Masked Duck
Description
The masked duck (Nomonyx dominicus) is a tiny stiff-tailed duck ranging through the tropical Americas. They are found from Mexico to South America and also in the Caribbean. Primarily not migratory, masked ducks are reported as very uncommon vagrants in the southernmost United States, along the Mexican border and in Florida. As of 2000, the conservation status for masked ducks in Texas is 3,800 birds. On April 1, 1962, it was recorded from Lowndes County, Georgia, where it was photographed by Alexander Wetmore.
Distribution & Habitat
The Masked Duck is a rare resident in Puerto Rico (Oberle
2018, Raffaele and others 1998)
and a rare visitor in Vieques
(Gemmill 2015). The atlas
fieldwork yielded a total of 20
records within 11 hexagons or 2
percent of the 479 total hexagons
(see map). Of the 11 hexagons
where this species was found,
breeding met the atlas definition
of confirmed in 18 percent (two)
of the hexagons, probable in 9
percent (one), and possible in
73 percent (eight) (see map).
This species inhabits freshwater
swamps and canals with plenty of fl oating vegetation, as well as
rice fields (Raffaele and others
1998), brackish water ponds, and
lagoons (Oberle 2018).
Breeding Habits
Previously published reports indicate that the Masked Duck
breeds from May to August and
nests on swamp vegetation near
or over the water (Raffaele and
others 1998). Atlas results show
that the Masked Duck breeding
season extends throughout the
year, but the most records were
reported in June (see chart).
Results show that the Masked
Duck mostly breeds within the Masked Duck distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in
Puerto Rico. Note: percentages may not total 100 due to rounding. 33Masked Duck/Pato Dominicosubtropical moist (73 percent of the hexagons) and subtropical
dry forest life zones (27 percent
of the hexagons) (see table
and map).
Conservation
The Masked Duck population is suspected to be declining
owing to over-hunting and
other human pressure but is
listed by the IUCN as a species
of least concern (BirdLife
International 2016). The Puerto
Rican population is composed of around 50 pairs and is
under pressure from illegal
hunting and habitat degradation
associated with human activities
(J.A. Salguero-Faría, personal
observation 2009). In Puerto
Rico, the Masked Duck is listed
as endangered (PRDNER 2016)
and has a protected habitat in
land of 15 percent or 39 km2 of the total area covered by
the hexagons where evidence
of breeding was found for this
species (264 km2).
Related Species
Family:
duck