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Batsof
Thickson’sWoodsPilotStudyandPublicEducationProgram
2015FinalReport
TobyJ.Thorne,NigelParr,andJessicaKroes
©2016MattHolderEnvironmentalEducationFund
PublishedbyHawkOwlPublishing
SummaryIn2015,apilotbatstudywasconductedattheThickson’sWoodsNatureReserveundertheauspices
oftheMattHolderEnvironmentalEducationFund.Thegoalsofthisprojectweretolearnaboutbats
intheReserveandtoengagethepublicinbatconservation.Aseriesofpublicwalkswasconducted,
withsimultaneous,formalisedacoustictransectsconductedbyvolunteer,JessicaKroes,approximately
weeklyfromJunethroughAugust2015.
AtotaloffivespecieswasidentifiedwithintheReserve.ThemostnumerousbatswereBigBrownor
Silver-haired(305sequences),twospecieswithhighlyoverlappingcallrepertoiresthataredifficultto
distinguish.SecondmostnumerouswereEasternRedBats(66sequences).Otherspeciesidentified
wereHoary,LittleBrown,andTri-coloredBats.
Batsweredetectedthroughoutthesurveyperiod,indicatingthatThickson’sWoodsisavaluablesite
foratleastBigBrown,Silver-haired,andEasternRedBats.HoaryBatsweredetectedinlownumbers
during formal surveys, but were repeatedly observed informally during public events, suggesting
theymayalsomakeuseofthesite.ThepresenceofLittleBrownandTri-coloredBats,bothrareand
threatened species, is significant despite the low numbers. Public engagement efforts were highly
successful,withatotalof180peopleattendingaseriesofeventsthroughtheyeartolistentotalks
aboutbatecologyandtoseenativebatsinflight.
Weplantocontinuethisprojectin2016,toincludefurtherpubliceventsandrepetitionoftheformal
transects, incorporating lessons learned in2015.Wewillalsoexplorepossibilitiesofexpanding the
projectwiththeuseofastaticdetectorandcapturesurveys.
ThankstoThickson’sWoodsLandTrustBoard
membersforsupportingtheongoingresearch.
Limitations:Ecologicalassessmentsprovideasnapshotofasiteataparticulartime.Observationscanbeusedtodraw
conclusionsastothelikelypresenceorabsenceofspeciesandtheiruseofthesite.Itisneitherdefinitivenorcomplete.
Seasonality,weatherconditionsandintra-sitevariationmayalsoaffectsurveyresults.
FormoreinformationaboutThickson’sWoodsandtheprogramsofferedby
theMattHolderEnvironmentalEducationFundgotowww.mattholderfund.com
Coverillustration:BigBrownBat(Eptesicusfuscus)onatree.©TobyThorne2014
1
Thickson’s Woods Land Trustbox 541,Whitby,OntarioL1N 5V3
www.thicksonswoods.com
1. Introduction 3
1.1. Objectives 3
1.2. StudySite 3
2. Methodology 5
2.1. DataCollection 5
2.2. DataAnalysis 5
3. Results 6
3.1. Surveys 6
3.2. DataSummary 6
3.3. EnvironmentalCorrelates 6
4. SpeciesDiscussion 8
4.1. BigbrownandSilver-hairedBats 8
4.2. EasternRedBat 9
4.3. HoaryBat 9
4.4. OtherSpecies 9
5. Outreach 9
5.1. PublicBatWalks 9
5.2. OtherEvents 10
6. Publications 11
6.1. Bats:AConservationGuide 11
6.2. BatsofOntario 11
7. FutureDirections 12
7.1. Qualityofrecordings 12
7.2. Transect 12
7.3. Staticmonitoring 12
7.4. Captureofbats 13
8. Appendix–EnvironmentalCorrelates 13
8.1. EnvironmentalCorrelates 13
2
1. Introduction
1.1.Objectives
1.1.1. ToinventorybatspeciespresentinThickson’sWoods,theadjoiningmeadowand
immediatesurroundings.
1.1.2. TolocateareasofhighbatactivitywithintheReserve.
1.1.3. Tomonitorseasonalvariationinspeciespresenceandactivity.
1.1.4. Toengagemembersofthepublicandpromoteinbatecologyandconservation.
1.2.StudySite
1.2.1. Thickson’sWoodsNatureReserveisaprivately-ownedconservationarealocatedon
thenorthshoreofLakeOntarioinWhitby,Ontario,ontheeasternoutskirtsofthe
GreaterTorontoArea(GTA).Thickson’sWoodsinitiallyconsistedofa6.9hectareold-
growth,mixed-specieswoodlotcontainingpine,beech,aspen,birch,poplar,oak,and
maple.Thewoodlotwaspurchasedin1983bytheThickson’sWoodsLandTrust,which
wasformedforthispurpose.TheReservewasexpandedin2001withthepurchaseof
anadjacent3.2hectaremeadowtothenorthofthewoods.Asmallwaterway,Corbett
Creek,flowsthroughthemeadowbeforeemptyingintoamedium-sized,open-water
wetlandtotheeastofthemeadowandwoodlot
1.2.2. ThecloseproximityoftheThickson’sWoodsNatureReservetothehighlypopulated
GTAresultsinrelativelyhighnumbersofvisitorstotheReserve,whichhasmultiple
publictrailsandisapopularsitewithnaturalists.Themajorityofinterestinwildlifeat
theReservehasfocusedonitsavifauna,inparticulartheprevalenceofrarerbird
speciestravellingalongthelakeshoreduringmigrationperiods.Atvariouspointsinthe
historyoftheReserve,attentionhasalsobeenpaidtosomeotheraspectsoftheflora
andfaunaofthewoodsandmeadow.
1.2.3. Tothebestofourknowledge,noparticularattentionhaspreviouslybeenpaidtobats
inThickson’sWoods,beyondtheobservationsoflocalresidents,severalofwhomhave
foundbatsroostingwithintheirproperties.
TheMattHolderEnvironmentalEducationFundwasestablishedtofindandencourageyoungpeople
withaninterestinthenaturalworld,andiscurrentlyfocusedonprojectswithintheThickson’sWoods
NatureReserve.Batswereidentifiedasagrouponwhichtofocusin2015.Well-attendedpublicevents
wereheldapproximatelymonthlythroughoutthesummer,educatingattendeesaboutbatbiology,and
assistingtheminwatchingandlisteningtobatsaroundthewoods.Additionally,moreformalsurveys
wereestablishedtomoreaccuratelyquantifybatactivityintheReserve.Thisreportsummarisesthe
methodologyandresultsofthesesurveys.
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Thickson Bay
Thickson Point
Thickson’s Woods
The Meadow
Camp X
Waterfront Trail
Corbett Creek Marsh
Waterfront Trail
Wentworth Street
Thic
kson
Roa
dC
orbe
tt C
reek
Thickson’s Wood Nature Reserve
Aerial view of Thickson’s Woods Reserve and surrounding area
4
2. Methodology
2.1.DataCollection
2.1.1. Batactivitywasmonitoredonanapproximatelyweeklybasisthroughthemonthsof
June,July,andAugust.SamplingbeganonJune10,2015andwasconcludedon
August21,2015.
2.1.2. Transectswerenotclearlydelineated,howeverthreeconsistentsurveylocations;
outlinedinFigure1,includedthemeadow(Zone17NEasting:669017Northing:
4857859),theintersectionoftheWaterfrontTrailandCorbettCreek(Zone17NEasting:
669180Northing:4857894),andthesoutheastcorneroftheThickson’sWoodstrail
atitsjunctionwithMcIntoshAvenue(Zone17NEasting:669163Northing:4857691).
Additionalsurveylocationswereaddedeverysurveynightwhenhighlevelsofbat
activitywerefound.Theseincluded,butwerenotlimitedto,theintersectionofCrystal
BeachRoadandMcIntoshAvenue(17NEasting:669195Northing:4857600),Crystal
BeachRoadandCorbettAvenue(17NEasting:669064Northing:4857515),andthe
southwestcorneroftheThickson’sWoodstrailatitsjunctionwithCorbettAvenue.
2.1.3. Temperature,relativehumidity,andpercentmoonilluminationwasrecordedhalfan
houraftersundownatthebeginningofeachfieldvisit.Volunteersstoppedateach
surveylocationforadurationoffiveminuteswiththebatdetectorprogramedto“auto
record”.Additionally,“autorecording”continuedbetweenprimarysurveylocations.Ifa
batwasdetectedthesurveyorwouldstopforoneminuteoruntilactivityceased.
Surveyswerenotcompletedifhighwindsorprecipitationpersisted.
2.1.4. BatecholocationsoundswererecordedusinganEchoMeterTouchultrasonic
microphonemodule(WildlifeAcoustics,U.S.A.)attachedtoaniPadMini.
RecordingwascontrolledusingtheWildlifeAcoustics‘EchoMeterTouchBatDetector’
applications(versions1.1–1.7)runningoniOS.Theappwassettoautomatically
triggerrecordings.Recordingsweresavedas.wavfilesfordataanalysis.
2.2.DataAnalysis:
2.2.1. Followingthecompletionofall2015surveys,thedatawerecollatedforspecies
identificationandanalysis.Manyfilescontainedextraneousnoise,oftencausedbythe
surveyormovingthroughgroundcover,anddidnotcontaininformationofinterest.
Inordertoreducetimespentonfurtheranalyses,thedatawerefirstfilteredusing
softwaretoautomaticallyidentifyfilescontainingpotentialbatsignals(SonobatBatch
Scrubber5.4;settings:highgrade,excludecalls<20kHz).
2.2.2 Filespassedbythefilterwerethensubjectedtomanualreview.Fileswerevisualised
asspectrogramsandparametersweremeasured(Sonobat4.0.5Base).Auralreview
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wasalsoconductedwherenecessary.Wherenobatsignalswerepresent,thefilewas
markedas‘noise’.Wherebatsignalscouldbediscernedbutnotidentifiedtospeciesthe
filewasmarkedas‘unidentifiedbat’.Otherwisethecallspresentwereidentifiedto
speciesorspeciesgroup.ThemajorityofBigBrownandSilver-hairedBatcallswere
groupedintoasinglecategoryduetothelargeoverlapincallparametersbythese
species.Similarly,callsbyMyotisspecieswerecombinedintoasinglecategorydueto
thelargeroverlapbythesespecies.
3. Results
3.1.Surveys:
3.1.1. Atotalof8surveyswereconductedin2015.Thesearesummarisedintable1.
3.2.DataSummary:
Atotalof3932ultrasonicsoundfileswererecordedacross8nights.Automaticfiltering
identified1248filesthatcontainedpotentialbatsignals.Manualanalysisshowedthat
afurther785ofthesefilescontainedonlyextraneousnoise.Theremaining463filesare
summarisedinTable2,andinFigures1and2.
3.3.EnvironmentalCorrelates
3.3.1. Avarietyofenvironmentalconditionswererecorded,andarediscussedinthe
appendix.
Table1:Summaryofsurveysconducted,withtimingsandlocalweatherconditions
SurveyStart
SurveyDuration(Mins)
MoonIllumination
%
AirTemperature
0C
RelativeHumidity
%
CloudCover
%
WindSpeedkm/hr
WindDirection
Big Brownor Silver-
hairedpasses per
min.
Red BatPasses per
min.
Total batPassesper min.
2015
June 10
June 25
July 2
July 9
July 23
July 29
Aug 8
Aug 21
21:16
21:15
21:43
21:26
21:43
21:36
20:50
21:35
33
14
46
47
56
31
115
44
39
61
100
41
45
96
33
39
18
15
16
17
21
24
18
16
72
89
63
88
46
85
73
86
100
0
50
0
75
33
3
9
3
12
4
N/A
3
NW
S
NNW
SW
NNW
SE
N/A
W
0.06
0.21
1.02
2.28
0.73
0.18
0.60
0.68
-
0.36
0.11
0.13
0.05
1.03
0.11
-
0.30
0.57
1.43
2.43
0.89
1.36
0.89
1.02
6
Table2:Speciestotalbysurveynight.
2015 June 10 June 25 July 2 July 9 July 23 July 29 Aug 8 Aug 21 Grand Total
Big Brown Bat
Big Brown or Silver-haired Bat
Eastern Red Bat
Hoary Bat
Little Brown Bat
Tri-colored Bat
Unidentified Bat
Grand Total
-
2
-
5
-
3
10
-
3
5
-
-
-
8
-
47
5
-
-
14
66
-
107
6
-
1
45
114
1
41
3
-
-
5
50
-
6
34
-
2
3
45
-
69
13
2
-
18
100
-
30
-
-
-
1
14
45
1
305
66
7
3
1
100
485
Figure 1: Breakdon of total bat sequences recorded by species
0%
63% 14%
1% 1%
0%
21%
Big brown bat
Big Brown or Silver Haired
Eastern red bat
Hoary bat
Little brown bat
Tri-colored bat
Unidentified Bat
Figure1:Breakdownoftotalbatsequencesrecordedbyspecies
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Big Brown BatBig Brown or Silver-haired BatsEastern Red BatHoary BatLittle Brown BatTri-colored BatUnidentified bat
Figure 2: Breakdon of total bat sequences recorded by species by survey
0
20
40
60
80
100
120
140
160
180
6/10/15 6/25/15 7/2/15 7/9/15 7/23/15 7/29/15 8/8/15 8/21/15
Unidentified Bat
Tri-Colored Bat
Myotis Species
Hoary Bat
Eastern Red Bat
Big Brown or Silver-Haired Bat
Big Brown Bat
Figure2:Breakdownoftotalbatsequencesrecordedbyspeciesbysurvey
4. SpeciesDiscussion
4.1.BigBrownandSilver-hairedBats
4.1.1. BothBigBrownBatsandSilver-hairedBatsarewidespreadinOntario.Thedifficulty
inseparatingthesespeciesviaacousticanalysisleadstodifficultyininterpretingour
data,confoundedbytheirdifferingecology.However,thepresenceofalargenumber
ofsignalsfromthisspeciesgroupisconsistentwithothersitesacrosssouthernOntario
wheretheyaccountforthemajorityofbatsencountered.Bothspeciesarelargerbats
andpredominantlyforageinopenspacesclosetocover.Bothspeciesalsoroostreadily
intrees,althoughBigBrownBatsoftenroostasgroupswhereasSilver-hairedBatsare
typicallysolitary.
4.1.2. Itislikelythatalargeproportionofthesignalsrecordedfromthisspeciesgroupare
fromBigBrownBats,whichareknowntoroostinnearbybuildings.However,incidental
observationsoutsidethedatacoveredbythisreportsuggestthatSilver-hairedBatsare
alsopresent.Capturesurveyswouldbethemostdefinitivemeanstoconfirmthe
presenceofbothspeciesandattempttoquantifyrelativeabundance,although
abundancemightvaryseasonallyduetomigrationbySilver-hairedBats.
4.1.3. FurtherinvestigationisrequiredtodetermineatruerelationshipbetweenBigBrown/
Silver-hairedBatactivityandcloudcover.
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Unidentified batTri-colored BatMyotis SpeciesHoary BatEastern Red BatBig Brown or Silver-haired BatsBig Brown Bat
4.2. EasternRedBat
4.2.1. ThisspeciesiswidespreadacrosssouthernOntario.Publishedreferencesfrequently
refertoitasaruralspecieslesscommonlyencounteredinurbanareas.However,this
claimlackssubstantiationandEasternRedBatsareincreasinglyencounteredaturban
sites.Forexample,unpublisheddatafromT.Thorneindicatesasignificantpresenceof
EasternRedBatsincentralTorontoin2015.
4.2.2. EasternRedBatstypicallyroostaloneintrees.Theirroostscanbedifficulttoidentifyor
protect,butitishighlypossiblethatthisspeciesmayroostinoraroundThickson’s
Woods.
4.2.3. AlthoughourEasternRedBatdatasetseemstobeheavilyinfluencedbyasingle
surveynightwithuncharacteristicallyhighEasternRedBatactivity,therelationships
betweenairtemperature,moonphase,andbatactivitywarrantfurtherinvestigation.
4.3.HoaryBat
4.3.1. HoaryBatsareanotherwidespreadspeciesinsouthernOntario.Theyarereliably
observedforagingalongthelakeshoretotheimmediatesouthofthewoods.Itis
surprisingthatHoaryBatsarelessfrequentlyencounteredinthetransectdata.This
mightreflectthedesignofthetransectoranotheraspectofthemethodologyandshould
berevisitedbeforedrawingfurtherconclusionsaboutthisspecies.
4.4.OtherSpecies
AsmallnumberofsignalsofMyotisspecieswerealsorecorded.Thesecallswere
relativelyshortinlengthandoflimitedquality,whichprecludedidentificationto
specieslevel.AllMyotisspeciesareprovinciallyendangeredandareprotectedas
SpeciesatRisk.AlthoughthenumbersrecordedatThickson’swerelow,thepresenceof
Myotisbatssuggestsfurtherinvestigationcouldbeworthwhile,withfurthersurveys
targetedtothesespeciestoevaluatetheiractivityatthissite.
5. Outreach
5.1.PublicBatWalks
5.1.1. WeheldourfirstpublicbatwalkandbatmonitoringdemonstrationonApril30,2015.
Throughoutthespringandsummerwehosted5publicbatwalksatThickson’sWoods.
Thecombinedattendanceforthebatwalkswas180.Attendanceduringtheseevents
increasedthroughouttheseasonandweanticipategreaterturnoutswhenwerestartthe
publicwalksin2016.
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A cool night on April 30th for our first Bat Walk
5.2. OtherEvents
1.2.1. WepromotedlocalbatconservationduringtheThickson’sWoodsLandTrustannualFall
FestivalinSeptember2015.InconjunctionwiththeOntarioSpecializedSpeciesCentre
wedisplayedtwospeciesofbatsatourboothduringthedaytimeandledapublicbat
walkintheevening.Ourexhibitwaspopular,reachingafurther600peopleduringthe
festival.
Our Booth exhibiting live bats was well attended at the Thickson’s Woods Fall Nature Festival
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Visitors to our booth got to touch live bat wings
6. Publications
6.1.Bats:AConservationGuide
6.1.1. IncollaborationwiththeTorontoZoo’sConservation,EducationandWildlifedivision,
wepublishedBats:AConservationGuide.This32pagebookletincludesinformation
aboutthebatsofEasternCanada,tipsforattractingbatstoyourproperty,blueprintsfor
theconstructionofbatboxes.Thisbookletalsoaimstodispelthemythsaboutbats
thathaveledtotheirpersecution.
6.2.BatsofOntario
6.2.1. In2016wewillpublishBatsofOntariobyTobyThorne,acomprehensiveguide
tothe8speciesofbatsthatoccurinOntario.Thisguidealsoincludeinformationon
ecolocationwithsonogramsandisfullyillustratedwithphotographsandlife-sizeartwork
byFionaReid.
Available from www.mattholderfund.com
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7. FutureDirections
7.1.Qualityofrecordings:
7.1.1. Analysisofourrecordingsrevealedmultiplequalityissues.Mostextraneousnoise
appearedtoresulteitherdirectlyfromsurveyornoise,e.g.clothesrustling,brushing
againstthemicrophoneenclosure,orasindirectsurveyornoise,e.g.noisefrommoving
throughlonggrassandundergrowth
7.1.2. Toaddresstheseissueswewilldevelopanimprovedprotocolforvolunteersurveyors,
informationaboutminimisingsurveyornoise.
7.2.Transect:
7.2.1. Multipleissueswereencounteredwithtransectsin2015,inparticulartheidentification
ofasuitablerouteandasuitablemethodologyforpausingatlisteningpoints.Attempts
toaddresstheseissuesledtovariabilityinthemethodologyofthesurveys,butwe
consideredthesevariationsjustifiedinordertomaximisesurveyeffectiveness.
7.2.2. Inthe2016surveys,wewilluseinformationfrom2015todevelopafixedtransectroute
thatwillbesurveyedconsistentlythroughouttheseason.Wewillinvestigatethe
possibilityofproducingaGPStrackfileorplacingphysicalwaymarkersforvolunteers
conductingtransects.
7.2.3. In2015transectswereconductedonanapproximatelyweeklybasis,withsome
variation.In2016wewilltrytoschedulemoreconsistentsurveys,subjecttovolunteer
availability.
7.2.4. ItistooearlythedeterminethelongtermviabilityoftransectsatThickson’sWoods,
eitherintermsofthevalueofdataprovidedortheavailabilityofinterestedvolunteers
toconductsurveys.Wewillaimtoconductacomprehensivetransectsurveyprogramin
2016,followedbyareviewofitseffectivenessandlong-termviability.
7.3.Staticmonitoring:
7.3.1. Followingtheinformationgainedfromtransectsandotheracousticmonitoringin2015,
inparticularthepresenceofMyotisspeciesandpossibleTri-coloredBat,increased
monitoringwithastaticbatdetectorwouldbeanidealexpansionofmonitoring.
7.3.2. Astaticbatdetectorwouldbedeployedtoautomaticallymonitorandrecordbat
echolocationatafixedpointintheReservethroughouttheseason.
7.3.3. Theprimarylimitationtousingastaticdetectoristhecostoftheequipment.Atthetime
ofwritingweawaittheresultsofagrantapplicationtoincludethecostofadeviceand
dataanalysistime.Ifthisgrantisnotsuccessful,otheravenueswillbeexplored.
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7.4. Captureofbats:
Toconfirmacousticspeciesidentifications,particularlyforthemoredifficultspecies,
havinganindividualinthehandisthemostreliableoption.Unlessroostsareknown,
thisisbestdonebycapturingbatsinflight,butdoingsorequiresanMNRFpermit.A
permitapplication,includingThickson’sWoods,iscurrentlyunderwayandthisoptionwill
beexploredfurtherdependingonthesuccessofthisapplication.
8. Appendix:
8.1.EnvironmentalCorrelates
8.1.1. Avarietyoflocalclimaticconditionsareknownorbelievedtoaffectbatactivity.We
recordedavarietyofenvironmentalcorrelatesofpotentialinterestatthetimesofthe
surveys.Thesearesummarisedintable1.Oursmallsamplesizemakesitimpossibleto
drawfirmconclusionsabouttheeffectofthesefactors,andweconsiderthisa
preliminaryinvestigationtobeaddressedinmoredetail,forexamplewithdatafroma
staticdetector.
8.1.2. Airtemperature:preliminaryresultssuggestthatRedBatsaremoreactiveduring
warmertemperatures.However,thisrelationshipwaslikelyinfluencedbythehigh
frequencyofRedBatpassesduringtheJuly29survey(AppendixFigure1).
8.1.3. Moonphase:manybatobserversbelievethatlunarilluminationaffectsbatactivity,
whichmaybelowerduringperiodsofhighillumination.Ourresultsaremixedwith
respecttobatactivityandmoonillumination,thoughRedBatactivityduringoursurveys
appearedtobeheightenedduringafullornear-fullmoon(AppendixFigure2).
8.1.4. Cloudcover:BigBrownandSilver-hairedBatpasseswerelessfrequentwhencloud
coverexceeded50%(i.e.mostlycloudyorovercast;AppendixFigure3).
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Appendix Figure 2: relationship between bat activity, expressed as average passes per minute, and moon phase
Appendix Figure 1: relationship between bat activity, expressed as average passes per minute, and air temperature
14
Appendix Figure 1: relationship between bat activity, expressed as average passes per minute, and air temperature
Appendix Figure 3: relationship between bat activity, expressed as average passes per minute, and cloud cover
15
Appendix Figure 3: relationship between bat activity, expressed as average passes per minute, and cloud cover