Female Knob Billed Duck (Sarkidiornis melanotos) Joel Sartore This is the KNOB BILLED DUCK, also known as the African Comb Duck (Sarkidiornis melanotos) This striking waterfowl is instantly recognizable by the large black knob on the bill of adult This bird wears its crown not of feathers, but of horn. The Knob billed Duck (Sarkidiornis melanotos), also known as the Comb Duck, is one of the most unmistakable waterfowl in the world. Avise's Birds of the World