The whistling ducks or tree ducks are a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

, Dendrocygninae, of the

duck Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfam ...

goose A goose (: geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera '' Anser'' (grey geese and white geese) and '' Branta'' (black geese). Some members of the Tadorninae subfamily (e.g., Egy ...

and

swan Swans are birds of the genus ''Cygnus'' within the family Anatidae. The swans' closest relatives include the goose, geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe (biology) ...

family of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

Anatidae The Anatidae are the biological family (biology), family of water birds that includes ducks, goose, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted f ...

. In other taxonomic schemes, they are considered a separate

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

, Dendrocygnidae. Some taxonomists list only one genus, ''Dendrocygna'', which contains eight living species, and one undescribed extinct species from

Aitutaki Aitutaki, also traditionally known as Araura and Utataki, is the second most-populated island in the Cook Islands, after Rarotonga. It is an "almost atoll", with fifteen islets in a lagoon adjacent to the main island. Total land area is , and the ...

of the

Cook Islands The Cook Islands is an island country in Polynesia, part of Oceania in the South Pacific Ocean. It consists of 15 islands whose total land area is approximately . The Cook Islands' Exclusive Economic Zone (EEZ) covers of ocean. Avarua is its ...

, but other taxonomists also list the white-backed duck (''Thalassornis leuconotus'') under the subfamily.

Taxonomy and evolution

Whistling ducks were first described by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the 10th edition of ''Systema Naturae'' in 1758: the black-bellied whistling duck (then ''Anas autumnalis'') and the West Indian whistling duck (then ''Anas arborea''). In 1837,

William Swainson William Swainson Fellow of the Linnean Society, FLS, Fellow of the Royal Society, FRS (8 October 1789 – 6 December 1855), was an English ornithologist, Malacology, malacologist, Conchology, conchologist, entomologist and artist. Life Swains ...

named the genus ''Dendrocygna'' to distinguish whistling ducks from the other

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

was listed as the wandering whistling duck (''D. arcuata''), formerly named by Thomas Horsfield as ''Anas arcuata''. Whistling duck

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

, including that of the entire

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Anseriformes Anseriformes is an order (biology), order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest f ...

, is complicated and disputed. Under a traditional classification proposed by

ornithologist Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...

Jean Théodore Delacour based on morphological and behavioral traits, whistling ducks belong to the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

Dendrocygnini under the

and subfamily

Anserinae The Anserinae are a subfamily in the waterfowl family Anatidae. It includes the swans and the true Goose, geese. Under alternative systematics, systematical concepts (see e.g., Terres & NAS, 1991), it is split into two subfamilies, the Anserina ...

. Following the revisions by ornithologist Paul Johnsgard, Dendrocygnini includes the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Thalassornis'' (the white-backed duck) under this system. In 1997, Bradley C. Livezey proposed that ''Dendrocygna'' were a separate lineage from Anserinae, placing it and its tribe in its own subfamily, Dendrocygninae. Alternatively Charles Sibley and Jon Edward Ahlquist recommended placing ''Dendrocygna'' in its own family, Dendrocygnidae, which includes the genus ''Thalassornis''.

Species

Eight species of whistling duck are currently recognized in the genus ''Dendrocygna''. However, Johnsgard considers the white-backed duck (''Thalassornis leuconotus'') from Africa and

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

to be distinct ninth species, a view first proposed in 1960 and initially supported by behavioral similarities. Later, similarities in anatomy, duckling vocalizations, and feather proteins gave additional support. Molecular analysis in 2009 also suggested that the white-backed duck was nested within the whistling duck

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

. In addition to the

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

species,

subfossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

remains of an extinct, undescribed species have been found on

of the

Description

Whistling ducks are found in the tropics and subtropics. As their name implies, they have distinctive whistling calls. The whistling ducks have long legs and necks, and are very gregarious, flying to and from night-time roosts in large flocks. Both sexes have the same

plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...

, and all have a hunched appearance and black underwings in flight. After breeding and pairing with a female, male whistling ducks (especially within the Fulvous whistling duck species) will often help with the construction of nests and will take turns with the female incubating the eggs.

Notes

References

Literature cited

* * * * * * * * * * * {{Authority control * Bird genera Taxa named by William Swainson