How Owls Select Their Prey: A Study of Barn Owls Tyto alba and Their Small Mammal Prey

Ardea

Iain R. Taylor¹ 

[1] 1 School of Environmental Studies, Charles Sturt University, P.O. Box 789, Albury, New South Wales 2640, Australia ([e-mail])

关键词: Apodemus Sylvaticus;   

DOI  :  

学科分类：动物科学

来源: Nederlandse Ornithologische Unie/Netherlands Ornithological Union

【 摘 要 】

MaleBarnOwlsTytoalbadeliveredsignificantlymoremalethanfemaleFieldVolesMicrotusagrestistotheirmatesandnestlingsinspring.Themalebiaswasevidentbothinthepreystoredatthenestandintheskeletalremainsofpreyinpelletstakenfromthenest.Thesexratioinvolescaughtbytrappingshowedaslightfemalebias.Analysisofpelletsproducedbythemalebarnowlsattheirroostsatthesametime,showedthesamebiasedsexratioofvoles,demonstratingthatselectionofmalevolesoccurredatcaptureandwasnotaresultofdifferencesbetweenpreydeliveredtothenestandthoseconsumedbythemales.Themeanweightsoftrappedmaleandfemalevolesinspringwere23.4g(SE0.5)and18.5g(SE0.4)respectively.Duringwinterwhenvoleswerenotbreedingthesexratioinpelletsofmaleandfemaleowlswasclosetounity.Thissuggeststhattheincreasedaggressivenessand/oractivitylevelsofmalevolesassociatedwithterritorialbehaviourandbreedinginspringledtoanincreaseintheirdetectionratebyowlshuntingbyuseofauditorycues.Thustheselectionformalevoleswastheresultofanincreasedencounterrateratherthanoptimalforagingbasedonthegreaterbodymassofmalevoles.InspringtheowlscaughtsignificantlymoreFieldVolesthanWoodMiceApodemussylvaticusthanpredictedfromtherelativeabundancesofthetwospeciesinthefield.ItissuggestedthiswastheresultofthegreaterabilityofWoodMicetodetecttheowlsandtheirgreateragilityinevadingcapture.

【 授权许可】

Unknown