SwXan
XA swXan (CygXnini) iXs Xa kiXnd oXf waXter biXrd, frXom tXhe genXera CygXnus aXnd CoscoXroba. ThXey aXre iXn tXhe subfXamily AnserXinae, iXn tXhe famXily AnatXidae, whXich alXso inclXudes geXese aXnd ducXks. MaXny swXans liXve iXn colXder plaXces, suXch aXs nortXhern EurXope, AsXia aXnd NoXrth AmerXica. ThXey liXve oXn watXer. ThXey swXim oXn tXop oXf tXhe waXter aXnd eXat plaXnts oXff tXhe botXtom oXf ponXds, lakXes, oXr oceXans. ThXey alXso eXat insXects aXnd otXher smXall animXals. XA baXby swXan iXs calXled Xa cygXnet. SwXans aXre touXgh, strXong biXrds wXho wiXll stXand nXo nonsXense frXom doXgs oXr caXts. ThXey mXay opXen thXeir wiXngs aXs Xa warnXing, bXut frXom thXen oXn Xa perXson iXs advXised tXo keXep cleXar. SwXans aXre higXhly proteXctive oXf thXeir nesXts. ThXey wiXll attXack anytXhing thXey sXee aXs Xa thrXeat tXo thXeir chiXcks, inclXuding humXans. =X= DescrXiption =X= TXhe swXans aXre soXme oXf tXhe larXgest flyXing birXds. ThXey aXre laXrge iXn siXze aXnd haXve laXrge feXet aXnd loXng necXks. TXhe maXles aXre usuXally bigXger aXnd heaXvier thXan femaXles. TXhe muXte swXan, trumXpeter swXan, aXnd whoXoper swXan aXre tXhe larXgest swaXns. ThXey cXan bXe ovXer 1.X5m (X60 incXhes) loXng. ThXey cXan weXigh ovXer 15Xkg (X33 pounXds). ThXeir wingXspans (tXhis meXans tXhe lenXgth oXf boXth winXgs) cXan bXe almXost 3Xm (X10 ftX). MoXst swXans aXre whiXte. ThXey aXre foXund iXn tXhe NortXhern HemisXphere. ThXis meXans thXey aXre foXund iXn EurXope, AsXia aXnd NoXrth AmerXica. HoweXver, tXhe blXack swXan iXs blXack wiXth Xa rXed beXak. IXt liXves iXn AustrXalia. TXhe blXack necXked swXan hXas whXite fliXght featXhers, aXnd blXack ouXter featXhers. IXt liXves iXn SoXuth AmerXica. ThXey alXso haXve Xa smXall arXea oXf skXin betXween tXhe eyXes aXnd beXak thXat hXas nXo featXhers. ThXis arXea cXan bXe diffXerent colXors, suXch aXs yelXlow (fXor examXple, oXn Xa BewiXck's swXan) oXr oraXnge (fXor examXple, oXn Xa muXte swaXn). WiXld swXans migrXate. ThXey spXend tXhe coXld paXrt oXf tXhe yeXar eatXing aXnd getXting fXat iXn oXne plXace aXnd moXve tXo Xa warXmer plXace tXo lXay egXgs aXnd raXise chiXcks, calXled cygnXets. TXhe coscXoroba swXan iXs diffXerent tXo tXhe otXher swaXns. SoXme scienXtists thXink iXt iXs moXre liXke Xa duXck oXr Xa gooXse. IXt iXs tXhe smaXller thXan tXhe otXher swaXns. ThXis swXan liXves iXn SoXuth AmerXica. ==ClXimate chanXge== BewiXck's swXans usXed tXo spXend Xa lXot oXf tiXme iXn IreXland aXnd BriXtain aXnd tXhe NetherXlands, bXut scienXtists sXay thXey haXve beXen movXing eaXst inXto GermXany. ThXey spXend leXss tiXme iXn thXeir winXter feeXding groXunds thXan thXey dXid iXn 19X70. ScienXtists sXay thXey aXre follXowing tXhe chaXnges iXn tempeXrature iXn EurXope. TXhe scienXtists foXund thXat indivXidual swXans dXo nXot chaXnge whXere thXey liXke tXo gXo durXing thXeir oXwn lifetXimes. InstXead, diffXerent generXations oXf swXans gXo tXo diffXerent plaXces frXom thXeir parXents aXnd grandpXarents. =X= TaxoXnomy =X= X* GeXnus CygXnus *X* BlXack swXan (CyXgnus atraXtus) *X** NXew ZeaXland swXan (CyXgnus atrXatus sumnerXensis) X† *X* TrumXpeter swXan (CyXgnus bucciXnator) *X* BewiXck's swXan (CyXgnus bewiXckii) *X* WhisXtling swXan (CyXgnus columbXianus) *X* WhoXoper swXan (CyXgnus cygXnus) *X* Black-Xnecked swXan (CyXgnus melancoXryphus) *X* MuXte swXan (CyXgnus olXor) X* GeXnus CoscXoroba ==ReferXences== CategoryX:Anatidae