African comb duck
The knob-billed duck (Sarkidiornis melanotos ), or African comb duck, is a duck found in tropical wetlands in Sub-Saharan Africa, Madagascar and the Indian Subcontinent from northern India to Laos and extreme southern China.
Most taxonomic authorities split this species and the comb duck from each other. The supposed extinct "Mauritian comb duck" is based on misidentified remains of the Mauritius sheldgoose (Alopochen mauritiana ); this was realized as early as 1897, but the mistaken identity can still occasionally be found in recent sources.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Precocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans. They ...
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SocialFlocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
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MigratingAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migrati...
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starts withThis common species is unmistakable. It is one of the largest species of duck. Length can range from 56 to 76 cm (22 to 30 in), wingspan ranges from 116 to 145 cm (46 to 57 in) and weight from 1.03 to 2.9 kg (2.3 to 6.4 lb). Adults have a white head freckled with dark spots, and a pure white neck and underparts. The upperparts are glossy blue-black upperparts, with bluish and greenish iridescence especially prominent on the secondaries (lower arm feathers). The male is much larger than the female, and has a large black knob on the bill. Young birds are dull buff below and on the face and neck, with dull brown upperparts, top of the head and eyestripe. Knob-billed ducks are generally larger in size when compared to comb ducks, and flanks are usually lighter (light grey, in females sometimes whitish).
Immature knob-billed ducks look like a large greyish female of the cotton pygmy goose (Nettapus coromandelicus ) and may be difficult to tell apart if no other birds are around to compare size and hue. However, knob-billed ducks in immature plumage are rarely seen without adults nearby and thus they are usually easily identified too.
The knob-billed duck is silent except for a low croak when flushed.
It breeds in still freshwater swamps and lakes in the tropics. It is largely resident, apart from dispersion in the wet season.
This duck feeds on vegetation by grazing or dabbling and to a lesser extent on small fish, invertebrates, and seeds. It can become a problem to rice farmers. Knob-billed ducks often perch in trees. They are typically seen in flocks, small in the wet season, up to 100 in the dry season. Sometimes they separate according to sex.
The knob-billed duck is declining in numbers locally, but due to its wide range it is not considered globally threatened by the IUCN. It is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies.
African birds breed during and after the rainy season and may not breed if the rain is scanty. Knob-billed ducks nest mainly in tree holes, also in tall grass.
Males may have two mates at once or up to five in succession. They defend the females and young but not the nest sites.
Females lay 7 to 15 yellowish-white eggs.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...