Muscovy ducks range from coastal Mexico through Central America and most of South America.  Females usually nest in tree cavities, and members of both sexes use trees for roosting.  Their diet is varied but they seem to prefer feeding in shallow areas of flooded vegetation.  Thus their preferred habitat is wetlands in or near forested areas.
 

male Muscovy, Tamaulipas, Mexico

flooded landscape, Nhecolândia region, Pantanal

Ducks Unlimited of Mexico, A.C. (DUMAC) manages Muscovy ducks through a nest box program similar to the one implemented in the U.S. for wood ducks (Aix sponsa).
 
 

Both males and females are mostly black with iridescent plumage on the upper body and white wing patches.  Males are almost twice as large as females, weighing up to 4.0 kg (about 10 lb) compared to a typical female weight of 2.0-2.5 kg.  Males also have more exaggerated caruncles, which are fleshy outgrowths of bare skin around the face and bill.
 
 

Although Muscovies are generally silent birds, they have a suite of visual displays and frequently engage in active display bouts.  Displays include head-bobbing, tail-wagging, crest-raising, and bill-clapping.  They seem to used in various contexts - e.g., aggression, courtship, and vigilance.

Muscovy ducks were domesticated by native South Americans before Europeans arrived in the New World.  Now domestic Muscovies can be found in farmyards (and escaped in parks!) worldwide.  The domestic form differs from its wild cousin in appearance - plumage color is variable and often includes extensive areas of white, and the caruncles tend to get out of control (especially in males).  Their behavior, however, is quite similar.
 

domestic feral Muscovy male,  Coral Reef Park, Miami, FL