Duck A typical duck has a torpedo-shaped body, a rounded head, and a slightly flattened and rounded bill. Some species are quite small, while others are larger, but they are smaller than geese and swans. They also have relatively long necks, but again, shorter than geese and swans.
Some black-bellied species of ducks such as the Fulvous Whistling-Duck have white underparts, which distinguish it from a pied duck. In females, most species are generally brown with some plumage coloration being different between them. Males on the other hand have a uniform black or black and white plumage that is sometimes marked with iridescent patches of color. In most species, a white wing stripe is seen in flight feathers when the birds are flying away from the observer.
One exception of this rule is the Speckled Teal which is predominantly grey with a light-brown head and neck speckles, except for the male’s mantle which is almost entirely black. Some species of duck, such as the Falcated Duck, have patterns of blue iridescent feathers.
The Mallard for example has a green speculum (patch on primaries visible in flight) bordered by white, and black outer tail feathers. The male has an iridescent dark green to purple head with a white patch near the bill, while the female is mottled brown with a white patch on her crown.
The cinnamon-colored female Mallard has an iridescent green speculum bordered by black and touches of white on each side of its head. They have a large dark green patch at the base of the bill. The male Common Teal has a distinctive green speculum bordered by white with an iridescent purple patch on its brown head. The male Northern Pintail has a blue-green speculum bordered by white and is surrounded by light grey body feathers.
The female Northern Pintail has two color morphs, gray or brown. These ducks also have dark bodies on top with varying amounts of speckles.
Speckled Ducks are on average 33-37 cm (13-15 in.) long, and generally feed by dabbling or walking on land. They are almost exclusively associated with freshwater lakes and ponds, though some species spend their winter around estuaries. When they fly, the speculum feathers do not form a complete ring, and the tail is short compared to other ducks.
Species of duck have relatively short necks, but longer ones than their relatives in Anatidae. They range from 50 to 65 cm (20-26 inches) long with a wingspan of 66 to 80 cm (26-32 inches). The males weigh about 500 g (1 lb.) and the females weigh about 400 g (14 ounces), which is significantly less than most geese and swans.