Recently, Jason T. Weir (University of Toronto Scarborough) and colleagues published a paper on the role of rivers in the origin of Amazonian bird species. In this paper, they also present genetic evidence (based on thousands of SNPs) for hybridization between seven bird species pairs at Amazonian headwaters. The hybridizing species belong to three different passerine families: Furnariidae (Ovenbirds), Pipridae (Manakins) and Thamnophilidae (Antbirds). Consequently, these pages have been updated!
Weir, J. T., Faccio, M. S., Pulido-Santacruz, P., Barrera-Guzman, A. O. & Aleixo, A. (2015). Hybridization in headwater regions, and the role of rivers as drivers of speciation in Amazonian birds. Evolution 69, 1823-1834.