Black-bellied whistling ducks are easily recognized. Males and females look similar with red bills, pink feet, white wing patches, and black bellies. The head is brownish-gray with a white eye-ring.
Black-bellied whistling ducks are gregarious. They can often be found perching in trees. While they prefer to nest in natural tree cavities, they will readily use nest boxes and have been reported to nest on the ground as well.
The behavior of black-bellied whistling ducks is similar to fulvous whistling ducks. They prefer the excellent feeding opportunities offered by agricultural lands in close proximity to water, rice culture, and shallow wetlands with exposed mud flats. Black-bellied whistling ducks prefer to feed at night but have been observed feeding at all hours of the day.
Since 1968, black-bellied whistling ducks frequently have been found in central and south Florida in late summer and early fall, sometimes in flocks of fulvous whistling ducks. During the Florida Breeding Bird Atlas project, 12 potential breeding records were obtained for this species in Hardee, Lake, Manatee, Palm Beach, Polk, and Sarasota counties. Three of the records occurred in natural wetlands, three in small ponds, three in phosphate mines, two in flooded agricultural fields, and one in a sewage treatment pond. Since 1992, additional birds have been reported in Hamilton, Hernando, Indian River, Leon, Jefferson, Orange, Volusia, and Wakulla counties, indicating the species continues to expand its range in Florida. In recent years, ducklings have been observed in Leon County during the summer. Florida Fish and Wildlife Conservation Commission biologists have observed flightless young at the T.M. Goodwin Waterfowl Management Area (Brevard County) annually since 1999. Flightless young have been observed as late as mid-November.