The masked duck (''Nomonyx dominicus'') is a tiny stiff-tailed duck ranging through the

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

Americas. They are found from

Mexico Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guate ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

and also in the Caribbean. Primarily not migratory, masked ducks are reported as very uncommon vagrants in the southernmost

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, along the

Mexican Mexican may refer to: Mexico and its culture *Being related to, from, or connected to the country of Mexico, in North America ** People *** Mexicans, inhabitants of the country Mexico and their descendants *** Mexica, ancient indigenous people ...

border and in

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

. 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 Lowndes County is a county located in the south central portion of the U.S. state of Georgia. As of the 2020 census the population was 118,251. The county seat is Valdosta. The county was created December 23, 1825. Lowndes County is included ...

, where it was photographed by

Alexander Wetmore Frank Alexander Wetmore (June 18, 1886 – December 7, 1978) was an American ornithologist and avian paleontologist. He was the sixth Secretary of the Smithsonian Institution. Early life and education The son of a Country Physician, Frank Ale ...

. The only member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Nomonyx'', it is intermediate between the rather primitive black-headed duck (''Heteronetta'') and the very

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

ic true stiff-tailed ducks. It is sometimes included with the latter in the genus '' Oxyura'', but apparently the masked ducks now are the descendants of a missing link in the

Oxyurini The Oxyurini are a tribe of the duck subfamily of birds, the Anatinae. It has been subject of considerable debate about its validity and circumscription. Some taxonomic authorities place the group in its own subfamily, the ''Oxyurinae''. Most of ...

evolution, having changed but little for millions of years.

Breeding Breeding is sexual reproduction that produces offspring, usually animals or plants. It can only occur between a male and a female animal or plant. Breeding may refer to: * Animal husbandry, through selected specimens such as dogs, horses, and rab ...

adult males have a rust-colored body with a black face and mottled wings. Adult females, winter males, and juveniles have a barred brownish gray body, with two horizontal, dark-colored stripes running through the buff-colored face. These ducks mainly feed on

seeds A seed is an Plant embryogenesis, embryonic plant enclosed in a testa (botany), protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, includ ...

, roots, stems,https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Nomonyx_dominicus%20-%20Masked%20Duck.pdf and leaves of aquatic

plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

. They also eat aquatic

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

and

crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gr ...

. They feed by diving. Masked ducks breed in any freshwater body with

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...

vegetation and surrounded by heavy tree cover. They also occur in

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several ...

swamps A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

. These ducks are usually very secretive, but they are not rare and not considered threatened by the IUCN.

References

Further reading