What to Know About the Knob-billed Duck in Uganda?

The Knob-Billed Duck in Uganda is one of the African Uganda Bird Species seen during Uganda Birding watching tours.

Scientifically referred to as the sarkidiornis melanotos, the knob billed duck which is sometimes also known as the African Comb duck is a bird species which that is found dwelling within the tropical wetlands in Madagascar, Sub Saharan Africa and extreme Southern China along with South Asia from Pakistan to Laos. It is made up by two sub species that include S.m. melanotos ranging from Africa South of the Sahara and Madagascar together with Tropical Asia mainly from Pakistan through Indian to S. China. The S.m. Sylvicola in which the race sylvicola is being considered as full species under the name Comb Duck and found inhabiting Tropical South America to N. Argentina from Colombia.

Physical description of the Knob Billed duck

This  Knob billed duck is characterized with a distinctive appearance and a fleshy knob of the male. It is a large bird species measuring about 56 to 76 centimeters and having a weight that ranges between 1,250 to 2,600 grams.

The adult male duck species features upperparts that are blackish in colour together with green, bluish purple and bronze gloss wing coverts and secondary flight feathers. It comprises of the white underparts that do bare grey flanks and narrow black bars on breast sides along with greyish rump.

It bares a white head and neck with black speckles. The bird’s undertail coverts are painted with white colour though often tinged yellow and the nape along with crown do bare black spots in which they almost appear black in colour.

Knob billed duck is characterized with a fleshy and prominent black knob located at the base of the upper mandible. It also features dark brown eyes and a bill that is black in colour together with the blackish webbed feet and legs.

Within the breeding knob billed species, the sides of the head and neck turn buff-yellowish with the knob being much larger. Both the male and female duck species are similar though the female lacks the fleshy knob and it is smaller and duller than the male hence baring less glossy layer feathers.

Juvenile Knob billed duck species features a generally brownish colour hence having a dark brown upperparts and crown along with scaled underparts.

Behaviour of the Knob billed duck species

This bird species normally clings into trees due to its strong claws. It is mostly seen singly and in colonies of small groups of about 30 to 40 duck species. During the feeding period, the knob billed duck species feeds both in water and on land where it grazes and eats terrestrial insects hence swimming in shallow water, dabbling and walking slowly while feeding on plants such as seeds of grasses, acquatic plants, sedges, invertebrates and small fish.

The Knob billed duck occassionally gather in larger flocks during the dry season at permanent waters thereby forming pairs at the beginning of the rainy season.  It spends most of the time resting on bank during day and feeding is done mainly in the late evening and early morning.

During the breeding period, this duck species is strongly territorial though outside the nesting season its fairly gregarious. Breeding occurs in loose colonies and the dominant male copulates with two or more breeding female species and it normally defends only its family rather than the entire nest site.

This duck species is mainly a sedentary bird in its range and it participates in dispersions and seasonal movements which occurs according to the availability of water. Normally the solitary male Knob billed duck species perches in trees from where it watches over the flocks and swoop down during the mating period to mate with the female.

While in flight, the duck species performs slow but steady wingbeats that are noisy and flies in irregular formation, V-formation or single file lines hence a good flier which moves insearch of water and food.

Generally the knob billed duck is a silent bird species though it may sometimes utter a low croaking sound. It releases whistle calls and grunts during the breeding and also when involved in a fight.

This duck species inhabits the wet areas such as rivers, lakes with scattered trees and swamps although sometimes occurs in more open grasslands and lowlands in the tropical regions.

The Breeding and Reproduction process of the Knob billed duck

During the breeding period  which occurs after the rainy season, the knob billed duck mainly breeds in the holes of dead trees measuring between 6 to 9 metres above the ground and also rarely far from water. Both the and female species do participate in the construction of the nest which is made of sticks with coarse grass and lined with softer materials such as feathers, reeds, leaves along side grass occasionally in tall grass on the ground or amongst the stones near water and this very nest is used year after year.

The adult female Knob billed duck species during the reproduction process, it lays a maximum number of 7 to 15 yellowish-white eggs. Incubation is done by both partners for a period of about 28 to 30 days. After hatching the chicks are characterized with a grey-brownish down above and yellowish underparts with face.

They develop feathers that are large and strong enough for flight to occur at the about 10 weeks after hatching.