Comb duck Male or Knob-billed duck with comb IN Breeding season नकटा, नक्टा बदक .राजुरा तलाव अमरावती
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Comb duck description
Kingdom Animalia.. Phylum Chordata Class Aves Order Anseriformes Family Anatidae Genus Sarkidiornis
The goose-like comb duck gets its common name from the large, fleshy, dark grey growth or ‘comb’ on the top of the male’s black beak , an unusual and distinctive structure which enlarges during the breeding season . Male comb ducks are large birds, with glossy blue-black or green-black upperparts, tail and wings, white underparts and pale grey or black flanks. The top of the head and back of the neck are black, and the rest of the head is white, speckled black, with yellow tinges on the sides and on the neck during the breeding season. Narrow black bands run along the sides of the upper breast. The comb duck’s legs and feet are dark grey, and the eyes dark brown. Females are much smaller than males, with less glossy plumage, less well-defined black breast bands, more speckling on the head, which lacks any yellowish tinge, and sometimes with brownish mottling on the underparts. Females may appear almost white, and also lack the male’s ‘comb’ . Young comb ducks are brownish, with a dark eye-stripe, and attain adult plumage in the second year .
There are two subspecies of comb duck: the Old World comb duck, Sarkidiornis melanotos melanotos, and the South American comb duck, Sarkidiornis melanotos sylvicola, which was previously treated as a separate species and is still considered a full species by some . South American comb ducks are distinguished from their Old World counterparts by their smaller size, smaller comb, and black rather than grey sides and flanks, which are dark grey or brown in the female
Also known asblack-backed goose, Knob-billed duck, knob-billed goose.FrenchCanard à bosse.SizeLength: 56 - 76 cm
Weight1.2 - 2.6 kg.
Comb duck biology
BComb ducks are usually found in single pairs or, particularly in parts of Africa, small groups (harems) during the breeding season, and in groups of up to 30 to 40 birds at other times, when they may join flocks of other wildfowl. Harems are not known in Asia, and the species’ social structure is poorly known in South America . The diet consists mainly of vegetable matter, such as aquatic vegetation, seeds of grasses and sedges, grain (including crops such as rice and corn), as well as various invertebrates, such as aquatic insect larvae and locusts . Comb ducks usually nest close to water, in large tree cavities, holes in the walls of isolated buildings, abandoned nests of other birds, including that of the hamerkop (Scopus umbretta), or sometimes on the ground. The nest is a rough structure built from twigs and course grass, and is lined with grass, leaves and feathers. The breeding season is variable, but usually coincides with the rainy season. In some areas comb ducks are monogamous, while in others males may hold small harems of two to four females, which they defend against other males.Between 6 and 20 eggs may be laid.though nests sometimes contain the eggs of more than one female. Incubation lasts 28 to 30 days, and is performed exclusively by the female. Within just a day or two of hatching, the ducklings leap from the nest, which may be up to 12 metres above the ground. when summoned by the female.Fledging occurs at about ten weeks .
Comb duck habitat
Swamps, rivers and lakes in open or lightly wooded areas, as well as more open grassland, marshes, floodplains, flooded forest, pastures and rice-paddies .Comb ducks are also often seen away from water, flying over woodland or perched in dead trees .Although mainly found in lowlands, they have also been reported up to elevations as high as 3,500 metres .
The comb duck has a wide distribution across sub-Saharan Africa, Madagascar, South and Central America, and tropical Asia, including Cambodia, China, India, Japan and Vietnam. S. m. sylvicola is found throughout South America, east of the Andes, as well as in Panama and Trinidad, while S. m. melanotos is found in Africa and Asia (India to South East Asia). In parts of Africa, comb ducks are partially migratory, undertaking sometimes extensive seasonal journeys in response to dry season water availability .