The Comb Duck is a large species of waterfowl, commonly found in South America, Mexico, and parts of the Caribbean. It belongs to the genus Sarkidiornis, and is also called the Knob-billed Duck, referring to the prominent knob or comb-shaped protuberance on the male's bill, which distinguishes it from other ducks.
Adult male Comb Ducks are distinctively large, weighing up to 1600 grams and measuring up to 66 cm in length, while females are slightly smaller. They have a chestnut-colored body, white wings, and a black belly, with a metallic green head, bright yellow eyes, and a knob-shaped bill. Female Comb Ducks have a duller appearance, with brownish-gray or mottled feathers, and smaller knob-like protuberances on their bills. Juveniles resemble females but lack the knobs and have a speckled plumage.
Comb Ducks are primarily found in wetland habitats such as marshes, ponds, and lagoons. They are known for their unique feeding techniques, which involve diving up to six meters deep to forage for aquatic vegetation, small fish, crustaceans, and insects. They can also feed on land, grazing on grasses and seeds. Comb Ducks are highly social and are often seen in flocks of up to 50 individuals, except during the breeding season when males become territorial and defend their mates.
During breeding season, male Comb Ducks display elaborate courtship behaviors, such as head-bobbing, wing-flapping, and calling, to attract females. Once paired, the female builds a nest on the ground or on a tree cavity near water, where she lays about 8-15 eggs. Incubation lasts for about 25-30 days, and both parents take turns to incubate and care for the young, which hatch as small, fluffy, and yellow ducklings.
Comb Ducks are not considered globally threatened, but they are hunted for their meat, eggs, and feathers, and are sometimes captured for the pet trade. Their wetland habitats are also under threat from habitat loss, pollution, and human disturbances. Conservation efforts are needed to protect their breeding and foraging sites and ensure sustainable hunting and trapping practices.