Anatidae
Temporal range: Early Oligocene – recent[1]
Clockwise from top left: mallard, mute swan, Brazilian teal, paradise shelduck, bufflehead, and greylag goose.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Suborder: Anseres
Superfamily: Anatoidea
Family: Anatidae
Leach, 1819
Type genus
Anas
Linnaeus, 1758
Genera

The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating on the water surface, and in some cases diving in at least shallow water. The family contains around 174 species in 43 genera (the magpie goose is no longer considered to be part of the Anatidae and is now placed in its own family, Anseranatidae).

They are generally herbivorous, and are monogamous breeders. A number of species undertake annual migrations. A few species have been domesticated for agriculture, and many others are hunted for food and recreation. Five species have become extinct since 1600, and many more are threatened with extinction.

Landing mallard drake

Description and ecology

The ducks, geese, and swans are small- to large-sized birds with a broad and elongated general body plan.[2] Diving species vary from this in being rounder. Extant species range in size from the cotton pygmy goose, at as little as 26.5 cm (10.5 in) and 164 g (5.8 oz), to the trumpeter swan, at as much as 183 cm (6 ft) and 17.2 kg (38 lb). The largest anatid ever known is the extinct flightless Garganornis ballmanni at 22 kg (49 lb). The wings are short and pointed, and supported by strong wing muscles that generate rapid beats in flight. They typically have long necks, although this varies in degree between species. The legs are short, strong, and set far to the back of the body (more so in the more aquatic species), and have a leathery feel with a scaly texture. Combined with their body shape, this can make some species awkward on land, but they are stronger walkers than other marine and water birds such as grebes or petrels. They typically have webbed feet, though a few species such as the Nene have secondarily lost their webbing. The bills are made of soft keratin with a thin and sensitive layer of skin on top (which has a leathery feel when touched). For most species, the shape of the bill tends to be more flattened to a greater or lesser extent. These contain serrated lamellae which are particularly well defined in the filter-feeding species.[2]

Their feathers are excellent at shedding water due to special oils. Many of the ducks display sexual dimorphism, with the males being more brightly coloured than the females (although the situation is reversed in species such as the paradise shelduck). The swans, geese, and whistling-ducks lack sexually dimorphic plumage. Anatids are vocal birds, producing a range of quacks, honks, squeaks, and trumpeting sounds, depending on species; the female often has a deeper voice than the male.[3]

Anatids are generally herbivorous as adults, feeding on various water-plants, although some species also eat fish, molluscs, or aquatic arthropods. One group, the mergansers, are primarily piscivorous, and have serrated bills to help them catch fish. In a number of species, the young include a high proportion of invertebrates in their diets, but become purely herbivorous as adults.[3]

Breeding

The anatids are generally seasonal and monogamous breeders. The level of monogamy varies within the family; many of the smaller ducks only maintain the bond for a single season and find a new partner the following year, whereas the larger swans, geese and some of the more territorial ducks maintain pair bonds over a number of years, and even for life in some species. However, forced extrapair copulation among anatids is common, occurring in 55 species in 17 genera.[4]

Anatidae is a large proportion of the 3% of bird species to possess a penis,[5][6] though they vary significantly in size, shape, and surface elaboration.[7] Most species are adapted for copulation on the water only. They construct simple nests from whatever material is close at hand, often lining them with a layer of down plucked from the mother's breast. In most species, only the female incubates the eggs. The young are precocial, and are able to feed themselves from birth.[3] One aberrant species, the black-headed duck, is an obligate brood parasite, laying its eggs in the nests of gulls and coots. While this species never raises its own young, a number of other ducks occasionally lay eggs in the nests of conspecifics (members of the same species) in addition to raising their own broods.

Relationship with humans

Duck, eider, and goose feathers and down have long been popular for bedspreads, pillows, sleeping bags, and coats. The members of this family also have long been used for food.

Humans have had a long relationship with ducks, geese, and swans; they are important economically and culturally to humans, and several duck species have benefited from an association with people. However, some anatids are agricultural pests, and have acted as vectors for zoonoses such as avian influenza.

Since 1600, five species of ducks have become extinct due to the activities of humans,[citation needed] and subfossil remains have shown that humans caused numerous extinctions in prehistory. Today, many more are considered threatened. Most of the historic and prehistoric extinctions were insular species, vulnerable due to small populations (often endemic to a single island), and island tameness. Evolving on islands that lacked predators, these species lost antipredator behaviours, as well as the ability to fly, and were vulnerable to human hunting pressure and introduced species. Other extinctions and declines are attributable to overhunting, habitat loss and modification, and hybridisation with introduced ducks (for example the introduced ruddy duck swamping the white-headed duck in Europe). Numerous governments and conservation and hunting organisations have made considerable progress in protecting ducks and duck populations through habitat protection and creation, laws and protection, and captive-breeding programmes.

Systematics

Anatidae: Eurasian teal (Anas crecca), gadwall (Anas strepera), northern pintail (Anas acuta), mallard (Anas platyrhynchos), greater scaup (Aythya marila), long-tailed duck (Clangula hyemalis), northern shoveler (Anas clypeata), garganey (Anas querquedula), Eurasian wigeon (Anas penelope), ferruginous duck (Aythya nyroca), common goldeneye (Bucephala clangula), common merganser (Mergus merganser), smew (Mergellus albellus), tufted duck (Aythya fuligula), red-breasted merganser (Mergus serrator), common pochard (Aythya ferina). Post of Belarus, 1996.

History of classification

The name Anatidae for the family was introduced by the English zoologist William Elford Leach in a guide to the contents of the British Museum published in 1819.[8][9] While the status of the Anatidae as a family is straightforward, and which species properly belong to it is little debated, the relationships of the different tribes and subfamilies within it are poorly understood. The listing in the box at right should be regarded as simply one of several possible ways of organising the many species within the Anatidae; see discussion in the next section.

The systematics of the Anatidae are in a state of flux. Previously divided into six subfamilies,[citation needed] a study of anatomical characters by Livezey[10] suggests the Anatidae are better treated in nine subfamilies. This classification was popular in the late 1980s to 1990s.[11] But mtDNA sequence analyses[12][13] indicate, for example, the dabbling and diving ducks do not belong in the same subfamily.

While shortcomings certainly occur in Livezey's analysis,[citation needed] mtDNA is an unreliable source for phylogenetic information in many waterfowl (especially dabbling ducks) due to their ability to produce fertile hybrids,[2] in rare cases possibly even beyond the level of genus (see for example the "Barbary duck"). Because the sample size of many molecular studies available to date is small, mtDNA results must be considered with caution.

While a comprehensive review of the Anatidae which unites all evidence into a robust phylogeny is still lacking, the reasons for the confusing data are at least clear: As demonstrated by the Late Cretaceous fossil Vegavis iaai — an early modern waterbird which belonged to an extinct lineage—the Anatidae are an ancient group among the modern birds. Their earliest direct ancestors, though not documented by fossils yet, likewise can be assumed[citation needed] to have been contemporaries with the non-avian dinosaurs. The long period of evolution and shifts from one kind of waterbird lifestyle to another have obscured many plesiomorphies, while apparent apomorphies are quite often the result of parallel evolution, for example the "non-diving duck" type displayed by such unrelated genera as Dendrocygna, Amazonetta, and Cairina. For the fossil record, see below.

Alternatively,[14] the Anatidae may be considered to consist of three subfamilies (ducks, geese, and swans, essentially) which contain the groups as presented here as tribes, with the swans separated as subfamily Cygninae, the goose subfamily Anserinae also containing the whistling ducks, and the Anatinae containing all other clades.

Genera

For the living and recently extinct members of each genus, see the article List of Anatidae species.[citation needed]

A male mallard duck

Prehistoric species

Maned duck is the only living member of the genus Chenonetta

From subfossil bones found on Kauaʻi (Hawaiian Islands), two enigmatic waterfowl are known.[17] The living and assignable prehistoric avifauna of the archipelago contains as Anseriformes Branta geese and their descendants, and the moa-nalos as mentioned above. The following taxa, although certainly new species, cannot be assigned even to subfamily; that Kauaʻi is the oldest of the large Hawaiian Islands, meaning the species may have been evolving in isolation for nearly 10 mya (since the Late Miocene), does not help in determining their affinities:

Similarly, Branta rhuax from the Big Island of Hawaiʻi, and a gigantic goose-like anatid from Oʻahu are known only from very incomplete, and in the former case much damaged, bone fragments. The former has been alleged to be a shelduck,[18] but this was generally dismissed because of the damage to the material and biogeographic considerations. The long-legged Kauaʻi bird, however, hints at the possibility of a former tadornine presence on the archipelago.

Fossil Anatidae

The fossil record of anatids is extensive, but many prehistoric genera cannot be unequivocally assigned to present-day subfamilies for the reasons given above. For prehistoric species of extant genera, see the respective genus accounts.

Dendrocheninae – a more advanced relative of the whistling-ducks or an ancestral relative of stifftail ducks paralleling whistling-ducks; if not extinct possibly belong in Oxyurinae (including Malacorhynchus)

Black swan (Cygnus atratus) skeleton on display at the Museum of Osteology.

Anserinae

Tadorninae

Anatinae

Oxyurinae

Incertae sedis

Putative or disputed prehistoric anatids are:

The Middle Oligocene Limicorallus (from Chelkar-Teniz (Kazakhstan) was sometimes considered an anserine. It is now recognized as a primitive cormorant. The middle Eocene Eonessa was formerly thought to belong to Anatidae, however reexamination of the holotype in 1978 resulted in the genus being placed as Aves incertae sedis.[1]

See also

References

  1. ^ a b Olson, Storrs L.; Feduccia, A. (1980). "Presbyornis and the Origin of the Anseriformes (Aves: Charadriomorphae)" (PDF). Smithsonian Contributions to Zoology. 323 (323). Smithsonian Institution: 1–24. doi:10.5479/si.00810282.323. Archived from the original (PDF) on 2012-02-27. Retrieved 2010-01-25.
  2. ^ a b c Carboneras, Carles (1992): Family Anatidae (Ducks, Geese and Swans). In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): Handbook of Birds of the World (Volume 1: Ostrich to Ducks): 536–629. Lynx Edicions, Barcelona. ISBN 84-87334-10-5
  3. ^ a b c Todd, Frank S. (1991). Forshaw, Joseph (ed.). Encyclopaedia of Animals: Birds. London: Merehurst Press. pp. 81–87. ISBN 1-85391-186-0.
  4. ^ McKinney, Frank; Evarts, Susan (1998). "Sexual coercion in waterfowl and other birds". Ornithological Monographs. 49 (49): 165–193. doi:10.2307/40166723. JSTOR 40166723.
  5. ^ McCracken, Kevin G. (2000). "The 20-cm Spiny Penis of the Argentine Lake Duck (Oxyura vittata)" (PDF). The Auk. 117 (3): 820–825. doi:10.2307/4089612. JSTOR 4089612. Archived from the original (PDF) on 2008-07-05.
  6. ^ Brennan, Patricia; Birkhead, Tim; Zyskowski, Kristof; Van Der Waag, Jessica; Prum, Richard (2008). "Independent evolutionary reductions of the phallus in basal birds" (PDF). Journal of Avian Biology. 39 (5): 487–492. doi:10.1111/j.0908-8857.2008.04610.x.
  7. ^ Briskie, James; Montgomerie, Robert (1997). "Sexual selection and the intromittent organ of birds". Journal of Avian Biology. 28 (1): 73–86. doi:10.2307/3677097. JSTOR 3677097.
  8. ^ Leach, William Elford (1819). "Eleventh Room". Synopsis of the Contents of the British Museum (15th ed.). London: British Museum. pp. 63-68 [67]. The name of the author is not specified in the document, Leach was the Keeper of Zoology at the time.
  9. ^ Bock, Walter J. (1994). History and Nomenclature of Avian Family-Group Names. Bulletin of the American Museum of Natural History. Vol. 222. New York: American Museum of Natural History. pp. 133, 245.
  10. ^ a b c d Livezey, Bradley C. (1986). "A phylogenetic analysis of recent anseriform genera using morphological characters" (PDF). Auk. 103 (4): 737–754. doi:10.1093/auk/103.4.737. JSTOR 4087184.
  11. ^ Madge, Steve & Burn, Hilary (1987): Wildfowl : an identification guide to the ducks, geese and swans of the world. Christopher Helm, London. ISBN 0-7470-2201-1
  12. ^ Sraml, M.; Christidis, L.; Easteal, S.; Horn, P.; Collet, C. (1996). "Molecular Relationships Within Australasian Waterfowl (Anseriformes)". Australian Journal of Zoology. 44 (1): 47–58. doi:10.1071/ZO9960047.
  13. ^ a b c Johnson, Kevin P.; Sorenson, Michael D. (1999). "Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence" (PDF). Auk. 116 (3): 792–805. doi:10.2307/4089339. JSTOR 4089339.
  14. ^ Terres, John K. & National Audubon Society (NAS) (1991): The Audubon Society Encyclopedia of North American Birds. Wings Books, New York. Reprint of 1980 edition. ISBN 0517032880
  15. ^ Collar, N. J.; Andreev, A. V.; Chan, S.; Crosby, M. J.; Subramanya, S. & Tobias, J. A. (eds.) (2001): Pink-headed Duck Archived 2007-03-11 at the Wayback Machine. In:Threatened Birds of Asia: The BirdLife International Red Data Book: 489–501. BirdLife International. ISBN 0-946888-44-2
  16. ^ Buckner, Janet C; Ellingson, Ryan; Gold, David A; Jones, Terry L; Jacobs, David K (2018). "Mitogenomics supports an unexpected taxonomic relationship for the extinct diving duck Chendytes lawi and definitively places the extinct Labrador Duck" (PDF). Molecular Phylogenetics and Evolution. 122: 102–109. doi:10.1016/j.ympev.2017.12.008. PMID 29247849.
  17. ^ Burney, David A.; James, Helen F.; Burney, Lida Pigott; Olson, Storrs L.; Kikuchi, William; Wagner, Warren L.; Burney, Mara; McCloskey, Deirdre; Kikuchi, Delores; Grady, Frederick V.; Gage, Reginald II; Nishek, Robert (2001). "Fossil Evidence for a Diverse Biota from Kauaʻi and Its Transformation since Human Arrival" (PDF). Ecological Monographs. 71 (4): 615–641. doi:10.2307/3100038. JSTOR 3100038.[permanent dead link]
  18. ^ Short, Lester L. (1970). "A new anseriform genus and species from the Nebraska Pliocene" (PDF). Auk. 87 (3): 537–543. doi:10.2307/4083796. JSTOR 4083796.
  19. ^ Mlíkovský, J. (1992). "The present state of knowledge of Tertiary birds of Central europe" (PDF). Science Series. Los Angeles County, CA: Natural History Museum. Archived from the original (PDF) on 2012-02-19. Retrieved 2013-03-11.
  20. ^ Gál, Erika; Hír, János; Kessler, Eugén & Kókay, József (1998–99): Középsõ-miocén õsmaradványok, a Mátraszõlõs, Rákóczi-kápolna alatti útbevágásból. I. A Mátraszõlõs 1. lelõhely Archived 2011-07-21 at the Wayback Machine [Middle Miocene fossils from the sections at the Rákóczi chapel at Mátraszőlős. Locality Mátraszõlõs I.]. Folia Historico Naturalia Musei Matraensis 23: 33–78. [Hungarian with English abstract]

Further reading

External links

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