The avian biogeography of an Amazonian headwater: the Upper Ucayali River, Peru

摘要: Abstract The Ucayali River is a major tributary of the Amazon, but it narrows considerably toward its headwater at base Andes. This region, upper Valley, biological interest for large number closely related birds elsewhere separated from each other by rivers that come into close proximity and potential contact. Between 2006–2011, we conducted first modern ornithological inventory sampled localities in all avian habitats on either side river. We document continued importance as biogeographic barrier, even headwater, also find some mixing occurs, both form taxa crossing to “wrong” bank intergradation distinct forms. describe biogeography characterize avifaunas habitats, discuss detail species particular biogeographical interest.