An update on the status and distribution of the Knob-billed Duck Sarkidiornis melanotos in Sri Lanka with notes on its behaviour.

Abstract

he Knob-billed Duck or African Comb Duck Sarkidiornis melanotos was formally described to science from Ceylon (now Sri Lanka) by Pennant (1769: 12). It disappeared and was believed to be extinct from the island by the 1960s (Henry 1998; Harrison & Worfolk 1999). Ali & Ripley (1987: 48) indicated the species as ‘Formerly sparse resident in Ceylon.’ Carboneras & Kirwan’s (2020) global distribution map for the species does not include Sri Lanka. The historical status of the duck in Sri Lanka is dubious and must be interpreted through numerous subjective statements. Legge (1880: 1064) wrote that the bird was ‘more common than is generally supposed…’ and that it was first described in Ceylon by Forster, ‘who erroneously states that it is common in the hills’ (ibid.). Legge himself characterized the status of the Comb Duck in the island as ‘… nowhere numerous, it is found here and there in … the north and east …’ (ibid.). Citing Layard, he wrote that it is ‘… not uncommon on the tanks of the Vanni …’ (ibid.). Also citing one ‘Mr. Parker’ [= H. Parker], (apparently based on Parker 1881, 1883) he wrote that the bird is ‘tolerably common, but not plentiful, in the North-western Province and in the Anaradhapura (sic) district …’ (ibid.). As for breeding, Legge wrote that one Mr. Fisher found it breeding near Yala (ibid.). The breeding season has been reported as February– March in Sri Lanka (Legge 1880; Henry 1971; Weerathunga et al. 2013). Based on these reports, we surmise that, prior to its disappearance, the species was never common but occasionally nested in the island. Young (2005: 392) indicated in the map that the species occurs in Sri Lanka, although the text (p. 393) says the contrary.