Combination of at-sea activity, geolocation and feather stable isotopes documents where and when seabirds molt

International audience Keyfacetsoftheforagingecologyofseabirdsduringtheinter-breedingperiodstillremainpoorlyunderstoodbecauseofthedifficultyofstudyingthematsea,includingduringtheenergy-demandingmoltingstage.Here,theextenttowhichthreesympatricpetrels(Antarcticandthin-billedprions,andbluepetrel)fromth...

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Bibliographic Details
Published in:Frontiers in Ecology and Evolution
Main Authors: Cherel, Yves, Quillfeldt, Petra, Delord, Karine, Weimerskirch, Henri
Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2016
Subjects:
Online Access:https://hal.science/hal-01291355
https://doi.org/10.3389/fevo.2016.00003
Description
Summary:International audience Keyfacetsoftheforagingecologyofseabirdsduringtheinter-breedingperiodstillremainpoorlyunderstoodbecauseofthedifficultyofstudyingthematsea,includingduringtheenergy-demandingmoltingstage.Here,theextenttowhichthreesympatricpetrels(Antarcticandthin-billedprions,andbluepetrel)fromthesubantarcticKerguelenIslandsmodifytheirforagingecologyduringmoltwasinvestigatedusingacombinationofcomplementarytools,namelyminiaturizedsaltwaterimmersiongeolocators(GLS)andtheisotopicmethod.Firstly,moltingbehaviorwasfirstcharacterizedinthebluepetrel,areferencespeciesthatisknowntorenewitsplumageinautumn.GLSandfeatherstableisotopes(13dCasaproxyofthebirds’foraginghabitat)indicatedthatthepost-breedingmoltofbluepetreloccurredinAntarcticwaters.Importantly,activityrecordersshowedthatmoltwasmarkedbyastrongpeakintimespentdailysittingonwater,whichthereafterdeclinedtolowervaluesduringtheremainingwintermonths.Secondly,thepeakintimespentsittingonwaterwasusedasaproxytocharacterizethecontrastedmoltstrategiesofthetwoprionspecies.Asbluepetrelsdemonstrated,thin-billedprionsmoltedduringthepost-breedingperiodincoldAntarcticwaterswheretheyfedprimarilyonlowtrophiclevelprey,mostlikelyAntarctickrill(15dNasaproxyofthebirds’diet).Bycontrast,Antarcticprionspresentedanunexpectedpre-breedingmoltoflongerdurationthattookplacefurthernorth,inwarmsubtropicalwaters.Interestingly,thetwoAntarcticmoltingspecies,thebluepetrelandthin-billedprion,renewedtheirplumageatthesametimeandwithinthesameoceaniczonethatislikelytobeapreviouslyundescribedhotspotofseabirddiversitydurintheAustralautumn.Thestudycontributestoagrowingbodyofevidencethatclosely-relatedspeciesexhibitvariousforagingstrategiesallowingecologicalsegregationandshedsnewlightonthepoorlyknowncriticalmoltingstagefseabirds.