Duck Identification Chart: What Type of Duck Is This?

If the duck tips forward and feeds with its rump in the air, it is a dabbling duck and you are choosing among about a dozen species. If it disappears under the surface, it is a diving duck, a merganser or a stiff-tail.

Even a bird that is only sitting there tells you which. Dabblers sit higher on the water with the tail held up; divers ride lower with the tail flat toward the water. When flushed, a dabbler springs straight up off the surface and a diver runs across it to take off.

The places differ too. Dabblers favor shallow marshes, flooded fields and small ponds; divers use deeper open water where they can reach the bottom or chase food down.

• Wide and spoon-shaped: Northern Shoveler. Black in the male, dusky orange in the female, and far larger than any other duck bill.
• Narrow, pointed and serrated: a merganser. The Common Merganser has a red bill thick at the base and narrow toward the tip; the Hooded Merganser is the smallest of the three merganser species, with a fan-shaped white crest on the male.
• Long, black and sloping into the forehead: Canvasback.
• Blue-grey with a white band at the base and a black tip: Ring-necked Duck.
• Pale blue with a small black nail: the scaups.
• Bright pale blue with a dark tip on a small, round duck: male Ruddy Duck.
• Orange with black markings on a mottled brown bird: female Mallard.
• Narrow and dark on a grey bird: male Gadwall.

• Green head, yellow bill, white neck ring: male Mallard.
• Green head, huge spoon bill, white chest, chestnut sides: male Northern Shoveler.
• Chestnut head with a white stripe up the neck, long pointed tail: male Northern Pintail.
• White forehead and crown with a green eye patch: male American Wigeon.
• Blue-grey head with a white crescent in front of the eye: male Blue-winged Teal.
• Cinnamon head with a green stripe behind the eye: male Green-winged Teal.
• Chestnut-red head with a long black sloping bill: male Canvasback. Chestnut-red head with a steep forehead and a blue-grey bill: male Redhead.
• Black head with a round white spot between bill and eye: male Common Goldeneye.
• Black head with a large white wedge behind the eye, small duck: male Bufflehead, the smallest North American diving duck at about 15 in.
• Crested head with a white eye-patch, grey: female Wood Duck.

Greater Scaup and Lesser Scaup. Ducks Unlimited puts the decisive mark on the wing: both have a bold white stripe on the secondaries, but in the Greater Scaup it continues into the primaries, and in the Lesser Scaup it does not. On the water, Greater has a rounder, larger head and a wider bill; Lesser often looks peaked, though not reliably.

Canvasback and Redhead. The profile decides it. The male Canvasback has a sloped forehead running straight into a long black bill and red eyes; the male Redhead has a steep forehead, a blue-grey bill with a white saddle near the tip, and yellow-gold eyes. The Canvasback's back is also much paler, white with fine grey markings, which is where the name comes from.

Two situations defeat any chart. The first is a park pond full of domestic and hybrid ducks, which can be white, black, blotchy or piebald in any combination, and are descended from the Mallard and the Muscovy Duck rather than being wild species. The second is late summer, when adult males are in eclipse plumage and this year's young are in between plumages; in both cases go back to the wing and the bill.

If a duck looks obviously wrong, oversized, unable to fly, or tame enough to walk up to you, it is almost certainly domestic. Photograph it and the app identifies it, but read the answer as a best match to a wild species, not proof that a wild bird is what you are looking at.