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 subfamily botanical names with "-oideae", and zoologi ...

, Dendrocygninae, of the duck, goose and

swan Swans are birds of the family (biology), family Anatidae within the genus ''Cygnus''. 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 t ...

family of birds, Anatidae. In other

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

schemes, they are considered a separate family, 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, but other taxonomists also list the

white-backed duck The white-backed duck (''Thalassornis leuconotus'') is a waterbird of the family Anatidae. It is distinct from all other ducks, but most closely related to the whistling ducks in the subfamily Dendrocygninae, though also showing some similarities ...

(''Thalassornis leuconotus'') under the subfamily.

Taxonomy and evolution

Whistling ducks were first described by Carl Linnaeus in the 10th edition of ''Systema Naturae'' in 1758: the

black-bellied whistling duck The black-bellied whistling duck (''Dendrocygna autumnalis''), formerly called the black-bellied tree duck, is a whistling duck that breeds from the southernmost United States, Mexico, and tropical Central to south-central South America. In the ...

(then ''Anas autumnalis'') and the West Indian whistling duck (then ''Anas arborea''). In 1837,

William John Swainson William John Swainson FLS, FRS (8 October 1789 – 6 December 1855), was an English ornithologist, malacologist, conchologist, entomologist and artist. Life Swainson was born in Dover Place, St Mary Newington, London, the eldest son of ...

named the genus ''Dendrocygna'' to distinguish whistling ducks from the other waterfowl. The type species was listed as the

wandering whistling duck The wandering whistling duck (''Dendrocygna arcuata'') is a species of whistling duck. They inhabit tropical and subtropical Australia, the Philippines, Borneo, Indonesia, Papua New Guinea and the Pacific Islands. Taxonomy There are three subspe ...

(''D. arcuata''), formerly named by Thomas Horsfield as ''Anas arcuata''. Whistling duck taxonomy, including that of the entire infraorder

Anseriformes 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 in ...

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

ornithologist Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

Jean Théodore Delacour Jean Théodore Delacour (26 September 1890 – 5 November 1985) was a French ornithologist and aviculturist. He later became American. He was renowned for not only discovering but also rearing some of the rarest birds in the world. He establish ...

based on morphological and behavioral traits, whistling ducks belong to the tribe Dendrocygnini under the family Anatidae and subfamily

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

. Following the revisions by ornithologist Paul Johnsgard, Dendrocygnini includes the genus ''Thalassornis'' (the

) under this system. In 1997,

Bradley C. Livezey Bradley Curtis Livezey (June 15, 1954 – February 8, 2011) was an American ornithologist with scores of publications. His main research included the evolution of flightless birds, the systematics of birds, and the ecology and behaviour of steame ...

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 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 Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

in 2009 also suggested that the white-backed duck was nested within the whistling duck

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. In addition to the

extant Extant 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 * Extant taxon, a taxon which is not extinct, ...

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 in ...

remains of an extinct, undescribed species have been found on

of the Cook Islands.

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 ( "feather") 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, ...

, and all have a hunched appearance and black underwings in flight.

Notes

References

Literature cited

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External links

* {{Authority control * Bird genera