After some looking at the duck you see in the photo, I decided that its usual name, knob-billed duck, fits it perfectly. I have no use for the alternative African comb duck or the Latin binomial Sarkidiornis melanotos. It is large, among the largest of ducks, and easily told at a distance by the black stippling on the head and neck, even if you don’t see its knob. The female lacks the knob, may have a duller wing, and is generally smaller, but is otherwise similar in appearance. On this morning at Lakhota lake, I didn’t see it upend to dabble in the water just below the surface, but several of them dipped their beaks into the water, perhaps filter feeding. I was happy to get that drop of water at the end of this one’s bill.
I’ve learnt to let sexual dimorphism in birds signal strange mating behaviour. Typically they nest in holes and hollows in trees, above a man’s head, but usually not too far above. But it has been known to appropriate the nests of other species for itself, even if they are much higher: vultures’, eagles’, storks’. Each female lays a clutch of 7 to 12 eggs. But one of the oddest things about this bird is that they breed in “dump nests” where several females deposit eggs, and once as many as 54 eggs have been found in such a nest. This suggests the possibility of polygyny among these birds. There are other waterfowl in which polygyny has been observed. Like several other birds in India, they breed late in the monsoon. This is an added reason for me to start thinking of a late monsoon birding trip, something which most birders think is a wild and useless trip.