Interpreting Variation in Growth of Eurasian Spoonbill Chicks: Disentangling the Effects of Age, Sex and Environment

Ardea

Tamar Lok²  Theunis Piersma²  Otto Overdijk¹ 

[1] 3 Werkgroep Lepelaar, Knuppeldam 4, 9166 NZ Schiermonnikoog, The Netherlands;1 Animal Ecology Group, Centre for Ecological and Evolutionary Studies (CEES), University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands2 Department of Marine Ecology, NIOZ Royal Netherlands Institute of Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands

关键词: Waterbirds;   

DOI  :  

学科分类：动物科学

来源: Nederlandse Ornithologische Unie/Netherlands Ornithological Union

【 摘 要 】

Chickbodyconditioncanbeasensitiveindicatoroflocalenvironmentalconditionsandhasbeenshowntobecorrelatedwithchicksurvival.Designingareliableindexofchickbodyconditionforagivenspeciesfromasinglemeasurementpointrequiresknowledgeabouttheextentofvariationinbodysize,aboutchickageandabouttherelativesensitivityofthegrowthofdifferentbiometricmeasurestovariationinenvironmentalconditions.Togainthisknowledge,wedescribesex-specificvariationingrowthofseveralmorphometricmeasuresandbodymassofEurasianSpoonbillsPlatalealeucorodia.Werepeatedlymeasured35chicksthatgrewupinsmallcoloniesontheislandofSchiermonnikoogtoderivedetailedgrowthcurvesuntilfledging(basedonthe12survivingchicks)andtoassesstheextentofreductioningrowthofstarvedchicksmeasuredatleasttwice(n=11)comparedtothosethatsurvived.Growthcurvesuntilfledgingwerecomparedwithbiometricmeasurementsoftwotofiveweekoldchicksfrom(mostly)largercoloniesofwhichhatchingdatewasaccuratelyestimated(n=631).Growthofallmeasures,excepttheeighthprimary,wassex-specific,withthemostpronouncedsexeffectontheasymptoticvaluesoftarsuslengthandbodymass:adultmaleswerepredictedtobecome17%heavierthanfemalesandtohave22%longertarsithanfemales.Bodymassandtarsusgrowthtendedtobemorereducedunderfooddeprivationthan(head-)billandeighthprimarygrowth.Asanindexofchickbodycondition,weproposetousetheproportionaldeviationinbodymassfromthepredictedbodymassforagivenageandsex.Todoso,measurementsofnearlyfledgedSpoonbillchicksshouldincludeatleasteighthprimarylengthtoestimateage,tarsuslengthtoestimatesex,andbodymassasameasurethatintegratesage,sexandenvironmentaleffects.

【 授权许可】

Unknown