Whistling ducks comprise a group of species that are primarily of tropical and subtropical distribution. In common with the swans and true geese (which with them comprise the subfamily Anserinae), the included species have a reticulated tarsal surface pattern, lack sexual dimorphism in plumage, produce vocalizations that are similar or identical in both sexes, form relatively permanent pair bonds, and lack complex pair-forming behavior patterns. Unlike the geese and swans, whistling ducks have clear, often melodious whistling voices that are the basis for their group name. The alternative name, tree ducks, is far less appropriate, since few of the species regularly perch or nest in trees. All the species have relatively long legs and large feet that extend beyond the fairly short tail when the birds are in flight. They dive well, and some species obtain much of their food in this manner.
Black-bellied Tree-Duck has tawny-brown to brown-cinnamon upperparts, turning black on rump and uppertail coverts. Upper wings show a broad white stripe, conspicuous in flight. Flight feathers are black. Underparts are paler. Lower neck and chest are tawny-brown. It has black belly and flanks. Undertail coverts are mottled black and white. Underwings are blackish. Head and upper neck are grey. Crown is dark brown. We can see a dark vertical hind neck stripe. Bill is bright pink-red, often yellowish at base. Eyes are dark brown, with conspicuous white eye ring. Legs and webbed feet are bright pinkish-red.
Both sexes are similar. Juvenile is paler, with grey bill, legs and feet. It has duller plumage than adults, with sooty-brown belly and flanks. It reaches its adult plumage at 8 months of age. Very young birds have very paler belly, with indistinct transversal bars.
Listen to the sound of Black-bellied Tree-Duck
Copyright remark: Most sounds derived from xeno-canto
Normally nesting is in a hole in a tree, but the nest could be on the ground. The nesting tree can be growing in the water or as far as a kilometer away from the nearest water deposit. Many pairs nesting in holes do not add any material to the location, the female lays the eggs on the bottom of the hole. Of those nesting on the ground some just deposit the eggs on the ground, while others build a cup-shaped nest with grass. Down is not added to the nest.
The clutch is eight to eighteen eggs. Once laying stars an egg is deposited every day. Some females lay eggs in the nest of others, some even on other ducks and even gulls nests. Some clutches are suspected to be where females lay because they have to, but the clutch itself is not incubated nor taken care of. One of these excess clutches was recorded to have 101 eggs. If the clutch is lost, it is possible that the pair may try again.
Incubation takes from 26 to 31 days and it is done by both parents. When the chicks hatch they are yellow with dark marks. Normally next day after hatching they drop from the hole in the tree, which could be as high as three meters, landing on the ground or water. They stay with the parents for the next six months. At two months they are able to fly, at eight moths they change to adult plumage and at one year of age they can start breeding.
Video Black-bellied Tree-Duck
copyright: J. del Hoyo
The Black-bellied Tree-Duck is natural to the Americas. Its distribution to the north includes southern United States (in the states of Texas, Arizona and Louisiana) and northern Mexico (state of Sonora on the Pacific side), although it is usual to see it further north than these limits. Continues its distribution south on both sides of Mexico thru Central America. Some make it to the Antilles in the Caribbean, being considered occasional in Puerto Rico.
In South America this species is native to Colombia, Venezuela, the Amazon Basin, southern Brazil, Paraguay and northern Argentina. West of the Andes it goes as far south as Peru. It is documented in Los Lagos, Chile.
A population descendent of escaped captive birds established in the 1960’s in the state of Florida, United States. In 1931 it was introduced to Cuba in the Zapata Swamp, earlier it had been introduced in Pinar del Rio. Still found in Cuba, although the ones seen could proceed from other places. Also introduce to Jamaica unsuccessfully, although it is seen there in winter and spring.