Sarkidiornis melanotos Monaco Nature Encyclopedia African Comb Duck Sarkidiornis melanotos Borrow others' nests Comb Duck, or Knob billed Duck males have a large growth, or comb, on the top of their black beak. During breeding season, the male's The Knob billed Duck (Sarkidiornis melanotos) is hard to missthe males grow a huge black knob on top of their bill during the breeding season. Found across Africa and South Asia, these ducks Knob billed duck Facts, Diet, Habitat & Pictures on Animalia.bio Knob billed Duck eBird