This species is named for the unusual knob at the base of the male's bill.
Sarkidiornis melanotos and S. sylvicola were previously lumped as Sarkidiornis melanotos following Sibley and Monroe (1990, 1993). Occasional treatment as full species (del Hoyo and Collar 2014) justifiable on basis of slightly smaller size (mean male wing 336 vs 360, mean male bill 56 vs 62) (allow 1); glossy blackish-grey vs matt greyish-white flanks (3); glossy blackish-grey vs matt greyish-white back and rump (extension of flanks, but notable in flight and wing-flapping; score 1); fully developed comb proportionately different, rising more at right angles from forehead and usually curving over more smoothly, forming disc-shape more than sail-shape, whereas in melanotos it rises at a forward angle in a longer straight line, curving at apex more sharply, so that surface area is larger and leading edge forms a longer vertical (2). Studies of voice and behaviour to supplement these distinctions needed. Source: http://www.hbw.com/species/american-comb-duck-sarkidiornis-sylvicola
The African Comb Duck (Sarkidiornis melanotos) is found throughout much of Africa, south of the Sahara and Madagascar. This species can also be found on the Indian subcontinent, Sri Lanka, Burma and Thailand. The South American Comb Duck, is native to the tropical regions of South America.
Both species are similar in appearance. The African is larger than the American, and has gray sides and flanks. The American subspecies has black flanks, but both share the spotted head. The hen of this species is much smaller than the male, and does not have the comb on the bill or black band of the breast.
Comb Ducks are a cavity nester and need a nest box to nest. Boxes can be raised or placed on the ground with the entrance hole at least 5 inches in diameter. There are exceptions as they will sometimes build a ground nest among thick vegetation. The hen incubates her clutch of 6 to 8 eggs for about 30 days. Unlike other species, the hen does not line her nest with down.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern (IUCN, 2014). Estimated as perhaps 25,000-100,000 individuals overall (Kear et al. 2005).
Mainly sedentary with seasonal or nomadic movements related to water availability; congregates in large numbers at few sites during the dry season This species inhabits grassy ponds or lakes in llanos, along large rivers and lakes (Johnsgard 1978), swamps (del Hoyo et al. 1992), marshes, floodplains, river deltas (Kear 2005a), flooded forest, pastures and rice-paddies (Kear 2005a) and occasionally sandbars and mudflats (Johnsgard 1978). Its diet is assumed to be similar to that of S. melanotos, though there is little specific data (Kirwan 2013).
Deforestation is likely to affect the species, as is the indiscriminate use of poison to control pests in rice fields (Kirwan 2013). Overhunting may be a problem in parts of the range such as in north east Brazil (Kirwan 2013).
Aviculture (ex-situ)
This species is not often seen in private collections. They are tropical and require heat during the cold Winter months. Comb Ducks are generally peaceful and do well in a mixed aviary, but males should be watched as they can be somewhat aggressive during the breeding season.
Above: adult male Sarkidiornis sylvatica
Above: Female Sarkidiornis sylvatica
Above: juvenile male Sarkidiornis sylvatica
Above: Females Sarkidiornis sylvatica