The knob billed duck (Sarkidiornis melanotos) or African comb duck is a type of duck found along the tropical sub tropical wetlands and waterways of Sub Saharan Africa and the island of Madagascar, as Knob billed Duck Sarkidiornis melanotos Barraimaging Details : Knob billed Duck BirdGuides Knob billed Duck The Knob billed Duck (Sarkidiornis melanotos), a large and distinctive waterfowl recognized by the bold black knob on the male's bill. This comb like structure becomes more prominent during breeding season and likely helps