The white-winged black tyrant (Knipolegus aterrimus ) is a species of bird in the family Tyrannidae. It has often included the Sao Francisco black tyrant (K. franciscanus ) as a subspecies.It is found in Argentina, Bolivia, Chile, Paraguay, Peru, and Uruguay.Its natural habitats are subtropical or tropical moist montane forests, subtropical or tropical moist shrubland, and heavily degraded former forest.