BackgroundThere is insufficient knowledge about the relation of avian influenza virus (AIV) to migratory birds in South America. Accordingly, we studied samples obtained over a 4‐year period (2009‐2012) from wild birds at a major wintering site in southern Brazil.MethodsWe obtained 1212 oropharyngeal/cloacal samples from wild birds at Lagoa do Peixe National Park and screened them for influenza A virus by RT‐PCR amplification of the matrix gene. Virus isolates were subjected to genomic sequencing and antigenic characterization.ResultsForty‐eight samples of 1212 (3.96%) contained detectable influenza virus RNA. Partial viral sequences were obtained from 12 of these samples, showing the presence of H2N2 (1), H6Nx (1), H6N1 (8), H9N2 (1), and H12N5 (1) viruses. As H6 viruses predominated, we generated complete genomes from all 9 H6 viruses. Phylogenetic analyses showed that they were most similar to viruses of South American lineage. The H6N1 viruses caused no disease signs in infected ferrets and, despite genetic differences, were antigenically similar to North American isolates.ConclusionsLagoa do Peixe National Park is a source of multiple AIV subtypes, with the levels of influenza virus in birds being highest at the end of their wintering period in this region. H6N1 viruses were the predominant subtype identified. These viruses were more similar to viruses of South American lineage than to those of North American lineage.

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ResumoDurante o presente estudo foram registradas no PMMM 103 espécies, sendo 15,7% residentes, 40,2% prováveis residentes e 44,1% ocasionais ou sobrevoantes. Onívoros e insetívoros somam 73,5%. Área úmida e campo são os hábitats mais utilizados, seguido de mata ciliar. A riqueza difere significativamente entre hábitats e estações do ano, enquanto que na interação hábitats/estações do ano não diferiu. A abundância entre hábitats não diferiu significativamente, mas difere significativamente entre estações do ano e na interação hábitats/ estações do ano.Unitermos: área úmida, área urbana, aves, conservação de aves, guilda alimentar AbstractTrophic structure and habitat occupation of avifauna in a Porto Alegre urban park. During the present study, 103 species were registered in the Parque Marechal Mascarenhas de Moraes (PMMM). Of these species, 15.7% were resident, 40.2% were probably resident, and 44.1% were occasional or overfliers. Omnivores and insectivores were the feeding guilds with the highest representation in the park, constituting 73.5% of the avifauna. The humid areas and fields were the habitats of the majority of the avifauna, followed by the ciliar forest. Comparing the richness of birds in the different habitats, significant differences were observed in the different seasons of the year during the study. However, regarding the interaction between habitats and seasons of the year, there were no significant differences. Comparing the abundances of birds in the different habitats, there were no significant differences, but they did differ significantly between seasons and also between the interactions of habitats and seasons.

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