If it walks like a duck or quacks like a duck, don't assume it's a duck! Hybridization of Dabbling Ducks

Mallard drake (Anas platyrhynchos) , Phippsburg Maine

  

Mallard hen, Phippsburg Maine Note her mottled breast feathers and orange and black bill

American Black Ducks (Anas rubripes), hens and drakes, Phippsburg Maine - Totman Cove in front of our house. Note that the males have yellow bills and the females have greenish bills. American Black ducks aren't actually black, but dusky. They were once called "Dusky" ducks.

American Black Duck and Mallard hen, Phippsburg Maine. Note that the Black duck doesn't have  distinctly mottled feathers as the Mallard hen.

Mallard hens and drakes with American Black Duck (in the middle with the yellow bill, slightly larger than Mallards), Smithville New Jersey

Mallard hens and drakes with American Black duck (far right, yellow bill) and Mallard x Black Duck hybrid (foreground, left - green and brown head, no neck ring, slightly mottled neck feathers), Smithville, New Jersey

Mallard hens and drakes with American Black duck and cross of the two species, Mallard x Black Duck

Mallard drakes and hen with single MallardxBlack duck cross - note mottled green and black head on third duck from the left, Bath Maine January 2012

Herring gulls with Mallard x Black duck cross and Mallard drake, Evergreen Cemetery Portland Maine 2011

    

     My father often said "If it walks like a duck and quacks like a duck, it must be a duck." Oh! If only things were that simple.

     When I was a kid, life seemed so mysterious and complex. But, adults seemed to know what was going on and be in command. I believed that when I got older, life would be clearer and I’d have a handle on it too, like my Dad. I always thought I'd get smarter, then armed with more information, I would be a grown up making big decisions. But, not so. It not only hasn’t gotten easier, it hasn’t become more straightforward, either. I've found that as I've become older, I often have too much information to be speedily decisive.

     When I was younger, I’d shoot from the hip quickly. I identified my target, aimed, then fired. Now, I’m bogged down by the layers I see in everything!  I now know there are too many things to consider. Do I call my friend whose husband is in the hospital? She's probably swamped with calls of concern. Maybe I'll leave her alone. When my pal who lost her job calls me, do I give suggestions about what to do, or do I just shut up and listen? Do I take my limping dog to the vet or wait and see if he gets better on his own? The older I get, the more complicated life reveals itself to be. Even birding has failed me there. Oh, if only a duck were a duck were a duck...

     The more I learn about birds and birding, the less I know. Wouldn't you think that a simple duck would be easy enough to identify? No, not so. Of all bird species, waterfowl are the most prone to hybridization, with over 400 hybrids documented! This renders identification of ducks to a huge game of “Who’s Your Daddy.”

     Mallards are one of our most colorful and abundant dabbling ducks. In the winter, I often see them in the company of another common quacker, American Black ducks. This winter, birding has been so mind numbingly dull that even humdrum birds have been a welcome sight. Boredom has prompted me to scan flocks of banausic waterfowl more closely than I might otherwise have bothered to do. And, lo! A star in the east! Nah. Just ducks, but there were ducks that looked funny, not exactly like Mallards, but not like Black ducks, either.

     Mallards were not common in the northeastern United States until after about 1920. In efforts to increase the populations of ducks for hunters, Pennsylvania and Maryland wildlife authorities released more than a half million of them from game farms. Mallards, it turns out, are pretty randy rascals, too. Those from game farms tend to be more aggressive in pairing and mating than wild ones. When their territories began to overlap with other species of ducks, they mixed it up without hesitation.  Mallards tend to hybridize more than any other waterfowl and have crossed with around fifty species other than their own kind (list below)! Some consider Mallards invasive and they are certainly a challenge for waterfowl conservationists.

   The Mallard’s tendency to get it on readily with others stems from numerous factors: there are lots of them, they have many close relatives and in urban areas, there are usually too many dude ducks.

     American Black ducks are genetically quite similar to Mallards. So, hybridization of the two species wasn’t much of a leap. Sadly, the American Black duck population has been on the decline for several decades. Competition for habitat with Mallard bad asses may be one reason.

     In the above photos, the Mallard drakes with the blotchy brown spots on their heads, lack of a neck ring and mottled breasts are actually crosses of Mallards and American Black Ducks. This observation prompted me to scrutinize photographs in my archives of ducks. Lo and behold, there were numerous Mallard x American Black ducks among the throngs from locations across the globe! Well, that’s an exaggeration - just around New England. However, that I have been able to photograph several hybrids without looking for them bodes well for finding crosses of other waterfowl species.

   Nearly twenty percent of the offspring of Mallard hybrids have been found to be fertile and they do back breed. This means that a mixed species duck can mate with another mixed species duck and produce, well…a complex mess for a geneticist. This fallout from duck love adds a maddening, though fascinating, new perspective to bird watching.  Like a three dimensional game of Scrabble, it gets more complicated with every turn if you are lucky enough. 

List of documented hybrids

Northern Pintails (most common cross with Mallards in the Northwestern United States),

Eurasian and American Wigeons,

Cinnamon and Green-winged Teals,

Northern Shoveller,

Gadwalls,

Mandarin and Wood ducks (next to Mallards, Wood ducks cross with the highest number of other species coming in at 26),

Redhead, Ring-necked and Tufted Duck,

Canvasback,

(all of the above have been documented to cross with other species besides Mallards, too! Can you say “paaaaaaaaarty?”)

Eiders,

Hooded Mergansers,

Common Goldeneyes,

Geese

The information  in this essay was obtained from a host of internet sources. Thanks to all who actually did the research for the rest of us.