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.

3

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

5

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.

8

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.

9

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).

13

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