Common Kingfishers Alcedo atthis along the Coast of Northern Iberia during the Autumn Migration Period

[摘要] Iberiareceivesmanydispersing,migratingandwinteringCommonKingfishersAlcedoatthis.Themajorityoftheseindividualsoccurincoastalmarshes.BetweenAugustandmid-October2007and2008,Kingfishersweremist-nettedatatidalmarshinTxingudi,northernIberia.TheywereespeciallyabundantfromAugusttoSeptember,indicatingthatTxingudireceivesaninfluxofmigrantsfromnorthernEuropeorlocalbirdsdispersingfromnearbynatalareas.Thepopulationmainlyconsistedofjuveniles(only5.8%adults),thesexratiowas1:1andthetimingofpassagewassimilarbetweenthesexes.Bodymasscontrolledforbodysizewasconstantwithtime.Thestopoverdurationwasaffectedbysex,date(monthoffirstcapture)andabodymass/sizeratio,hereusedasaproxyoffuelload.Femaleswithalowerbodymass/sizeratioweremorelikelytoremainforlongerthanthosewithhigherratios,buttheoppositewasfoundinmales.KingfisherscapturedinAugustweremorelikelytobealreadysettledintheareathanthosefirstcapturedinSeptember.Moreover,birdswithshortstopoverssystematicallylostmass,whilebirdsthatremainedintheareaforlongerdidnot.Thesefindingsarediscussedinthelightofpossiblecompetitionbetweennewlyarrivingandalreadysettledbirds.

[学科分类] 动物科学

[关键词] Stopover