Comb duck, Knob-billed duck Male

The comb duck is so called because the male has a round knob on top of the bill, which is particularly prominent in the breeding season (the word comb can mean the comb you use for your hair but also has a number of meanings relating to a crest). These large distinctive ducks are blue-black on the back, white on the front, and the head is white overlaid by black speckles. In the breeding season, males hold territories to which they often attract more than one female (polygynous). Females usually nest inside holes of trees. Comb ducks have a wide distribution including parts of Asia, South America and Africa. They prefer pans, lakes or rivers surrounded by woodland.