informationdezender

DownloadedFrom:https://bioone.
org/journals/Ardeaon04Mar2021TermsofUse:https://bioone.
org/terms-of-useIntroductionThePurpleHeronArdeapurpureaisacolonialmigratoryspecies,whichishighlysensitivetodis-turbanceandbreedspredominantlyinreedmarshes.
Becausereedmarshesarescarcehabitats,thebreedingdistributionofPurpleHeronsisverypatchyandthespeciesisconsideredoneofthemostvulnerableheronsinEuropeandtheMedi-terraneanregion(Hafner2000,Marionetal.
2000).
InFrance,mostindividualsbreedontheMediterraneancoastwherethepopulationsizewasabout800pairsin2004(B.
Poulin&Y.
Kayser,unpubl.
data).
AerialsurveysrevealedlargeannualfluctuationsinnumbersbreedingintheCamargue,withasteepdeclinefrom1982to1994andafurtherdeclinebetween1996and2000(Hafneretal.
2004).
Anthropogenicchangesofthebreedingsites,suchasreedharvestingandwatermanagementpractices,haveledtolowwaterlevelsinspringandprobablyexplainpartoftheobservedinter-annualvariation(Barbraudetal.
2002).
Satellite-trackingmigratingjuvenilePurpleHeronsArdeapurpureafromtheCamarguearea,FranceJourdainE.
,Gauthier-ClercM.
,KayserY.
,LafayeM.
&SabatierP.
2008.
Satellite-trackingmigratingjuvenilePurpleHeronsArdeapurpureafromtheCamarguearea,France.
Ardea96(1):121–124.
MigratorymovementsofjuvenilePurpleHeronsfromtheCamargueareainFrancewerestudiedbysatellite-tracking.
SixjuvenilebirdswerefittedwithtransmittersinearlyJuly2004.
Ofthesesix,foursuccessfullystartedmigrationinSeptember.
Trackedbirdsfollowedawesternmigra-toryroute,headingoutsouth-south-west,towardsSpain,theBalearicIslandsandthenAlgeria.
Theypursedtheirflighteithersouth-westtotheMoroccanAtlanticcoastorstraighttoMauritania,flyingovertheSaharadesert.
Flightspeedcouldbeestimatedforoneofthebirdsandwasabout40kilometresperhour.
Theresultsofthisstudyareconsis-tentwithpreviousringrecoverydataandprovideadditionalknowledgeonthespeedanddeparturedateofjuvenilePurpleHeronsduringautumnmigration.
Keywords:PurpleHeron,satellite-tracking,migrationroutes,autumnmigration,Camargue1SectionforZoonoticEcologyandEpidemiology,DepartmentofBiologyandEnvironmentalScience,Barlastgatan11,KalmarUniversity,SE-29182Kalmar,Sweden;2CentredeRecherchedelaTourduValat,LeSambuc,F-13200Arles,France;3UnitéEPSP-TIMC,UMR5525,EcoleNationaleVétérinairedeLyon,1avenueBourgelat,F-69280Marcyl'Etoile,France;4CNES,FrenchSpaceAgency,8AvenueEdouardBelin,F-31401ToulouseCedex04,France;*correspondingauthor(Elsa.
Jourdain@hik.
se)ElsaJourdain1,2,3,*,MichelGauthier-Clerc2,YvesKayser2,MurielleLafaye4&PhilippeSabatier3DownloadedFrom:https://bioone.
org/journals/Ardeaon04Mar2021TermsofUse:https://bioone.
org/terms-of-useBecausethePurpleHeronismigratory,itspop-ulationsizemayalsobeaffectedbyconditionsencounteredinwinteringareasoratstopoverplacesduringmigration.
SeveralstudiesshowedthatthebreedingpopulationsofPurpleHeronsinEuropeareinfluencedbytheamountofrainfallinsub-SaharanAfrica(DenHeld1980,Cavé1983,Barbraud&Hafner2001),butconsiderationsofexactlyhowwinteringconditionsaffectsurvivalishamperedbyourscantknowledgeoftheirdistrib-utionandhabitatonwinteringgrounds.
Thankstoringrecoveries,theFrenchpopulationsarebelievedtousethreedifferentmigratoryroutes(i.
e.
south-westtowardsSpain,south-easttoItaly,andeastwardsalongthePoRivertowardstheAdriaticSea),andtopredominantlywintersouthof10°NinWestAfrica(Voisin1996).
However,furtherresearchisneededonthedistribution,habitatuse,wintermortality,andenvironmentallimitingfactorsinthewinteringrange(Kushlan&Hancock2005).
TogathercomplementaryinformationonthestopoverplacesandwinteringquartersofPurpleHeronsfromsouthernFrance,weequippedsixjuvenilebirdswithArgostransmittersduringthespring2004.
WewerealsoaimingtodeterminewhetherjuvenilebirdsmigratebacktoEuropeinspringorspendtheirfirstsummerinAfrica,ashasbeensuspected(Voisin1996).
MethodsSatellitetransmitters(numbered942to947)werefittedon2July2004onsixjuvenilePurpleHeronsfromasinglebreedingcolonyintheCamarguearea(43°30'N,4°30'E).
Inordertominimizedis-turbanceatthebreedingsite,thecolonysize(42breedingpairs)andtheapproximatelayingdatehadbeenestimatedbeforehandusingaerialpho-tographs,asdescribedpreviously(Kayseretal.
1994,Moser1986).
Thebirdswerecapturedonthenestandreleasedwithin10minutes,sothatthetimespentintheheronrydidnotexceedonehour.
Weused30-gplatformtransmitterterminalsorPTTs(MicrowaveTelemetryInc.
,PTT100)thatweattachedasbackpacksusingflexibleTeflonribbonharnesses.
Becausewedidnotplantorecapturethebirds,abreakawaylinkmadeofbiodegradablesurgicalwirehadpreviouslybeensewedoneachharness,sothatthebirdswouldlosethetransmitterandtheharnessafterafewmonths.
WescheduledeachPTTtotransmitfor8hevery1–8days,withmorefrequentsamplingdur-ingtimesoftheyearwhenweexpectedmostlong-rangemovements.
ThePTTsweretrackedbyCLS/ServiceArgosinToulouse,France.
LocationsprovidedbytheArgossystemaredividedintodifferentclasses(labeledA,B,Zand0–3)dependingonvalidation,numberofmessagesreceivedandlocationaccu-racy.
Theaccuracyissupposedtobewithin1kmforthreeclassesoflocations(1–3),whiletheaccu-racyfor0,A,BandZisunspecified.
Thehigh-qualitylocationsrepresented13%ofourdataset,whichisclosetowhatwasfoundinotherstudies(Hakeetal.
2001).
Unlessspecified,onlyhigh-qualitylocationswereused.
ResultsOfthesixjuvenilebirdsequipped,onefacedtrans-mitterfailureordiedwithinthefirstweek(943),andasecondstoppedtransmittinginearlySeptember(944).
Thefourremainingbirdssuc-cessfullystartedmigration(Fig.
1).
Oneofthem(946)seemedtohavelefttheCamargueinlateAugustandspentsometimeinsouth-westFranceneartheSpanishborderbeforeflyingtoAlgeriainmid-September.
Thecorrespondinglocationclass-eswerelow(AandB),whichmeansthatlessthanfoursignalswerereceivedbythesatellites,butitisverylikelythatthelocationsregisteredwereaccu-rate(Haysetal.
2001).
UnlikePTTs942and946,locationaccuracywashighforPTTs945and947andallowedtoassessmigrationdeparturedates:PTT945and947werelastdetectedintheCamar-gueon12and14September,andwerereportedintheMediterraneanSeanorthofOranandAlgeron14and16September.
Allfourbirdstravelledsouth-south-westacrosstheMediterraneanSea,flyingovertheBalearicIslands(942and947)beforereachingtheAlgeriancoastnearCherchell,wherePTT945wasregisteredneartheDamous122ARDEA96(1),2008DownloadedFrom:https://bioone.
org/journals/Ardeaon04Mar2021TermsofUse:https://bioone.
org/terms-of-useriverinAlgeria.
Then,theypursuedtheirmigra-tionsouth-westtowardsMoroccoorMauritania(Fig.
1).
InMorocco,onebirdfollowedtheMou-louyavalley,south-eastofMelilla:PTT945waslocatednorthoftheriveron18Septemberandfurthersouthon20,24and26September.
TheotherbirddetectedinMorocco(942)waslocatedneartheAtlanticcoastofWesternSaharaon22September,south-eastofCapeBojador,about2000kmfromtheplacewhereithadbeencon-tactedsixdaysearlier.
Incontrast,thebirdcarry-ingPTT946seemedtohavechosenanotherroute,overtheSaharadesert.
On18SeptemberitwaslocatedinsouthernAlgeria,neartheMauritanianborderand16hourslaterabout660kmsouth-westinOuaraneSands,whichmeansthatitwasflyingwithanaveragespeedofabout40kmh–1.
Allfoursignalsstoppedmovingbetween20and24September(Fig.
2).
DiscussionAllfourjuvenilebirdstrackedinthisstudyfol-lowedthesamemigrationroute,goingsouth-westtowardsSpain,Algeria,Moroccoand/orMaurita-nia.
TheresultsobtainedarehighlyconsistentwithringrecoverydatafrombirdsringedinwesternFrancebetween1930and1982(Voisin1996).
Interestingly,transmittersweredetectedinareaswhereringedbirdshadpreviouslybeenrecoveredinspringorautumnbeforethe1990s(e.
g.
BalearicIslands,CherchellareainAlgeria,Mou-louyavalleyinMorocco),whichsuggeststhatmigratoryrouteshavenotchanged.
BecausePTTs942and947werelocatedonthesamedaysouthoftheBalearicIslands,wemayhypothesizethatthesebirdsweretravellingtogether,whichsup-portspreviousobservations(Voisin1996,Kushlan&Hancock2005).
Shortnotes12316Sep18Sep18Sep20Sep16Sep20SepOct73Aug71Aug69Aug96Oct83Sep59Nov80Oct71Oct82Sep82Oct70Sep71Sep70Aug75Sep70Oct72winter73Feb73Jan72Jan79Feb72Feb7418Sep14SepN2July2004PTT942PTT945PTT946PTT9471000kmFigure1.
MaindatesofdetectionandcorrespondinglocationsofthefourPurpleHeronsequippedwithPTTson2July2004intheCamarguearea(blackstar).
Allindicatedlocationshavebeenobtainedwithhighaccu-racy(class1,2or3)exceptforPTT942on16Septem-ber(classA).
Ringrecoverydata(adaptedfromVoisin1996)frombirdsringedintheCamarguebetween1930and1982areindicated(greysquare:autumnrecovery,blacksquare:winterrecovery).
5PTT94719224216720July520AugSepOctNovPTT946PTT945PTT944PTT943PTT942Figure2.
Recordingoftransmitterlocationsindicatingwhenatleastonehighlyaccurate(blackdot)orunspeci-fied(whitedot)signalwasreceivedwithin5-daysperi-ods.
Blackarrowspointoutwhentransmitterswerefirstdetectedwithahigh-accuracysignaloutsideoftheCamargueandgreyarrowswhensignalsstoppedmoving.
DownloadedFrom:https://bioone.
org/journals/Ardeaon04Mar2021TermsofUse:https://bioone.
org/terms-of-useUnfortunately,migratorymovementscouldnotbefollowedaslongasexpected.
Allfoursignalsstoppedmovingbeforethebirdsreachedtheirwinteringquarters,indicatingeitherthatthebirdsdiedorhaddroppedtheirtransmitter.
ThelatterhypothesisisthemostlikelyaseachharnesshadabreakawaylinkandallPTTsstoppedmovingalmostsimultaneously.
Thismishapisillustrativeofthetrade-offsthathavetobemadewhendeal-ingwithbothresearchandconservationissues.
Thedataobtainedonthefirstpartofmigrationhoweverallowedtogaininformationaboutdepar-turedatesandflightspeedofjuvenileheronsandconfirmedthewesternmigratoryroutepreviouslysuggestedbyringrecoverydata(Voisin1996).
124ARDEA96(1),2008WethankGuillaumePaulusandOlivierPineauforassis-tanceinthefieldandAdrianAebischerforrelevantadvi-ces.
WearealsoverythankfultoAnne-MarieBreonceandChristianOrtegafromCLS-Argos.
Thisstudywasfinanci-allysupportedbytheFrenchSpatialAgency(CNES)andtheFrenchInstituteforResearchinAgronomy(INRA).
REFERENCESBarbraudC.
&HafnerH.
2001.
VariationdeseffectifsnicheursdehéronspourprésArdeapurpureasurlelit-toralméditerranéenfranaisenrelationaveclaplu-viométriesurlesquartiersd'hivernage.
Alauda69:29–36.
BarbraudC.
,LepleyM.
,MathevetR.
&MauchampA.
2002.
ReedbedselectionandcolonysizeofbreedingPurpleHeronsArdeapurpureainsouthernFrance.
Ibis144:227–235.
CavéA.
J.
1983.
PurpleHeronsurvivalanddroughtintropicalWestAfrica.
Ardea71:217–224.
DenHeldJ.
J.
1980.
PopulationchangesinthePurpleHeroninrelationtodroughtinthewinteringarea.
Ardea69:185–191.
HafnerH.
2000.
HeronsintheMediterranean.
In:KushlanJ.
A.
(ed)Heronconservation.
AcademicPress,London,pp.
33–54.
HafnerH.
,PineauO.
,KayserY.
,PoulinB.
&LefebvreG.
2004.
Lesardéidés,hérons,aigrettesetbutors,enCamargue.
In:IsenmannP.
(ed)LesoiseauxdeCamargueetleurshabitats:unehistoiredecinquanteans1954–2004.
Buchet/Chastel,Tours,pp.
57–120.
HakeM.
,KjellenN.
&AlerstamT.
2001.
SatellitetrackingofSwedishOspreysPandionhaliaetus:autumnmigra-tionroutesandorientation.
J.
AvianBiol.
32:47–56.
HaysG.
C.
,kessonS.
,GodleyB.
J.
,LuschiP.
&SantidrianP.
2001.
Theimplicationsoflocationaccuracyfortheinterpretationofsatellite-trackingdata.
Anim.
Behav.
61:1035–1040.
KayserY.
,WalmsleyJ.
,PineauO.
&HafnerH.
1994.
EvolutionrécentedeseffectifsdeHéronscendrés(Ardeacinerea)etdeHéronspourprés(Ardeapur-purea)nicheurssurlelittoralméditerranéenfranais.
NosOiseaux42:341–355.
KushlanJ.
A.
&HancockJ.
A.
2005.
Theherons.
OxfordUniversityPress,Oxford.
MarionL.
,P.
Ulenaers&J.
vanVessem2000.
HeronsinEurope.
In:KushlanJ.
A.
&HafnerH.
(eds)Heronconservation.
AcademicPress,London,p.
480.
MoserM.
E.
1986.
BreedingstrategiesofPurpleHeronsintheCamargue,France.
Ardea74:91–100.
VoisinC.
1996.
ThemigrationofPurpleHerons(Ardeapurpurea)ringedinFrance.
Vogelwarte38:155–68.
SAMENVATTINGDezepilotstudiebeschrijfthoedetrekbewegingenvanjongePurperreigers,geborenindeCamargueinZuid-oost-Frankrijk,werdengevolgdmetbehulpvansatelliet-telemetrie.
Nahetbroedseizoen,beginjuli2004,werdenzesjongevogelsuitgerustmeteentuigjemeteensatel-lietzender.
Deonderzoekersgebruiktenafbreekbaardraadomerzekervantezijndathettuigjenaeenpaarmaandenzouafvallen.
Eénzendervielindeeersteweekaluit,terwijleentweedereedsbeginseptembernietmeerwerkte.
DeoverigeviergaveneensignaaltotdederdeweekvanseptemberensteldendeonderzoekersinstaateengrootdeelvandetrekroutedoorZuid-EuropaenNoordwest-Afrikatedocumenteren.
DePurperreigersvertrokkentussen12en14septemberenvolgdeneenwestelijketrekroute.
VanuitdeCamarguevlogenzerich-tingzuidzuidwestviaSpanjeendeBalearennaardekustvanAlgerije.
TweevogelsvlogendaarnainzuidwestelijkerichtingdoornaardeMarokkaansekust.
EenderdevogelvervolgdezijntrekrechtstreeksoverdeSaharaenwerdhetlaatstwaargenomeninhetnoordenvanMauritani.
Zijnvliegsnelheidopditdeelvanderoutewas40kmperuur.
ToendevierdePurperreigernoginNoord-Algerijewasvieldezenderuit,gelijktijdigmethetstoppenvandezendersvandeanderedrievogels.
DetrekbewegingenvandezevierjongePurperreigerskwamenovereenmetdepatronendieuitoudereringgegevensteherleidenwaren.
Erwordtdaaromgeopperddatdetrekroutesdelaatstetientallenjarennietzijnveranderd.
(YIV)Correspondingeditor:YvonneI.
VerkuilReceived6September2007;accepted25February2008DownloadedFrom:https://bioone.
org/journals/Ardeaon04Mar2021TermsofUse:https://bioone.
org/terms-of-use