Waterbirds in the jungle?! 25 years of censuses

Within the framework of the Neotropical Waterbird Census (Wetlands International), 31 winter and summer censuses were conducted, by canoeing at three sites in the Iguazú National Park, Misiones, Argentina. The sites differ in terms of flow and physiognomy: the Iguazu River with and without islands and the Yacuy stream. Seventeen species of aquatic birds and three species of Alcedinidae were detected; 2-10 species were observed per season of the year and no one season had greater richness. Between seasons of the same year, there were increases from zero to six species, with turnover. In the summer some species are much more frequent and abundant: Butorides striatus, Nycticorax nycticorax, Megaceryle torquata and Chloroceryle americana, and in winter: Mesembrinibis cayennensis. The richest summers were in 1993 and 2015 (10 spp) and the winter of 2012 (nine spp), the richest year was 2013 (11 spp). The richest site was the Iguazu River with islands, with an average of four spp/10 Km, then the Yacuy stream, with two spp/10 km and the Iguazú River without islands with 1.1 spp/10 Km. The Iguazú River without islands was the only site where Egretta thula, Cochlearius cochlearius and Amazonetta brasiliensis were recorded. In the Iguazú NP, the most abundant species were Phalacrocorax brasiliensis with an average of 11 ind./10 Km; Chloroceryle amazona with 1.7 ind./10 km and Butorides striatus with 1.1 ind./10 Km. Other frequent but less abundant species were: Anhinga anhinga, Mesembrinibis cayennensis, Cairina moschata, Megaceryle torquata and Chloroceryle americana.