Timing and location of reproduction in African waterfowl: an overview of >100 years of nest records

The timing and location of reproduction are fundamental elements of reproductive success for all organisms. Understanding why animals choose to reproduce at particular times and in particular places is also important for our understanding of other aspects of organismal ecology, such as their habitat requirements, movement strategies, and biogeography. Although breeding patterns in waterfowl are relatively well documented, most studies are from northern temperate regions and the influences of location and time of year on breeding in Afrotropical ducks (Anatidae) are poorly understood. We outline six alternative (but not mutually exclusive) hypotheses that might explain where and when Afrotropical ducks choose to breed. To explore these hypotheses, we assembled and analyzed a new database of c.22,000 breeding records for 16 Afrotropical ducks and one introduced Palearctic species (the Mallard Anas platyrhynchos). The full database is available on line as an appendix to this article. We identified five distinct breeding strategies as well as two outliers. Peak breeding for 9 of 16 indigenous duck species occurs during the dry season. We found no evidence for spatial synchrony or spatial autocorrelation in breeding, suggesting a high level of flexibility in waterfowl responses to prevailing conditions in any given year. More intensive analyses of alternative hypotheses are needed, but our initial analysis suggests that the timing of breeding for the majority of Afrotropical ducks is driven by a combination of resource availability and predation risk

infection in wildfowl: a continental-scale study across Africa Understanding the ecological drivers of avian influenza virus

Despite considerable effort for surveillance of wild birds for avian influenza viruses (AIVs), empirical investigations of ecological drivers of AIV prevalence in wild birds are still scarce. Here we used a continental-scale dataset, collected in tropical wetlands of 15 African countries, to test the relative roles of a range of ecological factors on patterns of AIV prevalence in wildfowl. Seasonal and geographical variations in prevalence were positively related to the local density of the wildfowl community and to the wintering period of Eurasian migratory birds in Africa. The predominant influence of wildfowl density with no influence of climatic conditions suggests, in contrast to temperate regions, a predominant role for inter-individual transmission rather than transmission via long-lived virus persisting in the environment. Higher prevalences were found in Anas species than in non-Anas species even when we account for differences in their foraging behaviour (primarily dabbling or not) or their geographical origin (Eurasian or Afro-tropical), suggesting the existence of intrinsic differences between wildfowl taxonomic groups in receptivity to infection. Birds were found infected as often in oropharyngeal as in cloacal samples, but rarely for both types of sample concurrently, indicating that both respiratory and digestive tracts may be important for AIV replication. Keywords: influenza A virus; pathogen transmission; disease ecology; wild birds; tropical; migratio

Size of black patches and spots on the upperwing and underwing greater secondary coverts in selected feathers are not good indicators of age and sex in Cape Vultures Gyps coprotheres

Cape Vultures Gyps coprotheres have black patches on their upperwing greater secondary coverts and black spots on their underwing greater secondary coverts. These have been physically observed to differ with individuals. This study examined the effects of age in years and sex on the size of the patches and spots using computer feather image analysis of birds with known ages in order account for differences that pure observation alone could possibly miss. Despite statistical analysis of computer enhanced imagery of micro detail the chosen plumage pattern failed to yield a reliable way to age and sex Cape Vultures. Annual moult is not expected in this species making the correlation of moult to age a muddle as it is also influenced by external factors such as captivity, stress, food, endocrine (sexual changes), and latitude. This study was limited by the lack of understanding of the exact moulting sequence of upperwing and underwing greater secondary coverts of the Cape Vulture, and as a direct result of this, analysis of the chosen plumage was maintained instead of the feather that is moulted in that particular year

Report on a five-year avian influenza survey in the manyame catchment

We report on an avian influenza virus (AIV) project implemented in the Manyame catchment between 2007 and 2011. This project was undertaken as collaboration between two larger programmes, GRIPAVI (Cirad) and SA-GAINS (PFIAO, Univ. of Cape Town). We found persistence of low pathogenic AIV in waterfowl between May 2007 and November 2008 and potential for AIV transmission between wild and domestic birds. The approach that we developed in this project, which integrated ecology and epidemiology (both academic and applied), has tremendous potential for future work in the domain of disease ecology at the wildlife/domestic animal interface

Avian viral pathogens in swallows, Zimbabwe infectious diseases in <em>Hirundinidae</em>: A risk to swallow?

International audienceWe sampled 417 swallows in a wetland ecosystem of Zimbabwe in February 2010 and October 2011. RT-PCR tests revealed circulation of avian paramyxovirus type I, avian influenza and West Nile disease viruses in these populations. We discuss the relevance of these findings in relation to what is known on the epidemiology of these viruses in these hosts and in relation to the host ecology. We conclude with recommendations to focus more research on Passeriformes in disease ecology and in particular on the hirundinidae family

Factors influencing long-term and seasonal waterbird abundance and composition at two adjacent lakes in Zimbabwe

The spatial and temporal structures of waterbird communities are dynamic and complex with many driving factors. We used long-term waterbird census data at two lakes in Zimbabwe to explore the ecological and anthropogenic drivers of waterbird community composition and abundance. Ecological drivers predicted to influence waterbird communities include rainfall quantity and distribution, waterbird movement, breeding and moulting; anthropogenic drivers include activities such as fishing and agriculture. Results suggest that seasonal variations in resource availability influenced the waterbird community composition and abundance, as did movements at local, regional, and intercontinental scales. Bird numbers in the two perennial lakes experienced large changes in structure during two droughts. We also used the study as a baseline for considering the risk of spread of avian influenza virus (AIV) spread in waterbird communities in Zimbabwean lakes, which is likely to be higher in dry seasons and during drought years when waterbird abundance is high. Our study emphasises the importance of long-term ecological data in understanding crucial aspects of biodiversity conservation as well as pathogen dynamics in wild waterbird communities, with important management implications.OSTRICH 2012, 83(2): 69&#8211;7

Empirical analysis suggests continuous and homogeneous circulation of Newcastle disease virus in a wide range of wild bird species in Africa

International audienceNewcastle disease (ND) is one of the most important poultry diseases worldwide and can lead to annual losses of up to 80% of backyard chickens in Africa. All bird species are considered susceptible to ND virus (NDV) infection but little is known about the role that wild birds play in the epidemiology of the virus. We present a long-term monitoring of 9000 wild birds in four African countries. Overall, 3.06% of the birds were PCR-positive for NDV infection, with prevalence ranging from 0% to 10% depending on the season, the site and the species considered. Our study shows that ND is circulating continuously and homogeneously in a large range of wild bird species. Several genotypes of NDV circulate concurrently in different species and are phylogenetically closely related to strains circulating in local domestic poultry, suggesting that wild birds may play several roles in the epidemiology of different NDV strains in Africa. We recommend that any strategic plan aiming at controlling ND in Africa should take into account the potential role of the local wild bird community in the transmission of the disease

Understanding the ecological drivers of avian influenza virus infection in wildfowl: a continental-scale study across Africa

Despite considerable effort for surveillance of wild birds for avian influenza viruses (AIVs), empirical investigations of ecological drivers of AIV prevalence in wild birds are still scarce. Here we used a continental-scale dataset, collected in tropical wetlands of 15 African countries, to test the relative roles of a range of ecological factors on patterns of AIV prevalence in wildfowl. Seasonal and geographical variations in prevalence were positively related to the local density of the wildfowl community and to the wintering period of Eurasian migratory birds in Africa. The predominant influence of wildfowl density with no influence of climatic conditions suggests, in contrast to temperate regions, a predominant role for inter-individual transmission rather than transmission via long-lived virus persisting in the environment. Higher prevalences were found in Anas species than in non-Anas species even when we account for differences in their foraging behaviour (primarily dabbling or not) or their geographical origin (Eurasian or Afro-tropical), suggesting the existence of intrinsic differences between wildfowl taxonomic groups in receptivity to infection. Birds were found infected as often in oropharyngeal as in cloacal samples, but rarely for both types of sample concurrently, indicating that both respiratory and digestive tracts may be important for AIV replication