infrared-triggered cameras for detecting wildlife: an evaluation and review

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Infrared-triggered cameras for detecting wildlife an evaluation and reviewAuthor(s) Don E Swann Christine C Hass David C Dalton and Sandy A WolfSource Wildlife Society Bulletin 32(2)357-365 2004Published By The Wildlife SocietyDOI httpdxdoiorg1021930091-7648(2004)32[357ICFDWA]20CO2URL httpwwwbiooneorgdoifull1021930091-764828200429325B3573AICFDWA5D20CO3B2

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Infrared-triggered cameras have been used toremotely record wildlife activity for more than 40years (see review in Cutler and Swann 1999)However due to the technical skills required tointegrate infrared and camera equipment this tech-nology did not become popular with biologistsuntil the development of commercial camera sys-tems particularly the TrailMaster (Goodson andAssociates Inc Lenexa Kans Kucera and Barrett1993) Infrared-triggered camera systems are nowwidely used in vertebrate ecology with applica-tions in nest ecology population estimation behav-ioral ecology mammal inventories and studies ofanimal damage (Karanth and Nichols 1998 Cutlerand Swann 1999 Martorello et al 2001Wilson andDelahay 2001) In this paper we restrict our dis-cussion to cameras triggered by infrared sensors

and not those that use pressure-plate triggeringdevices (egYork et al 2001 Moruzzi et al 2002)

An undeniable appeal of infrared-triggered pho-tography for wildlife managers is that the resultingphotographs often of elusive animals are useful forinterpreting wildlife to decision-makers and thepublic (Cutler and Swann 1999) However thistechnology has the added advantage of providingdata that are difficult to obtain using other meth-ods These include robust estimation of abundanceof species that are difficult to capture either byldquorecapturingrdquomarked individuals with photographsafter an initial capture (Martorello et al 2001) or byusing natural markings without capture (Karanthand Nichols 1998Trolle and Kery 2003) Becausespecies confirmation is more reliable than identifi-cation based on tracks or other sign this method is

EVALUATING INFRARED-TRIGGERED CAMERAS 357

Wildlife Society Bulletin 2004 32(2)357ndash365 Peer refereed

Address for Don E Swann Saguaro National Park 3693 Old Spanish Trail Tucson AZ 85730 USA e-mail Don_SwannnpsgovAddress for Christine C Hass Audubon Appleton-Whittell Research Ranch HC 1 Box 44 Elgin AZ 85611 USA Address forDavid C Dalton 9572 Banbridge Street Tucson AZ 85747 USA Address for Sandy A Wolf Coronado National Memorial Here-ford AZ 85616 USA

Infrared-triggered cameras fordetecting wildlife an evaluation and

review

Don E Swann Christine C Hass David C Dalton and Sandy A Wolf

Abstract We evaluated the abilities of 6 infrared-triggered camera systems (TrailMaster 1500TrailMaster 500 Buckshot RTV Buckshot Scout CamTrakker and DeerCam) to detect 3sizes of animal models at 2 heights above ground and from 3 distances We also deter-mined the size of the infrared detection zone and the relative sensitivity of different pas-sive camera systems All camera systems tested had a detection zone that was narrow inthe vertical dimension (3ndash7o) Except for the TrailMaster 500 all systems also had adetection zone that was narrow in the horizontal dimension (lt10o) Sensitivity variedamong camera systems Most performed well at default or high sensitivities theCamTrakker and the Buckshots set at highest sensitivity produced the most detections Allsystems except the Buckshot RTV performed better at lower ambient temperatures Wereview technical aspects of infrared-triggered photography and recommend howresearchers can improve their success in detecting animals by selecting the appropriatesystem for their study area and target species and by careful placement and precise align-ment of camera units in the field

Key words infrared photography remote camera sighting methods

07-Swannqxd 7204 1047 AM Page 357

ideal for confirming presence of rare species (Bullet al 1992) and determining use of areas of man-agement interest such as water catchments (Bleichet al 1997) and highway underpasses (Foster andHumphrey 1995) As a resultwe expect that use ofthe technology will continue to rise

Nearly all wildlife camera systems have featuresthat are necessary for work under rugged field con-ditions (weatherproof housingautomatic focus andflash and ability to attach to a tree or other struc-ture) but they vary greatly in optional featuresThey range in price from (US) lt$300 to gt$600Two sensor types are available through suppliers ofhunting and scientific equipment ldquoActiverdquo systemssuch as the TrailMaster1500 and 1550 operate inthe near infrared band(800ndash1000 nm) and senda single beam analogousto an invisible string to aseparate receiver When apassing animal interruptsthe beam the receiversends a signal to theattached camera to take aphotograph (Figure 1)

Most systems are ldquopas-siverdquo in that they detectdifferences between am-bient background temper-ature and the rapidchange in heat energy

caused by a moving ani-mal (Figure 2) Passivesystems operate in thethermal infrared band(3000ndash10000 nm) Be-cause some backgroundldquonoiserdquo is generated bythermal radiation fromnontarget objects and thesensor itself these sys-tems incorporate a presetthreshold to prevent falsetriggers Passive camerasystems have wider zonesof detection than activesystems with the size andshape of the zone depend-ent upon the configura-tion of the sensor andfocusing lens

As a result of differences in sensors features andcost researchers starting work with infrared-trig-gered camera systems face an array of options Thepurpose of this paper is to compare the importantparameters of 6 widely available camera systemsTo compare ability to detect animals in differentfield situations we experimentally determineddetection rates of model animals of different sizesat different distances We also directly measuredthe zone of detection and sensitivity of each systemat different temperatures in a controlled laboratorysituation Based on these results and on a summa-ry of the features available we offer recommenda-tions for choosing the most appropriate system for

358 Wildlife Society Bulletin 2004 32(2)357ndash365

Figure 1 Typical configuration of an active infrared camera system

Figure 2 View of passive infrared camera system shows 2 units 1 set high above ground and1 set low Unit height and distance to target animal influence the size of the detection zoneor area where animal is detected


different field applications and for making moreeffective use of infrared-triggered camera systemsin general

MethodsWe compared 6 camera systems manufactured

by 4 companies the TrailMaster 1500 (active) and500 (passive) models by Goodson amp AssociatesInc the CamTrakker (passive) by CamTrak South(Watkinsville Ga) the DeerCam (passive) by NonTypical Inc (Park FallsWis) and the Buckshot RTV(passive) and Buckshot Scout (passive) by ForesiteInc (Denham Springs La)

We tested abilities of the different camera sys-tems by conducting 3 separate tests First wedetermined the ability of the camera systems todetect animal models based on model sizedistancefrom camera and sensor height above the groundSecond we used a movable point source of heat todetermine each systemrsquos vertical and horizontalzone of detection or horizontal and vertical dimen-sions of the area in which an animal would bedetected if present Third we used a point sourceof heat across a range of temperatures to determinethe relative sensitivities of each system

Model animal trialsWe compared the number of detections by each

camera system for 3 sizes of animal models 2heights above the ground surface and 3 differentdistances Trials took place in a temperature-con-trolled room at the Audubon Appleton-WhittellResearch Ranch in Elgin Arizona USA duringJanuaryndashApril 2002

We mounted camera units on stationary posts ina line with approximately 50 cm between unitsand leveled and aligned each unit Sensor heightwas set at 120 cm above ground (upper height) or20 cm above ground (lower height) Prior to begin-ning trials we determined for all camera systemsthat performance was not affected by whether filmwas loaded or not to reduce costcameras were notloaded with film during the trials

Different sensitivity settings are available formost camera systems Where possible we set sen-sitivity settings to the defaults recommended by themanufacturer Because the DeerCam had 2 recom-mended sensitivities we used standard and highsensitivity settings The 2 Buckshot models did nothave default settings so we ran trials at low medi-um and high sensitivity settings For this test only

we used both Buckshot models and combinedresults

Animal models were plastic bottles filled withwater the water was allowed to range in tempera-ture between 35ndash38oC The small model (meant tosimulate a marten [Martes spp] or skunk [Mephitisspp]) was a 19-liter bottle (19 kg) the mediummodel (meant to simulate a bobcat [Lynx rufus] orcoyote [Canis latrans]) was a 95-liter bottle (95kg) and the large model (meant to simulate a puma[Puma concolor] or gray wolf [Clupus]) was a per-son weighing approximately 72 kg The small-ani-mal model was dragged across the floor using arope the medium model was dragged on a smallcart approximately 5 cm above the ground surfaceand the large (human) model crawled on feet andhands across the floor All trials were timed andsimulated animals were dragged or crawled 5 macross the floor at a rate of approximately 05msec Room temperature was kept at 18ndash19oCand monitored throughout the trial

We conducted a series of 5 trials for each possi-ble combination of receiver unit height sensitivitysetting and animal model size at distances of 2 m5 mand 10 m from the units These distances coverthe range of typical field placement at less than 2m photos may be blurry and camera flash zones donot extend much beyond 10 m Observers wereused to record whether an event (indicated by acamera flash or detection light) was registered dur-ing each trial

Determining zone of detectionWe determined zone of detection using a small

ceramic heat source (approximately 1 cm2) thatcould quickly be heated to a detection temperature(gt100oC) by adjusting the applied voltage All cam-era units were set at a fixed distance of 183 cmfrom the heat source The heat source was movedhorizontally in a straight line in front of an opaquescreen that blocked heat produced by theresearcher To determine vertical dimensions foreach camera unit we centered the heat source andleveled the unit then moved the unit vertically in06-cm increments to determine the height (upperand lower point) where an event was detected Todetermine the horizontal dimensions of the detec-tion zone at each point along the height continu-um between upper and lower points we moved theheat source horizontally and recorded the distancebetween end points where an event could bedetected We repeated the measurement 3ndash5 times

Evaluating infrared-triggered cameras bull Swann et al 359


at each point and took the modal value as the finalmeasurement We used the maximum distancebetween end points to calculate the horizontaldimension Measurements for vertical and horizon-tal dimensions were transformed to degrees foranalysis

The extremely wide zone of detection for theTrailMaster 500 (up to 150o) precluded testing withour apparatus Likewise the small beam of theTrailMaster 1500 was not suitable for testing there-fore we tested zones of detection only forCamTrakkers (n = 5) DeerCams (n = 3) BuckshotScouts (n=4) and Buckshot RTVs (n=4) Samplesizes were based on the number of available units

Determining relative sensitivityWe determined relative sensitivity or the mini-

mum difference in temperature between thesource and the ambient temperature needed to pro-duce a detection eventwith the same apparatus weused to determine the detection zone We set sen-sor distance at 123 cm and placed the sensor at theapproximate center of thezone of detection as deter-mined in the detection-zone trials We varied thetemperature of the heatsource by adjusting volt-age applied to the sourceTemperature of the heatsource and opaque back-ground screen were deter-mined using a noncontactthermal probe Becausesensitivity varies withbackground temperaturewe determined relativesensitivity at 3 ranges ofambient temperatureslow (11ndash13oC) medium(20ndash26oC) and high(31ndash36oC) We deter-mined sensitivity forCamTrakkers (n=5) Deer-Cams (n = 4) BuckshotScouts (n = 4) BuckshotRTVs (n = 4) and Trail-Master 500s (n = 2)Because temperature sen-sitivities as calculated inthis experiment are con-text-dependent we pres-

ent results as relative sensitivities among camerasystems

Comparison of featuresFor each camera system we recorded the trigger

type suggested retail cost battery type and cameratype (included in each system) We recorded whichof the following features were present sensitivity-level controls time delays onoff timers and addi-tional features

ResultsModel animal trials

Abilities of camera systems to detect events var-ied slightly within trial sets but if a positive detec-tion occurred 3ndash5 positive detections alwaysoccurred within the set (Table 1) Total number ofdetections varied among camera systems and with-in systems where more than one sensitivity settingwas used The system with the greatest number ofdetections was the CamTrakker at default sensitivi-


Table 1 Detections of model animals moved in front of infrared-triggered camera systems dur-ing controlled field trials (n = 5) in JanuaryndashApril 2002 for each combination of 3 models at 2sensor heights and 3 distances

Lower Upperheight (20 cm) height (120 cm)

Camera Sensitivity detections Animal size 2 m 5 m 10 m 2 m 5 m 10 m

TM1500 Default 52 Small 0 0 4 0 0 0Medium 5 5 5 0 0 5

Large 5 4 5 3 5 5TM500 Default 53 Small 5 5 5 0 0 0

Medium 5 5 5 0 0 0Large 5 5 5 0 3 0

CamTrakker Default 78 Small 5 5 5 0 0 5Medium 5 5 5 0 0 5

Large 5 5 5 5 5 5Buckshot Low 17 Small 0 0 0 0 0 0

Medium 0 0 0 0 0 5Large 0 0 0 3 5 2

Buckshot Med 21 Small 5 0 0 0 0 0Medium 5 0 0 0 0 0

Large 5 0 0 0 0 4Buckshot High 77 Small 5 5 5 0 0 4

Medium 5 5 5 0 0 5Large 5 5 5 5 5 5

DeerCam Low 54 Small 5 5 0 0 0 0Medium 5 5 5 0 0 0

Large 5 5 5 0 5 4DeerCam Standard 60 Small 5 5 5 0 0 0

Medium 5 5 5 0 0 0Large 5 5 5 0 4 5


ty followed by the Buckshot set at high sensitivityThe Buckshot at low sensitivity had the lowestnumber of detections of any camera system

In general cameras set at the upper height (120cm above ground) detected only large-animal mod-els Cameras set at the lower position (20 cm aboveground) detected all sizes of models except forBuckshot set at lowest sensitivities which consis-tently detected only larger models (Table 1)

Zone of detectionHorizontal and vertical dimensions of the zone of

detection varied among camera systems (Figure 3)The DeerCam had the smallest mean detectionzone whereas the Buckshot had the largest (Figure3) All but one individual CamTrakker unit and allBuckshot units were offset below their vertical cen-ter (Figure 3) that is when they were set at a cer-tain height and leveled the sensors were aimedtoward the ground

Variability among individual units of each camerasystem differed by model and manufacturer (Figure3) CamTrakkers and Buckshot RTVs were relative-ly consistent among individual units howeverBuckshot Scout units showed considerable variabil-ity in vertical and horizontal measures of the detec-tion zone as well as in degrees offset (Figure 3)

Relative sensitivityRelative sensitivity was dependent upon back-

ground temperature for some camera systems butnot all (Figure 4) Increasing ambient temperaturedid not affect Buckshot RTVs regardless of sensitiv-ity setting Buckshot Scouts at low and mediumsensitivity settings DeerCams Trailmasters andCamTrakkers were all less sensitive at higher ambi-ent temperatures (Figure 4) Buckshots set at thehighest sensitivity settings were the most sensitiveof all camera systems testedwhereas Buckshots setat low sensitivity were the least sensitive Most ofthe other camera systems clustered with moderatesensitivity scores Camera systems differed in avail-able features (Table 2) They varied widely indesign battery type estimated battery life and sug-gested price


Figure 3 Sizes and shapes of the detection zones for each pas-sive system tested Measurements are in degrees Detectionzones are placed relative to the horizontal axis (0 degrees) toindicate the degrees of vertical displacement of the zones

Figure 4 Relative sensitivities of passive infrared camera sys-tems Sensitivity score was determined by measuring the mini-mum heat detected against a background at different ambienttemperatures A higher sensitivity score indicated the systemwas capable of detecting a smaller temperature differencebetween target and background BS = Buckshot TM =Trailmaster


DiscussionAlthough infrared-triggered camera systems are

relatively easy to use problems associated withthem frequently are discussed and sometimesappear in the scientific literature (Rice 1995Hernandez et al 1997 Cutler and Swann 1999Peterson and Thomas 1998) Infrared-triggeredcameras are prone to 2 types of errors false triggers(taking a photo not triggered by a target animal)and failure to photograph a target animal Falsetriggers are obvious by the lack of an animal subjectin the photo and may be caused by wind or rainmoving either vegetation or the support to whichthe unit is attached radiant heat in a portion of thedetection zone (for example in a partially shadedarea) or by an animal that is within the detectionzone but outside the camerarsquos range

Our results indicate that false triggers are morecommon for camera systems with wider detectionzones For example the TrailMaster 500 has such awide detection zone that false triggers may easily becaused by animals triggering the sensor before theyappear in the camerarsquos field of view (Hernandez etal 1997 Trolle and Kery 2003) Camera systemswith very narrow detection zones seem to producefewer false positives although they also may fail tophotograph some target animals

The reasons for failure to photograph target ani-mals are less obvious than with false triggers and

often there is no clear explanation of why a unit hasfailed in the field The variation in results of ourrepeated animal model trials (Table 1) suggest thatsystems may not trigger due to very subtle differ-ences in animal speed or height Major problems inthe field include chronic mechanical problemsimproper programming and battery failure (Rice1995 Hernandez et al 1997) Our results indicatethat setting a sensor at the wrong height aboveground or at the wrong sensitivity level (whereapplicable) also can result in missed photosHowever our results also indicate that failure tophotograph animals may be less related to low sen-sitivity than to setup problems The detectionzones of many of the camera systems we testedwere offset below center animals beyond a certaindistance could not be detected because the zone ofdetection was pointed toward the ground Whensetting up a camera unit it is important to use thesystemrsquos test mode and walk (or crawl) in front ofthe unit at different distances to ensure that targetanimals will be detected

Because our experience suggests that most prob-lems are associated with operator error we believesuccessful use of wildlife camera systems dependslargely on the appropriateness of the system for aparticular user Put simply individuals who are nottechnically inclined may wish to select fairly simplesystems with fewer features whereas the morecomplicated systems are probably more appropri-


Table 2 Summary of features for different camera systems tested in this paper Specifications provided by manufacturers

Camera system Battery Sensitivity TimeOther features Trigger Cost Battery life Camerac levels delays

Trailmaster 1500a Active $550 8 C 6 wk Olympus 30 gt100Event counter timing (8ndash12 mo for 1550)and sensitivity adjustable

Trailmaster 500b Passive $470 4 C 6 wk Olympus 5 20Event counter timing (gt1 yr for 550) and sensitivity adjustable

CamTrakker Passive $427 4 C 6 wk Samsung 1 6Timing adjustable to Evocadaynight or continuous

Buckshot RTV Passive $379 8 D 2 yr Buckshot 3 3Buckshot Scout Passive $389 2 D 2 yr Buckshot 3 3

4 AADeerCam Passive $300 2 9V 8 wk Olympus 2 10

Event counter timing Infinityadjustable

a TrailMaster 1500 and 500 are no longer available and have been replaced with 1550 and 550 prices are for the replacementsystems

b As of August 2002c Camera models may vary with availability


ate for users who are willing to trouble-shoot andtinker with their instruments In addition environ-mental situations ranging from snow and rain tothe behavior of particular animals may affect dif-ferent camera systems in different ways The fol-lowing evaluation of the different camera systemsreviewed in this paper is aimed at addressing theseissues

TrailMaster 1500This system performed well for large animals at

the default sensitivity setting but poorly for small-er-animal models at both heights and for medium-animal models at the upper height Because theTrailmaster 1500 is an active system using aninfrared beam (essentially an invisible string) thepoor performance for smaller settings was theresult of smaller-animal models passing beneath thelight beam Setting the transmitter and receiver lownear the ground surface can solve this problemprovided vegetation does not obstruct the beam

The TrailMaster 1500 (and its replacement the1550) is the only active camera system widely avail-able and has been used by biologists for many years(eg Kucera and Barrett 1993) It is very durablewe know of individual units that have been in con-tinuous use for gt8 years The 1500 has many fea-tures including multiple sensitivity settings andtiming options It is a complicated system to usebecause some programming is required each timebatteries are changed (no longer the case with the1550) Four separate parts (transmitter receivercord and camera) provide great flexibility for cam-era placementand the receiver continues to recordevents after a full roll of film has been exposed Adisadvantage is that if any of these parts fail (forexample if the cord is chewed by a rodent) theentire camera system will fail to photograph eventsMoving vegetation small animals (eg lizards)crawling on the receiver and precipitation can pro-duce unwanted events

TrailMaster 500This camera system was sensitive for all animal

models at lower heights It performed poorly whenset at the upper height The Trailmaster 500 has azone of detection that is much broader horizontal-ly than other camera systems but shallow vertically(4o according to manufacturer) It is very sensitiveat ambient temperatures lt26oC but loses sensitivi-ty in warmer temperatures

The TrailMaster 500 has been available for many

years is durable and has many features Its broadzone of detection allows detection of animals with-in a wide areabut a major problem is that false trig-gers may occur when animals are outside the cam-erarsquos field of view However this unit can be modi-fied to decrease the size of the detection zone(Hernandez et al 1997Trolle and Kery 2003) Likethe TrailMaster 1500 the 500 has many useful fea-tures (eg separate camera placement) but thesefeatures also make use more complicated

CamTrakkerThe CamTrakker detected all animal models at

lower heights and large models at upper heights Itdetected models of all sizes at 10 m TheCamTrakker has a fairly narrow and shallow detec-tion zone It was moderately to very sensitive atlower temperatures however sensitivity declinedwhen ambient temperature increased

The CamTrakker is sold under the name WildlifePro in the Forestry Suppliers Inc catalog TheCamTrakker is relatively easy to use and intermedi-ate in price between the TrailMaster 1500 and less-expensive systems such as the DeerCam The entiresystem is housed in one box so there are few partsto break down but it lacks flexibility in cameraplacement Due to its shallow zone of detectionthe CamTrakker is better suited for detecting largeanimals than smaller (lt5 kg) ones

Buckshot RTV and ScoutResults from the 2 Buckshot models varied great-

ly among sensitivity settings At low and mediumsensitivities there were few detections but at highsensitivity Buckshots performed well except atcloser distances at the upper height In sensitivitytests both the RTV and Scout set at high sensitivitywere the most sensitive of all systems tested Wefound large differences in sensitivity between theBuckshot RTV and Buckshot Scout at the same set-tings even though they appeared to use the samesensors and Fresnel lens We speculate this may bedue to variations in alignment of the Fresnel lens infront of the sensor These variations may alsoexplain the differences between the results of fieldtrials and the bench sensitivity tests

Buckshots are provided with the most durablehousing of all tested camera systems (the RTVmodel comes in a steel ammunition box) Buckshotunits had a large detection zone averaging 5ndash6o

horizontally and 6ndash65o vertically The high sensi-tivity settings are very sensitive which may lead to



false triggers due to heated ground or photographsof small mammals near the edge of the camera flashzone However the Buckshot system is one of thebetter cameras for photographing animals of lt5 kgReducing the detection zone by adding a piece ofplastic pipe to the sensor lens may reduce false trig-gers The large variability in size and location ofdetection zones of the individual Buckshot Scoutunits makes estimating the zone boundaries andthus setup more difficult Both Buckshot modelshave test modes that are activated by an externalmagnet that closes an internal reed switch Theseswitches were sometimes difficult to engage par-ticularly for the Buckshot Scout

DeerCamThe DeerCam detected animal models at both

standard and high sensitivities Most trials in whichit failed to detect events were for small and mediummodels at the upper height probably because of itssmall detection zone The DeerCam is easy to useand produces a large percentage of photographswith animals in them The DeerCam was quite sen-sitive compared to the other camera systems Thishigh sensitivity coupled with the small detectionzone creates a camera system that minimizes falsetriggers but requires careful aiming The DeerCam isthe least expensive of the systems we tested

Optimizing performance of infrared-triggered camera systems

Based on our field experience and the results oftests reported here we offer the following guide-lines to increase the success rate of photographingwildlife with infrared-triggered cameras systems

1 If possible choose a camera system based onsize of target species some systems are betterat detecting smaller animals than othersdetect All will detect large animals (egdeer[Odocoileus spp] American black bear[Ursus americanus])

2 Choose a camera system based on size of thetarget area Systems with a very narrowdetection zone are more appropriate for areaswith a narrow entrance such as a nest or bur-row systems with a wider detection zone aremore appropriate for recording activity in alarger area such as a waterhole

3 For passive units set sensor height accordingto target species lt2timesshoulder height for ani-mals lt1m tall at shoulder height for animals

gt1 m tall4 Use a very firm support because motion of

the sensor may produce false triggers5 Place the sensor so there is no vegetation in

the foreground that may trigger the cameraAnticipate what will happen if nearby branch-es are blown by the wind

6 Remember that cameras are autofocus andwill focus on the object nearest to them Toavoid out-of-focus pictures we recommendsetting the camera 2ndash5 m from the target area

7 Infrared sensors work better at cooler ambi-ent temperatures and are less consistent inwarm environments

8 For multipart systems reinforcing the cords(with duct tape or similar materials) can helpreduce cord loss due to animals chewing onthem

The strongest recommendation we can make toresearchers just starting to work with infrared-trig-gered camera systems is to take the time to careful-ly read the instructions provided and to practiceusing the units extensively before beginning fieldwork Particularly for researchers working inremote areas trials with the units set in an easilyaccessible place beforehand will help reduce lossof important data later Although there are manydifferences between the camera systems reviewedin this paper we have used all of them with suc-cess Howeverwe have learned through hard expe-rience that all remote camera systems are capableof failure if they are not properly used and thattypes of failure vary among systems

Acknowledgments We thank B Branan and LKennedy of the Audubon Appleton-WhittellResearch Ranch for allowing use of the GrasslandConference Center and for assistance in data col-lection We thank Saguaro National Park particular-ly N Kline and the Phoenix Zoo particularly JWilliamson for support of this project SaguaroNational Park Fort Huachuca Wildlife Section andH G Shaw provided camera systems K BonineTEdwards L Kennedy C Schwalbe H Shaw E Stittand D Turner commented on early drafts of themanuscript

LLiitteerraattuurree cciitteeddBLEICHV C RT BOWYERAND J DWEHAUSEN 1997 Sexual segre-

gation in mountain sheep resources or predation WildlifeMonographs 134



BULL E L R S HOLTHAUSEN AND L R BRIGHT 1992 Comparisonof 3 techniques to monitor marten Wildlife Society Bulletin20406ndash410

CUTLERT L AND D E SWANN 1999 Using remote photographyin wildlife ecology a review Wildlife Society Bulletin 27571ndash581

FOSTER M L AND S R HUMPHREY 1995 Use of highway under-passes by Florida panthers and other wildlife WildlifeSociety Bulletin 2395ndash100

HERNANDEZ F D ROLLINS AND R CANTU 1997 An evaluation ofTrailmaster camera systems for identifying ground-nest pred-ators Wildlife Society Bulletin 25848ndash853

KARANTH K UAND J D NICHOLS 1998 Estimation of tiger den-sities in India using photographic captures and recapturesEcology 792852ndash2862

KUCERATEAND RHBARRETT 1993 The Trailmaster camera sys-tem for detecting wildlife Wildlife Society Bulletin 21505ndash508

MARTORELLO DAT H EASONAND M R PELTON 2001 A sightingtechnique using cameras to estimate population size of blackbears Wildlife Society Bulletin 29560ndash567

MORUZZIT LT K FULLER R M DEGRAAF RT BROOKS AND W LI2002 Assessing remotely triggered cameras for surveyingcarnivore distribution Wildlife Society Bulletin 30380ndash386

PETERSON L M AND J A THOMAS 1998 Performance ofTrailMaster infrared sensors in monitoring captive coyotesWildlife Society Bulletin 26592ndash596

RICE C G 1995 Trailmaster camera system the dark sideWildlife Society Bulletin 23110ndash111

TROLLEMAND MKERY 2003 Estimation of ocelot density in thePantanal using capturendashrecapture analysis of camera-trap-ping data Journal of Mammalogy 84607ndash614

WILSON G J AND R J DELAHAY 2001 A review of methods toestimate the abundance of terrestrial carnivores using fieldsigns and observation Wildlife Research 28151ndash164

YORK E CT L MORUZZIT K FULLER J F ORGAN R M SAUVAJOTAND

RMDEGRAAF 2001 Description and evaluation of a remotecamera and triggering system to monitor carnivores WildlifeSociety Bulletin 291228ndash1237

Don E Swann is a biologist at Saguaro National Park and hasused infrared-triggered cameras to photograph mammals innational parks in Arizona for more than 10 years Don has aBA in geologyndashbiology from Brown University and an MS inwildlife and fisheries sciences from the University of ArizonaChristine C (Chris) Hass is a senior research specialist at theUniversity of Arizona She previously worked as an independ-ent researcher studying social behavior and spatial ecology ofungulates and carnivores She has a BA and an MA in zool-ogy from the University of Montana and a PhD in biology fromthe University of North Dakota David C (Dave) Dalton is asenior design engineer at Roper Scientific Inc in TucsonArizona He has an AAS in electronics from County Collegeof Morris New Jersey a BS in computer science math andstatistics from Radford University and an MS in geophysicsfrom Virginia Polytechnic Institute and State University He has25 years of experience in bat research including developingfield techniques for cave and mine roost surveys microclimateenvironmental monitoring and foraging studies Sandy A Wolfhas worked for the National Park Service for 3 years and is cur-rently a biologist at Saguaro National Park She received a BSin wildlife and fisheries science and an MS in wildlife ecologyfrom the University of Arizona Her research interests includeurban wildlife particularly bats and techniques for monitoringand studying wildlife

Associate editor Applegate



Infrared-triggered cameras have been used toremotely record wildlife activity for more than 40years (see review in Cutler and Swann 1999)However due to the technical skills required tointegrate infrared and camera equipment this tech-nology did not become popular with biologistsuntil the development of commercial camera sys-tems particularly the TrailMaster (Goodson andAssociates Inc Lenexa Kans Kucera and Barrett1993) Infrared-triggered camera systems are nowwidely used in vertebrate ecology with applica-tions in nest ecology population estimation behav-ioral ecology mammal inventories and studies ofanimal damage (Karanth and Nichols 1998 Cutlerand Swann 1999 Martorello et al 2001Wilson andDelahay 2001) In this paper we restrict our dis-cussion to cameras triggered by infrared sensors

and not those that use pressure-plate triggeringdevices (egYork et al 2001 Moruzzi et al 2002)

An undeniable appeal of infrared-triggered pho-tography for wildlife managers is that the resultingphotographs often of elusive animals are useful forinterpreting wildlife to decision-makers and thepublic (Cutler and Swann 1999) However thistechnology has the added advantage of providingdata that are difficult to obtain using other meth-ods These include robust estimation of abundanceof species that are difficult to capture either byldquorecapturingrdquomarked individuals with photographsafter an initial capture (Martorello et al 2001) or byusing natural markings without capture (Karanthand Nichols 1998Trolle and Kery 2003) Becausespecies confirmation is more reliable than identifi-cation based on tracks or other sign this method is

EVALUATING INFRARED-TRIGGERED CAMERAS 357

Wildlife Society Bulletin 2004 32(2)357ndash365 Peer refereed

Address for Don E Swann Saguaro National Park 3693 Old Spanish Trail Tucson AZ 85730 USA e-mail Don_SwannnpsgovAddress for Christine C Hass Audubon Appleton-Whittell Research Ranch HC 1 Box 44 Elgin AZ 85611 USA Address forDavid C Dalton 9572 Banbridge Street Tucson AZ 85747 USA Address for Sandy A Wolf Coronado National Memorial Here-ford AZ 85616 USA

Infrared-triggered cameras fordetecting wildlife an evaluation and

review

Don E Swann Christine C Hass David C Dalton and Sandy A Wolf

Abstract We evaluated the abilities of 6 infrared-triggered camera systems (TrailMaster 1500TrailMaster 500 Buckshot RTV Buckshot Scout CamTrakker and DeerCam) to detect 3sizes of animal models at 2 heights above ground and from 3 distances We also deter-mined the size of the infrared detection zone and the relative sensitivity of different pas-sive camera systems All camera systems tested had a detection zone that was narrow inthe vertical dimension (3ndash7o) Except for the TrailMaster 500 all systems also had adetection zone that was narrow in the horizontal dimension (lt10o) Sensitivity variedamong camera systems Most performed well at default or high sensitivities theCamTrakker and the Buckshots set at highest sensitivity produced the most detections Allsystems except the Buckshot RTV performed better at lower ambient temperatures Wereview technical aspects of infrared-triggered photography and recommend howresearchers can improve their success in detecting animals by selecting the appropriatesystem for their study area and target species and by careful placement and precise align-ment of camera units in the field

Key words infrared photography remote camera sighting methods









































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infrared-triggered cameras for detecting wildlife: an evaluation and review

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