The waterfowl of the genus Dendrocygna, commonly known as Whistling Ducks, possess long legs and necks, giving them an upright, goose-like posture that distinguishes them from other aquatic fowl. Their common name comes from their distinct, high-pitched vocalizations. Unlike many ducks, Whistling Ducks exhibit complex social behaviors, including strong pair bonds and shared parental duties, which extend to their varied nesting habits.
Identifying Whistling Ducks and Their Range
In North and Central America, the two most commonly encountered species are the Black-bellied Whistling Duck (Dendrocygna autumnalis) and the Fulvous Whistling Duck (Dendrocygna bicolor). The Black-bellied species has expanded its range significantly and is found throughout the southern United States, including Texas, Louisiana, and Florida, extending south through Mexico and Central America to parts of South America. These gregarious birds prefer habitats near shallow freshwater, such as marshes, ponds, and agricultural fields, especially when surrounded by trees for perching and roosting.
The Fulvous Whistling Duck has a more cosmopolitan distribution, occurring across three continents, with populations in the southern US. Their preferred environment consists of shallow freshwater marshes, flooded pastures, and especially rice fields, which provide both foraging opportunities and cover. Both species are highly adaptable.
Specific Nest Site Selection
The location of a Whistling Duck nest depends heavily on the species. The Black-bellied Whistling Duck is the primary tree-nesting specialist, preferring natural tree cavities often resulting from a broken limb or trunk rot. The entrance size of these cavities typically ranges from five to twelve inches across.
These nests are commonly situated four to twenty feet above the ground or water. While often near a water source, they can be located up to a quarter mile away. Because suitable natural hollows are scarce, this species readily adopts human-made nest boxes, which has aided in their population expansion. If tree cavities are unavailable, the Black-bellied Whistling Duck will make a simple scrape nest on the ground, concealed within dense vegetation like thickets or shrubs.
In contrast, the Fulvous Whistling Duck is predominantly a ground nester, creating its nest in the dense cover of aquatic vegetation. Sites are chosen within or immediately adjacent to water, often utilizing thick stands of tall grasses, sedges, or cattails in marshes and flooded fields. The nest is a simple, woven structure of plant materials, sometimes featuring a canopy of vegetation overhead for concealment. The birds may also build their nest on floating vegetation or on low hummocks of dry ground between ponds. Although primarily a ground nester, the Fulvous Whistling Duck has occasionally been documented using tree holes.
The Nesting Process
Once the site is selected, the physical construction of the nest is minimal, especially for the cavity-nesting Black-bellied Whistling Duck. In tree hollows or nest boxes, the pair often lays their eggs directly on debris, such as wood chips or leaf litter, already present in the cavity. For the Fulvous Whistling Duck’s ground nest, the structure is a simple platform or bowl woven from marsh grasses and stems.
Unlike typical puddle ducks, neither species lines its nest with soft down feathers. The clutch size for a single female averages around 12 to 14 eggs, but this number is frequently inflated by “dump nesting.” Multiple females may lay their eggs in a single nest, leading to recorded clutches containing 50 to over 100 eggs.
The incubation of this large clutch is a shared duty, with both the male and female taking turns on the nest. This biparental care is important for nesting success, as the removal of either partner can lead to nest abandonment. The incubation period is relatively short, lasting between 24 and 30 days depending on the species.