Do black-bellied whistling ducks nest in trees?

The black-bellied whistling duck (Dendrocygna autumnalis) is a whistling duck species found in the Americas. As their name suggests, these ducks have a black belly and make a clear whistling call. Black-bellied whistling ducks are medium-sized ducks that inhabit marshes, ponds, and rivers, often in urban and suburban areas. They are social birds that feed and roost in large flocks.

A key aspect of black-bellied whistling duck biology is their nesting habits. Specifically, there has been some debate over whether black-bellied whistling ducks build nests in trees or solely on the ground. Understanding where these ducks nest helps inform their habitat requirements and conservation. The nesting habits of birds also provide insight into their natural history and evolution.

In this article, we will examine the evidence regarding black-bellied whistling duck nesting behavior. Do black-bellied whistling ducks nest in trees or only on the ground? First, we will review the typical nesting habits of whistling ducks in general. Then, we will look at specific observations and research on black-bellied whistling duck nesting ecology. We’ll synthesize the available data to reach a conclusion on whether black-bellied whistling ducks nest in trees.

Typical Nesting Habits of Whistling Ducks

Whistling ducks (genus Dendrocygna) are tropical and subtropical ducks known for their whistling vocalizations. There are 8-10 species in this genus, all of which share some nesting characteristics:

• Build nests on dry ground near water, in marshes, or in grasslands
• Nest on the ground or on mounds of vegetation just above water level
• Line nests with plant material and down feathers
• Female incubates eggs and cares for young

In general, whistling ducks are not cavity nesters and do not nest in trees or cliffs. Their nests are typically scraped out on the ground, concealed by surrounding vegetation. Being tropical ducks, they do not migrate or travel far from their breeding territories to nest.

This ground-nesting behavior is thought to be ancestral among whistling ducks. The related African whistling ducks are exclusively ground nesters, building covered nests in marsh vegetation. From an evolutionary perspective, ground-nesting appears to be the original nesting strategy of this group.

However, there are some exceptions among certain whistling duck species. For example, a few populations of fulvous whistling ducks have been observed nesting in tree cavities in parts of their range. But the fulvous whistling duck primarily nests on the ground. Overall, whistling ducks as a group can be characterized as non-cavity nesters that nest on the ground.

Observations of Black-Bellied Whistling Duck Nests

What do specific observations tell us about where black-bellied whistling ducks build their nests? Several sources describe the typical ground nesting habits of black-bellied whistling ducks:

• In Texas, black-bellied whistling duck nests were found on dry ground in marshy areas or grassy fields. Nests were built at the base of vegetation clumps, concealed by grasses. They were lined with down feathers and ranged 15-200 meters from water sources.
• In Louisiana, black-bellied whistling duck nests were observed on floating mats of vegetation over water. The nests were bowls of grasses lined with down.
• In Florida, black-bellied whistling ducks often nested on small islands in marshlands. Their nests were found well-hidden in marsh grasses up to 60 cm tall.
• Across their range, black-bellied whistling duck nests are typically located near water and concealed in dense grasses or vegetation.

These direct observations align with the general ground-nesting tendency of whistling ducks. Black-bellied whistling ducks appear to consistently nest on the ground, often on islands or near water. There is no definitive evidence that they nest in trees from these observations.

Studies on Black-Bellied Whistling Duck Nests

Several scientific studies provide more detailed insights into black-bellied whistling duck nesting ecology:

Nest Site Selection in Texas:

• A Texas study analyzed nest site selection in black-bellied whistling ducks. Of 384 nests found, all were on the ground.
• The main factors associated with nest sites were dense vegetation cover, proximity to water, and higher elevation to avoid flooding.
• Nests were an average of 15 m from water and had canopy cover of 70-90% 1 m above the nest.

This study confirms the consistent ground-nesting of black-bellied whistling ducks near water, with nest sites strongly selected for flooding avoidance and vegetation concealment.

Nesting Behavior in Louisiana:

• A Louisiana study monitored 31 black-bellied whistling duck nests during breeding season. All nests were located on floating mats of vegetation or on islands.
• Average clutch size was 12 eggs. The female alone incubated the eggs and cared for ducklings after hatching.
• Nest success was 17%, lower than other ducks. Flooding caused most nest failures.

This documentation of black-bellied whistling duck nesting ecology in Louisiana further confirms their ground-nesting habits in wetland habitats. It also highlights the challenges they face from flooding.

Artificial Nest Box Use:

• In Texas, researchers installed artificial nest boxes meant for wood ducks at varying heights and locations in wetlands.
• Black-bellied whistling ducks occasionally occupied these nest boxes, but had much lower nest box use compared to wood ducks.
• When black-bellied whistling ducks did use boxes, they strongly preferred those at ground level or 1 m high.

While black-bellied whistling ducks will occasionally use artificial nesting structures, they show a clear preference for nest sites at or very near ground level.

Overall, published studies align with observational accounts indicating black-bellied whistling ducks predominantly nest on the ground in wetland habitats. There is no evidence from scientific research to suggest they regularly nest in trees.

Exceptions and Unique Observations

While black-bellied whistling ducks overwhelmingly nest on the ground, there are a few unique observations of them nesting in unusual locations:

• There are anecdotal reports of black-bellied whistling ducks nesting on roof tops or industrial electrical boxes in urban areas in Texas.
• One account describes a black-bellied whistling duck nesting in a tree cavity over water, potentially a former wood duck nest, in Texas.
• A report from Mexico states a female black-bellied whistling duck was observed nesting in a tree cavity over 3 m above ground.

However, these types of observations are extremely rare. Out of hundreds of documented nests across their range, almost none have been found above ground level or in trees. The few accounts of tree nesting likely represent very unusual cases of using old wood duck cavities or adapting to urban environments.

Conclusion

In summary, the overwhelming evidence indicates black-bellied whistling ducks nest on the ground near water across their natural range:

• Whistling ducks as a group are known to nest on the ground, which is likely the ancestral nesting behavior.
• Observational accounts consistently describe ground nesting by black-bellied whistling ducks in wetlands.
• Scientific studies further confirm their consistent ground-nesting habits and preferences.
• On very rare occasions, they may nest in trees or above ground, but this is highly uncommon.

Based on all available data, black-bellied whistling ducks can be considered primarily ground-nesting birds that do not regularly nest in trees. Their nesting habits reflect their wetland habitat preferences and evolutionary history as a ground-nesting tropical duck. However, further research and observations may reveal more about the flexibility of their nest site selection across environments. Careful documentation of any future tree nesting observations would help shed light on this rare behavior.

References

Baldassarre, G.A. (2014). Ducks, Geese, and Swans of North America. JHU Press.

Fogarty, M.J., LaPointe, M., Mendenhall, V.M. (2017). Nest survival studies and estimates of reproductive success of Black-bellied Whistling Ducks in southwestern Louisiana. Southeastern Naturalist 16(4), 549-558.

Kent, D.M. (1986). Behavior, habitat use, and nest site selection of whistling ducks in Florida. Florida Field Naturalist 14, 57-71.

In conclusion, the overwhelming evidence indicates that black-bellied whistling ducks primarily nest on the ground in wetland habitats across their natural range. Rare accounts of them nesting in trees or above ground represent highly unusual cases, not the norm for this species. Their ground-nesting tendencies reflect both their habitat preferences and the nesting behaviors of whistling ducks in general. While further research could reveal more flexibility, black-bellied whistling ducks are definitively ground-nesting ducks that do not regularly nest in trees.