The knob-billed duck (Sarkidiornis melanotos), or comb duck, is an unusual, pan-tropical duck, found in tropical wetlands in sub-Saharan Africa, Madagascar and south Asia from Pakistan to Laos and extreme southern China. It also occurs in continental South America south to the Paraguay River region in eastern Paraguay, southeastern Brazil and the extreme northeast of Argentina, and as a vagrant on Trinidad.

It is the only known species of the genus Sarkidiornis. The supposed extinct "Mauritian comb duck" is based on misidentified remains of the Mauritian shelduck (Alopochen mauritianus); this was realized as early as 1897, but the mistaken identity can still occasionally be found in recent sources.
Comb Duck
Date Location Count
2021-05-21 10:31Etosha NP--Andoni Plains22
2021-05-18 08:40Shankara Rest Camp1
2021-06-10 05:33Murchison Falls NP--general area (please be more specific)1
2021-05-16 07:04Namushasha Lodge & Campground1
2021-05-18 07:07Caprivi Houseboat Lodge1
2021-05-21 10:30Mabamba Swamp2
2021-06-08 08:07Katombora3
2021-05-25 17:25Royal Chundu Lodge1
2021-06-12 06:30Maasai Mara NR* general (please use more precise location)2
2021-06-14 06:45Lake Baringo--West Shore (incl. Baringo Club and Robert's Camp and airstrip)4
2021-06-14 13:01Rondevlei Nature Reserve1
2021-06-03 13:45Strandfontein WTP1
2021-05-25 13:27Nkwali Camp1
2021-06-04 05:52South Luangwa NP--Mfuwe Lodge1
2021-05-30 06:11Luambe NP20
2021-06-12 09:30Nairobi NP2
2021-06-10 08:30Zaagkuildrift Rd (Please be more specific; Do not log Kgomo-Kgomo birds here.)5
2021-05-18 07:00Arabuko-Sokoke Forest5
2021-06-03 16:10Gonarezhou NP--Chipinda Pools2
2021-05-23 07:06Ranjitsagar Dam8
2021-05-20 14:27Khijadiya Bird Sanctuary
2021-06-14 00:20Narsinh Mehta Lake9
2021-06-06 17:20Khirasara Vidi2
2021-05-28 09:20Nikol Bandhara2
2021-06-05 07:19Nalsarovar--Flamingo Sankul4
2021-05-30 09:00Vishal's home2
2021-05-31 07:11Thol Lake View, Dipeshwari Temple60
2021-05-19 07:41Rancharda Lake1
2021-06-04 08:50Ratna Lake2
2021-06-03 10:45Gatehara Lake2
2021-06-06 06:06Vikram Nagar Housing Colony2
2021-06-09 17:14Indroda Nature Park4
2021-06-13 07:04Narmada Canal, Karai4
2021-06-03 18:00Sant Sarovar2
2021-05-16 12:20GEB Ash Pond, Pethapur4
2021-06-14 07:30Pariej Lake3
2021-05-20 09:25Wagh Bakri Tea Factory1
2021-06-05 06:46Sindhrot Nature Education Park1
2021-06-13 15:30Timbi Lake30
2021-06-05 07:00Jhal Thikriwala- Punjab4
2021-06-08 17:02Raiwasa Lake & surroundings3
2021-06-01 06:18Urban Estate Area Jalandhar Punjab1
2021-06-01 14:30Alania Dam28
2021-05-28 10:56Bhindawas Bird Sanctuary3
2021-06-06 08:50Mirzapur Check Dam6
2021-06-06 07:11Siswan Dam1
2021-05-23 06:00Siswan-Old Siswan road4
2021-05-30 07:25Hatnur Dam (IBA)26
2021-06-12 06:55Palighat, Chambal River (OBI)25
2021-06-01 08:47Kheda Jhanjraula (OBI)4
2021-06-12 16:09Dharampur (Najafgarh) Gurgaon2
2021-05-30 07:11Mas Reservoir and Spillway5
2021-06-14 06:20Bharatpur--Keoladeo Ghana NP--Sapan Mori2
2021-06-14 08:27Dhanauri Wetlands7
2021-06-01 18:14Ankasamudra Bird Sanctuary ಅಂಕಸಮುದ್ರ ಪಕ್ಷಿಧಾಮ1
2021-05-22 06:35Gokul Dham3
2021-05-24 16:28Wildlife Institute of India Campus3
2021-06-01 12:50Sajanpur Pili2
2021-06-07 07:13Sivandipatti Lake & Grassland40
2021-06-13 17:15Koonthakulam Bird Sanctuary
2021-06-13 15:45Kandan Kulam