How Owls Select Their Prey: A Study of Barn Owls Tyto alba and Their Small Mammal Prey
[摘要] MaleBarnOwlsTytoalbadeliveredsignificantlymoremalethanfemaleFieldVolesMicrotusagrestistotheirmatesandnestlingsinspring.Themalebiaswasevidentbothinthepreystoredatthenestandintheskeletalremainsofpreyinpelletstakenfromthenest.Thesexratioinvolescaughtbytrappingshowedaslightfemalebias.Analysisofpelletsproducedbythemalebarnowlsattheirroostsatthesametime,showedthesamebiasedsexratioofvoles,demonstratingthatselectionofmalevolesoccurredatcaptureandwasnotaresultofdifferencesbetweenpreydeliveredtothenestandthoseconsumedbythemales.Themeanweightsoftrappedmaleandfemalevolesinspringwere23.4g(SE0.5)and18.5g(SE0.4)respectively.Duringwinterwhenvoleswerenotbreedingthesexratioinpelletsofmaleandfemaleowlswasclosetounity.Thissuggeststhattheincreasedaggressivenessand/oractivitylevelsofmalevolesassociatedwithterritorialbehaviourandbreedinginspringledtoanincreaseintheirdetectionratebyowlshuntingbyuseofauditorycues.Thustheselectionformalevoleswastheresultofanincreasedencounterrateratherthanoptimalforagingbasedonthegreaterbodymassofmalevoles.InspringtheowlscaughtsignificantlymoreFieldVolesthanWoodMiceApodemussylvaticusthanpredictedfromtherelativeabundancesofthetwospeciesinthefield.ItissuggestedthiswastheresultofthegreaterabilityofWoodMicetodetecttheowlsandtheirgreateragilityinevadingcapture.
[发布日期] [发布机构]
[效力级别] [学科分类] 动物科学
[关键词] Apodemus Sylvaticus [时效性]
