animal welfare assessment of kangaroo culling - australian
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Animalwelfareassessmentofkangarooculling:ACT2017
AnimalWelfareAssessmentofKangarooCulling:
AustralianCapitalTerritory,2017
November2017
JordanHamptonEcotoneWildlifeVeterinaryServices
BrendanCowledAusvetPtyLtd
ausvet
Animalwelfareassessmentofkangarooculling:ACT2017
EcotoneWildlifeVeterinaryServices&AusvetPtyLtd
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ContactDetailsName: JordanHamptonCompany: EcotoneExtensionPtyLtd,tradingasEcotoneWildlifeVeterinaryServicesABN: 63608284582E–mail: j.hampton@ecotonewildlife.comName: BrendanCowledCompany: AusvetPtyLtdABN: 64613142939E–mail: brendan@ausvet.com.auDisclaimerTheinformationcontainedinthisreporthasbeenprovidedonthebasisthattherecipientassumesthesoleresponsibilityfortheinterpretationandapplicationofit.EcotoneWildlifeVeterinaryServicesgivesnowarranty,expressor implied,orassumesany legal liabilityorresponsibilityfortheaccuracy,completenessoruseoftheconceptsandcommentscontainedinthisreportbytherecipientoranythirdparty.
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EXECUTIVESUMMARYThisreportdescribedanindependentanimalwelfareassessmentofthe2017AustralianCapitalTerritorykangaroomanagementprogram.Thereportisintwoparts;Part1:descriptiveanalysisandauditingofcompliancewithproceduraldocuments(JordanHampton:EcotoneWildlifeVeterinaryServices)andPart2:dataanalysisofexplanatoryvariablesinfluencinganimalwelfareoutcomes(BrendanCowled:AusvetPtLtd).Part1ofthereportdescribesfieldobservationsperformedbytwoindependentveterinariansof338kangaroosthatwereshotatoversixnightsinMay−June2017.Importantanimalwelfareparameterswerequantifiedincludingthefrequencyofshotsmissingkangaroos,ofanimalsescaping,andofinaccurateshots.Generally,animalwelfareoutcomeswerecomparabletootherprofessionalshootingprograms.Theguidingproceduraldocument,theNationalcodeofpracticeforthehumaneshootingofkangaroosandwallabiesfornon-commercialpurposes(theCOP)wascompliedwithinallaspects.Aminorityofkangaroosweremissed(4%),killedbutnotrenderedimmediatelyinsensiblebyinitialshooting(4%),ornon-fatallywounded(1%).Theseoutcomeswereconsideredtoconstitute‘adverseanimalwelfareevents’anddataanalysiswasperformedtodeterminewhichvariablesbestexplainedtheiroccurrence.Part2ofthereportdescribesdataanalysisperformedtoelucidatetheroleofseveralexplanatoryvariablesininfluencingtheoccurrenceofadverseanimalwelfareevents.Variablesexaminedincludedanimalvariables(age,sex),shootingvariables(calibre,opticsetc.),andoperationalvariables(consecutivenightsofshooting,minimumtemperatureetc.)Modellingrevealedthatshooteridentity,inferredasshooterskill,wasmostlikelytoaffecttheprobabilityofanadverseoutcome.Inaddition,thesexofanimalswasakeyfactorforadverseoutcomes,withmalekangarooslesslikelytoberenderedimmediatelyinsensiblethanfemales.However,therewereun-recordedvariables(shootingdistanceetc.)thatwereresponsibleforinfluencingthelikelihoodofadverseanimalwelfareoutcomes.Threerecommendationsweremade:1. ForcontinuingcompliancewiththeCOP,currentlyusedshootingprotocolsshouldbemaintained.2. Themanagingagencyshouldexamineshooterselectionandtrainingastheidentityoftheshooteristhemostimportantvariableindeterminingwelfareoutcomes.3. Shootersshouldexerciseadditionalcautionwhentargetingmalekangaroosastheyaremorelikelytoexperienceadverseanimalwelfareoutcomes.
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CONTENTS
PART1:OBSERVATIONSANDPROCEDURALCOMPLIANCE……………………………………….…….51.1. Introduction..........................................................................................................51.2. Methods...............................................................................................................51.2.1. Studyarea.............................................................................................................61.2.2. Shootingconfigurationobservations....................................................................61.2.3. Ante-mortemobservations..................................................................................71.2.4. Post-mortemobservations...................................................................................7
1.3. Results..................................................................................................................81.3.1. Shootingconfiguration.........................................................................................81.3.2. Ante-mortemdata................................................................................................81.3.3. Post-mortemexamination..................................................................................10
1.4. Discussion...........................................................................................................111.4.1. CompliancewiththeCodeofPractice................................................................111.4.2. Animalwelfareoutcomes...................................................................................12
1.5. Conclusions.........................................................................................................121.6. Recommendations..............................................................................................12PART2:ANALYSISOFEXPLANATORYVARIABLES……………………………………………..….…...132.1 Background.........................................................................................................142.2 Methods.............................................................................................................142.3 Results................................................................................................................162.3.1 Analysis1:‘Alldata’............................................................................................162.3.2 Analysis2:‘Killeddata’.......................................................................................22
2.4 Conclusions.........................................................................................................272.5 Recommendations………………………………………….……………….………………………………..262.6 References..........................................................................................................28
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PART1:OBSERVATIONSANDPROCEDURALCOMPLIANCEJordanHampton
EcotoneWildlifeVeterinaryServices
IntroductionPopulationsofkangaroos(Macropusspp.)reachhighdensitiesonconservationestateinmanypartsofAustralia(Howlandetal.2014)andareoftensubjectedtoongoingreduction,or‘culling’programs(Mawsonetal.2016).Peri-urbanpopulationsofeasterngreykangaroos(M.giganteus)intheAustralianCapitalTerritory(ACT)havebeensubjectedtoongoingreductionprogramsforthisreason(ACTGovernment2010).Todate,reductionofkangaroopopulationsdeemedoverabundanthasbeenlargelyachievedbynon-commercialor“damage-mitigation”professionalshooting(describedinHamptonandForsyth2016).TheeasterngreykangaroointheACTisdeclaredacontrollednativespeciesundertheNatureConservationAct2014.Theuseofground-basednightshooting(shooting)asamanagementtoolforthereductionofkangaroopopulationdensitiesintheACTisdescribedintheEasternGreyKangaroo:ControlledNativeSpeciesManagementPlan(ACTGovernment2017).TheACTKangarooManagementPlan(ACTGovernment2010)remainsthesourcedocumentforthebackgroundandjustificationofkangaroomanagementintheACT,andisthesoleACTpolicydocumentforkangaroomanagementatGoogongForeshores,NewSouthWales(NSW). UndertheControlledNativeSpeciesManagementPlanandACTKangarooManagementPlan,allkangarooshootingprogramsarerequiredtobeconductedinaccordancewiththeNationalcodeofpracticeforthehumaneshootingofkangaroosandwallabiesfornon-commercialpurposes(hereafter‘theCOP’;CommonwealthofAustralia2008).TheCOPsetsaminimumstandardofhumaneconductforpersonsundertakingthenon-commercialcullingofkangaroos.The2017ACTkangaroomanagementprogramtargetedkangaroosinseveralperi-urbansitesintheACTaswellasonelargersiteinanadjacentareaofNSW(GoogongForeshores).TheprogramwasconductedwiththeintentofstrictadherencetothestandardsoutlinedintheCOP.TofacilitatecompliancewiththeCOPandtoallowtransparentdemonstrationofanimalwelfareoutcomes,anindependentanimalwelfareauditwasconducted.Twoveterinarians,independentoftheshootingprogram(i.e.notamemberoftheshootingteamoranemployeeofthemanagingagency)collectedante-mortem(beforedeath)andpost-mortem(afterdeath)datafromarepresentativesampleofshotanimals.Theindependenceoftheobserversfromtheshootingteamandthemanagingagencywasconsideredimportanttoprovideanunbiasedassessmentoftheprogramtostakeholdersandthegeneralpublic.Theimportanceofindependentobserversforthetransparentquantificationofanimalwelfareparametershasbeenrecognisedformanycontentiouswildlifemanagementprograms(e.g.HamptonandForsyth2016).
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MethodsMethodologyforthe2017independentanimalwelfareauditwasidenticaltothatusedtoassessthesamemanagementprogramin2015(Hampton2016).Themethodologyusedwasinitiallyderivedfrompeer-reviewedstudiesofanimalwelfareoutcomesinterrestrialwildlifeshootingprograms(Lewisetal.1997;Hamptonetal.2015;HamptonandForsyth2016).Methodswerealsoadaptedfromnon-peer-reviewedreportsthathavestudiedkangarooshooting(ACTParksandConservationService2013;McLeodandSharp2014)butwereadaptedtoensurethatselectionbiasresultingfromshooterselectionofanimalstobeassessedwasminimised(seeHamptonetal.2015).Resource-basedmeasureswereusedtoassessprotocolcompliance,andanimal-basedmeasureswereusedtoassessanimalwelfareoutcomes(Hamptonetal.2016).Oneindependentobserverwaspresentforeachassessedshootingevent,withoneobserverpresentforfournightsofshootingandtheotherobserverpresentforthreenightsofshooting.Bothobserverswerepresentforonenightofshootingtoensurethatmethodologyandinterpretationofdatawasconsistent.
StudyareaShootingeventswereobservedoversixnightsinMay−June2017.ShootingeventswereobservedatonesiteintheACT(CallumBraeNatureReserve)andonesiteinaneighbouringareaofNSW(GoogongForeshores;Table1).
ShootingconfigurationobservationsTheCOPspecifiesthatshootersshouldonlytake‘headshots’;toaimtohitadultkangaroosinthebrain,andthatjuvenile‘young-at-foot’animalsshouldbeshotsoastobehitinthebrainorheart.TheCOPspecifiesthatarifleofminimum.204Ruger®centrefirecalibreshouldbeused.TheCOPspecifiesthatimmediatelyaftershootingofadultkangaroos,pouchesofshotfemalesshouldbecheckedforthepresenceoflivepouchyoung,andifdetected,theyshouldbeeuthanasedwithbluntcranialtraumaordecapitation.Theindependentobserversrecordedthespecificationsofallequipmentusedanddocumentedproceduresfollowedbytheshootingteams.Theindependentobserversassessedshootingteamsfromthreeseparateagencies;twoagencieswereprivatecontractorsandthethirdagencywastheACTParksandConservationService.Eachshootingteamconsistedofashooterandadriver.Insomeinstances,ashooterfromaprivateagencyoperatedwithadriverfromtheACTParksandConservationService.Intotal,sevenshooterswereobservedduringtheassessment(Table1).Customisedfour-wheeldrivebuggyvehicles(withoutwindscreens)weredrivenslowly(5−10km/h),withashooteranddriversittingintheseatsandanobserverseatedbehindthem.ThevehiclewasstoppedwhenastationarykangaroowassightedandestimatedtobewithinthemaximumshootingdistancespecifiedbytheCOP(i.e.<200metres).Shootingwasnottobeundertakenfromamovingvehicle,nortargetingmovingornon-standinganimals.FollowingtheCOP,theshootershotatthecranium(brain)asthesoletargetanatomicalzoneforadultkangaroosandthebrainorthoraxastargetanatomicalzonesforsub-adults(young-at-foot).Twobolt-actionriflecalibreswereused:1).223Remington®
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rifleswereusedtofire55grainpolymer-tiphollow-pointammunition,and2).204Ruger®rifleswereusedtofire40grainpolymer-tiphollow-pointammunition.Toallowvisualisationofkangaroosfornight-timeshooting,twoilluminationapproacheswereused:1)animalswereshotatwiththeuseofwhite-lightspotlights(aspertheCOP),and2)infra-redtechnology(thermalandnight-vision)wasusedtopermitshootingwithoutspotlights(seeHamptonandForsyth2016).Furtherspecificationsoftheconfigurationofilluminationequipmenthavenotbeenpublishedtoprotecttheintellectualpropertyandanonymityoftheshootingteams.Forbothilluminationapproaches,rifleswerefittedwithtelescopicscopesaspertheCOP.Allriflesusednoisesuppressorstominimisedisturbancetonearbyhousing.Theobserversrecordedante-mortemandpost-mortemdataforallshootingeventsduringtheassessment.
Ante-mortemobservationsFromeachshootingevent,theobserverrecordedthefollowingdataasperHamptonetal.(2015)andHamptonandForsyth(2016):thenumberofshotsfiredateachanimal,whethershotshitanimals,theapparenttimetoinsensibilityforshotanimals(‘timetodeath’;TTD),whethershotanimalsdiedorescapedwounded,andwhetherkilledanimalswerefound.Assoonaspossibleaftershootingoneormorekangaroos,theanimalswereapproachedtoconfirmdeath,checkforthepresenceofpouchyoungandassessballisticpathology(bulletwoundinjuries).Animalsweresearchedforaftershootingusinginfra-redtechnologiesandlimitedwhitelightillumination.Whenadultfemalekangarooswereshot,anypouchyoungpresentwererequiredtobeeuthanasedimmediately,aspertheCOP.EuthanasiaprocedureswereperformedwiththeintentofcomplyingwiththeconditionsspecifiedbytheCOP.Toassessthiscomponentoftheoperation,observationmethodologywaslargelyderivedfromastudyofanimalwelfareoutcomesincommercialkangarooshooting(McLeodandSharp2014).Theauthorsofthisstudyarguedthatunfurredpouchyoungdonotmeetthescientificcriteriaforsentience,orthecapacitytosuffer,priortotheageoffurdevelopmentandeyeopening,duetolimitedbraindevelopment.Foradiscussionofneurologicaldevelopmentandtheonsetofsentienceinmarsupials,seeMcLeodandSharp(2014).Theprotocolusedbyallstaffinvolvedfurredandunfurredpouchyoungbeingeuthanasedviablunttrauma,whileverysmallunfurredpouchyoungwereeuthanasedusingthe‘thumbandforefinger’decapitationmethoddescribedbyMcLeodandSharp(2014).Somestaffusedasolidwoodenboardunderneaththepouchyoungwhiledeliveringblunttraumawhileothersdidnot.Foreachpouchyoungeuthanased,theobserverrecordedthefollowingdataasperMcLeodandSharp(2014)andHamptonandForsyth(2016):thenumberofpouchyoungpresent,theageclassofpouchyoung(furredorunfurred),andtheeuthanasiamethodapplied(bunttraumaand/ordecapitation).
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Table1.Logisticaldataforthecollectionofanimalwelfaredatafromthenon-commercialshootingofeasterngreykangaroos(Macropusgiganteus)inperi-urbanconservationestateintheACTandNSW,May−June2017.Observers,shootersandagenciesaredesignatedbynumbersratherthanbyname.Nightofobservations
Observer Shooteragency
Driveragency
Shootersobserved
Fieldsite Animalsshotat(n)
1 1 1 1 1,2,3 CallumBraeNatureReserve 51
2 1 2 2 4 GoogongForeshores 70
3 1 1 1 1,3 CallumBraeNatureReserve 27
4 1,2 2 2 5 GoogongForeshores 69
5 2 3 1 6 GoogongForeshores 72
6 2 3 1 7 GoogongForeshores 49
Total 338
Post-mortemobservationsAdultkangaroosweresubjectedtopost-mortemexaminationassoonasthevehiclecontainingtheshooter/driverandobserverapproachedtheirbody.Theobserverrecordedtheageofeachanimal(adultorsub-adult),thesexoftheanimal,andthelocationandnumberofbulletwoundtracts.LocationsofbulletwoundswererecordedfollowingthemethodologyofHamptonetal.(2015).Thepouchesofadultfemalekangarooswereinspected.
ResultsObservationsweremadeforatotalof338kangaroosthatwereshotatoversixnights,betweenthe29thofMayandthe24thofJune2017.Onlyoneshootingteamwasassessedoneachnightofobservations.ThenumberofkangarooshootingeventsobservedoneachnightoftheassessmentareshowninTable1,asarethefieldsite,observerandshootingteamforthatnight.
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Table2.Summaryofante-mortemdata(asperHamptonandForsyth2016)collectedfromthenon-commercialshootingofeasterngreykangaroos(Macropusgiganteus)inperi-urbanconservationestateintheACTandNSW,May−June2017.
Category Samplesize(n)
Numberofanimalstargeted 338
Numberofanimalsshot 324
Numberofanimalsrecovered 322
Numberofanimalsrenderedimmediatelyinsensible 309
Numberofanimalsescapingunwounded 14
Numberofanimalsnotrenderedimmediatelyinsensibleandkilledbyblunttrauma 6
Numberofanimalsmissedandthenshot 4
Numberofanimalsnotrenderedimmediatelyinsensibleandshotmultipletimes 3
Numberofanimalsescapingwounded 2
Numberofanimalsassumedtobekilledbutnotrecoveredduringobservations 0
ShootingconfigurationThefirearmsandammunitionusedbytheshootersaredescribedin2.2(above),andcompliedwiththeCOP.Onallshootingnightsobserved,thefirearmusedwasconfirmedtobezeroedpriortouse(andoftenduringnight)aspertheCOP.
Ante-mortemdataOversixnights,atotalof338kangaroosweretargeted(shotat).TheshootingoutcomesareshowninTable2,asperHamptonetal.(2015)andHamptonandForsyth(2016).Allkangarooswerestationaryandstandingpriortoshooting.Atotalof348shotswerefired,with21shotsobservedtomissanimalsentirely,hence94%ofshotsstruckkangaroos(n=327).Onfouroccasionswhereaninitialshotmissed,thetargetedkangaroowaskilledwithasubsequentshot.Allotherkangaroosthatweremissedwereobservedtoescapeuninjured(n=14).Threeanimalswereshotasecondtime,afterinitialshootingdidnotrenderthemimmediatelyinsensible(wounding).Anothersixkangarooswerenotrenderedinsensiblefromthefirstshot,butwererecumbentandimmobile,werekilledviablunttraumaratherthanrepeatshooting(aspertheCOP).Twokangarooswereshotatandappearedtobehit(wounding)butsubsequentshotsfailedtokillthem.Thesetwoanimalswerepresumedto
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havebeennon-fatallyinjured(Table2).Mediantimetodeath(TTD;thedurationfrominitialshootingtoinsensibility;Hamptonetal.2015)foranimalsthatwerekilledbutnotrenderedimmediatelyinsensible(n=9)was60seconds(range5−300seconds).Allothershotanimals(n=309)wererenderedimmediatelyinsensiblefromthefirstshot,basedonobservation.Instantaneousdeathrate(IDR;theproportionofkilledanimalsrenderedimmediatelyinsensible;Hamptonetal.2015),excludingthefouranimalsthatwerefirstmissedbutthenrenderedimmediatelyinsensible,washence96%.Twokangarooswereobservedtobenon-fatallywoundedandescaped,hence‘woundingrate’(Hamptonetal.2015)was0.6%.Thenumberofkangaroosshotandkilledbeforeshootingteamscollectedthemandperformedpost-morteminspectionsrangedfrom1−7animals(Table3).Onasingleoccasion,ashotandkilledkangaroocouldnotimmediatelybefoundbytheshootingteam.Thisanimalwaslocatedapproximatelytwohoursaftershooting.Shootingteamsconfirmedthesexandspeciesofallshotkangaroos,andinspectedthepouchesofallshotfemalekangaroosforpouchyoung.
Post-mortemexamination
ShotanimalsOfthe322kangaroosthatwereshotandkilled,allwerefoundbytheshootingteams.Hence,322animalswereavailableforpost-mortemexamination.Thesexratiooftheshotanimalswasfemale-biased(70:30).Sub-adultanimals(undevelopedtesticlesinmalesandundevelopedmammaryglandsinfemales)represented29%ofshotkangaroos(n=93)with71%(n=229)ofshotkangaroosclassifiedasadults.Allbutthreeexaminedanimals(99%;n=319)hadasinglebulletwoundtract,whilethreeanimalsdisplayedtwobulletwoundtracts.Oneofthekangaroosthatwasshottwicewasinitiallyshotinthelowerjaw(mandible)andwassubsequentlyshotinthecranium.Theotherkangaroosthatwereshottwicewereinitiallyshotinthelowerjaw(mandible)andwassubsequentlyshotinthethorax(aspertheCOP).Ofthe324bulletwoundtractsexamined,93%(n=320)affectedthebrainwhile7%(n=24)didnot.Bulletwoundtractsoutsidethebrainaffectedtheanteriorventralneck,theanteriorcentralneck(firstandsecondcervicalvertebrae),theorbit(eyesocket),thepinna(externalears)andthethorax.PouchyoungAtotalof165adultfemalekangarooswereinspectedforthepresenceofpouchyoung.Oftheseadultfemaleanimals,161(98%)hadonepouchyoungpresent,whilefour(2%)adultfemaleshadnopouchyoungpresent.Nofemaleswereobservedwithmorethanonepouchyoung.Ofpouchyoungdetected,76%(n=122)wereunfurredand24%(n=39)werefurred.Thevastmajorityofpouchyoung(99%)wereeuthanasedviablunttrauma,andtwoverysmallpouchyoungweredecapitatedusingthe‘thumbandforefinger’decapitationmethoddescribedbyMcLeodandSharp(2014).Whenblunttraumawasused,asolidboardwasplacedunder75%(n=121)ofpouchyoung.However,aboardwasnotusedfortheother
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25%(n=40)ofpouchyoung,constitutingallofthepouchyoungprocessedbyoneshooterononenightofobservations.Table3.Summaryoflogisticsforpost-mortemcollectionofeasterngreykangaroos(Macropusgiganteus)culledvianon-commercialshootinginperi-urbanconservationestateintheACTandNSW,May−June2017.
Numberofkangarooskilledbeforecollection Frequency(n)
1 61
2 96
3 48
4 60
5 30
6 12
7 14
Notrecoveredimmediately* 1
*Thiskangaroowasrecoveredbytheshootingteamapproximatelytwohoursaftershooting.
Theshootingteamswereobservedtocheckalleuthanasedpouchyoungtoconfirmdeathimmediatelyaftereuthanasiaprocedureshadbeenperformed.Nopreviouslyundetectedpouchyoungwerefoundbytheindependentobserversandnopouchyoungwerefoundtobealiveaftereuthanasiaprocedureshadbeenperformed.
Discussion CompliancewiththeCodeofPractice
ThekangaroocullingoperationwasobservedtobecompliantwithallaspectsoftheCOPforthenon-commercialshootingofkangaroos.Thefirearms,ammunitionandshootingproceduresusedtotargetkangaroosmettherequirementsoftheCOP.Themajority(94%)ofshotsfiredstruckkangaroos.Ofkangaroosthatwerekilled,97%wererenderedimmediatelyinsensiblefromthefirstshotfiredatthem.Themajority(93%)ofbulletwoundtractsinkilledkangarooscausedgrossballisticpathologytothebrain.Forkangaroosnotrenderedimmediatelyinsensible,eitherrepeat
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shootingorblunttraumawereusedasfollow-upkillingmethods.BothapproachesareallowedundertheCOP,whichstates“Incircumstanceswhere,fordispatchofaninjuredkangarooorwallaby,ashottoeitherthebrainorheartisimpracticalorunsafe(suchaswhentheanimalismovingbutnotabletostand),aheavyblowtothebaseoftheskullwithsufficientforcetodestroythebrain(seeSchedule2)ispermissible.”(CommonwealthofAustralia2008:pg.12).TheapproachestakentoinjuredkangarooswereconsistentwiththeCOP,whichstates“Whereanindividualkangarooorwallabyisinjured,nofurtheranimalscanbeshotuntilallreasonableeffortshavebeenmadetolocateandkilltheinjuredanimal”(CommonwealthofAustralia2008:pg.8).Onekangaroowasshotandassumedkilledbutwasnotrecovered(found)forapproximatelytwohoursbytheshootingteamduringobservations.Thiskangaroowasanadultmale,andhencedidnothavepouchyoung,buttheanimal’ssexwasnotknownuntilthebodywasfound.TheCOPstatesthat“shotfemalekangaroosmustbeexaminedforpouchyoungimmediatelyaftershooting”(CommonwealthofAustralia2008:pg.8).Otherstudieshaveobservedalowfrequencyofshotkangaroosnotbeingrecoveredbyshootingteams,includingthoseofMcLeodandSharp(2014)andHamptonandForsyth(2016).Themajority(98%)ofadultfemalekangaroosshothadpouchyoung,butmostpouchyoung(76%)wereunfurred,andhencewerenotconsideredsentient.Forpouchyoungeuthanasia,theuseofblunttraumaanddecapitationwerecompliantwiththeCOP.
AnimalwelfareoutcomesThepercentageofkangaroosrenderedimmediatelyinsensible(IDR;96%)washigherthanformostpublishedstudiesofwildlifeshooting(e.g.93%,Lewisetal.1997;60%,Hamptonetal.2015),andwassimilartothatobservedforthesamemanagementprogramin2015(IDR98%;n=139;Hampton2016).Thenon-fatalwoundingandescapeofanimalsoccurswithnearlyallexaminedshootingmethods(Hamptonetal.2015),includingkangarooshooting(McLeodandSharp2014)and0.6%ofkangarooswereobservedtobenon-fatallywoundedinthisstudy.Forcomparison,McLeodandSharp(2014)reportedanincidenceof0.3%fornon-fatalwoundingofkangaroosduringcommercialshooting.Itshouldbenotedthatitcanbedifficulttodistinguishminornon-fatalwoundingfrommissedshotsinfieldstudies(Pierceetal.2015),particularlywithnight-timeshootingmethods.Thisinherentdifficultycanleadtouncertaintyregardingwhetheranimalshavesufferedminornon-fatalwoundsorhavebeenmissed(DEFRA2014).
ConclusionsIndependentassessmentofthisshootingprogramindicatedthatanimalwelfareoutcomeswerecomparabletootherprofessionalshootingprograms.Whenkangarooswereshotat,theCOPfornon-commercialkangarooshootingwascompliedwithinallaspects.Aminorityofanimalsweremissed,non-fatallywounded,andshotinanatomicallocationsotherthanthecranium,asoccurswithnearlyallshootingmethods.Theshootingtechniqueandequipmentusedwerenotuniformforalloperators,asdifferentfirearmcalibresandprojectiles,illuminationapproaches,andpouchyoungeuthanasia
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methodswereemployed.Consequently,variablesassociatedwiththeoccurrenceofadverseanimalwelfareevents(e.g.kangaroosnotbeingrenderedimmediatelyinsensible)werenotobviousfromthesedescriptiveanalysesalone,butstatisticallysignificantassociationscouldbeelucidatedthroughmultivariablemodellingapproaches.Modellinghasallowedidentificationofimportantmanipulablevariables(e.g.identityofshooters)foraerialshootingprograms(Hamptonetal.2017),facilitatingrefinementofprocedures.ThisapproachwasusedinPart2ofthisreport.
RecommendationsFromfieldobservationsanddescriptiveanalyses,thefollowingrecommendationismade:1. ForcontinuingcompliancewiththeCOP,currentlyusedshootingprotocolsshouldbemaintained.
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PART2:ANALYSISOFEXPLANATORYVARIABLES
BrendanCowledAusvetPtyLtd
BackgroundThissectionpresentstheresultsofanalysesofanimalwelfaredataderivedfromtheAustralianCapitalTerritorykangaroomanagementprograminin2017.Theobjectiveoftheanalyseswastodetermineifexplanatoryvariableswereassociatedwithadverseanimalwelfareoutcomes.Thisallowedinferencesonthecauses(ifany)ofadverseoutcomes.
MethodsShootingoutcomesfromfieldobservations(Part1ofthisreport)weredichotomisedintothosethatproducedadverseanimalwelfareeventsandthosethatdidnot.CompliancewiththeCOP(Part1)wasnotconsidered.Shootingoutcomesweredichotomisedtwoways:
1. Alldata:Kangaroosexperiencingimmediateinsensibilityornotandincludesallmissedshots(n=338).
2. Killeddata:Kangaroosexperiencingimmediateinsensibilityornotbutnotincludingkangaroosthatescaped(n=322).
Severalexplanatoryvariableswerecollected.Theseexplanatoryvariableswereconsideredpotentiallyimportanttotheoccurrenceofadverseoutcomesormighthavebeenconfoundersanyobservedstatisticalrelationship.Theseincluded:
1. Individualshooter(categoricaldata:7shooters)
2. Individualdriver(categoricaldata:5drivers)
3. Agencyofshooter(categoricaldata:3agencies)
4. Agencyofdriver(categoricaldata:2agencies)
5. Site(categoricaldata:2sites)
6. Cumulative#animalstargetedthatnightbyshooter(continuous)
7. Cumulative#animalstargetedsinceafoodbreak(continuous)
8. Timeofnightwhenshootingoccurred(categoricaldata:4'sessions')
9. Illumination(categoricaldata:2technologies)
10. Optics(categoricaldata:2technologies)11. Firearmcalibre(categoricaldata:2technologies)
12. #animalsshotbeforecollection(continuous)*
13. Sex(categoricaldata:2sexes)*14. Age(categoricaldata:2ageclasses)*15. Nightoftheoperation(continuous)16. Consecutivenightsofshooting(1st,2ndnightetc.)
*Incompletedataforthen=338database.
ausvet
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Uni-variabledescriptionandbi-variableanalyseswereconductedtodescribebothvariablesandtheoutcomeofinterestandtolookatcrudemeasuresofassociationbetweenexplanatoryvariablesandtheoutcomeimmediateinsensibility.Thecrude(uncontrolled)associationbetweenbivariableexplanatoryvariablesandtheoutcome(immediateinsensibility)wasexaminedbycreatingsimplelogisticregressionmodelsofimmediateinsensibilityagainsttheexplanatoryvariableinquestion,andexponentiatingtheestimatedco-efficienttoestimatetheoddsratio.Inthecaseofvariableswithmultiplecategories,asimplecontingencytableandfisherexacttestwasconducted.Multivariablemodelswereimplementedtotestforassociationsbetweenexplanatoryvariablesandtheoutcomeofimmediateinsensibilitywhilstcontrollingforpotentiallyconfoundingvariables.Multivariablemodelswereimplementedasgeneralisedlinearmodelswithalogoddslinkfunction.Severalmodelswereimplemented,witheachmodelrepresentingaplausibleapriorihypothesis.Themodelswereassessedusinginformationtheoreticapproachestodeterminewhichmodels(hypotheses)weremostsupportedbythedata(BurnhamandAnderson2002;Burnhametal.2011).Thefitofthemostsupportedmodelwasexaminedusingstandardstatisticalapproaches.Twodatasetswereanalysedseparately.Inthefirstanalyses,‘Alldata’wasusedtoimplementHypotheses1−6,althoughhypothesis6(multivariablemodel)didnotincludesexorage.Inthesecondanalyses,‘Killeddata’,wasusedtoimplementhypotheses1−7.Thefollowingapriorihypotheseswereimplementedasappropriatemultivariablelogisticregressionmodels:Hypothesis1:ShooterskillTheskillofanindividualshooterinfluencesthelikelihoodofimmediateinsensibility,butisaffectedbythecalibreoftherifle,theilluminationandtheopticsused:
log$%
&'%= )* + )&,ℎ../01 + )23456710 + )8955:;6<4/6.< + )=>?/6@A
whereP=probabilityofoutcome
Hypothesis2:RhythmShootersaremostlikelytomakebadshotsbeforethey‘gettheireyein’.Thiswillbeinfluencedbythenumberofanimalsshotthatnight,thenumbershotsinceabreakandthenumberofshootingsessionsthatnight(mostlikelytomisswhenstartingeachnightandeachsession):
log$%
&'%= )* + )&B4<C41..AAℎ./ + )2B4<C41..AA6<@07104E + )8,0AA6.<A
Hypothesis3:FatigueTheoppositeofrhythm.Shootersaremostlikelytomakebadshotsasthenumberofanimalsshotthatnightincrease,inlatersessionsandasthenumberofanimalsshotsinceabreakincrease.Thismaybeconfoundedbytemperature:
log$%
&'%= )* + )&B4<C41..AAℎ./ + )2B4<C41..AA6<@07104E + )8,0AA6.<A +
)=F0;?014/:10
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Hypothesis4:TechnologyTheequipmentusedisthemostimportanteffectonimmediateinsensibility.Affectedbycalibre,illuminationandoptics:
log$%
&'%= )* + )&3456710 + )2955:;6<4/6.< + )8>?/6@A
Hypothesis5:AnimalnaivetyAnimalsgetwaryofshootersandarehardertoshootastheyareexposedforlonger.Influencedbythenightoftheoperationandthenumberofconsecutivenightsofshooting:
log$%
&'%= )* + )&3:;;:54/6G0H6Cℎ/ + )23.<A0@:/6G0<6Cℎ/A
Hypothesis6:MultivariableAllvariableshaveaninfluenceonoutcomesandhenceallvariablesareincludedintoasinglemodel:
log$%
&'%= )* + )&3::;:54/6G0H6Cℎ/ + )23.<A0@:/6G0<6Cℎ/A+)8,0I + )=JC0 +
)K3456710 + )L955:;6<4/6.< + )M>?/6@A +)NF0;?014/:10 + )OB4<C41..AAℎ./ +)&*B4<C41..AA6<@07104E + )&&,0AA6.<A + )&2,ℎ../01
Note,thatforalldata,nosexandagevariablewasincludeinthemultivariablemodelasthisdatawasincompleteassomekangarooswerenotkilledandcouldnotbeexamined.Hypothesis7:AnimalfactorsSexandagemayinfluenceoutcomes(e.g.largeadultmaleslesslikelytobekilled).Thishypothesisisonlyapplicabletooutcome2,Kangaroosexperiencingimmediateinsensibilityornotbutnotincludingmissedshots(n=322):log$
%&'%
= )* + )&,0I + )2JC0
Results2.3.1 Analysis1:‘Alldata’Note:Thisdoesnotincludesexandagedata,butrecordsallkangaroosthatwereshotorescaped.DescriptiveanalysisThefollowingdescriptiveanalysisispresentedtounderstandthedistributionofeachvariableandtoallowerrorchecking.Table4describesthecontinuousvariables.Table5describesthecategoricalvariables.
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Table4:Descriptivestatisticsforeachexplanatoryvariableinthemodels.Variable Minimum Quartile1 Median Mean Quartile3 Maximum
Adverseevent Prevalence=0.0858(95%CI:0.056−0.116)
Minimumtemperature(°C)
-5.100 -4.500 -4.250 -3.442 -2.900 -0.700
Cumulativenightofshooting
6 7 9 10.850 16 18
Consecutivenightsofshooting
1 1 2 2.213 3 5
Cumulativekangaroosshotinnight
1 10 23 27.990 44 72
Cumulativekangaroosshotsincebreak
1 5 10 10.87 15 33
Bi-variableanalysisThebi-variableanalysisexplorestherelationshipbetweentheoutcome(adverseevents)andeachexplanatoryvariable(Table6).Anoddsratioof1impliesthereisnorelationshipbetweentheexplanatoryvariableandtheoutcome,butshouldbeinterpretedforstatisticalsignificancebyexaminingthe95%confidenceintervals.95%Confidenceintervalsthatcontain1indicateanon-significantrelationshipbetweentheoutcomeandexplanatoryvariable.Itisimportanttonotethattheseareuncontrolledvariables.Therelationshipidentifiedmaybeconfoundedbyothervariables.Thisisgenerallydealtwithinthemultivariablemodellingsectionbelow.
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Table5:Distributionsofcategoricalexplanatoryvariables.
ShooterID:ShooterID
Numberofnights
1 332 233 224 705 696 727 49
Sex:Sex NumberF NAM NAMissingdata(escaped)
NA
Age:Age NumberAdult NASub-adult NAMissingdata(escaped)
NA
Calibre:Calibre Number1 2172 121
Illumination:Illuminationtype
Number
Infra-red 208Whitelight 130
Optics:Opticstype NumberC 9S 329
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Table6:Uncontrolledrelationshipbetweenadverseeventsandexplanatoryvariableasquantifiedbyoddsratio(note:sexandagearemissingasthesewerenotrecordedforallanimalsassomeescaped).Variable Oddsratio(95%CI)orFisherexacttest
Minimumtemperature(°C) 1.1231(0.8862−1.4080)
Cumulativenightofshooting 0.8777(0.7800−0.9679)
Consecutivenightsofshooting 0.8146(0.5786−1.0929)
Cumulativekangaroosshotinnight 0.9963(0.9769−1.0150)
Cumulativekangaroosshotsincebreak 1.0384(0.9855−1.0920)
ShooterID χ2=30.22,df=6,p<0.001ShooterID:Adverseevent:1234567032152260647046118010523
Calibre 0.3466(0.1143-0.8639)Calibre:Adverseevent:1201931161245
Illumination 1.1426(0.5156-2.4601)Lighttype:Adverseevent:IRW019111811712
Optics 0.1716(0.0426-0.8494)Optics:Adverseevent:CS063031326
MultivariablemodellingThemultivariablemodellingissummarisedinatablewhereallmodelsrepresentingthevarioushypothesesarerankedfrommostsupportedtoleastsupported(Table7).TheAkaikeweight(probability)andAICcdifferences(∆)allowconsiderationofwhicharethemostsupportedmodels.Ingeneralterms,adeltaoflessthan4−7indicatesthatthemodelhassomesupport(Burnhametal.2011).
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Table7:Akaikeinformationcriterion(AIC)valuesandothermodelcomparisonparametersformodelselectionusinginformationtheoreticapproaches(BurnhamandAnderson2002;Burnhametal.2011).Theprobabilityofthemulti-variableandsinglevariableshooterskillmodelsarehighandclearlythedatasupporteitherofthesemodels.ThereisasmallamountofsupportfortheMVmultivariablemodel(modelcontainingallparameters)althoughthissupportismostlyduetotheinclusionofexplanatoryvariablesforshooter.ModelsarelistedinAICrankedorderforeachhypothesis.Model Parameter
s(K)BiascorrectedAIC
(AICc)AICc
differences(∆)Probability(Akaike
weight)
MV*Shooterskill 5 186.8 0 0.499
SV**Shooterskill 2 187.2 0.39 0.411
MVMultivariable 11 191.3 4.49 0.053
MVAnimalNaivety 3 193.6 6.85 0.016
SVcumulativenightofshooting 2 194.8 7.98 0.009
SVCalibre 2 196.6 9.84 0.004
MVTechnology 4 197.1 10.28 0.003
SVOptics 2 197.4 10.58 0.003
SVCumulativekangaroosshotsincebreak 2 199.9 13.1 0.001
SVConsecutivenightsofshooting 2 200.1 13.33 0.001
SVminimumtemperature 2 201 14.17 0
SVCumulativekangaroosshotinnight 2 201.8 14.99 0
SVillumination 2 201.8 15.02 0
MVRhythm 4 204.6 17.84 0
MVFatigue 5 206.2 19.43 0
*Multivariablemodel**SinglevariablemodelWhereseveralmodelshavesomesupport,itisusefultomodelaveragetoassistinferencesandprediction(Grueberetal.2011).Inmoredetail,thevalueoftheco-efficientsfromeachoftheexplanatoryvariablescanestimatedwithweightingfromseveralmodelsbasedontheirlevelofsupport.Conditionalestimatesareusefulforprediction.Aconditionalestimateisproducedwhensettingallotherparameterstotheirmean.Table8presentsmodelaveragedpredictions.
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Table8:Conditionalaveragesofmodelcoefficientsacrossallmodels.
Coefficient Estimate(eB) Std.Error AdjustedSE zvalue Pr(>|z|)
(Intercept) 0.2840 1062.8933 1066.8782 0.0010 0.9991
Shooter(2cf.1) 20.3989 1.3815 1.3851 2.1770 0.0295
Shooter(3cf.1) 0.0000 1429.6335 1434.8999 0.0100 0.9918
Shooter(4cf.1) 9.7404 1.2873 1.2911 1.7630 0.0779
Shooter(5cf.1) 5.2403 1.4356 1.4397 1.1510 0.2499
Shooter(6cf.1) 0.9143 1.2432 1.2478 0.0720 0.9427
Shooter(7cf.1) 2.0870 1.1774 1.1818 0.6230 0.5336
Calibre(2cf.1) 1.6x1025 7865.4639 7894.9549 0.0080 0.9937
Illumination(Wcf.IR) 2.0157 697.8126 700.4288 0.0010 0.9992
Optics(Scf.C) 0.0000 2152.5513 2160.6221 0.0090 0.9929
Cumulativenightofshooting 0.0072 701.6368 704.2675 0.0070 0.9944
Consecutivenightsofshooting 33.9796 437.4148 439.0549 0.0080 0.9936
Cumulativeroosshotthatnight 1.1401 0.0646 0.0648 2.0240 0.0430
Cumulativeroosshotsincebreak 0.9000 0.0621 0.0623 1.6920 0.0907
Session(2cf.1) 0.0211 1.6046 1.6105 2.3970 0.0165
Session(3cf.1) 0.0016 3.1237 3.1353 2.0610 0.0393
Session(4cf.1) 0.0002 3.6815 3.6952 2.2690 0.0233
Minimumtemperature(°C) 0.0119 500.1930 502.0684 0.0090 0.9930
ModelfitThemostsupportedmodel,multivariable(MV)ShooterSkillmodel,wasexaminedfor
modelfit.AlikelihoodratiotestoftheMVShooterSkillmodelverseanintercept-only
modelrevealedthattheMVShooterSkillmodelfittedbetterthantheintercept-onlymodel
(H0=Reducedmodelistrue;HA=Currentmodelistrue;χ2=27.5326,df=7,p=0.0003).
TheR2was0.16.Thismeansthatapproximately16%ofthevariabilityinthedatais
explainedbythedata.Theseindicatethatthemodelfitsthedatamoderatelywell,butthat
therearevariablesthatexplainmuchofthedatathatarenotincludedinthedata.
SeveralcoefficientsaresignificantincludingShooter2cf.Shooter1(andmarginallyShooter
4cf.Shooter1).ThisindicatesthatShooter2hadmoreadverseoutcomesthanshooter1,
whereas3,5,6and7wereallnotstatisticallysignificantlydifferenttoShooter1.Shooter4
wastrendingtowardsapooreroutcomethanshooter1.Shooter2hadanoddsratioof
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20.3989,indicating20.3989timestheoddsofanadverseoutcomethanshooter1(or
practically,shooter3−7).
Inaddition,asthenumberofkangaroosshotincreaseseachnight,thelikelihoodofan
adverseoutcomeincreasesmarginally.Thatis,theoddsratiois1.14indicatingthatthereis
a0.14increaseintheoddsofanadverseoutcomeinroosshotinlatersessions
Incontrast,cf.session1,sessions2−4wereallsignificantlylesslikelytohaveroosshotwith
adverseoutcomes.
2.3.2 Analysis2:‘Killeddata’Note:Thisdoesincludesexandagedata,andrecordsallkangaroosthatwereshot(n=322),butnotthosethatescaped.
DescriptiveAnalysisThefollowingdescriptiveanalysisispresentedtounderstandthedistributionofeach
variableandtoallowerrorchecking.Table9describesthecontinuousvariablesandTable10showsthedistributionofcategoricalvariables.Bi-variableAnalysesAsdescribedabove(2.3.1),thebi-variableanalysisexplorestherelationshipbetweentheoutcome(adverseevents)andeachexplanatoryvariable.Oddsratiosenumeratethis
relationship(Table11).Theseareuncontrolledvariables.Therelationshipidentifiedmaybe
confoundedbyothervariables.Thisisgenerallydealtwithinthemultivariablesection.
MultivariableModellingThemultivariable(MV)modellingpresentsatablewhereallmodelsrepresentingthe
varioushypothesesarerankedfrommostsupportedtoleastsupported(Table12).TheAkaikeweight(probability)andAICcdifferences(∆)allowconsiderationofwhicharethemostsupportedmodels.Ingeneralterms,adeltaoflessthan4−7indicatesthatthemodel
hassomesupport(Burnhametal.2011).
Whereseveralmodelshavesomesupport,itisusefultomodelaveragetoassistinferences
andprediction(Grueberetal.2011).Inmoredetail,thevalueoftheco-efficientsfromeach
oftheexplanatoryvariablescanestimatedwithweightingfromseveralmodelsbasedon
theirlevelofsupport.Conditionalestimatesareusefulforprediction.Aconditionalestimate
isproducedwhensettingallotherparameterstotheirmean.Table13presentsmodel
averagedpredictions.
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Table9:Descriptivestatisticsforeachexplanatoryvariableinthemodels.
Variable Minimum Quartile1 Median Mean Quartile3 Maximum
Adverseevent Prevalence=0.0404(95%CI:0.0189-0.0619)
Minimumtemperature
(°C)
-5.100 -4.500 -4.200 -3.446 -2.900 -0.700
Cumulativenightof
shooting
6 7 9 11.0100 16 18
Consecutivenightsof
shooting
1 1 2 2.252 3 5
Cumulativekangaroos
shotinnight
1 10 24 28.2300 44 72
Cumulativekangaroos
shotsincebreak
1 5 10 20.7800 15 33
Table10:Distributionsofcategoricalexplanatoryvariables
ShooterID:
ShooterID
Numberofnights
1 33
2 17
3 22
4 65
5 65
6 71
7 49
Sex:
Sex NumberF 225
M 97
Age:
Age NumberAdult 239
Sub-adult 83
Calibre:
Calibre Number1 202
2 120
Illumination:
Illuminationtype
Number
Infra-red 199
Whitelight 123
Optics:
Opticstype NumberC 7
S 315
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Table11:Uncontrolledrelationshipbetweenadverseeventsandexplanatoryvariableasquantifiedbyoddsratio.
Variable Oddsratio(95%CI)orFisherexacttest
Minimumtemperature(°C) 1.2281(0.8737−1.7044)
Cumulativenightofshooting 0.9569(0.8316−1.0806)
Consecutivenightsofshooting 1.1118(0.7419−1.5990)
Cumulativekangaroosshotinnight 1.0067(0.9794−1.0336)
Cumulativekangaroosshotsincebreak 1.0363(0.9594−1.1128)
ShooterID χ2=8.737,df=6,p=0.1889
ShooterID:
Adverseevent:1234567
032152260647046
11205113
Calibre 0.7394(0.1968-2.3259)
Calibre:
Adverseevent:12
0193116
194
Illumination 1.0117(0.2997-3.1049)
Lighttype:
Adverseevent:IRW
0191118
185
Optics 0.2376(0.0364-4.6717)
Optics:
Adverseevent:CS
06303
1112
Sex 1.9551 (1.2845-13.3952)(Malecf.female)
Sex:
Adverseevent:FM
022089
158
Age 1.8510(0.5456-5.7153)
Age:
Adverseevent:ASA
023178
185
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Table12:Akaikeinformationcriterion(AIC)valuesandothermodelcomparisonparametersformodelselectionusinginformationtheoreticapproaches(BurnhamandAnderson2002;Burnhametal.2011).Theprobabilityofthesinglevariablesex,animalnaivetyandmultivariableanimalfactorsmodelsarehighest.However,thereareseveralothermodelswithsomelevelofsupportanditisdifficulttostatethedataclearlysupportthesehypothesesoverothers.Forexample,thefirst13modelsallhaveadelta(∆)oflessthan7.ModelsarelistedinAICrankedorderforeachhypothesis.
Model Degreesoffreedom
BiascorrectedAIC(AICc)
AICcdifferences(∆)
Probability(Akaikeweight)
SV*Sex 2 107.2 0 0.357
MV**AnimalNaivety 3 108.6 1.4 0.177
MVAnimalfactors 3 108.8 1.52 0.167
SVminimumtemperature 2 111.5 4.26 0.042
SVOptics 2 111.7 4.5 0.038
SVAge 2 111.9 4.67 0.035
SVCumulativekangaroosshot
sincebreak 2 112.1 4.85 0.032
SVcumulativenightofshooting 2 112.5 5.24 0.026
SVConsecutivenightsofshooting 2 112.7 5.42 0.024
SVCalibre 2 112.7 5.47 0.023
SVCumulativekangaroosshotin
night 2 112.7 5.47 0.023
SVillumination 2 113 5.72 0.021
MVMultivariable 16 114.2 6.93 0.011
SV**Shooterskill 7 114.3 7.07 0.01
MVTechnology 4 115.7 8.47 0.005
MV*Shooterskill 8 116 8.77 0.004
MVRhythm 6 117.1 9.83 0.003
MVFatigue 7 119.1 11.89 0.001
*Singlevariablemodel
*Multivariablemodel
ModelfitThemostsupportedmodel,singlevariable(SV)Sexmodel,wasexaminedformodelfit.A
likelihoodratiotestoftheSVSexmodelverseaninterceptonlymodelrevealedthattheSex
modelfittedbetterthantheinterceptonlymodel(H0=Reducedmodelistrue;HA=
Currentmodelistrue;χ2=5.7173,df=1,p=0.0168).TheR
2was0.061,whichisrelatively
lowandmeansmuchofthevarianceinthedataremainsunexplainedbythemodel.
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Table13:Conditionalaveragesofmodelcoefficientsacrossallmodels.Coefficient Estimate(eB) Std.Error AdjustedSE zvalue Pr(>|z|)
(Intercept) 0.0695 755.1000 758.1000 0.0040 0.9970
Shooter(2cf.1) 23623.5648 1042.0000 1046.0000 0.0100 0.9920
Shooter(3cf.1) 0.0000 2206.0000 2214.0000 0.0060 0.9960
Shooter(4cf.1) 3.2805 1.2780 1.2830 0.9270 0.3540
Shooter(5cf.1) 0.6374 1.6170 1.6230 0.2780 0.7810
Shooter(6cf.1) 0.4571 1.4300 1.4360 0.5450 0.5860
Shooter(7cf.1) 2.0869 1.1770 1.1820 0.6220 0.5340
Calibre(2cf.1) 563681537.4071 6676.0000 6703.0000 0.0030 0.9980
Illumination(Wcf.IR) 196.5663 1772.0000 1779.0000 0.0030 0.9980
Optics(Scf.C) 0.0002 1711.0000 1718.0000 0.0050 0.9960
Cumulativenightofshooting 0.5070 293.7000 294.8000 0.0020 0.9980
Consecutivenightsofshooting 3.3602 173.7000 174.4000 0.0070 0.9940
Cumulativeroosshotthatnight 1.0560 0.0840 0.0842 0.6470 0.5170
Cumulativeroosshotsincebreak 0.9984 0.0796 0.0797 0.0200 0.9840
Session(2cf.1) 0.0000 1387.0000 1392.0000 0.0120 0.9910
Session(3cf.1) 0.0030 4.3910 4.4030 1.3190 0.1870
Session(4cf.1) 0.0008 5.0960 5.1120 1.3830 0.1670
Minimumtemperature(C) 0.4408 342.8000 344.2000 0.0020 0.9980
Sex(Male) 3.9079 0.5887 0.5910 2.3070 0.0210
Age(SA) 1.5861 0.6038 0.6061 0.7610 0.4470
MultivariableanimalnaivetyThesecondmostsupportedmodel,multivariable(MV)AnimalNaivetymodelwasexamined
formodelfit.AlikelihoodratiotestoftheMVAnimalNaivetymodelverseanintercept-only
modelrevealedthattheAnimalNaivetymodelfittedbetterthantheintercept-onlymodel
(H0=Reducedmodelistrue;HA=Currentmodelistrue;χ2=6.35,df=2,p=0.0417).
TheR2was0.068,whichisrelativelylowandmeansmuchofthevarianceinthedata
remainsunexplainedbythemodel.
Itisclearthattheonlysignificantcoefficientissex,withmalesmorelikelytohaveadverse
outcomesthanfemales.However,othersignificantparameterswerenotevident(Table13).Thismaybeduetothesmallnumberofadverseoutcomesrecordedleadingtolowpowerin
theanalysis.
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Conclusions
Thedatasetthatincludedadverseoutcomesasescapedkangaroosandwoundedkangaroos
wasthemostamenabletoanalysesandproducedmodelsthatexplainedamoderate
amountofthedatavariability.
Analysesofthisdatasetrevealedthathypothesesassociatedwithshooteridentity(skill)
weremostsupportedbythedata.Ingreaterdetail,itappearedthatsomeshooterswere
morelikelytohaveadverseoutcomesthanothershooterswhilstcontrollingforpotentially
confoundingvariablessuchascalibreofrifle.
Theseconddatasetthatincludedonlykilledkangarooswaslessamenabletoanalyses.In
theseanalyses,itwasdifficulttodistinguishbetweenthevarioushypothesesasmanyhad
somesupportfromthedata.Inaddition,thesemodelsonlyexplainedasmallamountofthe
datavariability,withrelativelylowR2values.Despitethis,themodelsthatrepresentedthe
sex,multivariableandanimalnaivetyhypotheseshadthemostsupport.Theonlysignificant
variableonconditionalmodelaveragingwasthesexvariable,withmaleslikelytohave
adverseoutcomescomparedwithfemales.Thisresultlikelyreflectsthatmalesaremore
difficulttorenderimmediatelyinsensiblebecauseoftheirlargersize(e.g.thickerbone
structuremayprovidegreaterresistancetobulletpenetration;Hamptonetal.2017).Similarresultsformaleanimalshavebeenobservedforotherphysicalkillingmethods(e.g.
captiveboltuseforslaughteroflivestock;Gregoryetal.2007).
Insummary,shooterskillwasmostlikelytoaffecttheprobabilityofanadverseoutcome
(predominantlyescapes).Inaddition,sexwasakeyfactorforadverseoutcomes
(wounding).Therewasnoevidencethatothervariablessuchasillumination(whitelightvs.
infra-red)affectedoutcomes.Therearelikelyun-recordedvariablesthatareresponsiblefor
muchofprobabilityofadverseoutcomes.Furtherresearchisindicatedtodeterminewhat
thesevariablesareastheymaybeamenabletomanipulation,therebyreducingadverse
outcomes.Shootingdistance(Hamptonetal.2015),windspeedandthepresenceoffogmayallinfluenceshootingoutcomesandshouldbeexaminedinfuturestudies.
Despitethis,itisimportanttonotethatadverseoutcomes(especiallywounding)werevery
unlikelytooccurinthisdata.Afrequencyofadverseoutcomesof4%wasrecordedforall
killedkangaroos.
Recommendations
Forrefinementofanimalwelfareoutcomes,thefollowingrecommendationsaremade:
1. Themanagingagencyshouldexamineshooterselectionandtraining.
2. Shootersshouldexerciseadditionalcautionwhenshootingatmalekangaroos.
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