Masked Duck (Nomonyx dominica)

Masked Duck

[order] ANSERIFORMES | [family] Anatidae | [latin] Nomonyx dominica | [authority] Linnaeus, 1766 | [UK] Masked Duck | [FR] Erismature routoutou | [DE] Masken-Ruderente | [ES] Malvasia Enmascarada | [NL] Maskerstekelstaart


Monotypic species


The only member of the genus Nomonyx, it is intermediate between the rather primitive Black-headed Duck (Heteronetta) and the very apomorphic true stifftails. It is sometimes included with the latter in the genus Oxyura, but apparently the Masked Ducks of our time are the descendants of a missing link in the Oxyurinae evolution, having changed but little for millions of years

Physical charateristics

Small, chunky diving duck with a long stiff-tail which is often held vertically. Dark wings with white speculum. Immature and male eclipse similar to adult female. Adult male in alternate plumage has a brilliant blue bill,
black face, Brown neck and breast, brown and black body and black tail. Adult female has a dark bill, dark crown, eyeline, and line on cheek separated by pale lines above and below eyeline. greyish brown body with pale feather edging.

Listen to the sound of Masked Duck

[audio: Duck.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 43 cm wingspan max.: 45 cm
size min.: 33 cm size max.: 35 cm
incubation min.: 26 days incubation max.: 28 days
fledging min.: 43 days fledging max.: 28 days
broods: 1   eggs min.: 3  
      eggs max.: 6  


Latin America : widespread


Prefers marshes, ponds, rice fields. Appropriate habitat has been subjectively defined as overgrown swamps and marshes, where aquatic plants like water hyacinth and water lilies occur. Breeds on Texas coastline.


Presumably monogamous. Female builds roofed-over or deep cup nest in vegetation near water, lined with few down feathers. Clutch size is four to six buff-white eggs incubated by female for 23 to 24 days. Male stays for a portion of incubation period. Female alone tends precocial young.

Feeding habits

Feeds on variety of aquatic vegetation and seeds, occasionally insects and crustaceans. Primarily feeds by tipping up, also makes short dives.

Video Masked Duck


copyright: J. del Hoyo


This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Found primarily in the tropics and neotropics with populations throughout Mexico. Strays to Texas where it has breeded. Multiple records for Louisiana and Florida, single records for several other eastern U.S. states. Inhabits marshy ponds with heavy vegetation, often found in rice fields. In Suriname mainly confied to fresh water and riperian forest edges.
Masked Duck status Least Concern


Mostly sedentary, but subject to some wide-ranging dispersive movements when it may occur far beyond breeding range. Not uncommonly recorded in southern USA (Florida and Texas, where has bred) and occasionally further North in eastern North America (as far as Vermont).

Distribution map

Masked Duck distribution range map

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