Black ducks face a survival challenge from mallards


Recently I discussed a genetic cross between different species in plants. The result was a new plant that was infertile. This happens quite often in ducks. Usually, male mallards (Anas platyrhynchos) are the reason why.

Mallard males will cross with female black ducks (Anas rubripes). Mallard males are larger and far more aggressive than their black duck counterparts. Consequently, they usurp the opportunity to breed with any black duck female they wish.

These two species are closely related enough to produce offspring. The problem is that both male and female ducklings will be infertile. Eventually, black duck populations will be depressed and there’s not a whole lot anyone can do about it. It’s not a problem in places where their ranges don’t overlap, but if breeding areas are the same, black duck populations will continue to decline.

It doesn’t end there. If male mallards and female black ducks form a bond in their winter range, this could sustain the relationship to the breeding grounds. This will result in many more black mallard hybrids. For the past 60 years or so the eastern expansion of the mallard has cut pure black duck numbers significantly.

So what about the female mallards? There’s no worry there. The mallard drake is a very sexually active critter. He’ll take care of them too.

Normally, when a wildlife species population decreases, we can relate it to human activity such as habitat destruction. In this case that might be slightly true. Well-meaning folks who feed ducks could cause range expansion as could increased grain production in some places. Food plots aren’t natural habitat.

A bigger problem might be releasing human reared mallards into the environment. Sometimes this is accidental, but often it is done on purpose. Mallards are easy to raise, and eggs are readily available, so many escape into the wild. Some start out as pets but are deliberately released as owners tire of them. Many of them escape predators long enough to mate.

Mallards are among the most adaptable of all ducks. They are found in all 50 states. These guys are comfortable anywhere a water source is available. The water need not be deep, either. Conservation of black duck habitat won’t keep the mallards from encroaching.

Mallard and black ducks naturally migrate to related environments. Both have similar diets. Also, they are both dabbling ducks. This means they usually don’t dive underwater to obtain food. They simply stick their heads underwater leaving their butt in the air.

Crossbreeding of waterfowl is a fairly common thing. I’ve highlighted the most common cross, but others occur. Mallards will cross with pintails, widgeons, shovelers, teals and gadwalls.

I have a cabin in northeastern Maine. Ranges of black ducks and mallards don’t overlap in that breeding ground. Only black ducks live there, so if little pockets like that exist, black ducks should not become extinct. Moreover, there is little agriculture in that area to lure other species in.

That means populations will remain low but dominated by black ducks. Sometimes limited food and low populations are a good thing.

A small family of black ducks

young black ducks

Ted Manzer teaches agriculture at Northeastern High School.

About tedmanzer

I grew up in Old Town Maine and got a B.S. at the University of Maine in Plant Sciences/ minor in Botany. From there I moved to West Virginia and earned a M.S. in Agronomy at WVU. I also met my wife there. She grew up in rural WV as the daughter of tenant farmers who raised cattle and hogs. Their lifestyle at times was one of subsistence and I learned a lot from them. I've always been a foraging buff, but combining my formal botanical knowledge with their practical 'Foxfire-type' background opened up my eyes a little more. I now teach agriculture to high school students at Northeastern High School in Elizabeth City, NC. My wife teaches with me and we make a great team. I also write a weekly nature/foraging column for the local paper (dailyadvance.com). I also have written several Christian nature/adventure novels that I plan to publish eventually. One is a five book family saga I call the 'Forgotten Virtues' series. In the first book, Never Alone, a young boy comes of age after his father dies in a plane crash, and he has to make it alone. Never Alone is now available in paperback, Kindle and Nook. The second book, Strange Courage, takes Carl from his High School graduation to his recovery from a nasty divorce. The third book, Second Chances, takes Carl from his ex-wife's death and the custody of his son to his heroic death at age 59. The fourth book, Promises Kept, depicts how his grandchildren react and adjust to his death. In the final book, Grandfather's Way, his youngest and most timid granddaughter emerges from the shadow of her overachieving family and accomplishes more in four months than most do in a lifetime. I use many foraging references with a lot of the plants I profile in these articles in those books.
This entry was posted in general nature and tagged , , , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s