Gadwall

The gadwall is a common, widespread dabbling duck, 47 to 58cm long with a wingspan of 78 to 85cm. The breeding male is patterned grey with a black rear end, light chestnut wings and a brilliant white speculum, obvious in flight or at rest. The female is light brown, much like a female mallard. Females give a higher-pitched quack than a mallard's, rendered as 'gag-ag-ag-ag' (Wikipedia, general species account).

It breeds in the northern areas of Europe and across the Palearctic, and in central North America. The female lays a clutch of 7 to 12 eggs, incubated for 24 to 27 days, and the nestlings leave after one to two days. In non-breeding plumage the drake looks more like the female but keeps the male wing pattern. The sources opened do not describe it in Nepal.