Anser (genus)

:"See also Grey Goose (disambiguation)"Taxobox
name = "Anser"


image_width = 240px
image_caption = Greylag Goose, "Anser anser"
regnum = Animalia
phylum = Chordata
classis = Aves
superordo = Galloanserae
ordo = Anseriformes
familia = Anatidae
subfamilia = Anserinae
tribus = Anserini
genus = "Anser"
genus_authority = Brisson, 1760
subdivision_ranks = Species
subdivision ="Anser albifrons" "Anser anser" "Anser brachyrhynchus" "Anser caerulescens" "Anser canagicus" "Anser cygnoides" "Anser fabalis" "Anser erythropus" "Anser indicus" "Anser rossii" "Anser serrirostris" and see text
synonyms ="Chen" Boie, 1822 (but see text) "Cygnopsis" Brandt, 1836 "Cycnopsis" Agassiz, 1846 (emendation) "Eulabeia" Reichenbach, 1852 "Philacte" Bannister, 1870 "Heterochen" Short, 1970 (but see text)

The waterfowl genus "Anser" includes all grey geese and usually the white geese too. It belongs to the true geese and swan subfamily (Anserinae). The genus has a Holarctic distribution, with at least one species breeding in any open, wet habitats in the subarctic and cool temperate regions of the Northern Hemisphere in summer. Some also breed further south, reaching into warm temperate regions. They mostly migrate south in winter, typically to regions in the temperate zone between the January 0 °C (32 °F) to 5 °C (41 °F) isotherms.

The genus contains ten living species, which span nearly the whole range of true goose shapes and sizes. The largest is the Greylag Goose at 2.5-4.1 kg (5.5-9 lb) weight, and the smallest is the Ross's Goose at 1.2-1.6 kg. All have legs and feet that are pink, or orange, and bills that are pink, orange, or black. All have white under- and upper-tail coverts, and several have some extent of white on their heads. The neck, body and wings are grey or white, with black or blackish primary - and also often secondary - remiges (pinions). The closely related "black" geese in the genus "Branta" differ in having black legs, and generally darker body plumage.Carboneras (1992)]

ystematics, taxonomy and evolution

Living species and taxonomy

* Swan Goose "Anser cygnoides" - sometimes separated in "Cygnopsis"
* Taiga Bean-Goose "Anser fabalis"
* Tundra Bean-Goose "Anser serrirostris"
* Pink-footed Goose "Anser brachyrhynchus"
* White-fronted Goose "Anser albifrons"
** Greenland White-fronted Goose "Anser (albifrons) flavirostris"
* Lesser White-fronted Goose "Anser erythropus"
* Greylag Goose "Anser anser"

* Bar-headed Goose "Anser indicus" - sometimes separated in "Eulabeia"

* Snow Goose "Anser caerulescens" - sometimes separated in "Chen"
* Ross's Goose "Anser rossii" - sometimes separated in "Chen"
* Emperor Goose "Anser canagicus" - sometimes separated in "Chen" or "Philacte"

The white geese are sometimes separated as the genus "Chen", with one of them sometimes split off in the genus "Philacte". They cannot be distinguished anatomically, there is some evidence of a distinct lineage in evaluations of molecular dataFact|date=February 2007. While most ornithological works traditionally include "Chen" within "Anser" [E.g. Cramp (1977), Madge & Burn (1988), "Handbook of Birds of the World" (Carboneras 1992), and the 2006 British Ornithologists' Union checklist (Dudley "et al." 2006)] , the AOU and the IUCN are notable authorities which treat them as separate [AOU (1998), IUCN (2007)] .

Some authorities also treat some subspecies as distinct species (notably Tundra Bean Goose [Banks "et al." (2007), van den Berg (2007)] ) or as likely future species splits (notably Greenland White-fronted Goose [Fox & Stroud (2002)] ).

Fossil record

Numerous fossil species have been allocated to this genus. As the true geese are near-impossible to assign osteologically to genus, this must be viewed with caution. It can be assumed with limited certainty that European fossils from known inland sites belong into "Anser". As species related to the Canada Goose have been described from the Late Miocene onwards in North America too, sometimes from the same localities as the presumed grey geese, it casts serious doubt on the correct generic assignment of the supposed North American fossil geese [Brodkorb (1964), Short (1970), Livezey (1986)] . The Early Pliocene "Branta howardae" is one of the cases where doubts have been expressed about its generic assignmentFact|date=February 2007. Similarly, "Heterochen" = "Anser pratensis" seems to differ profoundly from other species of "Anser" and might be placed into a different genus; alternatively, it might have been a unique example of a grey goose adapted for perching in trees [Short (1970) considers this bird to be somewhat reminiscent of geese and swans, shelducks, and the "Cairinini" or "perching ducks". The latter are now known to be a paraphyletic assemblage of miscellaneous waterfowl the morphological similarities of which is the product of convergent evolution towards being able to perch in trees (Livezey 1986).] .

*"Anser atavus" (Middle/Late Miocene of Bavaria, Germany) - sometimes in "Cygnus"
*"Anser arenosus" (Big Sandy Late Miocene of Wickieup, USA)
*"Anser arizonae" (Big Sandy Late Miocene of Wickieup, USA)
*"Anser cygniformis" (Late Miocene of Steinheim, Germany)
*"Anser oeningensis" (Late Miocene of Oehningen, Switzerland)
*"Anser thraceiensis" (Late Miocene/Early Pliocene of Trojanovo, Bulgaria)
*"Anser pratensis" (Valentine Early Pliocene of Brown County, USA) - possibly separable in "Heterochen"
*"Anser pressus" (Glenns Ferry Late Pliocene of Hagerman, USA) - formerly "Chen pressa"
*"Anser thompsoni" (Pliocene of Nebraska)
*"Anser azerbaidzhanicus" (Early? Pleistocene of Binagady, Azerbaijan)

The Maltese swan "Cygnus equitum" was occasionally placed into "Anser", and "Anser condoni" is a synonym of "Cygnus paloregonus" [Brodkorb (1964)] . A goose fossil from the Early-Middle Pleistocene of El Salvador is highly similar to "Anser" [A left humerus (specimen MUHNES 2SSAP30-853) and a left clavicle (specimen MUHNES 2SSAP30-545), apparently of a single bird: Cisneros (2005).] . Given its age it is likely to belong to an extant genus, and biogeography indicates "Branta" as other likely candidate.

?"Anser scaldii" (Late Miocene of Antwerp, Belgium) may be a shelduck.

Relationship with humans and conservation status

Two species in the genus are of major commercial importance, having been domesticated as poultry: European domesticated geese are derived from the Greylag Goose, and Chinese and some African domesticated geese are derived from the Swan Goose.

Most species are hunted to a greater or lesser extent; in some areas, some populations are endangered by over-hunting. Most notably, the Lesser White-fronted Goose is listed by IUCN as Vulnerable throughout its range, and due to overhunting and rampant habitat destruction, the population of the Swan Goose is on the verge of collapsing, leading to a listing as Endangered. [IUCN (2007)]

Other species have benefitted from reductions in hunting since the late 19th/early 20th centuries, with most species in western Europe and North America showing marked increases in response to protectionFact|date=June 2008. In some cases, this has led to conflicts with farming, when large flocks of geese graze crops in the winter.Fact|date=June 2008

Footnotes

References

* (1998): "Check-list of North American Birds: the species of birds of North America from the Arctic through Panama, including the West Indies and Hawaiian Islands" (7th ed., 41st supplement). American Ornithologists' Union and Allen Press, Washington, D.C. and Lawrence, Kansas, USA. ISBN 1-891276-00-X [http://www.aou.org/checklist/index.php3 PDF fulltext]
* (2007): Forty-eighth Supplement to the American Ornithologists' Union Check-List of North American Birds. "Auk" 124(3): 1109-1115. DOI:10.1642/0004-8038(2007)124 [1109:FSTTAO] 2.0.CO;2 [http://www.aou.org/checklist/suppl/AOU_checklist_suppl_48.pdf PDF fulltext]
* (1964): Catalogue of Fossil Birds: Part 2 (Anseriformes through Galliformes). "Bulletin of the Florida State Museum" 8(3): 195-335. [http://fulltext10.fcla.edu/cgi/t/text/text-idx?cc=feol;subview=fullcitation;idno=UF00001511 PDF or JPEG fulltext]
* (1992): Family Anatidae (Ducks, Geese and Swans). "In:" aut|del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): "Handbook of Birds of the World" (Volume 1: Ostrich to Ducks): 536-629, plates 40-50. Lynx Edicions, Barcelona. ISBN 84-87334-10-5
* (2005): New Pleistocene vertebrate fauna from El Salvador. [English with Portuguese abstract] "Revista Brasileira de Paleontologia" 8(3): 239-255. [http://www.sbpbrasil.org/revista/edicoes/8_3/cisneros.pdf PDF fulltext]
* (1977): "The Birds of the Western Palearctic". Oxford. ISBN 0-19-857358-8
* (2006): The British List: A Checklist of Birds of Britain (7th edition). "Ibis" 148(3): 526–563. doi|10.1111/j.1474-919X.2006.00603.x [http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1474-919X.2006.00603.x PDF fulltext]
* (2002): Greenland White-fronted Goose. "Birds of the Western Palearctic Update" 4(2): 65-88.
* (2007): " [http://www.iucnredlist.org 2007 IUCN Red List of Threatened Species] ".
* (1986): A phylogenetic analysis of recent anseriform genera using morphological characters. "Auk" 103(4): 737-754. [http://elibrary.unm.edu/sora/Auk/v103n04/p0737-p0754.pdf PDF fulltext]
* (1987): "Wildfowl : an identification guide to the ducks, geese and swans of the world". Christopher Helm, London. ISBN 0-7470-2201-1
* (1970): A new anseriform genus and species from the Nebraska Pliocene. "Auk" 87(3): 537-543. [http://elibrary.unm.edu/sora/Auk/v087n03/DJVU/P0537-P0543.djvu DjVu fulltext] [http://elibrary.unm.edu/sora/Auk/v087n03/p0537-p0543.pdf PDF fulltext]
* (2007): Lijst van Nederlandse vogelsoorten ["List of Dutch bird taxa²] . [Dutch and English] [http://www.wpbirds.com/arnoud/files/webcon070407-31.pdf PDF fulltext]