American Black Duck
Anas rubripes
The American black duck weighs 720–1,640 g (1.59–3.62 lb) and measures 54–59 cm (21–23 in) in length with a 88–95 cm (35–37 in) wingspan. This species has the highest mean body mass in the genus Anas, with a sample of 376 males averaging 1.4 kg (3.1 lb) and 176 females averaging 1.1 kg (2.4 lb), although its size is typically quite similar to that of the familiar mallard. The American black duck somewhat resembles the female mallard in coloration, although the black duck's plumage is darker.
ID text from Wikipedia, CC BY-SA 4.0
Mallard
Anas platyrhynchos
The mallard is a medium-sized waterfowl species that is often slightly heavier than most other dabbling ducks. It is 50–65 cm (20–26 in) long – of which the body makes up around two-thirds – has a wingspan of 81–98 cm (32–39 in), and weighs 0.7–1.6 kg (1.5–3.5 lb). Among standard measurements, the wing chord is 25.7 to 30.6 cm (10.1 to 12.0 in), the bill is 4.4 to 6.1 cm (1.7 to 2.4 in), and the tarsus is 4.1 to 4.8 cm (1.6 to 1.9 in). Voice: A noisy species, the female has the deep quack stereotypically associated with ducks. The female will often call with a sequence of 2–10 quacks in a row, starting loud and with the volume gradually decreasing. Male mallards make a sound phonetically similar to that of the female, a typical quack, but it is deeper and quieter compared to that of the female.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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