Influence of lagoons size and prey availability on the wading birds (Ciconiiformes) in the upper Paraná river floodplain, Brazil

Abstract

The influence of lagoons size and prey availability on the Ciconiiformes in the upper Paraná river floodplain, Brazil, were analysed. The Ciconiiformes census was conducted quarterly in 2002, simultaneously to the fish census (gill nets and seining nets). There was strong relationship between the lagoons size and birds abundance, but modest relationship of lagoons size with the birds diversity and number of species. The presence of Ciconiiformes in the lagoons was better predicted by the fish density in seining nets than by the fish capture by unit of effort in gill nets. Except in the flood, there was strong relationship between the fishes density and birds relative abundance, and more modest relationship of the fishes density with birds diversity and number of species. The lagoon's size and prey availability were strong predictors of Ciconiiformes abundance and relative abundance, respectively. However, environmental variables not analysed probably could have significant influence in the determination of the birds diversity and number of species.