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Musger, D. M., N. H. EulrssJR,,B. H. HaNsoN, NoS. G. Zonpow.1997.A funnel trap for sampling salamanders n wetlands. Herpetol. Rev.28:132-133.PrrrnsoN, C. R., .lNo M. E. Donces. 1992. The use of automateddataacquisition echniques n monitoring amphibianand eptilepopulations.1n D. McCullough, and R. Barrett (eds.),Wildlife 2001: Populations,pp. 369-378. Elsevier Applied Science,London.RrcHrnn,K. O. 1995. A simple aquatic unnel trap and ts applications o

wetland amphibian monitoring. Herpetol. Rev. 26:90-91.Suerpen,H. 8., R.A. Alnono, B. D. Wooowano, S. J. Rrcuanos, R. G.

Aluc, aNnC. G.q.scoN.994.Quantitativesampling of amphibian ar-vae. 1nW. R. Heyer, M. A. Donnelly, R.W. McDiarmid, L. C. Hayek,and M. S. Foster (eds.),Measuring and Monitoring Biological Diver-sity: StandardMethods orAmphibians, pp. 130-141.Smithsonian nst.Press.Washington. .C .SnrrH, G. R., aNoJ. E. Reruc. 1996.Effectivenessof aquatic unnel trapsfor sampling amphibian arvae. Herpetol. Rev. 2'7:190-191.

Herpetological Review, 2003, 34(2), 130-132.O 2003 by Society for the Study ofAmphibims and Reptiles

Reconstructing Thermochron iButtons to ReduceSize and Weight as a New Technique in the Studyof SmallAnimal Thermal BiologyKYLIEA. ROBERT

Mrlrrc.r'^EL;:+FroMpsoNH eydon- rurence Zoology Building (A08

School of Biological Scienceand Institute ofWikllife ResearchThe University of Sydney, NSW 2006, Australiae-mail ( KAR) krobe t @bio.usyd.edu.at"

Recent developments n small electronic emperature ecordersdesigned or use n the food industry have he potential to revolu-tionize the collection of thermal data n small animals. Collectingtemperaturedata n small reptiles s most often restricted o labo-ratory studies n thermal gradients(Greenberg1976;Licht et al.1966;Sievet and Hutchison 1991),by the useof physicalmodelsplaced n the field (Hertz 1992;Porter et al. 1973),or by insertinga cloacal thermocouple/thermometersoon after capture in fieldstudies Avery 1982;Schwarzkopf nd Shine 1991).Thermalgra-dients measureselected hermal preferencesn an artificial envi-

ronment,modelsestimateoperative emperatures n the field, andcloacal thermocouple/thermometermeasurementsn field studiescan only measureactive individuals or those that take refuge inaccessible reas.Eachofthe above echniquesalone doesnot pro-vide a true representation f the animal's "natural" or "field" ther-mal biology, particularly in periods of inactivity, hibernation orwithin naccessile refugia.With modification, the DS1921 Thermochron iButtons manu-factured by Dal las Semiconductor (Texas, USA)

(www.ibutton.com/ibuttons/thermochron.html), small light-weight real ime and emperature ecordingdevice, can be attachedexternallyor implanted nternally into small animals.The unmodi-fied DS1921 Thermochron iButton weighs approximately 3.0 g,is 17 mm in diameter and 6 mm in thickness. By disassemblingunits and then reconstructingwithout the exterrral stainlesssteelhousing,the weight can be halved to approximately 1.5 g or lessand he dimensions educe o the size of the circuit board which is14 mm in diameterand the thickness dependsupon the new bat-tery size.The DS1921 Thermochron iButton integratesa thermometer,real time clock and memory for storing temperature eadings. taccuratelymeasures emperatures loC from as ow as-2OoC o+85"C in 0.5oC ncrements.Temperature eadingsare available ntwo formats which run concurrently 1) time vs. temperaturemodethat records emperatureand date-stampswhen it occurred,2) his-togram mode that measures he frequency of temperature n 2oCincrements ather than specific times of occurrence.The DS1921Thermochron Button can og up to 2048 consecutive emperaturereadings n read-only memory, after which readingscan be eitherstoppedor enabled o roll over. The histogrammode has 63 binsof memory set at 2oC intervals, and each bin can store 65,000readings Greaves 999).The DS1921Thermocron Button'scanbe launched and downloaded with the use of a reader(Blue DotReceptor")connected o an existing PC computer with free soft-

ware downloaded from Dallas Semiconductor (available atwww.iButton.com). Recordingsare madeat user defined ime andrates, with a maximum start delay of 45 days and recording rateranging from 1 every minute to one every 255 minutes. The lifeexpectancyof the DS1921Thermochron iButton is more than 10years or greater than I million samples, whichever occurs first(Greaves 1999)'.To date, our reconstruction of the DS1921

{II Grommet

VBAT trace

lO traceon backside

cBatteryB Outer anFrc. l. Construction of the DS1921 Thermochron Button, (A) Battery (B) Completeunit (C) Circuit board.See ext for explanation of components.

Inner an GND race

VBAT

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l

t

Thermochron iButton has not altered the per-formance or the life expectancy and not a singleunit has failed.

Construction of the DS192l ThermochroniButton.-The DS 1921 Thermochron Buttonis constructed(Fig. 1) of two stainless steelcups that rrake up the housing separated by aplastic grommet.The plastic grommet solatesthe IO (data) and GND (ground) sections ofthe circuit board externally and the VBAT(power) and GND connections internally.Springs are welded to thepositive andnegativeterminals of the battery. t is important that thepositive and negative terminals do not touchor the battery will short out causing rapidbattery drain. Thebattery "snaps" into the plas-tic grommet. The circuit board is positionedin the bottom of the inner horising with thecrystal facing up. The semicircle trace on thefront side of the circuit board is VBAL Theother arge race s GND, corresponding o thesprings on the battery. The back of the circuitboard s one arge IO fface, which makes contactwith the bottomof the nner housing.The grommetand battery slides on top of theinner housing with the VBAT and GND terminals aligned. Thiscombination then slides nto the outer housing and the GND bat-tery spring makes contact to the outer housing. The outer housingis crimped over the grommetand nner housing, holding the con-struction together.

De-housing of the DS192l Thermochron Button.-To reducethe sizeand weight of the DS1921 Thermochron iButton for useon small animals he iButton canbe opened o remove he internalcomponentsandreconstructedwithout the stainlesssteel housingthat accounts or a argeproportion of the weight A vise should beused o hold the DS1921 Thermochron Button and a small toothhacksaw (32 teethlinch) can be used tomake vertical cuts through the outerhousing n 3 or 4 evenly spaced utsaround the housing. By using a pair ofneedle nosedpliers, the outer housing canbepulled away from the inner, not unlikepealing abanana.

Reconstructionof theDSl92l iButtonwithout the housing.-Outside of thehousing the circuit board should besoldered o the battery Gig. 2). To avoiddamage o the battery it is best to use newbatterieswith solder tabs attached whichare available upon request from mostmajorbatterysuppliers.The DS 1921usesa 3 Volt lithium BRI225 battery; asmaller battery such as BR1216 orCR1025, can be substituted,but theyhave a shorter lifetime. The bottom tabis VBAI and the tab that comesover thetop of the battery is GND. If the batteryis not insulated, a piece of plastic tapeshould be used to prevent the GND tab

Frc. 2. Reconstructing he DS1921 Thermochron iButton without housing (A) Circuit boardsoldered o battery with rigid exposedwires attached(B) Insulated battery soldered o circuitboard viewed from above(C) Modified unit complete and coated n red Plastidip@.

touching the side of the battery which would cause the battery toshort. It is important to line the tabs up with the, traces on thecircuit board and solder them.

To attach he unit to the reader Blue Dot Receptor') a rigid wireneeds o be soldered to the IO trace and another to the GND traceon the reconstructedunit (Fig. 2). One wire should be thicker indiameter or color coded for easy identification when attaching tothe reader.These wo wires provide exposed eads or attachmentto the reader Fig. 3). The wire attached o the IO trace connects othe inner contact on the reader arrd the wire attached to the GNDtrace connects to the outer contact on the reader. To connect theunit to the reader,one end of a wire needs o be coiled around heinner contact of the readerand the other end with a small allieator

Frc. 3. Reader (Blue Dot Receptor@) howing wires coiled around contact points that then attach toexposed eads on the modified units via alligator clips.

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Frc. 4. A female EulamprusThermochron Button.

nmDanum fitted with a modified

DaysFrc.5. Thermal rofileof a captiveemaleEulamprusympanum vet

one-week t a 5-minute ampleate.clip can then be attached o the exposed O wire on the unit. An-other wire should be coiled around he outer contact ofthe readerwith the opposite end attached o the exposedGND wire on theunit also with a small alligator clip (Fig. 3). After testing the sol-dered unit, it should be sealed to ensure it is watertight withPlastidip' (Minnesota, USA) (www.PLASTIDIP.com ) with theexposed ends of the IO and GND wires emerging from thePlastidip"Fig. 2).We tested the modified unit on six gravid female Eulamprustympanum over severalweeks in laboratory enclosures.Lizardswere housed ndividually in 620 x 400 mm enclosureswith 20-30mm depth of soil, flat rocks and eaf litter for shelter.Lizards wereprovided with heat from 100 W incandescentbulbs at one end oftheir enclosure o allow them to thermoregulate.Enclosurespro-vided a thermal gradientof 20 to 40 + 1'C during daylight hoursand20+ 1oC during the night. The modified units where attachedto the backs of lizards with Super Glue' (cyanoacrylic glue) be-hind the head,between he shoulderblades(Fig. a) andgavecon-tinuous measurements f temperatureat 5-minute. intervals (Fig.5). Measurements an be downloadedand units can bere-launchedwhile the unit remainsattached o the animal.The unit will detachfrom reptiles upon shedding or acetonecan be applied to the site

of attachment to remove the unit prior to shedding.Acknowledgmenrs.-I thankPatrick Evans rom iButton support,Joerg

Suckau and Basil Panayotakos rom the School of Biological Sciencesworkshop for technical advice. Lizards were colleoted under scientificlicence from the New South Wales National Parks and Wildlife Service(82082) and researchwas approvedby the University of SydneyAnimalCare and Ethics Committee (L04ll0-981112855).The project was sup-pofted in part by an ARC Large Grant to M. B. Thompson and by anEthel Mary Read ResearchGrant.from the Zoological Society of NewSouthWales to K. A. Robert.

Ltrsuruns CrrnoAvpnv, R. A. 1982. Field studiesof body temperaturesand hermoregula-

tion. In C. Gans and F. H. Pough (eds.),Biology of the Reptilia, pp.93-166.Vol. 12.PhysiologyC. PhysiologicalEcology.Academic Press,New York.

GnrevEs,P. 1999.Media Release une 15, 1999.Dallas SemiconductorCorp.

GnenNnnnc, . 1976. Thermoregulatory aspectsofbehaviourin the bluespiny lizard Sceloporous cyanogenys Sauria, Iguanidae). Behaviour59:I-21.

Hsnrz, P. E. 1992. Evaluating thermal resourcepartitioning by sympatriclizards Anolis cooki andA. cristatellus'. a field test using null hypoth-eses.Oecologi 90:127 136.

LrcHr, P.,W R. DewsoN,V. H. SnoEuerrn, aNoA. R. MarN. 1966. Obser-vations on the thermal relations of westem Australian lizards. Copeia1966:97-110.

Ponrpn,W P.,J. W. MrrcHer-L,W. A. Bscxrr,reN,No C. B. osWnr. 1973.Behavioral implications of mechanistic ecology-thermal and behav-ioral modeling of desert ectotherms and their microenviroment.Oecologia73:1-54.

Scuunzrorr, L, eNo R. SsrNs.1991. Thermal biology of repoduction nviviparous skinks, Eulamprus tympanum: why do gravid females baskmore? Oecolog a 88 562-5 69.

Srevrnr,L. M., lNn V. H. HurcursoN. 1991. The influence of photoperiodand position of light source on behavioural thermoregulation inCrotaphytus collaris (Squamata: guanidae).Copeia I 991 105-1 10.

NATURAL HISTORY NOTESInstructions or contributors o Natural History Notes appear n Volume

34, Number I (March 2003).CAUDATA

AMBY STOMA TI GRI N UM (Tiger Salamander).PREDATION.Although a wide variety of birds havebeen documentedor impli-catedas predatorsof Ambystoma tigrinum (Lannoo and Phillips,in press In M. J Lannoo [ed.],StatusandConservation f U.S.Amphibians. Univ. California Press,Berkeley), most of the spe-cies argetaquatic arval forms. On 19June2001 n Taylor County,Georgia, USA, I encountered a cache of numerous animals im-paled on a barbed-wire fence by loggerhead shrikes (Laniusludovicianus).Herpetofauna ound among he cache ncluded sev-eral adult HyIa squirella and H. cinerea, and onepost-metamor-phic A. tigrinum. Although amphibians have beenreported n thediet of loggerhead hrikes Yosefand Grubb 1993.Condor95:I2l-13 1 , I believe this is the first reported observationof loggerheadshrikespredatinga salamander.

406 g sL$ e o$o t ca.Ef l 2 0

4 E

132 Herpetological Review 34(2 , 2003