Climate warming changes bird migration timing and body size

Climate change has likely caused migratory birds' bodies to get smaller and their wings to get longer over the years, and the timing of ... FieldmuseumornithologistandcollectionsmanageremeritusDavidWillardmeasuredallofthemorethan70,000migratorybirdsanalyzedinthestudy.Credit:FieldMuseum,JohnWeinstein Climatechangehaslikelycausedmigratorybirds’bodiestogetsmallerandtheirwingstogetlongerovertheyears,andthetimingoftheirmigrationshasshiftedsubstantially. Researchersdeterminedthisbytappingintoaone-of-a-kinddatasetfromtheFieldMuseuminChicago.Sincethe1970s,museumstaffandvolunteershavecollectedmigratingbirdsthatcrashedintoWindyCitybuildings.Oneresearcher—FieldMuseumornithologistDavidWillard,nowthecollectionsmanageremeritus—recordedbodysizeandwinglengthofeverysingledeadbird,wherethecrashoccurredandwhen.Together,thiseffortresultedinnearlyahalf-centuryofdataonmorethan70,000individualsof52migratorybirdspecies. Thathelpedateamofbiologistsaddtoagrowingbodyofresearchsuggestingthatclimatechangehasaffectedthesizeandshapeofavarietyofspecies.Intheirlateststudy,publishedintheJournalofAnimalEcology,theteamrevisitedthosefindingsbylookingathowchangesinbodysizewererelatedtochangesinmigrationtiming. “Forthefirsttime,wewereabletousethesebirdsthatcollidedwithbuildingstomeasureshiftsinmigrationphenology,thatis.whenbirdsmigratetoandfromtheirbreedinggroundsacrossthenorthernUnitedStatesandCanada,”saidMarketaZimova,anassistantprofessoratAppalachianStateUniversityandleadauthorofthestudy. Inapreviousstudy,publishedin2020inEcologyLetters,BrianWeeks,anassistantprofessorattheUniversityofMichigan,Zimova,andotherco-authorsextractedinformationfromthedatasetonbodysizeandwinglengthforspeciessuchasdark-eyedjuncos(Juncohyemalis)andwhite-throatedsparrows(Zonotrichiaalbicollis).Theyfoundthatover40years,bodiesgenerallygotsmallerandwingsgotlonger.Whentheyoverlaidthiswithclimateinformation,theyfoundaclearpattern.Periodsofrapidwarmingwerefollowedcloselybyperiodsofbodysizedecline. SomeofthebirdscollectedatChicago’sMcCormickPlace,aconventioncenter,includeaneasternmeadowlark(Sturnellamagna)andanindigobunting(Passerinacyanea).Credit:FieldMuseum,KarenBean “Thisamazingdatasetofmorethan70,000migratorybirdswasperfecttotestthehypothesisthatanimalbodysizeisdeclininginsizeinresponsetoclimatechange.”Zimovasaid. Inthismorerecentstudy,theteamlookedatmigrationtiminginrelationtothesechanges.Theyfoundthatspringmigrationgotearlierbyaboutfivedaysovertheyears,whilethetimingoffallmigrationbroadened.“Theearliestmigrantsarenowdepartingtheirbreedinggroundsearlier,whilelatemigrantsareflyingevenlaterthantheydid40yearsago,”shesaidaboutthefallmigration.“Asaresultofthis,thedurationoffallmigrationhasstretchedoutbyabout17days.” AhandwrittenledgerinwhichFieldMuseumornithologistandcollectionsemeritusDavidWillardtracksbirddata.Credit:FieldMuseum,KateGolembiewski Theteamwentontoinvestigatewhetherthewidespreadshiftsinmigrationphenologywererelatedtotheobservedshiftinmigrationtiming.“Oneofthemostcommonresponsestoclimatechangeareshiftsinmigrationphenology—flowersbloomearlierinthespringoranimalsmigratetotheirbreedinggroundsearlier.Andsowehypothesizedthatthepressuretoadvancespringmigrationresultedinthemorphologicalshiftsweobserveinthesebirds,”Zimovasaid.“Forexample,longerwingsareassociatedwithfasterandmoreefficientflight.Therefore,wepredictedthatspeciesthatexhibitthegreatestincreasesinwinglengthweretheonesthatadvancedtheirspringmigrationthemost.However,wedidn’tfindthisrelationship.” Instead,theteamreportedthatthewidespreadmorphologicalandphenologicalshiftsacrossthe52speciesofbirdsareoccurringindependentlyofoneanother. Zimovasaidthatthiswasasurprisingresult.“Giventhatbirdmorphologyandflightaresotightlylinked,wesuspectedthatwidespreadshiftsinbothofthesedimensionswouldbeconnectedinonewayoranother.Buttheyarenot,whichonlysuggeststhatanimalresponsestoclimatechangearelotmorecomplexthanwetendtothink.” DanaKobilinskyisassociateeditoratTheWildlifeSociety.Contactherat [email protected] withanyquestionsorcommentsaboutherarticle.YoucanfollowheronTwitterat@DanaKobi.ReadmoreofDana'sarticleshere. Shareyourthoughtsonthisarticle,andothers,onourFacebookandTwitterpages. birdmigrationbirdsbodysizeclimatechangephenologysparrowsthrusheswingsize Tweet Search MostPopular ReintroducedwhoopingcranesaredispersingacrossWisconsin Reportdocumentswolfattacksaroundtheworld WildCam:Scavengersreducebrucellosisriskinelk,mooseandcattle ForferalcatsinAustralia,implantmakesnativewildlifetheirlastmeal Araredeerspecieshasfacedplentyofthreats—butCWDmaynotbeone Wilddeercontractcoronavirus Iswildlifeincitiesaluxury? Yardcarecanhelpkeepcommonbirdscommon PaidAd TWSWebinarSeries ConnectonFacebook FeaturedJobs ViewallJobs PostaJob Copyright©2021|ThemebyMHThemes