Masked Duck inhabits ponds and small lakes covered with emergent vegetation from northern Argentina north through South America (east of the Andes), Central America, and the Caribbean to North America. In the United States it is considered an irregular visitor to Louisiana and Florida and a resident of Texas, the only state where nesting has been documented.
As with other members of the tribe Oxyurini, Masked Duck has elongated and pointed tail-feathers with stiffened shafts. It is distinguished from other stifftails by its large white wing-patch. Grebelike and secretive in its behavior, it is sighted only rarely, usually as it slips into dense reeds or below water. Often only the tip of its tail and head are visible, as it sinks noiselessly beneath the surface.
This species has a long breeding season: nests are found from October until August in Texas, June until October in the West Indies, and April to September in Venezuela (Eitniear 2001). The nest is a deep cup usually near water, sometimes roofed over (basketball-like), containing 4 to 8 eggs. Males are believed to play a minor role in rearing the young. Masked Duck numbers increase during the rainy season and following temperate wet cycles and hurricane rains that create new ponds with emergent vegetation.
Johnsgard and Carbonell’s (1996) treatise on the stiff-tailed ducks, the most thorough treatment to date of this group, points out how little is known of the Masked Duck compared to other stifftails.
Details from captive populations of Masked Duck are particularly lacking. Informed conservation of this species will depend on filling these gaps in knowledge.