a homeowner’s guide to northeastern bats and …...a.homeowner’s. guide.to. northeastern.bats....

College of Agricultural Sciences Agricultural Research and Cooperative Extension

A Homeowner’s Guide To Northeastern Bats And Bat Problems

Contents

Introduction........................................................... 1

Benefits.of.Bats....................................................... 2

Life.History.of.Northern.Bats................................ 3 BatBehavior4

Bats.In.Homes.and.Buildings................................ 5 ASingleBatintheHouse5 HouseBatMaternityColonies6 IfYouAreHousingaBatColony6

Bat-Proofing............................................................ 7 IdentifyingEntrances7 SealingEntrances8 TimingofBat-proofing8 One-wayDoors8 InstallingOne-wayDoors9 ProvidinganAlternativeRoost10 BatBoxDesign10 BatBoxPlacement11 TimingofInstallation11 CareofYourBatBox12 Bat-proofingSummary12

Attracting.Bats.With.Bat.Boxes........................... 13

Bats.and.Public.Health........................................ 13 Rabies13 Histoplasmosis14 BatParasites14

Bats.In.Caves........................................................ 15

Literature.Cited.................................................... 15

Appendix.1:.Bat-Proofing.Materials.and..Suppliers........................................................ 16

Appendix.2:.Bat.Box.Construction.Plans........... 17 SmallBatBoxAssembly17 SmallMaternityColonyBatBox

Assembly19 LargeMaternityColonyBatBox

Assembly20

Appendix.3:.Further.Information....................... 22

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A.Homeowner’s.Guide.To.Northeastern.Bats.And.Bat.Problems

NoothermammalsintheNortheastare

asmisunderstoodasbats.Avarietyof

mythsandmisconceptionssurroundthese

small,nocturnal,flyingmammals.Many

peoplethinkofbatsasviciousanimals

thatcarrydiseasesandgettangledin

hair.Othersconsiderthemtobefriendly,

cuddlyanimalsthatneedonlyourloveand

understanding.Bothimagesaresomewhat

misguided.

Thispublicationwilldescribethe

importantrolethatbatsplayinour

environmentandwillexplainwhatto

doifyoufindyourselfsharingliving

quarterswiththem.Itwillalsodiscuss

therealitybehindthemostcommonly

heldmisconceptionssurroundingthese

beneficialmammals.

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NortheasterN Bats

Common Name Summer Roosts Winter Roosts Notes

Little brown buildings caves, mines most common species

Big brown buildings caves, mines occasionally overwinters in buildings

Eastern pipistrelle trees caves, mines smallest bat in region

Northern long-eared trees, building exteriors caves, mines rarely seen by people

Indiana hollow trees, caves, mines federally endangered beneath tree bark, caves, mines

Small-footed beneath tree bark, caves, mines species of special concern rock piles

Silver-haired tree crevices migrates south forest-dwelling bat

Red tree foliage migrates south forest-dwelling bat

Hoary tree foliage migrates south forest-dwelling bat

Seminole tree foliage rarely reported in Pennsylvania

Evening buildings, hollow trees rarely reported in Pennsylvania

Big brown bats eat many agricultural pests, such as June beetles.

Benefits.of.Bats

Batsmakegoodneighbors.Astheonlymajorpreda-torsofnightflyinginsects,batsplayanimportantroleincontrollingmanyinsectpests.Asinglebatcanconsumeasmanyas500insectsinjustonehour,ornearly3,000insectseverynight.Acolonyofjust100littlebrownbats,themostabundantspeciesintheNortheast,mayconsumemorethanaquarterofamillionmosquitoesandothersmallinsectseachnight.

Bigbrownbats,whichliveprimarilyinagricul-turalareas,feedonJunebugs,cucumberbeetles,greenandbrownstinkbugs,andleafhoppers.Researchhasshownthatoverthecourseofasum-mer,acolonyof150bigbrownbatscaneat38,000cucumberbeetles,16,000Junebugs,19,000stink-bugs,and50,000leafhoppersandcanpreventthehatchingof18millioncornrootwormsbydevouringtheadultbeetles.

Thered,hoary,andsilver-hairedbatshelptomaintainforesthealthintheregionbyfeedingonforestpestssuchastentcaterpillarmoths.Becauseoftheirroleincontrollinginsectnumbersthrough-outtheNortheastandelsewhereintheUnitedStates,themaintenanceofwildbatpopulationsisimportantformaintainingecosystemhealth.

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tonabtheinsectanddrawitintoitsmouth.Thismaneuverabilitymakesbatsveryefficientinsectpredators:Abatmayconsumenearly50percentofitsbodyweightininsectsinasinglenight!

Althoughbatscanseequitewell,theyrelyontheirhearingfornightflying.Ahighlysophis-ticatedadaptation,calledecholocation,en-ablesbatstousetheirlargeandwelldevel-opedearstonavigateandcatchpreyintotaldarkness.Abat’secho-locationsystemmakesuseofultrasonicsoundpulsesandechoestolocateobjects.Batsopentheirmouthsinflightandemitaseriesofultrasonicsoundpulses.Thesepulsesbounceoffnearbyob-jects—suchasbushes,fences,branches,andinsects—thenreturnasechoestothebat’sears.Usingtheinfor-mationgatheredfromtheseechoes,abatcanmaneuvertocaptureaninsectoravoidflyingintoanobject.

Batshaveoneofthelowestreproductiveratesforanimalstheirsize.Mostnortheasternbatshavejustoneortwopupsperyear,andmanyfemalesdonotbreeduntiltheirsecondyear.Thislowreproduc-tiverateispartiallyoffsetbytheirlonglifespan.On

Life.History.of.Northeastern.Bats.NinespeciesofbatsliveatleastpartoftheyearinthenortheasternUnitedStates,andtwosouthernspeciesresideinfrequentlyinPennsylvania.(Seebox.)Northeasternbatsrangeinsizefromthehoarybat(length5.1to5.9inchesfromnosetotail;wing-span14.6to16.4inches;weight0.88to1.58ounces)tothepipistrellebat(length2.9to3.5inches;wing-span8.1to10.1inches;weight0.14to0.25ounces).Colorsrangefromthedrabbrownofthelittlebrownbattothestrikingfrostedredcoatoftheredbat.

Althoughsomemammalsareabletoglide,batsaretheonlymammalsthattrulyfly.Thatis,theyactuallyflaptheirwingstopropeltheminflight.Theybelongtotheirownuniqueorderofmammals,calledChiroptera,meaning“handwing,”whichreferstohowthefingerbonesofabatsupportitswings.Thewingsofabatareactuallythinmem-branesofskinthatstretchbetweenthefingersofthefrontlegandextendtothehindlegsandtail.Thebat’sfingerbonesaregreatlyelongatedandserveapurposesimilartostrutsonanairplanewing,providingsupportandmaneuverabilityduringflight.Whenatrest,abatfoldsitswingsalongsideitsbodytoprotectthedelicatefingerbonesandwingmembranes.

Batsliveinavarietyofhabitats,includingwetlands,fields,forests,cities,suburbs,andagricul-turalareas.Theyusuallyfeedinareaswhereinsectsswarm,suchasoverwaterandagriculturalfields,inforestclearingsandalongforestedges,andaroundstreetlights.

Allnortheasternbatseatinsectsandtaketheirpreyonthewing.Batsusetheirmouthstoscoopsmallinsectsoutoftheair.Largerinsectsareoftendisabledwithaquickbiteandthencarriedtothegroundortoaperchforeating.Ifaninsecttakeslast-secondevasiveaction,abatcanflickoutawing

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average,batsliveapproximatelyfourtosixyears,andtherearesomeincrediblerecordsofbatslivingtwentytothirtyyearsinthewild.

Mostbatsmateinlatesummerorearlyfall.However,themale’sspermremainsdormantinthefemale’sreproductivesystemuntilspring,atwhichtimethefemaleovulatesandfertilizationoccurs.Thepupsarebornapproximatelysixtoeightweekslater,duringlateMayandearlyJune.

Bat.BehaviorBecausefewflyinginsectsareactiveduringthewintermonths,batsthatremainintheNortheastyear-roundgatherincavesandabandonedminestohibernate.Hibernationisastateofprolongedtorporduringwhichbatsgreatlyreducetheirnormalmetabolicactivities.Bodytemperatureinhibernat-ingbatsfallsfromanormallevelofmorethan100oFtothatofthesurroundingcavetemperature,usually40–50oF.Theheartrateslowstoonlyabouttwentybeatsperminute,ascomparedto1,000beatsperminuteduringflight.Byallowingtheirbodilyprocessestoslowthisway,hibernatingbatscansurviveonaverysmallamountofstoredfatduringthefive-tosix-monthhibernationperiod,losingfromone-fourthtoone-halfoftheirprehibernationweight.

BatsarousefromhibernationduringMarchandusuallyarriveattheirsummerroostsinApril.Atthistime,pregnantfemalesseekoutshelteredroostsinrockcrevices,treecavities,andtreefoliage

inwhichtoreartheirpups.Femalered,hoary,andsilver-hairedbatsroostaloneduringthesummer,whilefemalesofotherspeciesgatherintolargeorsmallgroupingscalledmaternitycolonies.Malebatsusuallyroostaloneinfairlyexposedlocations.

Dependinguponthespecies,femalesgivebirthtoonetothreepupsinlateMayandearlyJune.Thepups,whicharebornhairless,blind,andhelpless,clingtightlytotheirmotherinthematernityroost.Onsummerevenings,femalesleavethepupsintheroostandhuntinsectsnearby,returningoftenthroughoutthenighttonursetheiroffspring.Asthepupsgrowolder,thefemalesreturnlessfrequentlyduringthenight.Thepupsbegintoflyandhuntontheirownbymid-July,whentheyareapproximatelyfiveweeksold.However,thepupswillcontinuetonurseuntiltheycanadequatelyfeedthemselves.

Maternitycoloniesbegintodisbandinlatesum-merandearlyfall.Atthistime,malesandfemalesofhibernatingspeciesbegintoswarmtogether.Largegroupsofthesebatswillswarminandoutofcaveentrancesthroughoutthenight,oftenroostinginthecavesduringtheday.Thisswarmingbehaviorbringsadultstogetherformating,andmayalsoteachyoungbatsthelocationofthehibernationcaves.Autumnalsopromptsthesilver-haired,red,andhoarybatstobegintheirmigrationtowarmerclimates.

Bat pups begin to fly and hunt in mid-July.

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Bats.In.Homes.and.BuildingsThereareprimarilytwoscenariosinwhichhumansandbatsfindthemselvesinconflict:(1)whenalonebatfliesintoabuilding,or(2)whenamaternitycolonyofbatsroostsinabuilding.Thepropertech-niquesfordealingwiththeseuninvitedvisitorswillbeoutlinedinthefollowingsections.

A.Single.Bat.in.the.HouseIndividualbatsoccasionallyenterhouses,mostof-tenduringsummereveningsinmid-JulyandAugust.Thesewaywardbatsareusuallypupsthatarejustbeginningtofly.Fortunately,theseincidentscanbedealtwithquiteeasily.Abatflyinginthehousewillusuallycirclearoomseveraltimesinsearchofanexit.Thebestmethodforgettingabatoutofthehouseistoallowittofinditsownwayout.Chas-ingorswattingatthebatwillcauseittopanicandflyerraticallyaroundtheroom,whichneedlesslyprolongstheincident.

Ifyoudoencounterabatflyinginaroom,fol-lowthisprocedure:

1. Shutalldoorsleadingintootherroomstocon-finethebattoassmallanareaaspossible.

2. Openallwindowsanddoorsleadingoutsidetogivethebatachancetoescape.(Don’tworryaboutotherbatsflyinginfromtheoutside.)

3. Removepetsfromtheroom,leavethelightson,standquietlyagainstawallordoor,andwatchthebatuntilitleaves.

4. Donottrytoherdthebattowardawindow.Justallowittocalmlygetitsbearings,anddon’tworryaboutitswoopingatyou.Whenindoors,abatmakessteep,bankingturns,soitfliesup-wardsasitapproachesawallandswoopslowernearthecenteroftheroom.

5. Withintentofifteenminutesthebatshouldsettledown,locatetheopendoororwindow,andflyoutoftheroom.

Ifthebattiresandcomestorestonacurtainorwall,youcaneasilyremoveitwithoutdirectlytouchingit.(Seediagram.)Followthestepsbelow,andremembertoneverhandleabat,oranyotherwildanimal,withyourbarehands.

1. Putonapairofleathergardeningorworkgloves.

2. Placeacontainer,suchasalargeplasticbowl,

You can easily remove a bat from a room without directly touching it.

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overthebatasitrestsonthewall.Atthispoint,thebatisprobablyexhaustedanddisoriented,andwillnotflyasyouapproachit.(Ifitdoestakeflight,followtheprocedureforflyingbats.)

3. Slideapieceofrigidcardboardbetweenthecontainerandthewalltotrapthebat.Holdthecardboardfirmlyagainstthecontainerandcarrythecontaineroutside.

4. Placethecontainer(facingawayfromyou)onasecureplaceabovetheground—suchasonaledge,oragainstatree—andslideawaythecardboard.Thebatwillnotflyrightaway,soreleasingitabovethegroundkeepsitsafefrompredatorsuntilithasitsbearings.Andunlikebirds,mostbatsmustdropfromaperchandcatchairundertheirwingsbeforetheycanfly.

Ifyouhaverecurringproblemswithbatsenteringyourhome,youmaywanttoinspectyourattictodetermineifyouarehousingabatmaternitycolony.

House.Bat.Maternity.ColoniesMostbatsintheNortheastroostinsecludedloca-tionsawayfromhumans,buttwospecies,thelittlebrownbatandthebigbrownbat,oftenattractattentionbecausetheyrepeatedlyroostinbuild-ings.Thesebatsonceroostedinhollowtrees,butadaptedtoroostinginhumanstructuresafterearlysettlerseliminatedlargeexpansesofforests.These‘housebats’situatetheirroostsinhotattics,whichactasincubatorsforthegrowingpups.

Becausetheyliveinsuchclosequarterswithhumans,uniquechallengesareinvolvedintheconservationofhousebats.Housebatshaveonlyoneortwopupsperyear,sotheprotectionoftheir

maternitycoloniesisimportanttothesurvivalofthesebeneficialmammals.Thedestructionofjustonematernitycolonythroughchemicalextermina-tionorvandalismcanhavealong-termimpactonthepopulationsofbothbatsandinsectsinalocalarea.Unfortunately,homeownersoftenconsidermaternitycoloniesanuisanceandmaymistakenlybelievethatexterminationordestructionofthecolonyistheironlysolution.Thereis,however,asafe,humane,andeffectiveprocedureforremovingabatcolonyfromabuilding.Thisprocedure,calledbat-proofing,isdescribedinthefollowingsections.

If You Are Housing a Bat ColonyOnewaytotellifyouaresharingyourhousewithabatcolonyistosimplygointotheatticandlookforroostingbats.Duringtheday,batswilllikelyberoostinginnarrowcrevicesintheatticwalls,be-tweentherafters,ortuckedintothespacebetweentheraftersandroofingmaterial.Whenyouentertheattic,thebatswillquicklyretreatoutofsight(ratherthantakingflight).Ifyoucan’tseethem,listenforthesqueakingorscurryingsoundsthatwillverifytheirpresence.

Ifyouareuncomfortableenteringtheatticwhenbatsmaybepresent,youcaninspecttheatticatnightforbatdroppings.Thedry,blackdroppingsareaboutthesizeofagrainofrice,andaccumulateinpilesbelowareaswherethebatsroost.(Mousedrop-pingslooksimilar,butyouwouldfindthemscatteredinsmallamountsthroughouttheattic.)Ifyoufindbatslivinginyouratticduringtheday,orifyoufindlargeaccumulationsofbatdroppings,thenyouprob-ablyhaveamaternitycolonyinyourhouse.

Maternity colonies of little brown and big brown bats roost in attics.

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Sometimes,whenhomeownersunderstandtheimportantrolethatbatsplayincontrollinginsects,theydecidetoallowthecolonytoremainintheatticoreaves.Inthiscase,thehomeownermustsealallopeningsthatwouldgivebatsaccessintothelivingspaces.Thissafetymeasureisparticularlyimportantforfamilieswithsmallchildrenandpets.

Ifyouhaveabatcolonyinyouratticandyouwanttoremoveit,youmustusethepropermethodstodoso.Donotusechemicalpoisonsorrepellentstoeliminateabatcolony.Poisonsoftenscatterdead,dying,ordisorientedbatsthroughoutthehouseandneighborhood,whichincreasestheriskofchildrenorpetscomingintocontactwithsickbats(Constantine1979).Repellents,suchasmothballsorflakes(naphthalene),sulfurcandles,orelectromagneticorultrasonicsounddevicesdonotpermanentlyremovebatsfromahome.Unlesstheirentrancesaresealed,thebatswillreturnassoonasthechemicalrepellentswearoff.

Thebestwaytosafelyandpermanentlyevictamaternitycolonyistosealallofthecolony’sentrances.Thisinexpensiveprocedure,calledbat-proofing,isdescribedinthefollowingsections.Inaddition,thePennStateCollegeofAgriculturalSciencesvideoentitledBat-Free Belfries: A Guide to Bat-ProofingisavailablethroughthePennStateCooperativeExtensionofficeinyourcountyorfrom:PublicationsDistributionCenter,ThePennsylvaniaStateUniversity,112AgriculturalAdministrationBuilding,UniversityPark,PA16802-2801.

Bat-Proofing

Bat-proofingabuildinginvolvessealingthebats’en-tranceholesandthenprovidingthematernitycolo-nywithanalternateroost,orbatbox.Bat-proofingabuildingisusuallyasimpleprocedurethatdoesnotrequiretheskillsofaprofessionaloranyexpensivematerials.Tobat-proofyourhome:(1)stagea“batwatch”toidentifybatentrances,(2)sealtheholestopreventtheirentry,(3)provideanalternativeroost,orbatbox,forthecolonytooccupy.

Identifying.EntrancesThefirststepinbat-proofingistolocatetheholesthatbatsusetoenterandexittheattic.Batscom-monlyenteratpointswherejoinedmaterialshavewarped,shrunk,orpulledawayfromoneanother.Somecommonpointsofaccessoccuratlouveredventswithloosescreening,attheroofpeak,andinareaswhereflashinghaspulledawayfromtherooforsiding.(Seediagram.)

Toidentifywhichoftheseareasareprovidingaccess,lookfortell-talebatdroppingsonthesideofthehousebelowasuspiciouscrackorcrevice.Also,entrancesthathavebeenusedforalongtimemayhaveaslightbrowndiscolorationattheedges.Inspectinginsidetheatticcanalsorevealopeningsthatneedtobesealed.Inside,batdroppingsoftenaccumulatebelowbatentrancesandexits.During

Bats usually enter at points where joined materials have warped or shrunk.

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theday,turnofftheattic’slightsandlookforopen-ingsthatareallowingoutsidelight,andpossiblybats,topassthrough.

Staginga“batwatch”canalsohelpyoulocatethebats’entrances.Atdusk,stationapersononeachsideofthebuildingandwatchasthebatsexitthebuilding.Oncethefirstbatsareseenleaving,focusonthatareaofthebuildingandwatchforotherexitingbatsuntilyouhavepinpointedtheirexit(s).Dawnisanothergoodtimetoidentifytheirentrances,becausethereturningbatswillswarmaroundtheirentrancesafewtimesbeforeactuallyenteringthebuilding.

Sealing.EntrancesOncethebatentranceshavebeenlocated,thenextstepinbat-proofingistosealtheseopenings.Usewindowscreeningorhardwareclothtocoverlou-veredventsorlargegapsandcracksinthebuilding.Tofillinsmallercracks,useexpandingfoaminsula-tionorcaulkingcompound.Afterhardening,thesecanbetrimmedorpaintedasneeded.Unlikemice,batswillnotgnawnewholesinthebuilding,soseal-ingtheexistingholeswillkeepthemout.Mostbat-proofingmaterialscanbeobtainedinlocalhardwareorbuildingsupplystores.Alistingofsuppliersofbatexclusionproductsisincludedattheendofthisbooklet(Appendix1).

Timing of Bat-proofingOneimportantaspecttoconsiderbeforebat-proof-ingyourbuildingisthetimingoftheprocedure.Because pups remain confined in the roost until they are old enough to fly, bat-proofing should never be completed from late May through mid-July. Otherwise the young, flightless bats would be trapped inside the building.Bat-proofingduringthesemonthswouldresultinpotentialhealthrisksandobviousodorproblemsastheyoungbatsdieanddecayinside

thebuilding.Also,thepupsmayenterhumanlivingareasinsearchofawayout,andfemalesmayfranti-callyattempttoreenterthebuilding,evenduringdaylighthours,torejointheiryoung.

Occasionally,ahomeownermayencounterthedifficultsituationofbat-proofingwhilethepupsarestillconfinedtotheattic.Thishappenswhenaroofingorsidingcontractordiscoversbatsattheworksitebutcannotstoptheproject.Inthiscase,thecontractorshouldcompletetheproject,butallowoneofthebats’accesspointstoremainopen,sothatnursingfemalescanenterandexittheattic.Then,afterthepupsareabletofly,aone-waydoorcanbeinstalledtoevictthebats.Onceallofthebatshavelefttheattic,theremainingbatentrancecanbesealed.

Thebesttimeforbat-proofingisinthespring,beforebatsentertheroost,orinthefall,afterthebatshaveleft.Ifbat-proofingmustbedonewhilebatsareinhabitingthebuilding,itshouldbedonebyinstallingaone-waydoorafterthepupsareabletofly.One-waydoors,whicharediscussedbelow,aredesignedtoallowbatstoleaveandnotreenterabuilding.

Bigbrownbatsoccasionallyoverwinterinabuildingbyhibernatingintheatticorbasement.Ifthehomeownersuspectsthisisthecase,bat-proof-ingshouldbedonebyinstallingaone-waydoorinthefall,beforethebatsbeginhibernating,orinthespring,beforethepupsareborn.

One-way DoorsOne-waydoorsarepiecesofmeshorscreeningplacedoverabatentrancetoformalongsleeveortent.(Seediagram.)Thesedoorsallowbatstoexitatnightbutpreventtheirreentryatdawn.One-waydoorsworkbecausebatsusetheirsenseofsmell,ratherthantheirvision,tolocatetheirentrances.Thebatswillexitatthebottom,butwhentheyre-turn,theywilllandonthemeshneartheirentrancehole.Theywillsmelltheirentrancethroughthemesh,andwillcrawlaroundinthevicinityoftheen-trance,tryingtofindawayinside.Thesmelloftheentrancefocusestheirattentiononthatportionofthemesh,andthebatswillnotmovetotheopeningatthebottomofthedoortogainentrance.Aneasy-to-installone-waydoor,designedbyDr.StephenFrantzoftheNewYorkDepartmentofHealth(Frantz1986),isdescribedinthefollowingsection.

timiNg of Bat-ProofiNg

Months Methods for Bat-proofing

Jan.–April Seal entrances before bats return to the building.

May–August Watch bats to identify entrances. Do not seal openings.

August–Oct. Install one way door(s).

Nov.–Dec. Seal entrances once bats have left the building. (If you suspect bats are hibernating in the building, install a one-way door in Sept.–Oct.)

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Installing.One-way.Doors

1. Choose0.25-to0.5-inchwirescreeningorheavyplasticmeshtocoverthebats’pointsofentry.Cutthescreeningsothatitcoversthewidthoftheholeandextendsapproximatelythreefeetbelowthehole.Thescreeningshouldprojectthree-to-fiveinchesclearofthehole,sothatthebatscancrawlbetweenthescreenandthebuildingandexitatthebottom.

2. Securethemeshatthetopandsideswithducttapeorstaplesandleavethebottomopen.

3. Leavethedoorinplaceforatleastthreetofourdays,oruntilyouaresurethatallbatshaveleftthebuilding,thenremovetheone-waydoorandpermanentlysealtheopening.

4. Again,neveruseaone-waydoorduringMaythroughAugust,oryoungbatswillbetrappedinsideanddie.

One-way doors allow bats to exit a building but prevent their reentry.

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Providing.an.Alternative.RoostBat-proofinghastwopotentialdrawbacks.Oneisthatexclusioncanbeverystressfulforamaternitycolony.Whenpreventedfromusingtheirtraditionalroost,thebatsmaymoveintoanearbybuilding,wheretheymaybeexpelledagain,orevenexter-minated.Also,researchhasshownthatdisplacedcolonieswillnotrelocateintobuildingsthatalreadyhouseothermaternitycolonies(Neilson1991).Inotherwords,anexcludedcolonycannotjustmovedowntheroadintoabarnorchurchthatalreadyhasbats.Ifadisplacedcolonycannotfindanewroost,itmayleavethearea.Infact,researchershavefoundthatexpellingbatcoloniescancontributetoseriousdeclinesinlocalbatpopulations(HumphreyandCope1976,Neilson1991).

Theseconddrawbackisthathomeownersmayfinditdifficulttocompletelybat-prooftheirhome.Batscancrawlthroughacrackassmallas0.5by1.25inches,sopersistentbatsmayfindawaytoreentertheirtraditionalroost.

Batboxesmaysolvebothoftheseproblemsbecausetheyprovidealternativeroostingsitesformaternitycolonies.Whenconstructedproperly,batboxescanserveassuitableplacesforfemalestoraisetheirpups.Withbatboxes,thebatsgetasaferoostingsiteoutsidethehome,whilehomeownersstillbenefitfromthebats’controlofinsects.

Bat Box DesignSize,interiorconstruction,andtemperaturecontrolarethethreemostimportantdesignelementsofbatboxes.Homeownersshouldconsiderbuildingtheirownbatbox,becausecommercialbatboxesdonotprovidethelivingspaceorroostingtemperaturesthatmaternitycoloniesrequire.

Abatboxmustbelargeenoughtoadequatelyhouseamaternitycolony.Boxesshouldbeatleast7inchesdeep,24incheswide,andeither12or24inchestall(dependingonthesizeofthecolony).Boxes12inchesinheightwillhouseupto100bats,andboxes24inchesinheightwillhouseasmany

The interior of a bat box is divided into several roost-ing crevices.

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as200bats.(Appendix2.)Tohouseevenlargercolo-nies,youcanjointwoboxesside-by-side,oryoucaninstallonelargeboxthatmeasures14to21inchesfromfronttoback.

Theinteriorconstructionofabatboxisim-portantbecausematernitycolonieshaveparticularrequirementsfortheirroostingchambers.Bafflesshouldbeusedtodividetheinteriorspaceintomul-tipleroostingcrevices.(Seediagram.)Thecrevicesshouldmeasurefrom0.75inchesupto1.5inchesindepth,withthemajorityinthe0.75inchto1inchrange.Inaddition,allofthebaffles,interiorsur-faces,andthelandingboardbelowtheboxshouldberoughenedwithsawcutstoprovidefootholdsforbats.

Finally,theboxesmustprovidehighincubationtemperaturesforthepregnantfemalesandgrowingpups.Stainingthebatboxesdarkbrownorblackenhancesabox’sabilitytoabsorbsunlight.Theboxesmustalsohavecoolerareasforthebatstomoveinto,incasetemperaturesrisetoohigh.Tack-ingblackroofingpapertotheupperportionsoftheboxandcuttingventilationslitsintothelowersidesandfrontwillhelptocontrolinteriortemperatureranges.

Bat Box PlacementBecauseoftheimportanceofhightemperaturesinthematernityroost,theamountofsunlightabatboxreceivesmaybethemostimportantfactortoconsider.InastudyrecentlycompletedatPennState,allbatboxesthatreceivedsevenormorehoursofdirectsunlightweresuccessfulinhousingmaternitycoloniesdisplacedbybat-proofing,whileboxesthatreceivedfewerhoursofdirectsunlightwereunsuccessfulinhousingcolonies.

BatboxesinPennsylvaniashouldfacesouth-eastorsouthwest,sothattheyreceiveatleastsevenhoursofdirectsunlightduringthespringandsummer.(InareasnorthofPennsylvania,batboxeswouldlikelyneedtoreceivemorethantheminimumsevenhoursofsunlight.)

Abatboxintendedtohouseadisplacedma-ternitycolonyshouldbeplacedonorverynearthebuildinginwhichthebatsroosted.Placetheboxonanoutsidewallorchimney,oronapolewithin10to20feetofthebuilding.Ifplacedonthebuilding,theboxshouldhaveatleast3feetofopenspaceunderit,sothatbatscanenterandexitfromthebottom.Donotplaceabatboxinanareathatisheavilytraf-fickedbypeople,oranywherethatdroppingsfromtheboxwillposeaproblem.Batboxesalsocanbeplacedontrees—aslongastheboxeswillreceivetherequiredsevenhoursofsunlight.Whetherona

building,pole,ortree,batboxesshouldalwaysbeplacedatleast10to15feetabovetheground.

Oncethebatsmoveintotheboxandestablishitastheirroost,theboxcangraduallybemovedfartherawayfromthebuilding.Thisshouldbedoneinthefallorwinterwhenbatsarenotpresent.Movingtheboxmorethan20yardsperyearisnotrecommended.

Timing of InstallationIdeally,batsshouldbeallowedtofamiliarizethem-selveswiththebatboxbeforebeingexpelledfromtheirtraditionalroost.Thiscanbedonebyinstall-ingtheboxinthewinterorspring,thenallowingthebatstoremainintheatticoverthesummer,duringwhichtimetheywillinvestigatethebox.Bat-proof-ingshouldthenbecompletedinthefallafterthebatshaveleftthebuilding.Thefollowingspring,whenthebatsreturn,theywillnotbeabletogetintothebuilding,buttheywillbefamiliarwiththebatboxandreadytoinhabitit.Thistimingofeventsmakesthetaskofbat-proofingeasierforthehom-eowner,becausethebatsshouldbelesspersistentintryingtoreenterthehouse.

Ifyoucannotallowthebatstoremaininthebuildingforanadditionalsummer,theninstallthebatboxandbat-proofthehousebeforethebatsarriveinApril.Thebatsmaynotmoveintotheunfamiliarboxrightaway,butthisoptionisstillpreferabletoexpellingacolonywithoutprovidinganalternativeroost.

Coloniesidentifytheirroosts,inpart,bytheirsmell,soitmayhelptoscenttheboxwiththecolony’sdroppingsbeforeinstallation.Gatheracupofdroppingsfromtheattic,mixthemwithwatertomakeaslurry,andpourthismixtureintothebatbox.Allowtheslurrytosoakintothebatboxbeforeinstallingit.Ifscentingtheboxisnotfeasible,newboxesshouldatleastbestoredoutsidepriortoinstallation,sothescentofnewmaterialsweathersoutofthem.

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Care.of.Your.Bat.BoxOncebatsmovein,homeownersshouldneverdisturbabatboxduringthedayandshouldalwayswatchthebats’eveningdeparturefromadistance.Fencingofftheareaunderthebatboxwillpreventpeopleandpetsfromwalkingunderneathit,andalsohelpstominimizeanydisturbancetothebats.(Seediagram.)Iffencingisnotpractical,plantingornamentalgroundcoverbeneaththeboxcanservethesamepurpose.(Thisoptionalsotakesadvan-tageofthefertilizingqualityofbatdroppings.)

Batboxesrequirenomaintenancewhenbatsarepresentinthespringandsummer.However,anyactivewaspnestscanberemovedwithalongstickduringcoolmorningsoreveningswhenwaspsarelessactive.(Donotdisturbtheboxifbatsarepresent.)Inthefallandwinter(afterthebatshaveleftthearea),homeownerscaninspecttheboxandmakeanynecessaryrepairstoit.Also,oldwaspnestsshouldberemovedatthistime.

Occasionally,abatpupmayfallfromthebox.Afallenpupwilldieunlessitisretrievedbyitsmotheroritcrawlsbackintothebox.Ifagroundedbatorbatpupmustbehandled,homeownersshouldwearthickworkgloves.Also,childrenshouldbetaughtnevertoapproachagroundedbatorbatpup.

Bat-proofing.Summary.Thesimplestprocedureforexpellingamaternitycolonybeginsinthespringwiththeinstallationofabatbox.Afterthat,thebats’entrancesintothebuildingcanbeidentifiedduringthesummerandsealedwhenthecolonyleavesinthefall.

Withalittlepatienceandeffort,youcanexcludebatsfromyourbuildingpermanentlyandsuccessfully.Withabatbox,youcantakeadvantageofthebats’abilitytocontrolinsects,whilemakingavaluablecontributiontotheprotectionandmanage-mentofthesebeneficialmammals.

Bat-ProofiNg summary

Months Bat-proofing Schedule

Jan.–April Install a bat box near the building in a loca-tion where it can receive seven hours of sunlight.

May–August Allow bats to remain in the building and watch them exit at dusk to identify openings.

Sept.–April Seal openings.

Fencing or planting an orna-mental ground cover below a bat box will prevent people from walking underneath it.

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Attracting.Bats.With.Bat.Boxes

Oncepeoplelearnofthebeneficialrolethatbatsplayincontrollinginsects,theyoftenwanttoattractbatstotheiryardsandgardens.Itisdifficulttopre-dictwhetherabatboxwillattractbatstohuntandfeedinadesiredarea.Batboxesprovideshelter,butanamplesupplyoffoodandwaterisalsoneededtoattractbats.Eveninalocationthathasbatslivingnearby,anewbatboxmayremainvacantbecausethebatshaveotherroostsinthearea.Conversely,inareaswhereroostsarescarce,batsmaymoveintoanewbatboxrightaway.

Whentryingtoattractamaternitycolonytoanarea,itisimportanttorememberthatthesecolo-niesareveryloyaltotheirtraditionalroostsandwillnotreadilyseekoutnewroosts.Thismeansthatabatboxmaysitunoccupiedforyears,eveninareasthathaveseveralmaternitycolonies.However,anunoccupiedboxcanalwaysserveasanemergencyshelterforacolonydisplacedfromanearbybuild-ing.Also,amalebatmaymoveintoabatboxevenwhenamaternitycolonywillnot,andevenonebatcanconsumenearly3,000insectspernight.

Arecentsurveyofbatboxowners,conductedbyBatConservationInternational,showedthattheoveralloccupancyrateofbatboxeswasapproxi-mately52percent.Successratesweresomewhatlowerforsmallerboxes(32percent),andsomewhathigherforlargerboxes(71percent).Thekeytoattractingbatstoyourpropertyistobepatientatfirstandtoexperimentifyourinitialattemptsareunsuccessful.

Bats.and.Public.Health

RabiesRabiesisthemostimportantpublichealthhazardassociatedwithbats,butitsimpacthasoftenbeenexaggerated.Allmammalsarevulnerabletothispotentiallyfataldisease,whichiscausedbyavirusthatattacksthecentralnervoussystem.

Animalswithrabieswillgothrougheithera“furious”stage,inwhichtheyattackanythingintheirpath,ora“dumb”stage,inwhichtheybecomeprogressivelyparalyzedbeforedeath.Batscanexpe-rienceeitherofthesestages,althoughthemajorityofinfectedbatsdisplaybehaviorassociatedwiththedumbstageofrabies(Constantine1979).Oncethesymptomsofrabiesappear,batsusuallybecomeimmobilizedwithintwodaysanddiewithinfourdays(Fenton1992).

Theincidenceofrabiesinthewildbatpopula-tionislow,andthespreadofrabieswithinindi-vidualcoloniesappearstobeveryrare(Constantine1979).ScientificsurveysofwildbatsintheUnitedStatesandCanadaindicatethattheincidenceofrabiesinclinicallynormalbatsislessthan0.5percent(Fenton1992).However,ofthesick,dead,orsuspectbatssubmittedtohealthdepartmentsfortesting,approximately2–5percenttestpositiveforrabies.Thusitisimporttotakeprecautionswhenhandlinggroundedbats.Mosthumanexposuretoinfectedbatsresultsfromcarelesshandlingofgroundedbats.

Almosteveryonerecognizestheneedtoseekimmediatemedicalattentionafteranunprovokedattackbyabat(oranyotheranimal).However,abatlyinghelplesslyonthegroundwilloftenarousehumanitarianinstincts.Thepersontryingtohelpthegroundedbatmaygetbittenandignorethebite,becauseitoccurredinself-defense.Regardlessofthecircumstances,anyonebittenbyawildanimalshouldimmediatelywashthewoundwithsoapandwaterandseekmedicalattention.(SeeRabiesPrecautions.)

Ofcourse,notallgroundedbatsarerabid.Forexample,youngpupsoftenbecomegroundedwhenlearningtofly.However,batsthatcanbecaught,particularlygroundedbatsorbatsfoundinunusualplaces,aremorelikelytobesickthanothers.Alwayshandleallbatswithleatherworkgloves,andwarnchildrennevertoapproachorpickupgroundedbats.Also,catsanddogs,whichcomeintocontactwithbatsandotherwildanimalsfar

It is not known yet whether forest-dwelling bats will use bat boxes.

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signsofhistoplasmosis,whichisoftenmistakenforinfluenza.Whilehistoplasmosisoftendoesnotproduceanysymptoms,severesymptomssuchashighfever,problemswithvision,andlife-threaten-ingcomplicationsoccasionallydooccur(Greenhall1982,Fenton1992).

Thefungusthatcausesthediseaseoccursnaturallyinsoilsthroughoutwarmerregionsoftheworld,includingpartsofNorthAmerica(Fenton1992).Thefungusalsoisassociatedwithbatdrop-pings,calledguano,whichaccumulatesincaveswherebatsliveinsummermonths.Hibernatingbatsdonotproduceguano,andthereforedonotdepositthefungusincaveswheretheyhibernate(Fenton1992).IntheeasternUnitedStates,surveysinbuildingsthathadaccumulationsofguanofromseveralcoloniesofbigbrownandlittlebrownbatsproducednoevidenceofthefunguscausinghisto-plasmosis(Fenton1992).

Homeownersshouldstilltakesafetyprecau-tionsagainstinhalinganyparticlesthatmaycontainthefungus,particularlyiflargeamountsofbatdrop-pingsaretobedisturbedinanattic.Tolimittheamountofairborneparticles,thedroppingsshouldbevacuumed,ratherthansweptorshoveled.Hom-eownersalsoshoulduseaproperlyfittedrespiratorcapableoffilteringparticlesassmallastwomicronsindiametertofurtherminimizetheriskofexposure(TuttleandKern1981).

Bat.ParasitesLikeotheranimals,batsarehoststoanumberofinternalandexternalparasites.Mostofthesepara-sitesarespecializedandcannotsurviveawayfromthebats,sotheyposelittlethreattohumansandotheranimals(Fenton1992).Aspeciesofbedbug,whichresemblesthespeciesthatfeedsonhumans,livesonthebatsandintheirroosts.However,reportsofthesebedbugsbitinghumansordomesticanimalsarerare.Onceabatcolonyisevictedfromabuilding,anyparasitesthatremainbehindmaymovearoundtheattic(andpossiblythehouse)insearchofbats.Fortunately,theseparasitesusuallydiequicklywhenseparatedfromthebats.

Ahomeownercansprinklediatomaceousearthintheroostareatoeliminateanyparasitesthatmayremainafterthebatsareevicted.(Appendix1.)Thisorganicpowder,whichismadefromthefossilsofsingle-celledorganisms,isabrasivetotheexoskele-tonsofinsects.Asaninsectcrawlsoverthepowder,itsprotectivecuticleisscratched,andtheinsectdiesofdehydration.Diatomaceousearthiseffectiveinkillingavarietyofotherinsectsinadditiontobatparasites.

moreoftenthantheirowners,shouldbeimmunizedregularlyforrabies.

Thereislittleevidencetosupportthenotionthatbatswithrabiescontributetooutbreaksofthediseaseinotherwildanimals(TuttleandKern1981).TheWorldHealthOrganization’sExpertCom-mitteeonRabiesfoundnoevidenceofnaturalbitetransmissionfrominsect-eatingbatstocarnivores(TuttleandKern1981).Laboratoryexperimentsshowedthatanimalscouldbeinfectedwithrabiesiftheyatelargeamountsofinfectedtissue(Fenton1992).Althoughthesignificanceofthisfindingtoanimalsinthewildisunknown,itagainhighlightstheneedtoimmunizedogsandcats.

Humansandothermammalshavecontractedrabiesthroughairbornetransmission,butthishap-penedinalargesouthwesterncaveharboringabout13millionbats.Thecave’suniqueconditionsofhightemperatureandhumidity,andairsaturatedwiththebats’salivaandurine,probablycontributedtotheairbornetransmissionofthevirus(Fenton1992).Mostbatroostsdonothavetherightcondi-tionsfortransmittingrabiesthroughtheair,andtherearenorecordsofairbornetransmissionsfrommaternitycolonieslivinginbuildings(Fenton1992).

HistoplasmosisHistoplasmosisisanairbornediseasecausedbyamicroscopicfungusthatoccursinsoilandinthenitrogen-richdroppingsofbirdsandbats(TuttleandKern1981,Greenhall1982,Fenton1992).Adrycoughandotherflu-likesymptomsaretheusual

raBies PrecautioNs

1. Bats of all sizes will bite in self-defense, but they almost never attack people.

2. If you must handle a bat, take precautions to minimize the chance of being bitten. By wearing leather gloves and scooping a grounded bat into a coffee can or some other container, you make it virtually impossible for a bat to bite you.

3. If you are bitten by a bat, immediately wash the bite with soap and water and see a physician. If the bat is captured, it should be killed (without destroying the head) and submitted for testing. If there is any possibility that you have been infected, the physi-cian will recommend rabies shots. Today, most people receive the rabies vaccine in a series of five relatively painless shots in the arm administered during a one month period.

4. People usually know when they are bitten by a bat. However, because bats have very small teeth, the bite is rarely obvious. Consequently, if a bat is found in the same room with a young child or mentally incapacitated person or even a very heavy sleeper, and the possibility of a bite cannot be eliminated, rabies treatment should be given.

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Bats.In.Caves

Peopleoccasionallycomeintoclosecontactwithbatsincaves,particularlyduringwinter,whenbatsarehibernating.Asstatedearlier,theriskofexpo-suretohistoplasmosisandairbornetransmissionofrabiesinnortheasternhibernationcavesisnegli-gible.Infact,batsexperiencethegreaterriskwhenpeopleentertheircavesinwinter.

Recreationalcaveexploring,orspelunking,canthreatenthesurvivalofbatcolonies.Duringhibernation,batssurvivewithouteatingbyslowlymetabolizingstoredfat.Toconservetheirfatre-sources,batsdrasticallylowertheirmetabolicrateandenterastateofdeepsleep.Whenpeopleenteracave,theirlights,voices,andbodyheatdisturbthebats’sleep,oftentothepointwheretheyawakecompletelyandtakeflight.Itisestimatedthatabatcanburntentothirtydaysworthofstoredfatreservesduringeachoftheseawakenings.Ifthishappenstoomanytimesoverthecourseofawinter,thebatsmaystarvetodeathbeforespringorleavethecaveinsuchaweakenedconditionthattheycannotsuccessfullyreproduce.

Recreationalcaverscanpreventdisturbingbatsbyavoidingtripstorecreationalandcommercialcavesduringthehibernationseason(DecemberthroughMarch).Whencaversdoencounterhiber-natingbats,theyshouldleavethecavequicklyandquietly,takingcarenottoshinetheirlightsonthesleepingbats.Fortunately,mostspelunkersareveryconsiderateofbatsandhavefoundwaystomini-mizetheirimpactonbatsandcaveenvironments.

Responsiblecavingisanimportantaspectofbatconservation.SomecavesintheNortheasthavehadgatesinstalledtolimithumanaccess.Thisisusuallydonetoprotectvulnerablebatpopulationsorcavesthathavebeenheavilyvandalized.Thesegatesshouldberespectedtogivethecavesandbatpopulationstimetorecover.

Literature.Cited

Constantine,D.G.“Batrabiesandbatmanagement.”Bul-letin of the Society of Vector Ecology4(1979):1–9.

Fenton,M.B.1992.Bats.NewYork:FactsonFile.

Frantz,S.C.1986.“Batproofingstructureswithbirdnettingcheckvalves.”InProceedings of the Twelfth Vertebrate Pest Conference,ed.T.P.Salmon,Davis,Ca.:UniversityofCalifornia260-268.

Greenhall,A.M.1982.U.S.DeptarmentofInterior.FishandWildlifeService.House Bat Management.ResourcePublicationNo.143.Washington,D.C.

Humphrey,S.R.,andJ.B.Cope.1976.“Populationecologyofthelittlebrownbat,Myotis lucifugus,inIndianaandNorth-centralKentucky.”Special Publication, American Society of Mammalogists,81pp.

Neilson,A.L.1991.“Populationecologyofthelittlebrownbat,Myotis lucifugus,attheChautauquaInstitution,Chautauqua,NewYork.”Master’sthesis,YorkUniver-sity,NorthYork,Ontario.

Tuttle,M.D.,andS.J.Kern.“Batsandpublichealth.”Milwaukee Public Museum Contributions in Biology and Geology48(1981):1–11.

Tuttle,M.D.,andD.L.Hensley.“Thebathousestudy.”Bats2(1993):4–10.

Whitaker,J.O.“Bats,beetles,andbugs.”Bats2(1993):23.

Most northeastern bats hibernate in caves and mines during the winter months.

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Appendix.1

Bat-Proofing.Materials.And.Suppliers

One-Way Doors:Metal.Hardware.Cloth/Window.Screening/Plastic.Structural.Grade.Bird-NettingAvailablefrommostgardensupplystores.Anymate-rialusedforone-waydoorsshouldhaveameshnolargerthan0.25to0.5inchindiameter.(Meshdiameterismeasuredonthediagonal,fromcornertocorner.)Meshwithlargersizeopeningswillallowbatstocrawlthroughandreenterthebuilding.

InterNet,Inc.1201LundBlvd.Anoka,MN55303-1092800-328-8456www.internetplastic.com(nettingandfastenerclips)

“Bat.Net”The“BatNet”kitcontainsa14x20footpieceofstructuralgradebirdnettingwithVelcrofastenersforattachmenttobuildings.Theyalsosellrollsofnettingformakingone-waydoorsofanysize.

WildlifeControlTechnology,Inc.2501N.SunnysideAve.Fresno,CA93727800-235-0262www.wildlife-control.com

“Bat.Check.Valve”The“BatCheckValve”kitincludesa100squarefoot(7by14foot)sectionofstructuralgradebirdnetting,includingmountingclipsandinstallationinstructions.Thecompanyalsosellsrollsofnettingformakingone-waydoorsofanysize.

WildlifeManagementSupplies9435E.CherryBendTraverseCity,MI49684800-451-6544www.wildlifemanagementsupplies.com

Diatomaceous Earth:Diatomaceousearthscratchesthecuticleofinsectsastheycrawlthroughit.Itisusefulineliminatingbatparasitesfromanatticafterthebatshavebeenevicted.

BiocontrolNetwork615-370-4301www.biconet.com

Materials for Sealing Holes:Expanding.Foam.Insulation/Caulking.CompoundAvailablefrommostbuildingsupplystores.Expand-ingfoaminsulationisavailableasanaerosolandcanbesprayedintocracksandcrevices.Thefoamexpandstofilltheopeningandthenhardens,afterwhichitcanbetrimmedorpainted.

“Flashband”“Flashband”isaself-adhesive,aluminum-facedseal-antthatpermanentlyadherestoalmostanysurface.Itcanbeusefulforsealingroofjunctions,looseflashing,eaves,andgapsbetweenchimneysandwalls.Itiseasilyapplied,requiresnospecialtools,andresistswater,rust,mold,andmildew.

AndekCorporation850GlenAvenueP.O.Box392Moorestown,NJ08057-0392856-786-6900888-462-6335www.andek.com

Copper.MeshCoppercleaningmeshisarolled,flattenedstripofknittedcoppermeshthatcanbecuttoanylength.(Itissimilartoflattenedsteelwool.)Itwillnotrustandisexcellentforstuffingintocracksandcrevicesinbuildings.

Koch-OttoYork6611KilloughRd.Houston,TX77086800-736-7036koch-ottoyork.com

“Stuff-It”“Stuff-It”isacoppergauzeproductwhichisusefulforpluggingholesthataretoobigtocaulkandtoosmalltowarrantcarpentryrepair(suchasopeningsaroundeaves).Itwillnotrust,stain,orbreakdown.

AllenSpecialProducts,Inc.P.O.Box605Montgomeryville,PA18936800-848-6805

Chimney.Caps Chim-a-latorCo. VestalManufacturing

5205208thSt. P.O.Box420Farmington,MN55024 Sweetwater,TN37874800-729-9505 423-337-6125www.dalsinmfg.com 800-456-9562 www.vestalmfg.com

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Appendix.2

Bat.Box.Construction.Plans

spacerstrips:ten1"x1"x10"boardstrips

1. Cutoutpieces.

2. Useaknife,saw,orroutertoroughenallinteriorsurfaceswithhorizontalscratchesorgrooves1/4"to1/2"apart.Payspecialattentiontoland-ingboardatbottomofbox.(Theportionofthebackthatextendsbelowtheboxwillserveasthelandingboard.)

Noteforrouterusers:Atthispoint,usearoutertocut1/4"verticalgroovesinsidepiecesat1inchintervals,thenskipthefollowinginstruc-tionsoninstallingspacerstripsandbaffles.Simplyfitthebafflesintothesidepiecegrooves,thenattachfront,back,androof.

If.not.using.a.router:

3. Attachsidestofrontusingwoodscrews.(Caulktheseams,butdonotusewoodglueonanypartofthebatbox.)

4. Attachrooftosidesandfrontusingwoodscrews(caulktheseams).Roofcanbeslightlyslantedtopromotewaterrunoff.

Installing spacer strips and baffles:5. Positiontheboxsothatthefrontrestsonata-

bletop,andthesidesandroofextendupwards.

6. Attachtwo1"x1"x10"interiorspacerstripstoinsideoffrontpieceusingfinishingnailsorwoodscrews.Makesurethestripsfittightlyagainstthesidepieces.

7. Attachfirst1/4"x10"x101/2"baffletothespacerstripsusingfinishingnails.

8. Attachtwo1"x1"x10"interiorspacerstripsontothefirstbaffleusingfinishingnailsorwoodscrews.Makesurethestripsfittightlyagainstthesidesofbox.

9. Attach1/4"x11"x101/2"baffletothespacerstripsusingfinishingnails.

10–15.Continueattachinginteriorspacerstripsandbafflesaspreviouslydirected.Thisboxshouldhaveatotaloffivebaffles.

Tools:circularsaw

jigsaw

screwdriver

hammer

Materials:3/4"boardorexteriorgradeplywoodforfrontand

back

3/4"boardor1/2"to3/4"exteriorgradeplywoodforroof

1/4"lightweightplywoodforinteriorbaffles

1"x8"boardforsides(actualwidthafterplaning:73/4")

ten1"x1"x10"woodstripsforspacinginteriorbaffles

latexsiliconizedcaulk

darkbrownlatexpaintorstain

blackroofingpaper

exteriorgradewoodscrews

galvanizedfinishingnails

Small.Bat.Box.(12".x.12".x.8").AssemblyCapacity:.50.Bats

Thisbatboxshouldbeusefulwhentryingtoattractbatstoanarea.Itmaybeacceptedbymalebatsornon-reproductivefemales.Itisnotlargeenoughformostbatcolonies.

Pieces: (height x width)front:12"x12"exteriorplywoodorboard

back/landingboard:18"x12"exteriorplywoodorboard

sides:12"x~73/4"board

baffles:1/4"lightweightplywood

three10"x101/2"(ifusingspacerstrips)

two11"x101/2"

three10"x11"(ifrouter)

two11"x11"

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Small.Bat.Box.(12".x.12".x.8").

16. Attachthebackofboxtotheroofandsides(caulktheseams).Thebackpieceshouldextendbelowthebodyofthebox.(Theportionthatextendsbelowtheboxwillserveasthelandingboard.)

17. Paintorstaintheexteriorusingalatex-basedstain.(Donotstaintheinterior.)

18. Attachroofingpapertoroof.Caulktheseamatthebackwheretheroofattachestothebackpanel.

19. Tackroofingpaperontothefrontandsides,extendingitapproximatelysixinchesdownfromthetop.Thiswillhelpcreatedifferencesintemperaturesfromthetopoftheboxtothebottom.(Thisstepisveryimportant.)

Installation:Orienttheboxtowardsthesoutheastorsouthwest.

Toattractamaternitycolony,aboxshouldbeplacedinalocationthatreceivesatleastsevenhoursofsunlight.Boxcanbeplacedinacooler

locationtoattractmalesornon-reproductivefemales.

Installtheboxatleasttenfeethighontothesideofabuildingorpole.Boxescanbeplacedontrees,buttheymustreceiveadequatesunlight.

Donotinstallaboxoverawindowsill,deck,porch,oranyotherareawheredroppingsthatfallfromtheboxwillbeanuisance.

Maintenance:Batboxesrequirenomaintenancewhenbatsare

presentinthespringandsummer.Inspecttheboxeverywintertoidentifyareasinneedofrepair.

Wasps:Usealongthinsticktoremoveoldwaspnestsinthefallorwinter.NewnestscanbeknockedoutinMayorearlyJuneduringcoolmorningsoreveningswhenwaspsarelessac-tive.Do not disturb the box if bats are present.

2"

12" 12" 18"

4"

12"

7 3/4"

Front View Side View Cutaway View

Roo�ngPaper

Crevice widths:1" �rst 5 crevices3/4"–1 1/2" rear

Back

LandingBoard

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Small.Maternity.Colony.Bat.Box.(12".x.24".x.8").AssemblyCapacity:.150.Bats

Thisbatboxissuitableforsmalltomedium-sizedsummermaternitycolonies(upto150bats).Thisboxshouldbeinstalledinthespringbeforethecolonyisevictedfromthebuilding.

Tools/Materials: SeeSmallBatBoxInstructions



sides:12"x~73/4"board



two11"x221/2"

three10"x23"(ifrouter)

two11"x23"


1. Cutoutpieces.Cutvents(3"x1/2")intofrontandsidesusingjigsaw.

2–4.Followsteps2through4intheSmallBatBoxAssemblyinstructions.



6. Attachtwo1"x1"x10"interiorspacerstripstotheinsideofthefrontpieceusingfinishingnailsorwoodscrews.Makesurethestripsfittightagainstthesidepieces.

7. Attachfirst1/4"x10"x221/2"baffletothespacerstripsusingfinishingnails.

8. Attachtwo1"x1"x10"interiorspacerstripsontothefirstbaffleusingfinishingnailsorwoodscrews.Makesurethestripsfittightagainstthesidesofthebox.

9. Attach1/4"x11"x221/2"baffletothespacerstripsusingfinishingnails.


16–19.Followsteps16through19intheSmallBatBoxAssemblyinstructions.

Note:Ifagreatercapacityisneeded,additionalboxescanbeplacedside-by-side,oralargermater-nityboxcanbebuilt.

Installation and Maintenance: SeeinstallationandmaintenancenotesforSmallBatBox.

Small.Maternity.Colony.Bat.Box.(12".x.24".x.8")

2"

4"

12" 18"

24"

7 3/4"


Roo�ngPaper

Crevice widths:1" �rst 5 crevices3/4"–1 1/2" rear

Back

LandingBoard

Vent

Crevice

Baf�eVent

(one on each side)

�0

Large.Maternity.Colony.Bat.Box.(18".x.24".x.8")

Large.Maternity.Colony.Bat.Box.(18".x.24".x.8")Capacity:.150–300.Bats

Thisbatboxissuitableforlargesummermaternitycoloniesof150–300bats.Itshouldbeinstalledinthespringbeforethecolonyisevicted.Ifacolonylargerthan300batsistobeevicted,twoboxescanbeinstalledsidebysideoralargerbatboxcanbeused.ContactthePennsylvaniaGameCommissionorPennStateforfurtherinformationonlargerbatboxdesigns.

Tools:circularsaw

jigsaw

hammer

screwdriver

Materials:3/4"boardorexteriorgradeplywoodforfrontand

back

3/4"boardor1/2"to3/4"exteriorgradeplywoodforroof

1"x8"boardforsides(actualwidthafterplaning~73/4")

1/4"lightweightplywoodforinteriorbaffles

ten1"x1"x22"woodstripsforspacinginteriorbaffles

latexsiliconizedcaulk

darkbrownlatexpaintorstain

blackroofingpaper

exteriorgradewoodscrews

galvanizedfinishingnails


Crevice widths:1" �rst 5 crevices3/4"–1 3/4" rearLanding

Board

18"

24"

4"

2"

Roo�ngPaper

Vent

Vent(one on each side)

7 3/4"

24"

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sides:24"x73/4"board



two23"x221/2"

three22"x23"(ifusingrouter)

two23"x23"


Assembly:1. Cutoutpieces.

2. Useaknife,saw,orroutertoroughenallinteriorsurfaceswithhorizontalscratchesorgrooves1/4"to1/2"apart.Payspecialattentiontoland-ingboardatbottomofbox.(Theportionofthebackthatextendsbelowtheboxwillserveasthelandingboard.)

Noteforrouterusers:Atthispoint,usearoutertocut1/4"verticalgroovesinsidepiecesat1inchintervals,thenskipthefollowinginstruc-tionsoninstallingspacerstripsandbaffles.Simplyfitthebafflesintothesidepiecegrooves,thenattachfront,back,androof.

If.not.using.a.router:

3. Attachsidestofrontusingwoodscrews.(Caulktheseams,butdonotusewoodglueonanypartofthebatbox.)

4. Attachrooftosidesandfrontusingwoodscrews(caulktheseams).Roofcanbeslightlyslantedtopromotewaterrunoff.



6. Attachtwo1"x1"x22"interiorspacerstripstotheinsideofthefrontpieceusingfinishingnailsorwoodscrews.Makesurethestripsfittightlyagainstthesidepieces.

7. Attachthefirst1/4"x22"x221/2"baffletothespacerstripsusingfinishingnails.

8. Attachtwo1"x1"x22"interiorspacerstripstothatbaffleusingfinishingnailsorwoodscrews.Makesurethestripsfittightlyagainstthesidepieces.

9. Attachthe1/4"x23"x221/2"baffletospacerstripsusingfinishingnails.


16. Attachthebackofboxtotheroofandsides(caulktheseams).Thebackpieceshouldextendbelowthebodyofthebox.(Theportionthatextendsbelowtheboxwillserveasthelandingboard.)

17. Paintorstaintheexteriorusingalatex-basedstain.(Donotstaintheinterior.)

18. Attachroofingpapertoroof.Caulktheseamatthebackwheretheroofattachestothebackpanel.

19. Tackroofingpaperontothefrontandsides,extendingitapproximatelysixinchesdownfromthetop.Thiswillhelpcreatedifferencesintemperaturesfromthetopoftheboxtothebottom.(Thisstepisveryimportant.)

Note:Ifmorecapacityisneeded,additionalboxescanbeplacedsidebyside.

Installation.and.Maintenance:.SeeinstallationandmaintenancenotesforSmallBatBox.

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Appendix.3

Further.Information

General InformationFenton,M.B.1983.Just Bats.Toronto:Universityof

TorontoPress.

Fenton,M.B.1992.Bats.NewYork:FactsonFile.

Richarz,K.,andA.Lumbrunner.1993.The World of Bats: Flying Goblins of the Night.NeptuneCity,N.J.:T.F.H.

Robertson,J.1990.The Complete Bat.London:ChattoandWindus.Schober,W.1984.TheLivesofBats.NewYork:Arco.

Tuttle,M.D.1988.America's Neighborhood Bats.Austin:UniversityofTexasPress.

Advanced ReadingFindley,J.S.1993.Bats: A Community Perspective.

Cambridge:CambridgeUniversityPress.

Hill,J.E.,andJ.D.Smith.1984.Bats: A Natural His-tory.Austin:UniversityofTexasPress.

Kunz,T.H.1982.Ecology of Bats.NewYork:PlenumPress.

Kunz,T.H.1988.Ecological and Behavioral Methods for the Study of Bats.Washington,D.C.:Smithso-nianInstitutionPress.

Wimsatt,W.A.1977.The Biology of Bats.Vols.1–3.NewYork:AcademicPress.

Books for Younger ReadersCannon,J.1993.Stellaluna.SanDiego:Harcourt

Brace.

Gibbons,Gail.1999.Bats.NewYork:HolidayHouse.

Halton,C.M.1991.Those Amazing Bats.Minneapo-lis:DillonPress.

Harrison,V.1989.The World of Bats.Milwaukee:G.Stevens.

Jarrell,R.1964.The Bat Poet.NewYork:CollierBooks.

Lovett,S.1991.Extremely Wierd Bats.NewYork:J.Muir.

Mulleneux,J.1989.Discovering Bats.NewYork:FranklinWatts.

Selsam,M.E.,andJ.Hunt.1991.A First Look at Bats.NewYork:Walker.

Ungerer,T.1961.Rufus.NewYork:Harper.

Wood,L.C.1991.Bats.Mankato,MN:CreativeEducation.

VideosThe Season of the Bat.(27minutes)availablefrom:

ThePennsylvaniaWildResourceConservationFundP.O.Box8764Harrisburg,PA17105-8764

Bat-Free Belfries: A Guide to Bat-Proofing.(23min-utes)availablefrom:ThePennStateCooperativeExtensionofficeinyourcounty.

or

PublicationsDistributionCenterThePennsylvaniaStateUniversity112AgriculturalAdministrationBuildingUniversityPark,PA16802

Web SitesBatConservationandManagement

BCMisaPennsylvaniacompanythatprovidesextensiveinformationandon-siteassistanceforbothattractingandexcludingbats.www.batmanagement.com

BatConservationInternational TheBCIWebsitehasinformationonbatecology,management,andconservation.www.batcon.org

��

Lisa M. Williams, PennsylvaniaGameCommissionMargaret C. Brittingham, professorofwildliferesources

Originally printed August 1995; revised October 2006.

Partial funding for this publication was provided by the Pennsylvania Wild Resource Conservation Fund and the National Fish and Wildlife Foundation. Illustrations on pages 1,2,3 (top), 4, and 13 by Ned Smith, courtesy of Marie Smith. Illustrations on pages 3 (bottom), 5, 7, 9, 10, 12, and 15 by Jeffery Mathison. Illustrations on the cover and on page 6 by Phil Sharbaugh.

Visit Penn State’s College of Agricultural Sciences on the Web: www.cas.psu.edu

Penn State College of Agricultural Sciences research, extension, and resident education programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylva-nia, and the U.S. Department of Agriculture.

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