Knob-billed Duck Sarkidiornis melanotos

Large bicolored waterbird. Both sexes are iridescent purplish-green above with a white or buffy breast. Males have a large black lump on the bill, gray flanks and whitish belly, whereas females have a plain bill and gray flanks. Note all dark wings. Occurs throughout much of Africa, India, and Southeast Asia. Found in freshwater rivers, lakes, and marshes where it is usually uncommon. Normally silent.