Efficacy of bird deterrent devices in agricultural areas ... · 1994). Starlings can be found in flocks of up to 1.5 million birds and cause an ... Rocha intern Becky Kern conducted

Eff icacyof birddeterrentdevices inEff icacyof birddeterrentdevices inagricultural areasof theFraserVal leyagricultural areasof theFraserVal leyof Brit ishColumbia: a pi lot studyofBrit ishColumbia: a pi lot study January2009Preparedfor:TheMinistryofAgricultureandLands(MAL),ProvinceofBritishColumbiaandTheFraserValleyRegionalDistrict(FVRD)PrincipalInvestigator:ProfessorKarenM.M.Steensma Co‐director,EnvironmentalStudiesProgram AssistantProfessor,DepartmentofBiology TrinityWesternUniversity

Studentassistants:AmandaEdworthy,KatherineHartline,DeniseWong,BeckyKernandAmyGardner

Steensma - Efficacy of bird deterrent devices 2

ExecutiveSummary

AseriesofbirdcountstationsweresetupintheSumasPrairieregionofBritishColumbia,

CanadainJune2008inordertogaugetheefficacyofbirddeterrentdevicesoverasingle

blueberryharvestseason.Birdswerecountedintheearlymorningandlateafternoonatsix

differentstationsfortwoweekspriortotheinstallationofdeterrentsinJuly.Threestations

remainedascontrolcountsitesthroughoutthestudy.Theremainingthreesiteseachhada

differentdeterrentinstalled:anauditorybirddistresscaller,apropanecannon,andahawk

kite.CountscontinuedthroughAugustwithdeterrentsinplace,andonthroughSeptember

afteralldeterrentswereremoved.Statisticalanalysisrevealedthatboththehawkkiteandthe

propanecannonshowedsignificantdecreasesinstarlingpopulationnumbersinitially,but

starlingsslowlyreturnedtohighernumbersaftertheinitialintroductionofthesedeterrents.

Thehawkkitedeterrenteffectlastedlongerthanthepropanecannoneffectwithinthispilot

study.Thebirddistresscallershowednostatisticallysignificantdeterrenteffectalthough

problemsattheparticularsiteapparentlyskewedresultsforthatdeterrenttrial,asinitial

starlingpopulationsatthatsiteweresignificantlyhigherthanthecontrolpopulations.Though

theoverallstudywasofapilotnatureandextremelylimitedinscope,theresultspointtosome

possiblerecommendationsforstarlingmanagementandtothepotentialvalueoffurther

researchonthistopic.


ListofFiguresandTablesFigure1.BirdcountsitesinSumasPrairieregionofBritishColumbia………..……………….…..page7Figure2.StarlingpopulationnumbersinresponsetointroductionofaBirdGardaudibledistresscalleratasiteinSumasPrairie,BC…………………………………….….page10Figure3.StarlingpopulationnumbersinresponsetointroductionofapropanecannonatasiteinSumasPrairie,BC…………………………………………………………….….page11Figure4.StarlingpopulationnumbersinresponsetointroductionofahawkkiteinSumasPrairie,BC…………………………………………………………………………………….….page12Figure5.PercentdifferenceinbirdnumbersattransitionpointsforintroductionandremovalofvariousdeterrenttechniquesatsitesinSumasPrairie,BC……………….……page13Figure6.PercentdifferenceinbirdnumbersattransitionpointsforintroductionandremovalofvariousdeterrenttechniquesatsitesinSumasPrairie,BC,withcontrolpopulationchangessubtracted………………………………………………………………..………..page14Table1.Summaryofeffectivenessofbirdcontroltechniques…………………………………,..…page18ListofAppendicesAppendix1.LandownercontactletterAppendix2.SampledatacollectionsheetsAppendix3.Summarystatisticalanalysis


Introduction TheinvasiveEuropeanStarling(Sturnusvulgaris)reproducesprolificallyandishighly

adaptable,whichhasresultedinnuisancepopulationsacrossNorthAmerica(Currieetal.

1977).Knownfortheirintelligence,theseglossyblackbirdsalsospreaddiseases,suchas

gastroenteritis,footandmouthdisease,salmonella,aviantuberculosisandhistoplasmosis

(Feare1984,JohnsonandGlahn1994).Starlingscanbefoundinflocksofupto1.5millionbirds

andcauseanestimated$800millionindamageintheUnitedStatesannually(Norrisetal.

2003).

Starlingsposeaseriousthreattotheagriculturalindustry,especiallyberryfarmers.

Starlingsdescendonberryfields,consumingtheripefruitandsometimesdestroyingentire

crops(PrittsandHancock1992,Gough1994,Sweeney2003).InthePacificNorthwest,which

producesathirdoftheworld’sblueberrysupply,farmersreportlossesofupto30%annually

(WhatcomFarmFriends2008).Othersectorsofagriculture,mostnotablydairiesandorchards,

arealsoaffectedbythesebirds.Withdairycommoditybarnsandstoredforagesproviding

winterfeedandblueberriesprovidingsummerfeed,starlingsparticularlythriveatberry‐dairy

interfaceareasinthisregion(GilkesonandAdams1996,2000;Steensmaetal.2007).

Numerousmethodsofstarlingcontrolhavebeenattempted,butnonehasproventobe

theidealsolution.Auditorydeterrents,suchasaircannonsorelectronicdistresscalls,and

visualrepellentssuchasreflectivetape,havebeenusedtofrightenstarlingsaway,butthebirds

mayquicklyreturnoncetheyrealizetheyarenotharmed(Johnsonetal1985;Bomford1990;

BomfordandO’Brien1990;JohnsonandGlahn1994;GilkesonandAdams1996,2000;Harris

andDavis1998;Norrisetal.2003).Additionally,auditorydevicesincreasethepotentialforand

incidenceofconflictswithneighbours(PrittsandHancock1992,Gough1994,Johnsonand

Glahn1994).Trapscanbeusedtolegallyremovestarlings,buttheyareonlyeffectiveagainsta

fewbirdsratherthanentireflocks(PrittsandHancock1992,HarrisandDavis1998).Chemicals,

suchasMethiocarbandAvitrol,canefficientlyeliminatestarlings(Conover1982,Conover

1984,TobinandDolbeer1987,Bruggeretal.1993,Sweeney2003)thoughnaphthaleneshows

norepellency(Dolbeeretal1998).Thesechemicalsarenotavailableforuseonfruitcropsdue


totoxicitytohumansandothernon‐targetspecies.Reflectivetapecanbesomewhateffective

againstsimilarbirds,incertaininstances,butbirdsmaybecomehabituatedtothistechnique

(Dolbeeretal1986).Nettingoffieldscanbeaneffectivemethodofpreventingcroploss,butit

isexpensiveandinterfereswithharvesterequipment(Conover1982;JohnsonandGlahn1994;

GilkesonandAdams1996,2000;FlintandDreistadt1998;Norrisetal.2003;Sweeney2003).

ConcernsaboutdamagetoagriculturalproductioninthelowermainlandofBritish

Columbia,combinedwiththeconflictsposedbyauditorydeterrentsusedinaregionofhigh

urban‐ruralresidentialgrowth,havecreatedademandforaccurateinformationontheefficacy

ofvariousbirddeterrentdevicesintheregion.Thepurposeofthispilotstudywastoassess

backgroundstarlingpopulationsandthentesttheeffectivenessofthreeparticulardevices–an

audiblebirddistresscaller,apropanecannon,andahawkkite–indeterringstarlingsandother

birdsfromagriculturalareasoftheFraserValley.

Methods

TheFraserValleyRegionalDistrictandtheBCMinistryofAgricultureapprovedfunding

basedonaproposalforthisprojectinspring2008.Faculty,studentsandstaffofTrinity

WesternUniversity(Langley,BC)andinternswiththeinternationalconservationgroupA

Rocha,assistedinthedesignanddatacollectionfortheproject.

Atimelineofeventsintheprojectoccurredasfollows:

• March‐April2008:ARochainternBeckyKernconductedvolunteerliteratureresearch

• May‐June2008:TWUstudentKatherineHartlineandIconductedfurtherliterature

research,begancontactinglandowners,mappedpotentialexperimentaltreatment

sites,andmappedthecropsgrowninthesurroundingareasusingaGIS(Geographic

InformationSystem).TWUstudentDeniseWongjoinedinconductinginitialbirdcounts

(allspecies)intheregionforbackgroundinformationonbirdpopulationsandtheir

habitsassiteswerechosen.

• July2008:DeniseandIcompletedlandownercontactsandprotocolwasestablishedat7

sites:4controlsites,1sitewithaPurivoxTriple‐Johnpropanecannonsetonlowest


setting,1sitewithaBirdGardbrandaudibledistresscaller,and1sitewithahawkkite.

Allsiteswereprovidedwithadditionalfoodsources(beyondwhattheywouldforage

fromthesurroundingarea).Starlingsandotherincidentalspecieswerecountedforat

least2weekspriortointroductionofdeterrentdevicestoestablishbaselinepopulation

numbers.Siteswerecountedtwiceperday,onceintheearlymorning,andonceinthe

lateafternoon/earlyevening.Atleast10‐15minuteswerespentateachsitevisit.

• August2008:DeniseandTWUstudentAmandaEdworthy,andvolunteerARocha

internAmyGardner,conductedcountsduringthebusiestportionoftheblueberry

harvestseason.Countscontinuedwithdeterrentdevicesinplaceat3ofthe7

locations.Dataentrytospreadsheetsbegan.

• September2008:AmandaandAmycontinuedtodothecounts.Deterrentdeviceswere

stoppedtheweekendofSeptember5,astheblueberryseasonwaswindingdown.

CountscontinuedthroughSeptember24,togaugebothseasonalbirdbehaviourand

effectofdeterrentremoval.

• October2008:DataentrywascompletedbyAmandaandspreadsheetswere

reformattedforstatisticalanalysis.WeconsultedwithstatisticiansatbothTWUand

UniversityofBritishColumbiainconductingtheanalysis.

• November2008:Rawdatawereconvertedforentryintoastatisticalanalysisprogram

atUBC.Graphsandchartssummarizingstatisticalresultsweredeveloped.Mappingof

SumasPrairiewasfinalized.

• December2008:Draftfinalreportwaswritten.

Initiallanduseanalysisandbirdsurveysduringthelatespringandearlysummer

showedthatdairyfarmsandberryfarmsweremostlikelytoharbourlargepopulationsof

starlings.Duetotheconfoundingfactorspresentedbyblueberrygrowers’ownuseof

deterrents,andvariableattractivenessofblueberrycropsindifferentfields,treatmentsites

weredeliberatelychosenawayfromexistingblueberryfarms(Fig.1).Sevensiteswereinitially

chosenandlandownerpermissionwasobtained.Allbutoneofthesesiteswereondairyfarms;

theseventhwasonasodfarm.Asthesodfarmsitedidnotshowanappreciablebird

population,thesitewaseventuallydroppedfromthestudy.


Figure1.SumasPrairie,BCstarlingbehaviorstudysites

1=Cedarwal;controlsite 4=Meier;hawkkite

2=Driessen;controlsite 5=Luymes;controlsite

3=Driessen;BirdGardsite 6=Kielstra;propanecannonsite


Asheetofplywoodwasplacedonthegroundateachsite,inproximitytobirdroosting

areasandtoawatersource.Theplywoodwaskeptevenlycoveredwithascatteringofcracked

cornandblueberriestoserveasastablefoodsourceforthebirds.Duringeachsitevisit,the

observerswoulddriveuptowithin15‐20mofthefeedingstationandremaininthevehicle,

usingthevehicleasablindsoasnottoalarmthebirds(asperHolmes1993). Birdsonand

withina100mradiusofthefeedingstationwerecountedusingbinocularsandbirdguidesto

identifyspecies.Anyunusualindividualorflockbehaviourswerealsonoted.

Atthetimeofdeterrentintroduction,threesiteshaddevicesinstalledasfollows:1)the

BirdGardwassetupatadistanceof20mfromthebirdfeedingstationandsetaccordingto

dealerspecificationstomakenoiseatafrequenttimeintervalduringdaylighthours;2)the

propanecannonwassetupatadistanceof50mfromthebirdfeedingstationandwasset

accordingtodealerspecificationstofireattheleastfrequenttimeintervalfrom6:30amuntil

8:00pm;3)thehawkkitewassetupatadistanceof20mfromthebirdfeedingstation.All

deterrentswereleftunchangedintheirpositionandinthefrequencysettingofnoisefromthe

timeofinitialset‐uptothetimeofremoval.

Datawereorganizedforpresentationshowingmeandailystarlingcountsgroupedinto

periodsofninetotwelvedays,showingtrendsandtransitionsresultingfromaddingand

removingthedeterrents.Thepropanecannonandhawkkitesiteshadtwopre‐deterrent

periods(July9toJuly29),fourperiodswhilethedeterrentwasdeployed(July30toSeptember

7),andtwopost‐deterrentperiods(September8toSeptember24).TheBirdGardwasremoved

slightlyearlier(September1)duetobatteryfailure,andthushadonlythreedeterrent‐

deployedperiods.Wecompareddatafromthedeterrentsitestodatafromthethreecontrol

sites,whichwereaveragedtoshowbackgroundtrendsinstarlingabundance.Inaddition,

deterrentsiteswerecomparedtocontrolsitesateachtimeperiodusingat‐test.Analysesand

graphicsweredoneusingthestatisticalpackageR(RVersion2.4.0;RDevelopmentCoreTeam

2006)atUBC.


Percentdifferencewasusedtoassesstheoveralldegreeofchangeinstarling

abundanceateachoftwotransitionpoints:1)Thepre‐deterrenttodeterrent‐deployed

transitiontime,and2)thedeterrent‐deployedtopost‐deterrenttransitiontime.

Results

ThevastmajorityofbirdsseenfrequentingthetreatmentsiteswereEuropeanstarlings,

althoughoccasionalredwingblackbirds,robinsandotherbirdswereseen.Aswell,occasional

predatorbirdssuchasbaldeagles,redtailhawks,harriers,andmerlinswereseeninthe

vicinity.

Ofthethreedeterrentsused,theBirdGardaudibledistresscaller(Fig.2)appearedto

showtheleasteffect.Infact,thesitehadahighstarlingpopulationtobeginwith,andthis

becameastatisticallysignificantdifferencejustpriortodeterrentintroduction.Midway

throughtheuseofthedeterrent,thestarlingnumbersactuallyclimbedto110,muchhigher

thanbothcontrolandpre‐deterrentnumbers.Birdpopulationsdidbegintodropaftermid‐

August.Anotherfeaturetonotewasthatanonsitemanurelagoonaroundwhichthestarlings

werecongregatingwaspumpedoutonAugust27th,atwhichtimethebirdcountdroppedto

fewerthan20birds.Thus,duringthetimeitwasoperating,itappearedthattheoveralltrend

wasfortheBirdGardtoactuallyattractbirdstothesiteinitially,followedbyaprecipitousmid‐

deterrentdrop.However,thedatahereshouldnotbeconsideredvalidafterthedateofthe

pumpingincidentsincethatapparentlyremovedamajorfoodsourcethathadbeenattracting

thebirds.

Thepropanecannonshowedaneffectonstarlingnumbersatthesitetested,withpeak

effectoccurringwithinthefirst15daysafterintroductionofthedeterrent(Fig.3).Though

starlingnumbersremainedlowerthanbackgroundcontrolnumbers,theydidbegintoclimb

againafter15days,showingnosignificantdifferencefromthecontrolafterthepeak

effectiveness.

Thehawkkiteshowedthestrongesteffectofthethreedeterrents(Fig.4).Starling

numberstookthesteepestdiveduringtheperiodinwhichthekitewasintroduced,withpeak

effectoccurring15daysafterkiteintroduction,andbirdnumbersremainingsignificantlylower

thanbackgroundstarlingpopulationlevelsfor10moredays.Numberscontinuedtoremain


lowerthancontrolsanddidnotfullyoverlapwithcontrolnumbersuntilabout15daysafterthe

kitewasremoved.

Figure2.Starlingpopulationnumbersinresponsetointroductionofa BirdGardaudibledistresscalleratasiteinSumasPrairie,BC.Filledtriangles= significantdifferencefromcontrol,open=notsignificant.


Figure3.Starlingpopulationnumbersinresponsetointroductionofapropane cannonatasiteinSumasPrairie,BC.Filledtriangles=significantdifferencefrom control;open=notsignificant.


Figure4.Starlingpopulationnumbersinresponsetointroductionofahawkkitein SumasPrairie,BC.Filledtriangles=significantdifferencefromcontrol;open=not significantlydifferent.


Figure5.PercentdifferenceinbirdnumbersattransitionpointsforintroductionandremovalofvariousdeterrenttechniquesatsitesinSumasPrairie,BC.


Figure6.PercentdifferenceinbirdnumbersattransitionpointsforintroductionandremovalofvariousdeterrenttechniquesatsitesinSumasPrairie,BC,withcontrolpopulationchangessubtracted.


Percentdifferencesinstarlingpopulationsatthedifferentdeterrentsitesareshownin

Figures5and6.Theapparentlackofeffect,orseeminglypositiveinitialeffectoftheBirdGard

onstarlingnumbers,mayrelatetoconfoundingfactorsmentionedabove.Usingpercent

changenumbersillustratesevenmorestronglythesuccessofthehawkkite,andalsoshows

thatbirddecreasesinresponsetothecannonmayhavebeenmutedsomewhatbythegeneral

increaseinthecontrolpopulation.Nostatisticaltestingofpercentdifferencevalueswas

possibleduetothesmallscaleofthestudy.

Trendsinnine‐to‐twelve‐daymeans(asshowninFigs.2,3,and4)weremoreinteresting

thanactualt‐testsforsignificantdifference,thoughthetesthelpsgivemeaningtoerrorbars

andgivesanideaofhowmuchofadifferenceisneededforsignificance.Thet‐testswouldhave

beenmoremeaningfulifpre‐deterrentstarlingabundancehadbeenstatisticallyidenticalfor

controlanddeterrentsites.Controlsitesshowedconsistentgradualincreasesinstarling

numbersastheseasonprogressed.Thethreecontrolsites,whentakentogether,forman

indicationofbackgroundtrendinbirdnumbers,whichwasusefulforcomparisontotrendsat

siteswheredeterrentswereintroduced.Deterrenteffectscanalsobeexaminedbysimply

notingthechangesinpopulationlevelspre‐deterrent,deterrent,andpost‐deterrentin

Figures2‐4.

Discussion

Therelativelysimpletechniquesusedinthisstudy,andthelimitedscopeofthestudy

duetotimeandbudgetconstraints,shouldbestronglyconsideredwhenoneattemptsto

interpretresults.Inparticular,thelackofmultiplereplicationsofeachdeterrenttechniqueina

greaternumberoflocations,andoveranumberofgrowingseasons,withcomplete

randomizationoflocations,makesstatisticalinferencesdifficult(BomfordandO’Brien1990).

However,giventhepilot‐studynatureofthisresearch,severalstrengthsofourstudy

thathavebeenlackinginmanypreviousbirddeterrentresearchstudies,shouldbenoted:

1)Controlareaswereestablishedfarenoughfromdeterrentareastominimizepotentialof

“scared”birdsmovingintocontrolplots.Controlandtreatmentsitesdonotneedtobe

matched,althoughideallybothshouldbereplicated(BomfordandO’Brien1990).Onlythe


controlswerereplicatedhere.2)Deterrentplotsdidnothavetheireffectsconfoundedby

surroundingfarmers’deterrentuse.3)Resultsofthestudywerenottiedtocropdamage

measurements,whichcanbehighlyvariablebasedonfieldproductivityandotherconfounding

factors.4)Sincethe“before”orpre‐deterrentphaseisnotacontrolonthe“after”orpost‐

deterrentphase(BomfordandO’Brien1990)duetoseasonalchangesinbackgroundbird

populationsandbehaviors,theestablishmentofcontrolsitesisimportantandallows

comparisonofdeterrentsitetrendstobackgroundtrends.Ourcontrolswerenotsurprisingin

showingoverallupwardtrendsinstarlingnumbersastheseasonprogressed,sincestarlings

typicallyfledgeseveralclutchesofyoungbirdsthroughouttheseason,whichthenjointhe

flocks(Bent1950,Elliot1964).Thustheinformationgainedfromourstudyhasmeritfor

examiningsingle‐caseeffectsofdeterrentsintheseparticularlocationsovertime,eventhough

replicationofdeterrentplotswasnotpossible.

Lackofeffectiveness,orevenapparentcounter‐effectiveness,ofaudibledistresscallers,

correspondswithpreviousresearchindicatinglimitedsuccessandgreatvariabilityofthis

technique(Johnsonetal1985,Feare1989,BomfordandO’Brien1990,Conover1994,Harris

andDavis1998).Inparticular,Conover(1994)foundthatdistresscallsareeffectiveonlyfora

shorttimeatbest,andareideallycombinedwithanactualpredator‐causedfatality,whichwas

notimplementedinourstudy.Sinceintroductionofactualnativepredatorssuchassharp‐

shinnedorCooper’shawks,merlins,orkestrelfalconswasnotconducted,thereisnowayto

measurewhetherthiscombinationofdeterrentswouldhaveworked.

ItisworthnotingthattheoperatorofthedairyfarmatwhichtheBirdGardwasplaced,

indicatedneartheendofourprojectthathehadpreviouslytriedusingaBirdGardinanearby

locationafewyearsearlier.Hefoundittobeeffectiveforatimebutdeterminedthatthe

effectivenessdecreasedtonilafterafewmonths.Itispossiblethatresidualolderbirdsfrom

thattimewerestillpresentatthetimeofourstudy,andmayhavebeenresistanttothe

BirdGardasaresult.OveralltheproblemsattheBirdGardsite,includingthemanurepump‐

out,limitconclusionsthatcanbedrawnregardingaudibledistresscallersonthissinglestudy.

Habituationofbirdstopropanecannonshasbeendocumentedinpreviousstudies

(BomfordandO’Brien1990,HarrisandDavis1998).Inourstudytherelativelyinfrequentuse


ofthecannon(firingfrequencyofnomorethan3times/hour)mayhaveincreasedthelengthof

itseffectiveperiod,ashasbeendocumentedelsewhere(HarrisandDavis1998).The

comparisonoffiringfrequencies,however,wasbeyondthescopeofthisstudy.Propane

cannoneffectivenesscanalsobeincreasedifitismovedrandomlyaroundthefieldand

combinedwithvisualdeterrentssuchasartificialpredatorsorpop‐upscarecrows(Cummingset

al1986,BomfordandO’Brien1990).Aswiththedistresscallers,however,thebestincreasein

effectivenessofcannonscomeswhentheyarecoupledwithactualpredator‐causeddeathsor

shootingdeathsofbirds(BomfordandO’Brien1990,Conover1994).Shootingisnotanoption

withinoraroundblueberryfields,however,becauseoftheriskofcontaminatingfruitwithshot.

Olderresearchhasshowncannonstobeeffectiveatleastintheshortterm(Stickleyaetal

1972,DecalestaandHayes1979,PotvinandBergeron1981).

Effectivenessofhawkkites,aswellaseventualhabituationofbirdstothekites,has

beenshownpreviously(Conover1982,1984;Nakamura1997;HarrisandDavis1998).

Increasedrandomizationofhawkkiteplacement,whichwasnotdoneinourstudy,keepspest

birdsfrombecominghabituatedtothekites.Ideallythekitesshouldbemovedfrequentlyand

irregularly,andcombinedwithotherdeterrents(BomfordandO’Brien1990,HarrisandDavis

1998).Thiswasbeyondthescopeofoursimplepilotstudybutwouldcertainlybeofinterestin

pursuingnon‐auditoryoptionsforeffectivebirdcontrol.Forexample,hawkkitesin

conjunctionwithreflectivetape,actualshootingfatalities,orfalconrymaybehighlyeffective.

Consideringthesimplicityofourexperimentwiththehawkkite,itssuccessinthislocalewas

remarkable.

Successofanytechnique,whetherauditory(distresscaller,cannon)orvisual(hawk

kites,reflectivetape)isdependentontheattentivenessandskilloftheoperatorandrequires

randomizationofintervals,location,andcombinationsoftechnique(BomfordandO’Brien

1990,HarrisandDavis1998).Ourresultsagreewithlarge‐scalesurveysofvarioustechniques

thatrankeffectiveness(Table1).Professionalfalconry,conductedbyanexpertfalconeronsite

throughoutdaylighthours,isavirtualguaranteeofeliminatingbirddamage(HarrisandDavis

1998).Howeverthisisanexpensivealternative.Aclearunderstandingofbirdbiologyand

habitatrelatedtotheuniquenessofeachindividualsite,asprovidedbyaprofessionalbiologist,


isanimportantsteptoeffectivebirdcontrol.Habitatrecommendations,suchasprovisionof

predatorperchsitesandnestboxes,canthenbeimplemented(HarrisandDavis1998).

Table1.Summaryofeffectivenessofbirdcontroltechniques

Not recommended Limited recommendation Highly recommended High intensity, infra- or ultra-sound

Hawk kites and other visual predator simulations

Habitat modification to encourage natural predators such as birds of prey

Lasers Distress and predator callers such as BirdGard

Falconry

Lights Propane cannons Active shooting of pest birds

Microwaves Reflective tape Habitat modification to discourage pest birds

Smoke Scarecrows Netting, when feasible (as in small, handpicked fields)

(adaptedprimarilyfromHarrisandDavis1998.Recommendationsandeffectivenessarebasedon operationbyskilledpersonnelwithanunderstandingofbiologyofbothpestandpredatorbirds) .

Thebestpossibledeterrentforpestbirdsisnaturalpresenceofnativepredatorbirds

(FlintandDreistadt1998,Daly2002,Steensma2008),whichmayexplaintherelative

effectivenessofthehawkkitehere.SeveralstudieshaveshownthattheAmericankestrel

(Falcosparverius)caneffectivelypreyon,orterritoriallydefendagainst,theEuropeanstarling

(Balgooyen1976,Ashkam1990,Village1990,Suhonenetal.1994,BechardandBechard1996,

Parrish2000,Dover2008).AsthekestrelisnativetothePacificNorthwestbutdecliningin

numbersinWesternWashingtonandtheBCLowerMainlandoverthepast20years(Wahl

1995,Ireland2008;Pike2008),enhancementofnesting,foragingandperchinghabitatforthis

speciescouldprovidealow‐costalternativecontrolmeasureagainststarlings(TolandandElder

1987,DawsonandBortolotti2000,Valdezetal2007).Apilotkestrelreleaseprogramhas

showninitialsuccessinWashingtonState(Steensma2008)andisplannedforexpansioninto

BritishColumbia.


SummaryandRecommendations Basedonbothourliteratureandfieldresearch,wewouldsummarizeandmakethe

followingpreliminaryrecommendationsregardingbirddeterrenttechniques:

• BirddistresscallerssuchastheBirdGardmaybeeffectiveinsomesituationsbutwere

notshowntobeofuseinthisparticularsettingandapplicationduetositeproblems

• Propanecannonscanbeofuseinshorter‐termapplications

• Hawkkitescanbeofuseinshorter‐termapplications

• Combinationsofaudibledistresstechniquesandactualshootingofpestbirdsare

moreeffectivethanaudibledistressalone.Shootingisnotanoptionwithinor

adjacenttoblueberryfields,however,duetotheriskofcontaminatingfruitwithshot.

• Hawkkitesincombinationwithactualshootingorpredator‐causedfatalitiesaremore

effectivethanhawkkitesalone

• Alloftheabovetechniquesareenhancedthroughrandomizationand

combination/integrationofaudibleandvisualdevices

• Falconryandpresenceofnaturalpredatorsareconsideredhighlyeffectivedeterrents

• Enhancementofnativebirdsofpreythroughhabitatimprovement,andreleaseof

youngbirdsofpreyshouldbeatoppriorityforcost‐effectivebirdcontrolresearch

Acknowledgments

ThisstudywasmadepossiblebyajointgrantfromtheBritishColumbiaMinistryofAgricultureandtheFraserValleyRegionalDistrict,andspecialthanksaregiventoDirectorDickBogstieandMs.SiriBertelsonofFVRD,andtoMr.MarkSweeneyandMr.BertvanDalfsenofMAL.Wearegratefulforthegraciousnessofthefollowingfarmsinallowingourpresenceduringthecourseofthestudy:CedarwalFarms,DriessenFarms,BosSod,MeierDairy,LuymesDairy,andKielstraDairy.TheassistanceofMr.MarkSweeneyinobtainingplywoodandfeedwasverymuchappreciated.Theco‐operationofHi‐TechDistributorsinprovidingandsettingupthedeterrentdeviceswasappreciated.Ms.MelissaOakesofTWUandARochaCanadaprovidedbudgetoversightandDr.TracyStobbeoftheTWUSchoolofBusinessconsultedonthestatisticalanalysis.Mr.PatrickLilleyofRaincoastAppliedEcologyandMr.GlenCarlsonofARochaCanadaprovidedinitialadviceonstudydesign.Finally,variousmembersofourfamiliesprovidedcompanyonsurveydaysandpatiencethroughouttheprocess.


Literaturecited

Askham,L.R.1990.Effectofartificialperchesandnestsinattractingraptorstoorchards.ProceedingsfromtheFourteenthVertebratePestConferenceinLincoln,Nebraska. BalgooyenT.G.1976.BehaviorandecologyoftheAmericankestrel[dissertation].Berkeley,California:UniversityofCalifornia. BechardM.J.andJ.M.Bechard.1996.CompetitionfornestboxesbetweenAmericankestrelsandEuropeanstarlingsinanagriculturalareaofsouthernIdaho.In:Raptorsinhumanlandscapes.1sted.SanDiego,California:AcademicPressInc. BentC.1950.LifehistoriesofNorthAmericanwagtails,shrikes,vireos,andtheirallies.U.S.NationalMuseumBulletin197. Bomford,M.1990.Ineffectivenessofasonicdevicefordeterringstarlings.WildlifeSocietyBulletin. Bomford,M.andO’BrienP.1990.Sonicdeterrentsinbirddamagecontrol:areviewofdevicetestsandeffectiveness.WildlifeSocietyBulletin18:411–422. Conover,M.R.1994.Howbirdsinterpretdistresscalls:implicationsofappliedusesofdistresscallplaybacks.Proc.SixteenthAnnualVertebratePestConference.Lincoln,Nebraska. CurrieF.A.,D.ElgyandS.J.Petty.1977.StarlingRoostDispersalfromWoodlands.ForestryCommissionLeaflet69. DalyM.A.2002.AmericanKestrel:TheBarnyardFriend.CollegePark,Maryland:UniversityofMarylandCooperativeExtension. DawsonD.R.andG.R.Bortolotti.2000.ReproductivesuccessofAmericanKestrels:theroleofpreyabundanceandweather.Condor102:814‐822. DoverB.S.2008.Owner,OrchardGuard,Yakima,Washington.Personalcommunication. ElliotH.N.1964.StarlingsinthePacificNorthwest.VertebratePestConferenceProceedingsCollection:Proceedingsofthe2ndVertebratePestControlConference,U.S.BureauofSportFisheriesandWildlife,Portland,Oregon. FeareC.1984.TheStarling.Oxford,England:OxfordUniversityPress. FlintM.L.andS.H.Dreistadt.1998.Naturalenemieshandbook.Berkeley,California:UniversityofCaliforniaPress.


GilkesonL.A.andR.W.Adams.1996.IntegratedpestmanagementforstructuralpestsinBritishColumbia.4thed.Vancouver,BritishColumbia:BritishColumbiaMinistryofEnvironment,Land,andParks;PollutionPreventionandPesticideManagementBranch. GilkesonL.A.andR.W.Adams.2000.IntegratedpestmanagementmanualforlandscapepestsinBritishColumbia.3rded.Vancouver,BritishColumbia:BritishColumbiaMinistryofEnvironment,LandsandParks;PollutionPreventionandRemediationBranch GoughR.E.1994.Thehighbushblueberryanditsmanagement.1sted.NewYork,NewYork:FoodProductsPress. HarrisR.E.andR.A.Davis.1998.Evaluationoftheefficacyofproductsandtechniquesforairportbirdcontrol.LGLLimitedforAerodromeSafetyBranch,TransportCanada. HolmesE.L.1993.Responsesofwinteringgrasslandraptorstohumandisturbance.WildlifeSocietyBulletin21:461‐468. Ireland,J.2008.Director,ReifelBirdSanctuary,Delta,BC.Personalcommunication. Johnson,R.J.,P.H.Cole,andW.W.Stroup.1985.Starlingresponsetothreeauditorystimuli.J.WildlifeManagement49:620‐625. JohnsonR.J.andJ.F.Glahn.1994.Preventionandcontrolofwildlifedamage:Europeanstarlings.In:WildlifeDamageManagementHandbook.2nded.Lincoln,Nebraska:UniversityofNebraska. Nakamura,K.1997.EstimationofEffectiveAreaofBirdScarers.J.WildlifeManagement.61(3):925‐934 NorrisR.F.,E.P.Caswell‐ChenandM.Kogan,editors.2003.Conceptsinintegratedpestmanagement.1sted.UpperSaddleRiver,NewJersey:PrenticeHall. ParrishJ.W.2000.PossiblepreventionofEuropeanstarlingnestingbySoutheasternAmericanKestrelsatapowersubstationinsouthernGeorgia.J.RaptorResearch34:152. PikeD.2008.MasterFalconer,Lynden,Washington.Personalcommunication. PrittsM.P.andJ.F.Hancock,editors.1992.Highbushblueberryproductionguide.1sted.Ithaca,NewYork:NortheastRegionalAgriculturalEngineeringService. Steensma,K.M.M.2008.AdvancesinbirddeterrentmethodsforagriculturalareasofsouthwestBritishColumbiaandnorthwestWashington.Invitedpresentation,WSUWesternWashingtonSmallFruitWorkshop,Dec.16,Lynden,Washington.


Steensma,K.M.M.,B.DoverandK.Hartline.2007.Useofkestrelsforbiologicalcontrolofstarlingsonfruitanddairyfarms.Invitedpresentation,WSUWesternWashingtonSmallFruitWorkshop,Dec.5,Lynden,Washington. SuhonenJ.,K.Norrdahl,andE.Korpimaki.1994.Avianpredationriskmodifiesbreedingbirdcommunityonafarmlandarea.Ecology75(6):1626‐34. Sweeney,M.2003.AnoverviewoftheBChighbushblueberryindustry.Abbotsford,BritishColumbia:BritishColumbiaMinistryofAgriculture,FoodandFisheries,IndustryCompetitivenessBranch. TolandB.T.andW.H.Elder.1987.Influenceofnest‐boxplacementonabundanceandproductivityofAmericanKestrelsincentralMissouri.WilsonBull.99:712‐17. ValdezU.,S.Robertson,B.RobertsonandK.L.Bildstein.2007.NestboxusebyAmericankestrels(Falcosparverius)andEuropeanstarlings(Sturnusvulgaris)ineasternPennsylvania.PennsylvaniaBirds14(3):150‐53. VillageA.1990.Thekestrel.London,England:TandAPoyser. Wahl,T.R.1995.BirdsofWhatcomCounty:statusanddistribution.Bellingham,WA:TRWahl.184pp. WhatcomFarmFriends.2008.Starlingcontrol.FebruaryFarmFlash.


Appendix1.Landownercontactletter 30 June 2008 To: Select landowners in the Sumas Prairie area As you are likely aware, the presence of starlings has increased in our area in recent years. The resulting damage to farm crops, and the efforts to deter these birds through various devices such as propane cannons and other means have created some controversy in the community. The Ministry of Agriculture and the Fraser Valley Regional District have commissioned me to carry out a study this summer, to survey the overall bird population in the Sumas Prairie area, and to test the usefulness of several starling deterrent techniques. Assisted by senior-level Trinity Western University environmental studies and biology students, and by volunteers with specific expertise on starlings, I will undertake the following approach:

• Identify locations in which starlings are particularly numerous • Deliberately create feeding stations to attract starlings regularly • Count numbers of starlings frequenting the stations • Introduce various deterrent techniques to some of the feeding stations • Continue to count starling numbers at all stations through September • Analyze results statistically to determine effectiveness of these deterrents

This is a pilot study, and part of a larger overall study in the Fraser Valley and northwest Washington State, that is seeking solutions to starling problems. The goal is to identify solutions that are workable for farmers, farm neighbors, and the natural environment. Your land may provide a suitable location for one of the feeding stations, if you are willing to participate in this research. If you are interested in allowing us space for the project, we will attempt to minimize disruption to your property, and the study will be concluded by mid- to late September. Thank you for your consideration, and please feel free to contact me with any questions. Karen M.M. Steensma Assistant Professor of Biology Co-director, Environmental Studies Program [email protected] Other partners: BC Blueberry Council, Whatcom Farm Friends, Washington Department of Fish and Wildlife, Washington State University Cooperative Extension, A Rocha Canada & USA, and various BC & Washington dairy and blueberry farmers

7600 Glover Road Langley, BC V2Y 1Y1 Canada Tel: (604) 888-7511


Appendix2.Sampledatacollectionsheets Luymes Time:9:21am Weather:Grayskies,coolbreeze FeedAdded?None Table7:AvianObservationonJuly23rd2008

Species Number OtherObservationsLatinName

CommonName

Onfeed

Withina100mradius

HouseSparrow 0 12

RockPigeon 0 3

Robin 0 1

EuropeanStarling 0 25

Nobirdsseenonfeed.Allblueberriesarestillpresentonfeed.

Kielstra Time:7:50am Weather:Cold,cloudy,noprecipitation FeedAdded?None Table13:AvianObservationonJuly31st2008

Species Number OtherObservations

LatinName CommonName Onfeed Withina100mradius

EuropeanStarling 0 102

FemaleBrewer'sBlackbird 0 2

RockPigeon 0 18

HouseSparrow 0 3

Cannonfired,birdsfledyetwithinaminuteofthelastblastbirdsreturned(20returnedtothepowerline)


Appendix3.Summaryoft‐testvaluesfortimeperiodsshowninFigs.2,3,4

Characteristics of starling populations at deterrent and control sites throughout the experiment

Deterrent status (time period) mean ± SE

Test statistic df p*

Site Deterrent Control

Off (1) 41.1 ± 18.0 12.6 ± 6.4 1.55 5 0.18 Off (2) 52.1 ± 19.8 23.6 ± 10.9 1.37 6 0.22 On (3) 10.1 ± 7.4 27.5 ± 8.7 -1.93 14 0.07 On (4) 4.7 ± 1.8 42.6 ± 16.3 -3.96 21 0.00 On (5) 18.1 ± 7.1 69.3 ± 34.9 -2.33 19 0.03 On (6) 42.8 ± 16.8 69.7 ± 42.3 -0.91 13 0.38 Off (7) 57.8 ± 14.6 94.4 ± 46.4 -1.20 22 0.24

Kite

Off (8) 58.2 ± 18.3 82.7 ± 34.1 -0.91 17 0.38

Off (1) 21.2 ± 9.2 12.6 ± 6.4 0.86 7 0.42 Off (2) 62.1 ± 18.2 23.6 ± 10.9 2.00 6 0.09 On (3) 55.0 ± 21.2 27.5 ± 8.7 1.26 8 0.24 On (4) 13.4 ± 4.4 42.6 ± 16.3 -2.81 26 0.01 On (5) 43.2 ± 14.7 69.3 ± 34.9 -1.03 20 0.32 On (6) 28.5 ± 8.0 69.7 ± 42.3 -1.60 13 0.13 Off (7) 60.0 ± 14.8 94.4 ± 46.4 -1.12 22 0.27

Cannon

Off (8) 75.8 ± 27.6 82.7 ± 34.1 -0.21 11 0.84

Off (1) 56.2 ± 19.7 12.6 ± 6.4 2.17 5 0.08 Off (2) 87.8 ± 8.7 23.6 ± 10.9 5.99 11 0.00 On (3) 67.8 ± 15.9 27.5 ± 8.7 2.42 9 0.04 On (4) 115.0 ± 16.9 42.6 ± 16.3 3.74 10 0.00 On (5) 60.9 ± 17.2 69.3 ± 34.9 -0.31 18 0.76 Off (6) 23.4 ± 21.2 69.7 ± 42.3 -1.43 11 0.18 Off (7) 10.8 ± 3.8 94.4 ± 46.4 -3.09 18 0.01

Bird Guard

Off (8) 7.6 ± 3.0 82.7 ± 34.1 -3.77 18 0.00 *Values bolded if p ≤ 0.05; indicates significant difference between deterrent and control means.

Efficacy of bird deterrent devices in agricultural areas ... · 1994). Starlings can be found in flocks of up to 1.5 million birds and cause an ... Rocha intern Becky Kern conducted

Documents