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Brown ducks are a good identification challenge

Through the winter, London birders have the opportunity to see many duck species. Although brown ducks can present a perplexing challenge, birders can have success in identifying them by paying attention to all of the information they see, not just the field marks. The “bathtub duck” shape of this bird tells us it’s a Ruddy Duck. Photo by Paul Nicholson

I put the challenge of identifying our brown ducks right up there with identifying gulls, sandpipers, and sparrows. While I do sometimes end up with my hands in the air, I usually try to identify the species.

Too often when we bird, we rely exclusively or too heavily on a bird’s field marks while ignoring other powerful clues such as size, shape, seasonal distribution, and behavior. If we use all of the information, we will have greater confidence and success.

A good first step is to understand which brown ducks we are most likely to be seeing in Middlesex County now. The other duck species can usually be set aside.

This group can then be divided by behavior into two groups. Dabbling brown ducks typically feed on the surface of the water or they might just tip their tails up while feeding. Dabblers include female Mallard, Black Duck, Green-winged Teal, Blue-winged Teal, Northern Pintail, Shoveler, American Widgeon, Wood Duck, and Gadwall.

The other group is populated by diving ducks. Brown diving ducks include female Canvasback, Redhead, Ruddy Duck, Ring-necked Duck, Greater and Lesser Scaup, Bufflehead, and Hooded Merganser.

Size is another relatively easy way to zero in on a species. For example, among the dabblers, Mallards are large and teal are small. Among diving ducks, Canvasbacks are larger while Buffleheads and Ruddy Ducks are small.

Shape is another powerful clue. A Ruddy Duck will often swim or drift with its stiff tail sticking up. The profile of a Canvasback is distinctive since there is a straight line as opposed to a scooped line that runs from the bird’s crown to the end of its beak. Similarly, it is important to remember that mergansers have long and very narrow beaks. A Northern Shoveler’s bill is long and almost comically chunky.

Pay attention to the company that your brown duck is keeping. If it is with a male Ring-necked Duck, you might short-circuit your ID process and look for traits with a view to confirming a female Ring-necked Duck identification.

Already, without having fretted about how similar plumage is, we have significantly shortened our list of candidate species. Once this list of two or three candidate species has been established, then it’s time to key in on field marks. Most brown ducks will have some subtle but distinctive markings, so even if you learn just one for each bird you will be reasonably well equipped for success.

Consider for example a female Green-winged Teal. It is a small dabbling duck that has a light tan patch by the tail that is often viewable. You might also see a bit a green on the bird’s speculum or secondary wing feathers. This green patch that gives the bird its name is even more visible when the bird is in flight.

If you have a camera, snap off a photograph so that you can study your bird in more detail once you are home. If we study the photo of the small brown duck above, we will immediately notice the perky tail and stout bill of a Ruddy Duck.

It’s more easily said than done, but identifying our brown ducks is doable. Give it a try.

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