Adult members of this species can be identified by their gray heads, chestnut-colored back and chest, black undersides, and brown-and-black wings with a white stripe. They also have long, pink legs and a bright pink bill. Females and males are similar in color.

Adults are about 19 inches (48 centimeters) long and weigh around 1.8 pounds (0.9 kilograms).

Black-bellied whistling ducks are found in areas with a nearby supply of shallow fresh water, like marshes, swamps, lakes and ponds. They are also commonly found in farm fields, prairies and pastures. 

They occur in Southern Texas, Louisiana, Arizona, Florida and rarely in other parts of the southern U.S.; also in Mexico, Central America, northern South America and the Caribbean.

While most black-bellied whistling ducks are non-migratory, those that live on the farthest northern and southern fringes of their range will fly to warmer areas during the winter months.

The longest living individual known from banding data was more than 8 years old.

In addition to their signature whistling call, they have a series of calls and chirps they use to communicate while flocking. 

Black-bellied whistling ducks search among fields and shallow freshwater areas for plants, seeds, grains, small insects and invertebrates to eat. Once they locate a good place to nest and forage for food, they will often stay in that area year-round.

These ducks feed mainly at night, although they are active at both daytime and nighttime.

Black-bellied whistling ducks are gregarious, sociable birds, often gathering in noisy flocks with hundreds of other members of their species. 

Black-bellied whistling ducks build nests either in tree hollows or, when predator animals are not present, on the ground among bushes or thickets. Nests built in tree hollows tend to be quite bare, but on the ground, the ducks will wave grasses and twigs into a shallow bowl-shape. Females lay nine-18 whitish-colored eggs per clutch. Sometimes, several females will lay their eggs in the same nesting area, with such nests containing up to 60 eggs at one time.

Both males and females take turns incubating the eggs, which hatch after about 25-30 days. Babies are born with soft yellow-and-white downy feathers and are ready to leave the nest after a day or two. They can feed themselves immediately, although they remain close to their parents for about eight weeks.

Black-bellied whistling ducks form monogamous pair bonds, staying together with the same mate to feed, nest and raise their young for many years.

In areas where local populations are threatened, nest boxes have been used to create nesting habitat in some areas where natural cavities are rare.