Black-bellied Whistling Duck

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Common Name: Black-bellied Whistling Duck
Scientific Name: Dendrocygna autumnalis

Size: 18.5 – 20.1 inches (47-51 cm); Wingspan: 30-37 inches (76-94 cm)

Habitat: North and South America; found in the Southern United States and Arizona to Mexico, the Yucatan and to Brazil. The Whistling Duck is a resident to short-distance migrant. Populations within the United States are at the extreme north of this species’ range, and many of these birds migrate south a few hundred miles into Mexico for the winter. Across their extensive range in Central and South America, Black-bellied Whistling Ducks do not migrate.

They nest in thickets or stands of mesquite, hackberry, willow, live oak, and other trees. They forage in fields, lawns, and shallow, freshwater ponds that often contain water hyacinth, water lilies, and cattails. In the tropics, they also use mangroves, rivers, and lagoons.

Status: Least Concern. Global population: 1,550,000 adult individuals. Black-bellied Whistling-Ducks have been expanding their range in the southern United States, and the North American Breeding Bird Survey shows strong population growth, estimated at 6.9 percent per year from 1966–2010. Although it’s legal to hunt whistling-ducks in season, they are only rarely targeted by hunters. Like all aquatic species, Black-bellied Whistling-Ducks are vulnerable to poor water quality—in the 1980s birds in Mexico were reported with high levels of DDT, dieldrin, and other persistent organic compounds. Degradation or clearing of wetlands can reduce habitat availability; however, in general Black-bellied Whistling-Ducks seem to be doing well around human development.

Diet: Plant material; including smartweed, grasses, swamp timothy, amaranth, sedges, bindweed, and nightshade. They also eat many agricultural crops including sorghum, millet, corn, rice, and wheat. They will eat a smaller amount of aquatic animals such as snails, insects, and spiders.

This duck typically forages at night, leaving roosts at sunset to fly to foraging areas. They will feed in fields or by dabbling in shallow ponds

Nesting: Sexes are alike. They have a long red bill, long head and longish legs, pale grey head and mostly grey-brown plumage. The belly and tail are black, and the body plumage, back of the neck and cap are a rich chestnut brown. The face and upper neck are grey, and they sport a thin but distinct white eye-ring. The extensive white in the wings is obvious in flight, less so on the ground; it is formed by the secondary remiges while the primaries are black; the wing-coverts are brown. Juveniles are similar but have a grey bill and less contrasting belly.

They form lifelong pair bonds and breed in their first year of life. Males spar by chasing or nipping at each other, or with a threat display that involves stretching their neck forward and opening their bill. Pairs form in winter; courtship includes birds stretching their necks out horizontally, dipping their bill, and flicking water over the back.

Both sexes help select the nest site. Nests are often found in tree hollows where a limb has broken or the trunk has rotted away. They may also use nest boxes or nest on the ground. No matter what nesting site has been chosen, they typically don’t build a formal nest; rather they lay their eggs directly on whatever material was collected there. Cavity openings range from 5–12 inches across. When nesting on the ground, they make a scrape or a shallow bowl of grasses, with thick vegetation overhead, such as willow, mesquite, or cactus. Typically a clutch is 9-18 eggs with the incubation period being 25-30 days. Eggs are white in appearance and are 1.8-2.4 inches (3-4.2cm) in length. The fledging period is 10-13 days.

Females often lay eggs in the nests of other whistling-ducks—a behavior known as egg-dumping. Nest predators include raccoons, rat snakes, and bull snakes; ducklings may be killed by fire ants, bass, catfish, and gar. Great Horned Owls sometimes take adults.

Cool Facts: The whistling-ducks were formerly known as tree-ducks, but only a few, such as the Black-bellied Whistling-Duck actually perch or nest in trees. As the name implies, these are noisy birds with a clear whistling waa-chooo call.

Black-bellied Whistling-Ducks have long legs and spend more time than other ducks walking on land or perching in trees, fences, telephone lines, or in Spanish moss. They are gregarious year-round, forming flocks of up to 1,000 birds. Individuals are attracted to areas where corn and rice are grown and can cause damage to crops.

There are two subspecies, which intergrade in Panama:

  • Northern Black-bellied Whistling Duck, Dendrocygna autumnalis autumnalis – Southern USA to Panama. It is larger, with a brown breast and upper back.
  • Southern Black-bellied Whistling Duck, Dendrocygna autumnalis discolor – Panama to Paraguay and adjacent regions. It is smaller, with grey breast and upper back.

Found in Songbird Remix Waterfowl Volume I: Dabbling Ducks

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