Mute swan Cygnus olor, photographed by Andrew Dunn.

Belongs within: Anatidae.
Contains: Branta, Anser.

The Anserinae contains the swans and (the majority of the) geese. In general, Anserinae have longer necks than most other waterfowl, and more robust, less flattened bills. However, recent phylogenetic analyses (e.g. Burleigh et al. 2015) place the pink-eared duck Malacorhynchus membranaceus of Australia as a basal anserine despite its short neck and broadly flattened bill. A second species of this genus, M. scarletti, is known from the subfossil record of New Zealand. Also placed within the Anserinae are the coscoroba Coscoroba coscoroba, a white swan-like bird from southern South America, and the Cape Barren goose Cereopsis novaehollandiae of southern Australia. Cnemiornis, a recently extinct genus of two species of large flightless goose from New Zealand, is generally believed to have been closely allied to the Cape Barren goose.

The swans of the genus Cygnus are particularly large and long-necked birds. The majority of swan species are found in higher latitudes of the Northern Hemisphere and are predominantly white in coloration. However, distinctive in both distribution and coloration are the black swan Cygnus atratus of Australia and the black-necked swan C. melancoryphus of South America. The mute swan Cygnus olor has an orange-red bill with a large black knob at the base, and has been widely introduced outside its native Palaearctic range as an ornamental bird.

Published 27 May 2011
Coscoroba Coscoroba coscoroba, photographed by Christopher Valentine at the Jardin des Plantes, Paris. Photographing this animal was not entirely easy: it was in the process of preening, and every time that we tried to get a photo, its head would dive back into its feathers and we’d have yet another photo of a headless coscoroba.

The coscoroba (its name refers to the sound of its call) is a waterbird of coastward parts of southern South America, with its range having extended over the past century as far north as Uruguay (Kear 2005). In general appearance, it resembles a small swan (and is often called the ‘coscoroba swan’). The most obvious difference between a swan and a coscoroba is that the latter lacks a bare patch of skin between its eyes and its beak. Coscorobas also have a flatter, more ‘duck-like’ beak than swans. Another significant difference can be seen in their behaviour: swans and geese are characterised by what is called a ‘triumph ceremony’, where a male approaches his partner (swans form life-long pair bonds), raising and lowering his head while calling, and is answered by her in kind. This behaviour is particularly common after the male has seen off a potential rival (hence the name), and probably serves to maintain the pair bond. Coscorobas, it seems, are far too refined for such brazen posturing, and limit themselves to a little quiet murmuring of their eponymous call (Johnsgard 1965).

The Cape Barren goose Cereopsis novaehollandiae, potential sister to the coscoroba. Photographed by Norm Hanson.

Because of its ‘not-quite-swannish’ nature, the coscoroba has often been seen as a link between swans and some other group of waterfowl, such as geese or whistling ducks. Molecular studies (e.g. Donne-Goussé et al. 2002) have placed it as sister to the Cape Barren goose Cereopsis novaehollandiae of Australia, with the two together sister to the swans. This does seem a little counter-intuitive, as superficially Cereopsis does not appear very coscoroba-like, but it is relatively well-supported. The purported similarities between the coscoroba and whistling ducks, on the other hand, are quite possibly plesiomorphies retained from the ancestral waterfowl.

Systematics of Anserinae
<==Anserinae [Anseriinae, Anserina, Cygnopsidinae]
    |  i. s.: Geochen rhuax (n. d.)PJ02
    |--+--Malacorhynchus Swainson 1831BKB15, CC10 [Malacorhynchini]
    |  |    |--*M. membranaceus (Latham 1802) [=Anas membranacea; incl. M. membranaceus assimilis Mathews 1912]CC10
    |  |    `--M. scarletti Olson 1977CC10
    |  `--+--Coscoroba Reichenbach 1853BKB15, B94 [Coscorobinae]
    |     |    `--C. coscorobaBKB15
    |     `--Cereopsini [Cereopsina]CC10
    |          |--Cereopsis Latham 1802BKB15, CC10 [Cereopseinae]
    |          |    `--*C. novaehollandiae Latham 1802 (see below for synonymy)CC10
    |          `--Cnemiornis Owen 1866 [Cnemiornithidae]CC10
    |               |--*C. calcitrans Owen 1866 [incl. Cn. minor Forbes 1892, Cereopsis novaezealandiae Forbes 1892]CC10
    |               `--C. gracilis Forbes 1892 [incl. C. septentrionalis Oliver 1955]CC10
       |    |--BrantaBKB15
       |    `--+--+--‘Chen’ canagicaBKB15
       |       |  `--AnserBKB15
       |       `--Chen Boie 1822BKB15, S05
       |            |--C. caerulescensBKB15
       |            `--C. rossii (Cass. 1861)BKB15, S05 [=Anser rossiiS05, Exanthemos rossiS05]
       `--Cygnus Bechstein 1803BKB15, CC10 (see below for synonymy)
            |  i. s.: C. atavus (Fraas 1870) (see below for synonymy)M02
            |         C. equitum Bate 1916 [=Anser equitum, C. (Olor) equitum]M02
            |         C. herenthalsi Beneden in Lambrecht 1933 [=C. herrenthalsi]M02
            |         C. verae Boev 2000M02
            |         C. (Olor Wagler 1832)M02
            |           |--C. (O.) bewickii Yarrell 1830M02 (see below for synonymy)
            |           |--C. (O.) csakvarensis Lambrecht 1933 [=*Cygnanser csakvarensis]M02
            |           `--C. (O.) falconeri Parker 1865 (see below for synonymy)M02
            |--C. melancoryphusBKB15
            `--+--+--*C. (Cygnus) olor (Gmelin 1789)CC10, BKB15, CC10 [=Anas olorCC10]
               |  `--C. atratus (Latham 1790)BKB15, CC10 (see below for synonymy)
               `--+--C. buccinator Richardson in Swainson & Richardson 1831BKB15, S05 (see below for synonymy)
                  `--+--C. columbianus (Ord 1815)BKB15, CS77 (see below for synonymy)
                     `--C. cygnus (Linnaeus 1758)BKB15, M02 (see below for synonymy)

*Cereopsis novaehollandiae Latham 1802 [=C. cinerea Vieillot 1816; incl. C. australis Swainson 1837, C. novaehollandiae georgi Mathews 1912, C. novaehollandiae grisea Storr 1980, Anser griseus Vieillot 1818, C. novaezealandiae Oliver 1955 non Forbes 1892, Anas terraeleeuwin Bennett 1830]CC10

Cygnus Bechstein 1803BKB15, CC10 [incl. Chenopis Wagler 1832CC10, Cygnanser Kretzoi 1957M02, Palaeocycnus Stejneger 1882M02, Palaeocygnus Oberholser 1908M02; Cygnina, Cygninae, Olorinae]

Cygnus atavus (Fraas 1870) [=Anas atava, Anser atavus; incl. Anas cygniformis Fraas 1870, Anser cygniformis, Palaelodus steinheimensis Fraas 1870]M02

Cygnus atratus (Latham 1790)BKB15, CC10 [=Anas atrataCC10, *Chenopis atrataCC10, Chenopis atratusCC10, Chenopsis (l. c.) atrataCC10, Chenopsis (l. c.) atratusCC10; incl. Cygnus chathamicus Oliver 1955CC10, Cy. chathamensisCC10, Cy. chathamicaCC10, Anas cygnus niger Perry 1811CC10, Anser novaehollandiae Bonnaterre 1791CC10, Anas plutonia Shaw 1792CC10, Cygnus plutoniusCC10, Chenopis atrata roberti Mathews 1912CC10, Chenopis sumnerensis Forbes 1890CC10, Cygnus sumnerensisCC10]

Cygnus buccinator Richardson in Swainson & Richardson 1831BKB15, S05 [=C. cygnus buccinatorRN72, Olor buccinatorL81]

Cygnus columbianus (Ord 1815)BKB15, CS77 [=Anas columbianusCS77, Olor columbianusS05; incl. O. americanus Murdoch 1885S05, Cygnus columbianus jankowskii Alpheraky 1904CS77]

Cygnus cygnus (Linnaeus 1758)BKB15, M02 [=Anas cygnusM02, Olor cygnusS05; incl. C. cygnus islandicus Brehm 1831CS77]

Cygnus (Olor) bewickii Yarrell 1830M02 [=C. columbianus bewickiiCS77; incl. Anser liskunae Kuročkin 1976M02, Olor liskunaeM02, Cygnus minor Heuglin 1874S05, C. musicus Spörer 1868S05, Anser subanser Jánossy 1983M02]

Cygnus (Olor) falconeri Parker 1865 [=*Palaeocycnus falconeri, *Palaeocygnus falconeri; incl. Cygnus melitensis Falconer 1868]M02

*Type species of generic name indicated


[B94] Bock, W. J. 1994. History and nomenclature of avian family-group names. Bulletin of the American Museum of Natural History 222: 1–281.

[BKB15] Burleigh, J. G., R. T. Kimball & E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Molecular Phylogenetics and Evolution 84: 53–63.

[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.

[CS77] Cramp, S., & K. E. L. Simmons (eds) 1977. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palaearctic vol. 1. Ostrich to Ducks. Oxford University Press: Oxford.

Donne-Goussé, C., V. Laudet & C. Hänni. 2002. A molecular phylogeny of Anseriformes based on mitochondrial DNA analysis. Molecular Phylogenetics and Evolution 23: 339–356.

Johnsgard, P. 1965. Handbook of Waterfowl Behavior. University of Nebraska: Lincoln.

Kear, J. 2005. Ducks, Geese and Swans. Oxford University Press.

[L81] Long, J. L. 1981. Introduced Birds of the World: The worldwide history, distribution and influence of birds introduced to new environments. Reed: Sydney.

[M02] Mlíkovský, J. 2002. Cenozoic Birds of the World. Part 1: Europe. Ninox Press: Praha.

[PJ02] Paxinos, E. E., H. F. James, S. L. Olson, M. D. Sorenson, J. Jackson & R. C. Fleischer. 2002. MtDNA from fossils reveals a radiation of Hawaiian geese recently derived from the Canada goose (Branta canadensis). Proceedings of the National Academy of Sciences of the USA 99: 1399–1404.

[RN72] Rutgers, A., & K. A. Norris (eds.) 1972. Encyclopaedia of Aviculture vol. 1. Blandford Press: London.

[S05] Schalow, H. 1905. Die Vögel der Arktis. In: Römer, F., & F. Schaudinn (eds) Fauna Arctica. Eine Zusammenstellun der arktischen Tierformen, mit besonder Berücksichtigung des Spitzbergen-Gebietes auf Grund der Ergebnisse der Deutschen Expedition in das Nördliche Eismeer im Jahre 1898 vol. 4 pp. 79–288. Gustav Fischer: Jena.

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