Extended Primary Moult as an Adaptation of Adult Wood Sandpipers Tringa glareola to Their Freshwater Habitats in Southern Africa

[摘要] Migrantwadersusingfreshwaterhabitatsarehypothesizedtohaveslowerprimarymoultthanwadersusingcoastalhabitats.WechosetheWoodSandpiperTringaglareolaasarepresentativespeciesusingthefreshwaterhabitatsandcompareitsmoultpatternwitharangeoffresh-waterandcoastalwaderspeciestotestthehabitathypothesis.OnlyfragmentarydescriptionsofWoodSandpipers'primarymoultintheirsub-Saharannon-breedingquartershadexisted.Weanalysedtheprimarymoultformulaeof1496adultWoodSandpipersobtainedinsouthernAfrica.TheUnderhillamp;Zucchinimoultmodelwasusedtoestimatethetiminganddurationofmoultforall10primariescombinedandforeachprimaryindividually.Wealsoestimatedtherateofproductionoffeathermaterialduringmoult.AdultWoodSandpipersarriveinsouthernAfricabetweenlateJulyandNovember,anddepartfrommid-MarchtoApril.Suspensionofmoultwasobservedin56birds(7.5%)aftertwotonineprimarieshadbeenreplaced.Theremainingbirdsperformedacontinuouscompleteprimarymoult,withaveragestartandcompletiondatesof21Augustand30December,respectively;estimateddurationwas131days.Theoverallrateofproductionofprimaryfeathermaterialwasuniform,achievedbygrowinguptofivesmallinnerprimariessimultaneouslyatthebeginningofthemoultbutonlyoneortwosimultaneouslywhilethelargeouterprimariesweregrowing.PrimarymoultofadultWoodSandpiperstooklongerbutendedearlierthaninsimilar-sizedwadersusingcoastalhabitats.Comparedwithwadersusingcoastalhabitats,WoodSandpipersprolongedmoultbysheddingtheirprimariesatlongerintervalsandbyextendingthegrowthperiodofeachprimary.ThelongerprimarymoultanditsearlierendingcomparedwithcoastalwadersareprobablyadaptationstoWoodSandpipers'useoffreshwaterhabitats,whichinsouthernAfricaprovideunpredictablefoodsuppliesandmightrequirenomadicmovementsbetweenephemeralinlandwetlands.

[学科分类] 动物科学

[关键词] Shorebirds