What’s the Difference Between Wild and Domestic Muscovy Ducks?

In this story you'll learn: 

• the differences between domestic and wild Muscovy Ducks.
• where wild Muscovy Ducks live.
• why Muscovy Ducks have red bumps on their face.
• whether Muscovy Ducks are invasive. 

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Let's just say it: Muscovy Ducks look weird. You know it, we know it, and, well, they actually might not know it. That’s because while all of those red fleshy face bumps, called caruncles, might seem strange to us, they serve a few valuable functions, including attracting mates. 

The largest duck in North America, the Muscovy is a fascinating bird with a rich history. Indigenous people in South America first domesticated them long ago, and the species was a totem animal for the Aztecs, who used their iridescent feathers for royal clothing. Nowadays, a decidedly less glamorous version of the domestic Muscovy is common throughout the United States. Here's what you need to know the next time you encounter one, wild or domestic. 

How Are Wild and Domestic Muscovy Ducks Different? 

The biggest clue: If the bird has an abundance of white body or head plumage, it's a domestic-type Muscovy. Wild Muscovies have a big patch of white on their wings—and that's about it. Otherwise, their plumage is dark and glossy with a green sheen on their back feathers. Wild Muscovies also have fewer and smaller caruncles, which are often a mix of red and black. Domestic Muscovies, on the other hand, have large and numerous caruncles that are almost always bright red. Finally, domestic versions of the ducks have been bred to be much larger than their wild relatives. 

Where Do Wild Muscovy Ducks Live? 

Muscovy Ducks are native to Mexico, Central America, and South America. Beginning in the 1980s, a small population expanded into southern Texas and has since taken hold in the Rio Grande Valley. In the wild, Muscovies are cavity-nesting birds and prefer swampy or wooded areas near water. They have strong, clawed feed for perching on limbs and are fast, nimble flyers. Outside of South Texas, all other Muscovies in the United Sates can be considered feral versions of domestic ducks, living everywhere from parks and industrial complexes to farms and agriculture fields. 

What Are All Those Red Bumps About?

Caruncles can be found on a variety of bird species (perhaps most recognizable on Wild Turkeys) and serve a variety of purposes. In Muscovies, they are valuable for both courtship and maintenance. Muscovies are born without caruncles and develop them as they age, with females having a less prominent mask. During breeding season, the male's bumps become bright red to attract potential mates. Additionally, Muscovy caruncles have glands that secrete oil, which the birds then rub on their plumage as they preen to keep feathers healthy and water resistant. It's believed that the caruncles also prevent the birds from getting their faces covered in muck while dabbling and foraging for food. 

Are Muscovy Ducks Invasive?

If you're talking about the feral populations of the domestic-type ducks that can be found across the United States and elsewhere in the world, then yes, they are considered invasive. In many areas, the birds are prevalent enough to compete for food and nesting holes with native species or become an annoyance to people, which qualifies a non-native species as invasive. In fact, the U.S. Fish & Wildlife Service officially classifies the Muscovy Duck as an invasive species and allows U.S. property owners outside of the Rio Grande Valley to control their population. 

That said, feral Muscovies are as close to the real deal as most people will get, so the next time you see one of these peculiar ducks, take a moment to observe them, and maybe—just maybe—you'll come to see them and their caruncles in a new light. 

This article was fact-checked by Kenn Kaufman.