Australia’s rarest waterfowl, the Freckled Duck breeds in swamps in inland Australia. When these wetlands dry out in the summer months, the Freckled Ducks are forced to disperse towards coastal and subcoastal wetlands, usually swamps where there is much fallen timber that they can loaf amongst. Sometimes, if there is a drought, there may be few of these wetlands available for them, so they may congregate into flocks on whatever wetlands are available, sometimes giving the impression that they are more common than they really are.
The Freckled Duck is a dark greyish-brown duck with a large head that is peaked at the rear, and a distinctive narrow and slightly upturned bill. The dark brown plumage is evenly freckled all over with white or buff. During the breeding season the male’s bill becomes crimson at the base. The Freckled Duck is also know as Canvasback, Oatmeal Duck, Speckled Duck and the Diamantina Duck
[Info from http://www.birdlife.org.au/bird-profile/freckled-duck]