By Dr. Robert Norman, Clinical Professor, Dermatology, Nova Southeastern University
While exploring the ponds around Starkey Wilderness Park at sunset, I noticed a flock of wonderful Black-bellied Whistling-Ducks. I’ve seen them fly over my house on many occasions or when I’ve been out biking and I’ve always marveled at these incredible creatures.
The Black-bellied Whistling-Duck is a boisterous duck with a brilliant pink bill and displays an unusual, long-legged silhouette. Watch for noisy flocks of these gaudy ducks dropping into fields to forage on seeds, or loafing on golf course or suburban or city ponds. Listen carefully and you will hear that these ducks really do have a whistle for their call. Common south of the U.S., Black-bellied Whistling-Ducks are prominent in Florida and occur in several southern states and are now expanding northward.
Where do they nest, live and eat? What is their conservation status?
Black-bellied Whistling-Ducks nest in tree hollows where a limb has broken or the trunk has rotted away. They also use nest boxes and sometimes nest on the ground. The birds may nest in thickets or stands of mesquite, hackberry, willow, live oak, and other trees. Both sexes help select the nest site.
Whether nesting in natural cavities or nest boxes, Black-bellied Whistling-Ducks typically don’t build a nest; they lay their eggs directly on whatever debris has 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. Clutch size is 9-18 eggs and they have 1-2 broods. The incubation period is 25-30 days and the nestling period is10-13 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.
They forage in fields, lawns, and shallow, freshwater ponds that often contain water hyacinth, water lilies, and cattails. Black-bellied Whistling-Ducks eat mainly plants, including smartweed, grasses, swamp timothy, amaranth, sedges, bindweed, and nightshade. They also eat many agricultural crops including sorghum, millet, corn, rice, and wheat. They eat a smaller amount of aquatic animals such as snails, insects, and spiders. They typically forage at night, leaving roosts at sunset to fly to foraging areas. They feed in fields or by dabbling in shallow ponds.
Black-bellied Whistling-Ducks have long legs and spend more time than other ducks walking on land or perching in trees. You may see them perched on fences, telephone lines, or in Spanish moss. They are gregarious year-round, forming flocks of up to 1,000 birds. 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.
Black-bellied Whistling-Ducks have steadily expanded their range in the southern U.S. and their numbers have increased by approximately 6% per year from 1966–2019, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 1 million and rates them 8 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. 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.
Thank you to Audubon and All About Birds (Cornell)
WHERE CAN YOU FIND THIS SPECTACULAR BIRD?
Get out into The Great Florida Outdoors!
Dr. Norman is an advanced master naturalist graduate of the FMNP program from UF and a board-certified dermatologist based in Tampa and Riverview. He can be reached at 813-880-7546.
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