The role of breeding phenology and aggregation of waterfowl on avian influenza dynamics in southern Africa

Recent outbreaks of highly pathogenic avian influenza virus (AIV) in birds, humans and other mammalian species calls for a better understanding of virus dynamics in wild bird species and populations that act as maintenance hosts. Host ecology influences the transmission of pathogens and can be used to explore and infer pathogen dynamics. Most of the ecological processes proposed to explain AIV transmission in wild birds have been derived from studies conducted in the temperate and boreal regions of the northern hemisphere. We evaluate the role of two key drivers of AIV dynamics in a waterfowl community in Zimbabwe (southern Africa): (1) the recruitment of young birds and (2) the seasonal aggregation of birds. We analyse the seasonal variation of AIV prevalence in waterfowl and overlay these data with the phenology of reproduction and the seasonal variation in the local abundance of these species. We find that the breeding period of southern Afrotropical waterfowl species is more extended and somewhat less synchronized among species in the community than is the case in temperate and boreal waterfowl communities. Young birds are recorded at most times of the year, and these immunologically naïve individuals can therefore act as new hosts for AIV throughout the year within the wild bird population. Although host aggregation peaks in the cold‐dry to hot‐dry season, birds still aggregate throughout the year and this potentially spreads the opportunities for first infection of juveniles and other naïve birds temporally. We did not find a relationship between season, AIV prevalence in waterfowl, the influx of juveniles or the gradual aggregation of birds during the dry season. Therefore, the main drivers of AIV dynamics (juvenile influx and host abundance/aggregation), although present in Afrotropical regions, could not explain the AIV seasonal patterns in our study in contrast to results reported from temperate and boreal regions. These differences imply variation in the risk of AIV circulation in waterfowl and in the risk of spread to poultry, other animals or humans.     

Model to track wild birds for avian influenza by means of population dynamics and surveillance information

Design, sampling and data interpretation constitute an important challenge for wildlife surveillance of avian influenza viruses (AIV). The aim of this study was to construct a model to improve and enhance identification in both different periods and locations of avian species likely at high risk of contact with AIV in a specific wetland. This study presents an individual-based stochastic model for the Ebre Delta as an example of this appliance. Based on the Monte-Carlo method, the model simulates the dynamics of the spread of AIV among wild birds in a natural park following introduction of an infected bird. Data on wild bird species population, apparent AIV prevalence recorded in wild birds during the period of study, and ecological information on factors such as behaviour, contact rates or patterns of movements of waterfowl were incorporated as inputs of the model. From these inputs, the model predicted those species that would introduce most of AIV in different periods and those species and areas that would be at high risk as a consequence of the spread of these AIV incursions. This method can serve as a complementary tool to previous studies to optimize the allocation of the limited AI surveillance resources in a local complex ecosystem. However, this study indicates that in order to predict the evolution of the spread of AIV at the local scale, there is a need for further research on the identification of host factors involved in the interspecies transmission of AIV.     

Are Poultry or Wild Birds the Main Reservoirs for Avian Influenza in Bangladesh?

Avian influenza viruses (AIV) are of great socioeconomic and health concern, notably in Southeast Asia where highly pathogenic strains, such as highly pathogenic avian influenza (HPAI) H5N1 and other H5 and H7 AIVs, continue to occur. Wild bird migrants are often implicated in the maintenance and spread of AIV. However, little systematic surveillance of wild birds has been conducted in Southeast Asia to evaluate whether the prevalence of AIV in wild birds is higher than in other parts of the world where HPAI outbreaks occur less frequently. Across Bangladesh, we randomly sampled a total of 3585 wild and domestic birds to assess the prevalence of AIV and antibodies against AIV and compared these with prevalence levels found in other endemic and non-endemic countries. Our study showed that both resident and migratory wild birds in Bangladesh do not have a particularly elevated AIV prevalence and AIV sero-prevalence compared to wild birds from regions in the world where H5N1 is not endemic and fewer AIV outbreaks in poultry occur. Like elsewhere, notably wild birds of the orders Anseriformes were identified as the main wild bird reservoir, although we found exceptionally high sero-prevalence in one representative of the order Passeriformes, the house crow (Corvus splendens), importantly living on offal from live bird markets. This finding, together with high sero- and viral prevalence levels of AIV in domestic birds, suggests that wild birds are not at the base of the perpetuation of AIV problems in the local poultry sector, but may easily become victim to AIV spill back from poultry into some species of wild birds, potentially assisting in further spread of the virus.     

Investigating Avian Influenza Infection Hotspots in Old-World Shorebirds

Heterogeneity in the transmission rates of pathogens across hosts or environments may produce disease hotspots, which are defined as specific sites, times or species associations in which the infection rate is consistently elevated. Hotspots for avian influenza virus (AIV) in wild birds are largely unstudied and poorly understood. A striking feature is the existence of a unique but consistent AIV hotspot in shorebirds (Charadriiformes) associated with a single species at a specific location and time (ruddy turnstone Arenaria interpres at Delaware Bay, USA, in May). This unique case, though a valuable reference, limits our capacity to explore and understand the general properties of AIV hotspots in shorebirds. Unfortunately, relatively few shorebirds have been sampled outside Delaware Bay and they belong to only a few shorebird families; there also has been a lack of consistent oropharyngeal sampling as a complement to cloacal sampling. In this study we looked for AIV hotspots associated with other shorebird species and/or with some of the larger congregation sites of shorebirds in the old world. We assembled and analysed a regionally extensive dataset of AIV prevalence from 69 shorebird species sampled in 25 countries across Africa and Western Eurasia. Despite this diverse and extensive coverage we did not detect any new shorebird AIV hotspots. Neither large shorebird congregation sites nor the ruddy turnstone were consistently associated with AIV hotspots. We did, however, find a low but widespread circulation of AIV in shorebirds that contrast with the absence of AIV previously reported in shorebirds in Europe. A very high AIV antibody prevalence coupled to a low infection rate was found in both first-year and adult birds of two migratory sandpiper species, suggesting the potential existence of an AIV hotspot along their migratory flyway that is yet to be discovered.     

Avian Influenza Virus Surveillance in Wild Birds in Georgia: 2009–2011

The Caucasus, at the border of Europe and Asia, is important for migration and over-wintering of wild waterbirds. Three flyways, the Central Asian, East Africa-West Asia, and Mediterranean/Black Sea flyways, converge in the Caucasus region. Thus, the Caucasus region might act as a migratory bridge for influenza virus transmission when birds aggregate in high concentrations in the post-breeding, migrating and overwintering periods. Since August 2009, we have established a surveillance network for influenza viruses in wild birds, using five sample areas geographically spread throughout suitable habitats in both eastern and western Georgia. We took paired tracheal and cloacal swabs and fresh feces samples. We collected 8343 swabs from 76 species belonging to 17 families in 11 orders of birds, of which 84 were real-time RT-PCR positive for avian influenza virus (AIV). No highly pathogenic AIV (HPAIV) H5 or H7 viruses were detected. The overall AIV prevalence was 1.6%. We observed peak prevalence in large gulls during the autumn migration (5.3–9.8%), but peak prevalence in Black-headed Gulls in spring (4.2–13%). In ducks, we observed increased AIV prevalence during the autumn post-moult aggregations and migration stop-over period (6.3%) but at lower levels to those observed in other more northerly post-moult areas in Eurasia. We observed another prevalence peak in the overwintering period (0.14–5.9%). Serological and virological monitoring of a breeding colony of Armenian Gulls showed that adult birds were seropositive on arrival at the breeding colony, but juveniles remained serologically and virologically negative for AIV throughout their time on the breeding grounds, in contrast to gull AIV data from other geographic regions. We show that close phylogenetic relatives of viruses isolated in Georgia are sourced from a wide geographic area throughout Western and Central Eurasia, and from areas that are represented by multiple different flyways, likely linking different host sub-populations.     

A robust tool highlights the influence of bird migration on influenza A virus evolution

One of the fundamental unknowns in the field of influenza biology is a panoramic understanding of the role wild birds play in the global maintenance and spread of influenza A viruses. Wild aquatic birds are considered a reservoir host for all lowly pathogenic avian influenza A viruses (AIV) and thus serve as a potential source of zoonotic AIV, such as Australasian‐origin H5N1 responsible for morbidity and mortality in both poultry and humans, as well as genes that may contribute to the emergence of pandemic viruses. Years of broad, in‐depth wild bird AIV surveillance have helped to decipher key observations and ideas regarding AIV evolution and viral ecology including the trending of viral lineages, patterns of gene flow within and between migratory flyways and the role of geographic boundaries in shaping viral evolution (Bahl et al. 2009 ; Lam et al. 2012 ). While these generally ‘virus‐centric’ studies have ultimately advanced our broader understanding of AIV dynamics, recent studies have been more host‐focused, directed at determining the potential impact of host behaviour on AIV, specifically, the influence of bird migration upon AIV maintenance and transmission. A large number of surveillance studies have taken place in Alaska, United States—a region where several global flyways overlap—with the aim of detecting the introduction of novel, Australasian‐origin highly pathogenic H5N1 AIV into North America. By targeting bird species with known migration habits, long‐distance migrators were determined to be involved in the intercontinental movement of individual AIV gene segments, but not entire viruses, between the Australasian and North American flyways (Koehler et al. 2008 ; Pearce et al. 2010 ). Yet, bird movement is not solely limited to long‐distance migration, and the relationship of resident or nonmigratory and intermediate‐distance migrant populations with AIV ecology has only recently been explored by Hill et al. ( 2012 ) in this issue of Molecular Ecology. Applying a uniquely refined, multidimensional approach, Hill et al. validate the innovative use of stable isotope assays for qualifying migration status of wild mallards within the Pacific flyway. The authors reveal that AIV prevalence and diversity did not differ in wintering mallard ducks with different migration strategies, and while migrant mallards do indeed introduce AIV, these viruses do not circulate as the predominant viruses in resident birds. On the other hand, resident mallards from more temperate regions act as reservoirs, possibly contributing to the unseasonal circulation and extended transmission period of AIV. This study highlights the impact of animal behaviour on shaping viral evolution, and the unique observations made will help inform prospective AIV surveillance efforts in wild birds.     

我国野生鸟类疫病传播风险及防范措施

众多疫病病毒来源于野生动物,具有向人类传播的风险,尤其是具有飞翔能力的鸟类不易控制,所携带的病毒传播广泛,威胁人畜安全。因此,充分了解鸟类携带疫病情况以及鸟类迁徙路线中重点区域的疫病风险,对疫病防控非常重要。本文总结了鸟类主要携带的病原类型,如冠状病毒、流感病毒、寄生虫和新城疫病毒等。着重探讨鸟类携带病原对生物安全防范重点区域的人员和动物的疫病风险,包括自然保护区、机场和禽类养殖场等,并从加强候鸟迁徙的动态监测、加强栖息地检疫和保护、家禽定期疫苗接种等方面提出疫病防范措施。     

The consequences of climate change at an avian influenza ‘hotspot’

Avian influenza viruses (AIVs) pose significant danger to human health. A key step in managing this threat is understanding the maintenance of AIVs in wild birds, their natural reservoir. Ruddy turnstones (Arenaria interpres) are an atypical bird species in this regard, annually experiencing high AIV prevalence in only one location—Delaware Bay, USA, during their spring migration. While there, they congregate on beaches, attracted by the super-abundance of horseshoe crab eggs. A relationship between ruddy turnstone and horseshoe crab (Limulus polyphemus) population sizes has been established, with a declining horseshoe crab population linked to a corresponding drop in ruddy turnstone population sizes. The effect of this interaction on AIV prevalence in ruddy turnstones has also been addressed. Here, we employ a transmission model to investigate how the interaction between these two species is likely to be altered by climate change. We explore the consequences of this modified interaction on both ruddy turnstone population size and AIV prevalence and show that, if climate change leads to a large enough mismatch in species phenology, AIV prevalence in ruddy turnstones will increase even as their population size decreases.     

Influenza a viruses from wild birds in Guatemala belong to the North American lineage

The role wild bird species play in the transmission and ecology of avian influenza virus (AIV) is well established; however, there are significant gaps in our understanding of the worldwide distribution of these viruses, specifically about the prevalence and/or significance of AIV in Central and South America. As part of an assessment of the ecology of AIV in Guatemala, we conducted active surveillance in wild birds on the Pacific and Atlantic coasts. Cloacal and tracheal swab samples taken from resident and migratory wild birds were collected from February 2007 to January 2010.1913 samples were collected and virus was detected by real time RT-PCR (rRT-PCR) in 28 swab samples from ducks (Anas discors). Virus isolation was attempted for these positive samples, and 15 isolates were obtained from the migratory duck species Blue-winged teal. The subtypes identified included H7N9, H11N2, H3N8, H5N3, H8N4, and H5N4. Phylogenetic analysis of the viral sequences revealed that AIV isolates are highly similar to viruses from the North American lineage suggesting that bird migration dictates the ecology of these viruses in the Guatemalan bird population.     

Epizootiology of avian cholera in wildfowl

Pasteurella multocida, the cause of avian cholera, has naturally infected over 100 species of free-living birds. Among wild birds, avian cholera has its greatest impact on North American wildfowl. Epizootics usually are explosive in onset and may involve thousands of birds. The disease has been reported in every month of the year among wildfowl. Disproportionate mortality, with some species suffering proportionately greater mortality than others, has been a common feature of this disease. Presence of animal organic matter plays a significant role in the survival of P. multocida. There are conflicting reports or a lack of information on the role of host sex, age, body size, other physical features, genetic variation or behavioral differences, as predisposing factors to infection by P. multocida. There also are ambiguities on the relationship between season, precipitation, temperature, nutritional stress, water quality, other microorganisms, and environmental contaminants, and the occurrence of avian cholera in wildfowl. Two competing hypotheses for the year-round reservoir of wildfowl strains of P. multocida are ambient soil or water of enzootic sites, and carrier animals; most current evidence favors the role of carrier animals. Transmission most likely occurs by ingestion of contaminated water, inhalation of bacteria-rich aerosols, or both. While many techniques have been proposed to prevent or control avian cholera, none have been rigorously tested to determine their effectiveness.     

Ecological Factors Driving Avian Influenza Virus Dynamics in Spanish Wetland Ecosystems

Studies exploring the ecological interactions between avian influenza viruses (AIV), natural hosts and the environment are scarce. Most work has focused on viral survival and transmission under laboratory conditions and through mathematical modelling. However, more integrated studies performed under field conditions are required to validate these results. In this study, we combined information on bird community, environmental factors and viral epidemiology to assess the contribution of biotic and abiotic factors in the occurrence of low pathogenic AIV in Spanish wetlands. For that purpose, seven locations in five different wetlands were studied during two years (2007–2009), including seven sampling visits by location. In each survey, fresh faeces (n = 4578) of wild birds and water samples were collected for viral detection. Also, the vegetation structure, water physical properties of wetlands, climatic conditions and wild bird community composition were determined. An overall AIV prevalence of 1.7%±0.4 was detected in faecal samples with important fluctuations among seasons and locations. Twenty-six AIV were isolated from the 78 RRT-PCR positive samples and eight different haemagglutinines and five neuraminidases were identified, being the combination H3N8 the most frequent. Variation partitioning procedures identified the combination of space and time variables as the most important pure factor – independently to other factors – explaining the variation in AIV prevalence (36.8%), followed by meteorological factor (21.5%) and wild bird community composition/vegetation structure (21.1%). These results contribute to the understanding of AIV ecological drivers in Spanish ecosystems and provide useful guidelines for AIV risk assessment identifying potential hotspots of AIV activity.     

Characterization of Avian-like Influenza A (H4N6) Virus Isolated from Caspian Seal in 2012

正Dear Editor Marine mammals are widely distributed and can be found almost in all coastal waters and coastlines around the world. The interface areas between marine and terrestrial environments provide natural habitats for aquatic and semiaquatic mammals as well as for reservoir species of avian influenza viruses (AIV)(Runstadler et al. 2013). Previous     

Avian influenza virus infection dynamics in shorebird hosts

To gain insight into avian influenza virus (AIV) transmission, exposure, and maintenance patterns in shorebirds at Delaware Bay during spring migration, we examined temporal AIV prevalence trends in four Charadriiformes species with the use of serial cross-sectional data from 2000 through 2008 and generalized linear and additive models. Prevalence of AIV in Ruddy Turnstones (Arenaria interpres morinella) increased after arrival, peaked in mid-late May, and decreased prior to departure. Antibody prevalence also increased over this period; together, these results suggested local infection and recovery prior to departure. Red Knots (Calidris canutus rufa), Sanderlings (Calidris alba), and Laughing Gulls (Leucophaeus atricilla) were rarely infected, but dynamic changes in antibody prevalence differed among species. In Red Knots, declining antibody prevalence over the stopover period suggested AIV exposure prior to arrival at Delaware Bay with limited infection at this site. Antibody prevalence was consistently high in Laughing Gulls and low in Sanderlings. Both viral prevalence and antibody prevalence in Sanderlings varied directly with those in turnstones, suggesting virus spillover to Sanderlings. Results indicate that, although hundreds of thousands of birds concentrate at Delaware Bay during spring, dynamics of AIV infection differ among species, perhaps due to differences in susceptibility, potential for contact with AIV at this site, or prior exposure. Additionally, Ruddy Turnstones possibly act as a local AIV amplifying host rather than a reservoir.     

High Seroprevalence of Antibodies to Avian Influenza Viruses among Wild Waterfowl in Alaska: Implications for Surveillance

We examined seroprevalence (presence of detectable antibodies in serum) for avian influenza viruses (AIV) among 4,485 birds, from 11 species of wild waterfowl in Alaska (1998–2010), sampled during breeding/molting periods. Seroprevalence varied among species (highest in eiders (Somateria and Polysticta species), and emperor geese (Chen canagica)), ages (adults higher than juveniles), across geographic locations (highest in the Arctic and Alaska Peninsula) and among years in tundra swans (Cygnus columbianus). All seroprevalence rates in excess of 60% were found in marine-dependent species. Seroprevalence was much higher than AIV infection based on rRT-PCR or virus isolation alone. Because pre-existing AIV antibodies can infer some protection against highly pathogenic AIV (HPAI H5N1), our results imply that some wild waterfowl in Alaska could be protected from lethal HPAIV infections. Seroprevalence should be considered in deciphering patterns of exposure, differential infection, and rates of AIV transmission. Our results suggest surveillance programs include species and populations with high AIV seroprevalences, in addition to those with high infection rates. Serologic testing, including examination of serotype-specific antibodies throughout the annual cycle, would help to better assess spatial and temporal patterns of AIV transmission and overall disease dynamics.     

Avian influenza a virus in wild birds in highly urbanized areas

Avian influenza virus (AIV) surveillance studies in wild birds are usually conducted in rural areas and nature reserves. Less is known of avian influenza virus prevalence in wild birds located in densely populated urban areas, while these birds are more likely to be in close contact with humans. Influenza virus prevalence was investigated in 6059 wild birds sampled in cities in the Netherlands between 2006 and 2009, and compared with parallel AIV surveillance data from low urbanized areas in the Netherlands. Viral prevalence varied with the level of urbanization, with highest prevalence in low urbanized areas. Within cities virus was detected in 0.5% of birds, while seroprevalence exceeded 50%. Ring recoveries of urban wild birds sampled for virus detection demonstrated that most birds were sighted within the same city, while few were sighted in other cities or migrated up to 2659 km away from the sample location in the Netherlands. Here we show that urban birds were infected with AIVs and that urban birds were not separated completely from populations of long-distance migrants. The latter suggests that wild birds in cities may play a role in the introduction of AIVs into cities. Thus, urban bird populations should not be excluded as a human-animal interface for influenza viruses.     

三江自然保护区野生迁徙水禽携带禽流感病毒和新城疫病毒状况的监测

[目的]为了对途经三江保护区的野生迁徙水禽携带禽流感病毒(AIV)和新城疫病毒(NDV)的状况进行有效监测.[方法]在2005年10月、2006年4月、2006年10月3个候鸟的迁徙季节从三江保护区采集了158只野鸟的咽拭子和肛拭子样本.应用SPF鸡胚盲传、血凝和血凝抑制试验和RT-PCR等方法进行了病毒的分离和鉴定.[结果]结果共分离到20株AIV和13株NDV.20株AIV均来自2006年10月采集的样品,经常规血清学分型鉴定分为12个亚型,11个亚型来源于绿头鸭,分别为H2N2(2/20),H2N6(2/20),H3N4(1/20),H3N6(2/20),H3N7(2/20),H3N8(2/20),H6N2(2/20),H11N2(1/20),H11N3(1/20),H11N5(2/20),H11N6(1/20),另外一株来源于白眉鸭,为H5N2(1/20).13株NDV则来自3个迁徙季节的5种不同水禽采,其中包括绿头鸭(8/13),豆雁(1/13),白额雁(1/13),绿翅鸭(1/13)和鸳鸯(2/13).[结论]这一结果表明,拥有极大种群数量、在世界范围内广泛分布的绿头鸭,被认为可能是AIV和NDV最重要的自然宿主之一,并在病毒的传播上比其他野生鸟类具有更为重要的生态学意义.     

Investigation of Avian Influenza Infections in Wild Birds,Poultry and Humans in Eastern Dongting Lake,China

We investigated avian influenza infections in wild birds, poultry, and humans at Eastern Dongting Lake, China. We analyzed 6,621 environmental samples, including fresh fecal and water samples, from wild birds and domestic ducks that were collected from the Eastern Dongting Lake area from November 2011 to April 2012. We also conducted two cross-sectional serological studies in November 2011 and April 2012, with 1,050 serum samples collected from people exposed to wild birds and/or domestic ducks. Environmental samples were tested for the presence of avian influenza virus (AIV) using quantitative PCR assays and virus isolation techniques. Hemagglutination inhibition assays were used to detect antibodies against AIV H5N1, and microneutralization assays were used to confirm these results. Among the environmental samples from wild birds and domestic ducks, AIV prevalence was 5.19 and 5.32%, respectively. We isolated 39 and 5 AIVs from the fecal samples of wild birds and domestic ducks, respectively. Our analysis indicated 12 subtypes of AIV were present, suggesting that wild birds in the Eastern Dongting Lake area carried a diverse array of AIVs with low pathogenicity. We were unable to detect any antibodies against AIV H5N1 in humans, suggesting that human infection with H5N1 was rare in this region.     

Influenza A viruses in American White Pelican (Pelecanus erythrorhynchos)

The role of many wild waterbird species in the ecology and epidemiology of avian influenza viruses (AIV) remains unclear. We report the first isolation of AIV from American White Pelicans (Pelecanus erythrorhynchos; Pelecaniformes) in North America. Two H13N9 AIVs were isolated from hatchling birds in breeding colonies in Minnesota, USA, during 2007 and 2008. Based on molecular sequencing of the hemagglutinin and neuraminidase genes, the 2008 virus was genetically related to AIVs previously isolated from gulls and shorebirds in North America. The 2007 isolate was most related to AIVs from Eurasian gulls and North American ducks, reflecting both global movement of these viruses and reassortment between viruses associated with duck and gull reservoirs.     

Genetic Structure of Avian Influenza Viruses from Ducks of the Atlantic Flyway of North America

Wild birds, including waterfowl such as ducks, are reservoir hosts of influenza A viruses. Despite the increased number of avian influenza virus (AIV) genome sequences available, our understanding of AIV genetic structure and transmission through space and time in waterfowl in North America is still limited. In particular, AIVs in ducks of the Atlantic flyway of North America have not been thoroughly investigated. To begin to address this gap, we analyzed 109 AIV genome sequences from ducks in the Atlantic flyway to determine their genetic structure and to document the extent of gene flow in the context of sequences from other locations and other avian and mammalian host groups. The analyses included 25 AIVs from ducks from Newfoundland, Canada, from 2008–2011 and 84 available reference duck AIVs from the Atlantic flyway from 2006–2011. A vast diversity of viral genes and genomes was identified in the 109 viruses. The genetic structure differed amongst the 8 viral segments with predominant single lineages found for the PB2, PB1 and M segments, increased diversity found for the PA, NP and NS segments (2, 3 and 3 lineages, respectively), and the highest diversity found for the HA and NA segments (12 and 9 lineages, respectively). Identification of inter-hemispheric transmissions was rare with only 2% of the genes of Eurasian origin. Virus transmission between ducks and other bird groups was investigated, with 57.3% of the genes having highly similar (≥99% nucleotide identity) genes detected in birds other than ducks. Transmission between North American flyways has been frequent and 75.8% of the genes were highly similar to genes found in other North American flyways. However, the duck AIV genes did display spatial distribution bias, which was demonstrated by the different population sizes of specific viral genes in one or two neighbouring flyways compared to more distant flyways.     

Habitat selection and waterbody-complex use by wintering Gadwall and Shoveler in South West London: Implications for the designation and management of multi-site protected areas

The degree to which Special Protection Area (SPA) designation reflects ecological reality is of critical importance to wildlife conservation. We examined whether the designation of a large SPA designated to conserve wintering waterfowl (chiefly Gadwall Anas strepera and Northern Shoveler Anas clypeata), reflected the birds’ habitat preferences and their use of the SPA in the context of the broader geographic area. To do this, 67 discrete waterbodies in and around the South-West London Waterbodies Special Protection Area (SWL SPA) were surveyed regularly each winter from 2004/5 to 2006/7, and new analytical methods developed, to investigate habitat selection and multiple-site use by the birds. Significant pressure on these waterbodies for mineral extraction, development and recreation, together with a long history of human usage has resulted in a wide range of habitats and conditions for these wildfowl.We found that Gadwall and Shoveler were able to adjust their site preferences and patterns of site use in response to changes in food resources and other ecological variables both within and between winters. Akaike's Information Criterion (AIC) was used to model the distribution of wildfowl between sites using a large number of physical and ecological predictor variables. This showed that Gadwall and Shoveler differ in many of their habitat preferences, to the extent that managing a site for one will not necessarily directly benefit the other.At the time of this study the habitat preferences of Gadwall and Shoveler do not closely match the ecological condition of the SWL SPA waterbodies. Furthermore, an investigation into the use of multiple sites by Gadwall and Shoveler indicated that although there is evidence for populations of wintering birds using groups of waterbodies in the SW London area, their patterns of site use do not closely match the distribution of the seven separate SPA component waterbodies.We provide guidelines for managing habitats for Gadwall and Shoveler, and suggest that in addition to bird counts the SPA designation process for multi-site protected areas should consider the behaviour, habitat requirements and the influence of human disturbance on the species concerned. In this instance, the patterns of wildfowl site use present a reasoned argument for the inclusion of additional sites in the SW London Waterbodies SPA, or for dealing with the SPA in a different manner to a site with a more contiguous boundary.