1. Systematics, taxonomy and evolution
    Phylogeny  Living species and taxonomy  Fossil record 

2. Relationship with humans and conservation status

3. Footnotes

4. See also

5. References

• Anser anser

A. a. anser

A. a. rubrirostris

A. a. domesticus

• Anser brachyrhynchus
• Anser caerulescens
• Anser canagicus
• Anser cygnoides

A. c. cygnoides

A. c. domesticus

• Anser fabalis
• Anser erythropus
• Anser indicus
• Anser rossii
• Anser serrirostris

and see text

The waterfowl genus Anser includes all grey geese (and sometimes the white geese). Its name is derived from anser the Latin for "goose".^[1] 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 {{convert|2.5|-|4.1|kg|lb|abbr=on}}. 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.^[2]

Systematics, taxonomy and evolution

Phylogeny

The evolutionary relationship between Anser geese have been difficult to resolve because of their rapid radiation during the Pleistocene and frequent hybridization.^[2][3][4] Based on the Taxonomy in Flux from John Boyd's website.^[5]

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Living species and taxonomy

The following white geese were separated as the genus Chen. Most ornithological works traditionally now include Chen within Anser,^[7][8][9]

• Snow goose, Anser caerulescens
• Ross's goose, Anser rossii
• Emperor goose, Anser canagicus – sometimes separated in Philacte

Some authorities also treat some subspecies as distinct species (notably tundra bean goose^[11][12]) or as likely future species splits (notably Greenland white-fronted goose).^[13]

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.^[14][15][16] 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.^[6][7]

• †Anser atavus (Middle/Late Miocene of Bavaria, Germany) – sometimes in Cygnus
• †Anser arenosus Bickart 1990 (Big Sandy Late Miocene of Wickieup, USA)
• †Anser arizonae Bickart 1990 (Big Sandy Late Miocene of Wickieup, USA)
• †Anser cygniformis (Late Miocene of Steinheim, Germany)
• †Anser oeningensis (Meyer 1865) Milne-Edwards 1867b [Anas oeningensis Meyer 1865] (Late Miocene of Oehningen, Switzerland)
• †Anser thraceiensis Burchak-Abramovich & Nikolov 1984 (Late Miocene/Early Pliocene of Trojanovo, Bulgaria)
• †Anser pratensis (Short 1970) [Heterochen pratensis Short 1970] (Valentine Early Pliocene of Brown County, USA)
• †Anser pressus (Brodkorb 1964) [Chen pressa Brodkorb 1964] (Dwarf Snow goose) (Glenns Ferry Late Pliocene of Hagerman, USA)
• †Anser thompsoni Martin & Mengel 1980 (Pliocene of Nebraska)
• †Anser azerbaidzhanicus (Early? Pleistocene of Binagady, Azerbaijan)
• †Anser devjatkini Kuročkin 1971
• †Anser eldaricus Burchak-Abramovich & Gadzyev 1978
• †Anser tchikoicus Kuročkin 1985

The Maltese swan Cygnus equitum was occasionally placed into Anser, and Anser condoni is a synonym of Cygnus paloregonus.^[14] A goose fossil from the Early-Middle Pleistocene of El Salvador is highly similar to Anser.^[20] Given its age it is likely to belong to an extant genus, and biogeography indicates Branta as other likely candidate.

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 Red List 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.^[21]

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

Footnotes

See also

• List of recently extinct birds
• Late Quaternary prehistoric birds
• List of fossil bird genera

References

• Draft:Dr. Braj Bhushan Mishra
• Draft:Dr. Brent Reynolds
• Draft:Dr. Brij Bhushan Mani Tripathi
• Draft:Dr. B.S Srinath
• Draft:Dr. Burton MacDonald
• Draft:Dr. Candi Clark
• Draft:Dr. Carl Wright (Commonwealth)
• Draft:Dr. Casali Paolo
• Draft:Dr Catrin Rutland
• Draft:Dr. Chaman Lal
• Draft:Dr. Chandrabhan Rao, Ph.D., AIIMS, New Delhi (Scientist)
• Draft:Dr Chandril Chugh
• Draft:Dr. Charles Knife Chief MD
• Draft:Dr. Chris Simpson
• Draft:Dr. Christian Chris Wigwe
• Draft:Dr. Christopher W. Smithmyer
• Draft:Dr. Clemens Fischer
• Draft:Dr. Collins Santhanasamy
• Draft:Dr. Cristobal Martinez Gomez
• Draft:Dr Cryme (rapper)
• Draft:DRCVisuals
• Draft:Dr. C.V.S.K. Sarma
• Draft:Dr. Dana Carson
• Draft:Dr. Daniel A. Wagner
• Draft:Dr. Danny & The Patients