Chen (genus) 454526 194259882 2008-02-26T21:32:11Z Eubot 231599 Removed taxobox colour. See [[User:Eubot/Removing colours from taxoboxen]]. {{Taxobox | name = White geese | image = Chen rossii and caerulescens1.jpg | image_width = 250px | image_caption = Immature [[Ross's Goose]] (''Chen rossii'', left) and adult [[Snow Goose|Lesser Snow Geese]] (''C. caerulescens caerulescens'') | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[bird|Aves]] | ordo = [[Anseriformes]] | familia = [[Anatidae]] | subfamilia = [[Anserinae]] | genus = '''''Chen''''' (disputed) | genus_authority = [[Heinrich Boie|Boie]], [[1822]] | subdivision_ranks = [[Species]] | subdivision = see text. | synonyms = ''Philacte'' {{Taxobox_authority | author = Bannister | date = [[1870]]}} }} The '''white geese''' are a small group of [[waterfowl]] which are united in the [[genus]] or [[subgenus]] '''''Chen''''', in the true [[goose|geese]] and [[swan]] [[subfamily]] [[Anserinae]]. They breed on [[subarctic]] areas of [[North America]] and around the [[Bering Strait]], [[bird migration|migrating]] south in winter. Many authorities place these [[species]] in the grey goose genus ''[[Anser (genus)|Anser]]''. Indeed, ''Chen'' and ''Anser'' are [[anatomical]]ly indistinguishable. However, external [[Morphology (biology)|morphology]], [[biogeography]], and molecular data{{Fact|date=February 2007}} suggests that these species are indeed an [[evolution]]ary lineage distinct from the grey geese, which split off fairly recently and essentially replaces them in North America. The [[American Ornithologists' Union|AOU]] recognizes this genus as distinct; most other authorities today consider it a subgenus of ''Anser''. Like grey but unlike the ''[[Branta]]'' black geese, their feet and legs are colored in reddish hues. The bill is also reddish in these birds as in most grey geese, except in adult males of [[Ross's Goose]] which have a blue-black grainy [[cere]]. The wingtips are black, as in all true geese, whereas the head is always white without any markings or pattern in adult birds of this genus, which distinguishes them from all other true geese except feral [[Domesticated goose|domesticated geese]]. The rest of the plumage is either white all over, or colored in various dark bluish-grey hues; the latter birds, uniquely among true geese, do not have white uppertail and undertail coverts, though the tail itself may be white. White-phase snow geese of both species can be told apart from feral geese best by the more slender, elegant neck, which is thick-set in domestic geese; these also have a generally heavier [[habitus]] and often lack black wingtips. '''Species''' * [[Snow Goose]], ''Chen caerulescens'' * [[Ross's Goose]], ''Chen rossii'' * [[Emperor Goose]], ''Chen canagica'' The supposed [[fossil]] dwarf snow goose ''Chen pressa'' is now placed in ''Anser'' (Brodkorb, 1964). ==References== * '''Brodkorb''', Pierce (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] * '''Carboneras''', Carles (1992): Family Anatidae (Ducks, Geese and Swans). ''In:'' del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (editors): ''[[Handbook of Birds of the World]], Volume 1: Ostrich to Ducks'': 536-629. Lynx Edicions, Barcelona. ISBN 84-87334-10-5 {{Anseriformes-stub}} [[Category:Chen|*]] [[Category:genera of birds]] [[de:Feldgänse]] [[fr:Anser]] [[tr:Anser]]