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Aves > Anseriformes > Anatidae > Sarkidiornis

Sarkidiornis melanotos (Pennant, 1769) – Comb Duck

Taxonomic Notes:

Alternative Names: Knob-billed Duck, African Comb Duck or Nakta.

Old Taxonomy: Anas melanotos Pennant, 1769.


Breeding season:
 July–September, Pair-bonds probably temporary.

Nest: In hollows of treen near waterbodies lined with leaves, grasses and feathers.

Eggs: Eggs, 7 -15, pale cream in colour and size 61.8 x 43.3 mm

Indian and global distribution:
records (based on images):

64–79 cm 

Distinguishing characters: 

Male: Upper back is black, glossed with blue-green and purple. Head and neck spotted, a prominent fleshy knob, or comb, on base of bill at forehead, that becomes significantly distended in breeding season.

Female: Similar to male, but without comb on bill and considerably smaller and duller. Bill dark black. 

Young/Immature: Similar to females but not glossy, overall off-white/muddy white, shows a black eye-stripe.

Similar Species in India: Males are distinctive with the knob on beak and cannot be confused with any other species, however, female can be confused with White-winged duck, but absence of white patch on wings sets Knob-billed duck apart.

Sexual, seasonal & individual variation:

This species is sexually dimorphic. Males are easily distinguished from females by having a fleshy knob like extension of beak on the forehead. There is no distinguishable individual and seasonal variation.

Status, Habitat and Habits:

Widespread in Africa S of Sahara, and Madagascar; tropical Asia from Pakistan (where probably extirpated) through Indian Subcontinent to S Indochina. Family parties of 4 to 10 birds but flock of around 20-35 individuals. Strong flight similar to geese; Resident bird with seasonal movement with availability of water. 

Food: Largely herbivorous feeding on shoots and seeds of aquatic and marsh plants, grains of wild and cultivated rice. Also, aquatic insects and their larvae; occasionally frogs and fish.

Call/Song: Usually silent with low harsh croak. A ' fine loud honk ' in the breeding season by male.

Migration Status: Resident.

IUCN Status: 
Least Concern.


1. Rasmussen, P. C., and J. C. Anderton. 2005. Birds of South Asia: The Ripley Guide. Washington, DC.

2. Ali, S., and S. D. Ripley. 1968. Handbook of the Birds of India and Pakistan: Together with those of Nepal, Sikkim, Bhutan and Ceylon (Vol. 1). Oxford University Press.

3. Stuart Baker, E. C. 1933. The Nidification of Birds of the Indian Empire. Taylor And Francis.

4. BirdLife International. 2016. Sarkidiornis melanotosThe IUCN Red List of Threatened Species 2016: e.T45953631A95159254.

Aves > Anseriformes > Anatidae > Sarkidiornis

Cite this page along with its URL as:
Satose, V., and A. Bayani. 2023. Sarkidiornis melanotos (Pennant, 1769) – Comb Duck. Satose, V., A. Bayani, V. Ramachandran, P. Roy, and K. Kunte (Chief Editors). Birds of India, v. 2.17. Indian Foundation for Butterflies.
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