Notes on the breeding biology of birds in riverine floodplains of western Amazonia

New information on the breeding biology of six bird species from riverine floodplains in Brazilian and Ecuadorian Amazonia has been presented. The study sites are located in the Madeira River, near Porto Velho, Rondônia, Brazil, and the Napo River in eastern Ecuador. The Madeira River is the largest muddy-water affluent of the Solimões / Amazonas system, accounting for 50% of sediment input and 15% of total discharge in the Solimões / Amazonas system. The breeding biology of the White-bellied Spinetail Mazaria propinqua has been described for the first time. The nest was an enclosed, globular mass of dry vegetative material, entered via a laterally oriented tube, and sited 60 cm above ground. It was supported from below by three nearly horizontal crisscrossed stalks of Gynerium cane and many smaller stems and leaf blades. The nest was 300 mm long, including the globular portion that contained the nest chamber and the 120 mm-long entrance tube. The breeding biology of the White-bearded Hermit Phaethornis hispidus has also been studied. The nest was a funnel-shaped cup, sited 1.01 m above ground in a Costus plant. The cup measured 31 × 52 mm internally, and was 130 mm tall externally, with an elongated 'tail' of 70 mm at the base of the cup. The nest comprised fine, pale, dry palm fibres, tightly bound with spider webs, and attached to the underside of a damaged strip of leaf. The breeding biology of the Plain-winged Antshrike Thamnophilus schistaceus has been observed. A single fledgling was found, perched 2 m above ground. Nests have been described from Brazil in February and October, and from Peru in March and September. The breeding biology of the Plain-winged Antshrike is characterized by a single fledgling being found, suggesting that the young had probably fledged the same or previous day. The breeding biology of birds in riverine floodplains of western Amazonia is a complex and multifaceted topic. The study of the breeding biology of six bird species from riverine floodplains in Brazilian and Ecuadorian Amazonia has provided new insights into the natural history of birds in floodplain forests. The data presented contribute to our cumulative knowledge of the natural history of birds in floodplain forests, a historically neglected environment in the Amazon. The breeding biology of birds in riverine floodplains of western Amazonia is influenced by the unique characteristics of the floodplain environment. The floodplain environment is characterized by periodic flooding, which can have a significant impact on the breeding biology of birds. The study of the breeding biology of birds in riverine floodplains of western Amazonia highlights the importance of understanding the complex interactions between birds and their environment.