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First published May 1, 2017

Mottled Ducks are the "default" duck in Florida (photo 4)

Mallard Confusion

“Why do we see so many female Mallards here in Florida, but no males?” This is a common question from many of our northern birder friends who join us birding in Florida.

There is a simple answer: Those are not Mallards, they are Mottled Ducks. Mallards are the common “default” ducks in most of the United States and Canada, but in south Florida, the only Mallards I have ever seen have been captive bred or introduced Mallards. While the range maps in the field guides and on the internet generally show Mallards as wintering throughout Florida, my personal field experience has been to the contrary. Conversely, the Mottled Duck is the “default” Florida duck species and is found quite commonly just about everywhere.

The male Mallard, (above, right) with its distinctive green head and brown breast, is easily recognized and is found on just about every kind of body of water available north of Florida. Its mate, (left) however, is more similar to both male and female American Black Duck (below, right) and male and female Mottled Duck (top). To add to the confusion, there is also the Mexican Duck of the southwest United States and Mexico which is generally considered another very closely related species, but not the subject of this column.

There is uncertainty in the true taxonomic status of all four of these species, as they are known to interbreed and create hybrids, and over the years, arguing ornithologists have lumped or split all four into one or separate species depending upon which group is holding sway at the moment. (The most recent work in 2014 calls for more study, claiming that Mallard, American Black Duck and Mexican Duck are virtually genetically indistinguishable, but Mottled Duck has diagnostic genetic differences from the other three.)

“Okay, how do you tell them apart?” My good friend, George Armistead, in his excellent book, Better Birding: Tips, Tools, and Concepts for the Field, points out: “Always consider range, but pay particular attention to the head and the pattern of the speculum (Latin for “mirror”), which is the colorful area at the rear of the wing in the secondaries.” Mallards have a pronounced white edging on both the top and bottom of the blue patch or speculum on their wings, which is best seen when they are flying.

American Black Ducks appear to have no white edging on the speculum, and Mottled Ducks have a very narrow white line at the bottom, or trailing edge of the speculum when flying, (left), but distinct white edging on the upper, or leading edge of the speculum when flying. (below).

I have also found bill color helpful. Male Mallards have yellow, almost gold bills; female Mallards, black bills; American Black Ducks, a greenish or olive drab bill; male Mottled Ducks, a yellow bill, while female Mottled Ducks have orange bills. Care must be taken in relying on the speculum edging only, for sometimes the edges are not in full view and can be tricky, (Mottled Duck below ), whereas the bill of the bird is almost always in view.

Mallards, Black and Mottled Ducks are all pretty common in their respective ranges and are generally more approachable than other duck species. Consequently, we are more likely to be inclined to ignore them and say, “Oh, it’s just another Mallard/Black/Mottled Duck,” and move on to the next more exciting bird species, giving it no respect, like Pied-billed Grebes. (stlucieaudubon.org/hartBeat/hb2015/hb151101PieBilledGrebes.html)

But, here is a question for you: if American Black Ducks, Mottled Ducks and Mexican Ducks are all divergent descendants of the Mallard, why are all of these descendant duck species copycats of the female Mallard, without any of the striking features, like the green head, white ring around the neck and brown breast, or white tail, and unique up-curled tail feathers of the male Mallard? Put it into a human context and think of future descendants of humans that would all appear to be female. Now there is something to contemplate!


For more on the threat of Mallards to Mottled Ducks in Florida: www.10000birds.com/mallards-are-a-threat-to-mottled-ducks-in-florida.htm.

For more on George Armistead’s information on identifying this species group, see: www.dnr.sc.gov/wildlife/waterfowl/pdf/MottledDuckPoster.pdf. Better Birding: Tips, Tools, and Concepts for the Field by George L. Armistead and Brian L. Sullivan, Princeton University Press, Page 57.

For more on the genetic difference study on this species group, see the AOU 2014 study: americanornithologypubsblog.org/2014/07/23/surprising-genetic-sameness-in-three-mallard-like-ducks-and-one-distinctive-variety/.