Commensal Foraging with Bewick's Swans Cygnus bewickii Doubles Instantaneous Intake Rate of Common Pochards Aythya ferina
[摘要] AquaticallyforagingBewick'sSwansCygnusbewickiihavebeenrepeatedlyreportedtobeaccompaniedbydivingducks,buttheexactnatureofthisrelationshipisunclear.Basedonfieldobservations,wefoundastrongcorrelationbetweenthenumberofforagingswansandthenumberofforagingCommonPochardsAythyaferinaandTuftedDucksAythyafuligulaatourstudysite(Lauwersmeer,theNetherlands),withthemedianratiobeingclosetoonedivingduckperswan.Todeterminewhethertheassociationwaskleptoparasiticorcommensal,wemeasuredinaseriesofexperimentaltrialstheinstantaneousintakeratesofBewick'sSwansandCommonPochardswhenforagingaloneandwhenforagingtogether.Onaverage,pochardsincompanywithaswanattainedtwicetheinstantaneousintakerateascomparedwithforagingalone.Thiswasmainlyduetogleaningfooditemsthatfloatedawayasaresultoftheswan'stramplingactivity,andwasnotduetostealing:infact,foodintakeratesofswanswerenotaffectedbythepresenceofapochard.
[发布日期] [发布机构]
[效力级别] [学科分类] 动物科学
[关键词] Depletion [时效性]
