced bottlenecks during historical urbanization, while the local populations in urban areas maintained comparable contemporary effective population sizes (Ne) and genetic diversity with suburban and rural populations. Nevertheless, the rapid modern urbanization has already imposed significant negative effects to the integrity of populations. The 15 local populations were differentiated into eight genetic clusters, showing a spatial distribution pattern consistent with the current urbanization gradient and island–mainland geography. Although moderate gene flow still occurred from the rural peripheral cluster to urban and suburban clusters, population fragmentation was more serious in the urban and suburban populations, where higher urbanization levels within 2‐km radius areas showed significant negative relationships to the Ne and genetic diversity of local populations. Therefore, to protect urban wildlife with limited dispersal ability, improving conditions in fragmented habitat remnants might be most essential for local populations living in more urbanized areas. Meanwhile, we highlight the need to preserve large unfragmented rural habitats and to construct corridor networks to connect discrete urban habitat remnants for the long‐term wildlife conservation in intensively urbanizing environments.

Seed germination is the key stage of population recruitment. Competition between native and invasive species can greatly influence the seed germination and the stability of the affected populations and communities, which in turn will affect the stability of native ecosystems. In this paper, we studied the interactions between dominant species in Chongming Dongtan wetland at seed germination stage using a germination experiment. We found that both salinity and interspecific interaction significantly affected the seed germination process of dominant marsh plants, but the effects were not consistent among different species. Generally, germination rate of Scirpus mariqueter was inhibited by high salinity, whereas that of Suaeda glauca was promoted by salt. Almost all the species germinated more slowly in salt water than in fresh water. Invasive Spartina alterniflora seeds significantly promoted the germination rate of Scirpus mariqueter in salt water despite of its heavy competitive effects on this native sedge in the adult stage. Besides, the germination rate of Spartina alterniflora was significantly inhibited by Phragmites australis and Suaeda glauca seeds in salt water, whereas its germination speed was significantly inhibited by Phragmites australis in fresh water. Our study revealed the pattern of interspecific interactions in the early life stages of plants, which may improve our understanding of population and community dynamics and provide some guidance to invasive species control and wetland management.

From 2016 to 2018, surveillance of influenza A viruses in wild birds was conducted in Shanghai, located at the East Asian–Australian flyway, China. A total of 5112 samples from 51 species of wild birds were collected from three different wetlands. The total three-year prevalence of influenza A viruses among them was 8.8%, as assessed using real-time polymerase chain reaction (PCR) methods, and the total prevalence was higher in Anseriformes (26.3%) than in the Charadriiformes (2.3%) and the other orders (2.4%) in the Chongmin wetlands. Anseriformes should be the key monitoring group in future surveillance efforts. The peak prevalence of influenza A viruses in Charadriiformes were in April and September, and in other bird orders, the peaks were in November and December. Twelve subtypes of haemagglutinin (HA; H1–H12) and eight subtypes of neuraminidase (NA; N1, N2, N4–N9) were identified in 21 different combinations. The greatest subtype diversity could be found in common teal, suggesting that this species of the bird might play an important role in the ecology and epidemiology of influenza A viruses in Shanghai. These results will increase our understanding of the ecology and epidemiology of influenza A viruses in wild bird hosts in eastern China, and provide references for subsequent surveillance of influenza A virus in wild birds in this area.