The Significance of Female Body Stores for Egg Laying and Incubation in Dark-Bellied Brent Geese Branta Bernicla Bernicla

[摘要] TheprobabilityofsuccessfulbreedingbyBrentgeeseintheArcticappearstobepositivelycorrelatedwiththemassoffemaleswhentheydepartfromspringstagingareasinNorth-westernEurope.Toclarifythemechanismbehindthisrelationshipweinvestigatedthesignificanceofflown-infemalebodystoresforbreedingoversixsummerseasons(1990–1995)inthePyasinaDeltainTaimyr,Russia.FemaleBrentGeesewerecaughtuponarrivalonthebreedinggrounds.Changesinfemalebodymassandthetiminganddurationofnestrecesseswererecordedviaelectronicweighingplatformsplacedundertheirnests.Averagefemalebodymassesdeclinedthroughthebreedingseason;from1464gatarrivalto1269gafteregglayingand1066gathatching,whichwassupposedtobeclosetoleanbodymass.Thushalfofthestoreswereusedbetweenarrivalandclutchcompletion,theotherhalfduringincubation.Allfemalesforagedduringincubation.Onaveragetheyleftthenest13.1timesevery24hours,resultinginadailyrecesstimeof198minduringthefirst21daysofincubation.Femaleswerelesslikelytoleavethenestduringthelastthreedaysofincubation.Leavingthenestwasrisky:40%oftheBrentGoosenestsinthestudyarealostoneormoreeggstogullsduringabsenceofthefemale.Weestimatedthat52%oftheenergyrequiredduringincubationwasderivedfrombodystoresandtherest(48%)fromfoodintake.

[学科分类] 动物科学

[关键词] Egg Predation