Capture and radio-transmitterattachment techniquesfor Roadrunners

SandraL. Vehrencampand Liza Halpenny

walksand jumpson the trap to peckat it, and eventual- sbreedingpart ofphysiologya two-year ofstudy Roadrunnersonthe behavior(Geococcyx and ly gets its feet caughtin the nooses.It usually takes californianus),a variety of techniqueswere employed several minutesof active lungingat the bait before a to capturethe birds and to attachradio transmitters.In bird becomessnared. Occasionally birds will work at a this paper we describethese techniquesand evaluate trap for 15 minuteswithout being caught,then lose their relative success.The studywas conductedat the interestin it. It is esse•,•t '.•,monitor the trap continu- Gamp PendletonMarine GorpsBase Reserve, about 10 ously.If the bird is not caughtsecurely, it can work its milesnorth of Oceanside,San Diego Gounty, Galifornia. way out of the noose in a few seconds,and if it is The Roadrunnersin thisarea were very shyand wary, securelycaught, it can injure its legsif left in the trap presumablydue to theoccasional appearance of Marine longerthan a few minutes.The trap is light enoughto troops and heaw vehicles.The birds preferentially be draggeda short distanceby the bird, but doesnot nestedin the largestclumps of prickly pear (Opuntia} need to be staked. cactus.Opuntia was typicallylocated in denseaggrega- This trap is inexpensiveand easyto construct.Many can tions on south-facingslopes. Seven active nestswere be set out simultaneously,and one personcan monitor found during one breedingseason by systematically 3 to 4 traps if they are carefully placed.However, the searchingthese areas. trap has 2 major disadvantages.The first is the low encounterrate of birds with traps, resultingin poor efficiencyof trappingeffort. We spentapproximately 12 Traps man-hoursmonitoring traps per capturedRoadrunner. Secondly,the trap selectivelycaught small males in our Raptor trap studyarea. None of thesebirds were seen again,and the few that were radio-trackeddisappeared from the Thistrap is a modifiedversion of theBal-chatri or studyarea within a few daysof capture.We surmised live-baitedfootnoose trap {Bergerand Mueller, 1959}. that thesewere youngdispersing or itinerantbirds, and We use an 18"square piece of 1/2"meshhardware cloth that their interestand persistenceat the trapsreflected as a base and attacha 12"x 8"x 11/2"cage of 1/4" their inexperience,unfamiliarity with the area, and re- hardwarecloth to it. The finer meshof the bait cageis ducedforaging success. Known breeding birds, especial- necessaryto preventthe bait fromescaping and to pre- ly females,actively avoided the trap or made a single vent the Roadrunnerfrom injuringthe bait. The trap is lunge at the mouse,then continuedon their foraging thenspray-painted a flat blackto improvevisibility of route.Traps placednear nestswere never successful. the bait. Noosesof medium-gauge{40 lb. test}monofila- ment fishingline are tied to the top of the base and cage.Noose loops of 2"to 3" in diameterplaced about Treadle trap 3"apart work best.The trapsare relativelylight, and severalcan be stackedtogether for transport,but they Thistrap employs a treadle-activated, spring-loaded tend to become entangled.White laboratorymice are door to captureforaging Roadrunners. It consistsof an the mosteffective type of bait; brownor blackmice are 18"-highband-shell-shaped body of 1/4"or 1/8"hardware less conspicuous,wild mice are much less active, and clothattached to a fiat 12" x 18"wooden base (Fig.1). lizardsare generallycryptic and inactive.The micedid The fine meshis necessaryto preventthe capturedbird notperish when left in the trapswithout food and water from injuringits bill. A smallmouse cage is attachedto and in full sunlightfor the entire morning. the insideback wall of the shell.A rat trap is attached to the base to supplythe closingmechanism. A wire This trap is placed either along trails and roadsfre- shapedthe sameas, but a bit largerthan, the mouthof quented by Roadrunners or near nests. A bird that the shell is connectedto the closingspring of the rat encountersa trap is usually attractedby the mouse, trap. Restraining"L's" are put on the rat trap springto

Page 128 North American Bird Bander Vol. 6, No. 4 keep the wire framefrom closingpast the mouthof the Mist net shell. Heavy black nettingis sewn looselyto the wire frame to completethe door.A "T" of woodattached to A standardheavy gauge 4"mesh mist net was used to the triggerof the rat trap forms a large treadle.The net nestingRoadrunners. The net was either mounted wire that holds down the springand attachesto the on poles in the standardmanner in the vicinity of triggermust be reshapedto sustainthe addedweight of knownnests, or gentlydraped around the cactusclump the treadle. The entire trap is spray-paintedblack. containinga nest.(The latter proceduredid not destroy When the'trap is set,the wire hoopdoor lies flat on the the net.) In generalthe net wasplaced on the downhill groundand the treadle is elevatedinside the shell. A side of the nest. The bird was then flushed off the nest white laboratory mouseis used as bait. from the uphill side, whereuponit glided or ran into the net. This methodsuccessfully captured all birds at This trap was placed alongRoadrunner foraging trails active nests,and failed only at nests that were later where birds leaving their nestswere known to pass. Birds attracted to the mouse hit the treadle at the first discoveredto be abandoned.The disadvantagesof the method are: 1) the large amount of time involved in lunge,thereby quickly snapping the doorshut. The trap searchingfor nests,and 2) a high probabilitythat the was developedtoward the end of our study and was adults will abandon their nest as a result of the distur- thereforeemployed only a few times,but it successfully bance. capturedall birds that encounteredit. It worked espe- ciallywell on breedingfemales. The primarydisadvan- Rock net tagesare its large size and heavy weight, making it difficult to store and carry. Roadrunnershave been knownto enterthe commerciallyavailable, collapsible, Thistrap was designed tocapture birds that habitually squirrel-sizedtreadle traps, but we believe that the perchon rockoutcroppings for displayingor sunning.It higher and shorterhome-made trap with the flexible consistsof a 3'-squarepiece of heavy black netting, door is more effective for tall birds. weighted on four corners, and covered with monofila- ment noosessimilar to thoseused in the raptortrap. It was drapedover a rockwhere a male was seengiving courtshipcalls severaltimes. His feet were caughtin the noosesthe next time he returned to the rock, but he slippedout before we couldreach him. This trap seems to work aboutas well as the raptortraps, but sinceit containsno bait, it mustbe placedin a commonlyused site.

Foot noose on a stick Thistrap consists ofa monofilament nooseattached to the endof a 6' stick.The nooseis openedand placed in a nest over the eggs,with the stick directedtowards the outsideof the nest clump. After the bird has settled onto the nest,the stickis pulled by a hidden person, closingthe noosearound the incubatingbird's feet. A similartrap is describedby Gartshore(1978). The noosestick was successfulthe one time we usedit, but it causeda great deal of trauma to both the bird and the investigator.The bird dove into the surround- ing cactusand becameentangled there. The investiga- tor was therefore forced to wade into the cactus as well. The nestsite was damaged,and the extremedis- turbance caused abandonment of the nest.

Summaryof trappingmethods Forstudies requiring thecapture ofbreeding Road- runners,it is muchmore productiveto searchfor nests, Figure 1: A home-madetreadle trap employinga rat- observethe movementsof thebreeders, then trap the sizedsnap trap for the closingmechanism. birdsaway from thenest in a treadletrap or footnoose

Oct.- Dec.1981 NorthAmerican Bird Bander Page129 trap. As discussed,trapping birds directlyat the nest were tiedaround the radioafter the wax-sealingstep, risks abandonment,and randomlytrapping foraging and potted in with the dental acrylic so that they birds and hopingto follow themto their nestsvia radio- emergedfrom the 4 cornersof theradio package. A soft trackingis inefficientbecause of thelarge proportion of vinyl pad wasglued to the backof theradio to prevent non-breedingbirds captured. chafingof the skin.The radio restedon the bird's back betweenthe scapulartracts with the antennapointing posteriorly.The top strapswere placedover the bird's Radio-trackingand attachmenttechniques shouldersand the bottomstraps went aroundthe rib cageunder the wings.Several methods of tying the Types of radios strapsover the chestwere attemptedwith varying success.Following Dunstan (1972) and Godfrey(1970) Threetypes of radio-transmitters wereused on the we tied the 2 shoulderstraps straight across the upper Roadrunners:1) a standardexternally mountedradio chestand the 2 underwingstraps straight across the rib for monitoringmovements and home ranges,2} an ex- cage,with a shortperpendicular piece connectingthe ternally,mounted radio with an internally implanted strapsat the midline. A secondmethod was to criss- thermistorlead for monitoringboth movementsand in- crossthe shoulderand under-wingstraps to form an ternal body temperature,and 3] an internally implant- "x" on the chest.With both of these methods,the birds ed thermistor radio. All transmitters were constructed managedto get their lower mandiblepermanently following the designof Bradbury et al [1979).Each caughtunder the straps,and thesemethods are there- radio operatedat a uniquecrystal-controlled frequency fore emphaticallynot recommended.The onlysuccess- in the 148 mHz range.Several modificationswere intro- ful harnesstechnique was a "back-pack"design, in duced. A 100 K ohm thermistor in series with a 150 K which only the under-wingstraps were tied acrossthe ohm resistor replaced the 220 K ohm resistor in all chest.The shoulderstraps were connectedto the un- temperature-sensitiveunits. Miniature crystals avail- able from Sentry ManufacturingCo., Chickasha,Okla- homa, and miniaturetransistors (Siemens BFS 20] were substitutedin the implantedradios to reducetheir size. Receivers from AVM Co., Dublin, CA, with hand-held Yagi antennas, were used to follow the radio-instru- mented birds. All externallymounted radios possessed a whip an- tenna, and were sealedin wax and pottedwith dental acrylic; finished weight ranged from 10 to 15 gm, dependingon the size of the batteryand the amountof potting. Implanted radios had no antenna, and were dipped in a special wax available from Mini-Mitter, Indianapolis,Indiana; finishedweight was between 1 and 2 •,,rn (dimensions8 mm by 15 mm]. The pulse interval of the temperature-sensitiveunits decreased with increasing temperature. The interval was mon- itored with either a homemadepulse timer that direct- ed continuousoutput into a Rustrakstrip chart record- er, or a commerciallyavailable pulse timer from AVM which had no provisionfor automaticrecording. Tem- perature-sensitiveradios were calibrated in a slowly coolingwater bath between 30øC and 45øC using a Schulteisfast-reading thermometer. A final check on the thermistor'saccuracy was made after implantation by comparingthe radio readingto the measuredcloacal temperatureof the bird.

Methods of attachment Figure 2. Ventral view of the "backpack"-styleharness- All externallymounted radios were harnessed tothe •ng techniquerecommended for all long- birds with 1/4"cottontwill. Two long lengthsof twill billed birds.

Page130 North AmericanBird Bander Vol. 6, No. 4 der-wingstrap on the sameside of the body (Fig2). The Discussion shoulderstraps were cut to the correctlength and looped at the end in advance,so that the under-wing •n thissection we attempt toevaluate the effects ofthe straps could be pulled throughthese loops and then varioustrapping and trackingprocedures on the behav- tied together.The final positionof the shoulderstraps ior of the Roadrunners.Roadrunners appear to be very couldtherefore be adjustedto comfortby the bird. This sensitiveto such disturbanceand many nests were methodof attachmentwas very quick and avoidedthe abandoned.We thereforehope that future studentsof problemof stuckbills. Roadrunnerbehavior and physiologycan avoid many of the mistakes we made. The externally mounted thermistorradio was harness- ed to the bird in the manner described above. The thermistorlead extendedabout 5 cm beyondthe radio A totalof 22 birdswere caughtin trapsplaced in forag- packageand was encasedin silasticsurgical tubing and ing areas.Five of thesewere females (4 of theseclearly sealed at the tip with medical silasticcement. A small in breedingcondition) and 17 were males (breeding incision was made in the skin on the back under the conditionuncertain, but only 5 were within weight radio package.A standardlaparotomy incision (Risser, range of known breedingmales). Of 20 birds released 1971)was then made on the left side under the last rib. in the study area, 9 were banded only, and '11were A wire with a loop on the end was passedfrom this bandedand outfittedwith radio transmitters.Only I of secondincision under the skin up towardsthe first in- the banded and releasedbirds was ever seen again, cision,and the thermistorlead was loopedthrough the and all of the radio-equippedbirds disappeared within hook and pulled under the skin. The thermistorwas 2-14days. Thus we were not able to detectany notice- directed into the peritoneum,sutured in place to a rib, able differencein behaviorbetween radio-equipped and the laparotomyincision sutured shut. A local anes- and non-radio-equippedbirds. Further, birds which thetic (Xylocaine ointment) and Neosporin antibiotic received thermistorradios requiring surgerydid not ointmentwere spreadon all incisionpoints. differ in disappearancerate from birds receivingstan- dardexternal radios. We thereforesuspect that the high To insert the internally mounted radio into the peri- disappearancerate of thesebirds is due to a highly toneum,standard laparotomy techniques were employ- mobilenon-breeding population rather than to the dis- ed (Risser,1971). The incisionwas only slightlylarger turbanceof captureand tracking. than that needed to view the gonads.The small wax- embeddedradio was coatedwith Neosporinantibiotic Nine additionalbirds were capturedfollowing discov- ointmentand gentlypushed into the peritoneum.The ery of their nests.Seven were caughtwith mist nets or musclelayer and skin layer were suturedseparately. traps in the immediate vicinity of their nests and 2 No anestheticwas necessary,the entire procedurewas were caughtin trapsplaced along predetermined travel very quick,and the birdsdid not appearstressed. routeswell away from their nests.Four of thesebirds remainedwith their nests,despite receiving type 2 or 3 thermistor radios, and 5 abandoned their nests but re- Comparisonof internal and external thermistors mainedon their territoriesfollowing either surgical im- Theexternally mounted thermistor radios had the im- plants or standard radios. Thus some birds did not portant advantagesof long-rangetransmission (1 km) abandoneven thoughthey were capturedon the nest due to the presenceof the whip antenna, and long and underwentsurgery, whereas others captured on radio life (3-6months/ due to the larger battery mount- the nest but not unnecessarilyhandled did abandon. ed to the back.However, the surgerywas very difficult The male and female of a matedpair abandonedtheir to performin the field, and the apparatusis undoubted- firstnest following capture in a mistnet at the nest,but ly more uncomfortablefor the bird. More importantly, did not abandontheir secondnest followingcapture well away from the nest. We therefore concludethat it the externally mounted thermistorsdid not give accu- rate readingsof body temperature.This appearedto be is capturenear the nestthat most disturbs the breeding Roadrunners,and not the surgical or radio-trackingpro- due to the fact that the radiobody was itselfsomewhat cedures. temperaturesensitive, causing a shift in the calibration curve when the radio was placed on the bird's body. Havingovercome most of the problemsof trappingand The miniaturized,implantable thermistors were there- monitoringRoadrunners, we havebeen able to quanti- fore developedto alleviatethis problem.While they fy the relative parental efforts of male and female did give accuratereadings of body temperature,they breeders and to obtain diurnal/noctural measurements had the distinct disadvantagesof short transmission of male, female,and non-breederbody temperatures. range (25-50m / due to the lack of an antenna, and short These data are reportedelsewhere (Vehrencamp, in life/1-2 weeks)due to thenecessarily small battery. press). In general, we have found the Roadrunner to

Oct.- Dec.1981 NorthAmerican Bird Bander Page131 be a verydifficult and inefficient subject for a stud•; much shortertransmitting range. The presenceor ab- involvingmanipulation of free-rangingnesting birds. senceof surgicalmanipulation did not appearto affect the probabilityof abandonmentby the bird. • Summary Literature cited As partof a study on the behavior andbreeding phys- Berger, D.D. and H.C. Mueller. 1959. The Balchatri: a iology of Roadrunners,a variety of capture and radio trap for the birds of prey. Bird Banding30:18-26. transmitter attachment techniqueswere devised and Bradbury, J.B., Morrison, D., and Stashko, E. 1979. tested. Capture proceduresincluded: a modified Bal- Radio-trackingmethods for bats.Bat ResearchNews chatrifootnoose trap, a home-madetreadle trap,a mist 20:9:17. net, an unbaitedfootnoose trap for rock perches,and a Dunstan,T.C. 1972.Radio-tagging falconiform and strigi- footnooseon a stick.Several types of radio-transmitters form birds.Raptor Research 6(3):93-102. and attachmentprocedures were alsoused: an extern- Gartshore,M.E. 1978.A noosetrap for catchingnesting ally-harnessedthermistor radio with temperature-sensi- birds. North American Bird Bander 3:102. tive leads implantedin the body cavity, and an inter- Godfrey, G.A. 1970. A transmitter harness for small nally implanted thermistorradio. The relative success birds. IBBA News 42:3-.• of these methods and their effects on the birds are Risser,A. '1971.A techniquefor performinglaparotomy evaluated.Capture of breedingbirds couldbe guaran- on small birds. Condor 73:376-379. teed only by first locatinga nest,but capturetechniques Vehrencamp,$.L. Bodytemperatures of breedingmale involvingthe nestoften causedabandonment. Only one versusfemale Roadrunners(Condor, in press]. harnessing technique for externally mounted radio transmittersproved successful.Internally implanted Departmentof Biology,C-016, University of California thermistorradios gave more accuratebody temperature (San Diego),LaJolla, CA 92093. readingsthan externallymounted thermistors but had a

Bird Banding in Alberta. Martin K. McNicholl (Edi- hearted contribution on the trials and tribulations of a tor]. 1981.The Alberta Naturalist,Special Issue No. 2, bander'swife are similarly agelessand do not reflect 73 pp. Available from: Federationof Alberta Natural- that they were written decadesago. ists, Box 1472, Edmonton,Alberta T5J 2N5, Canada. $3.50 Canadian. The recent studiesaddress an array of topics;papers by M. McNicholl and R. Fyfe and U. Banaschprovide A compendiumof 13 contributionsdealing with bird overviews of banding and raptor banding in Alberta bandingin Alberta and producedto commemoratethe while other authors provide new data on the local meeting of the American Ornithologists'Union in Ed- movementsof color-markedgulls, chickadeepopula- monton,this issuewas designedto provide an historical tions, and sex determinationof dippers to mention a perspectivefor the currentactive banding program in few. No discussionof banding in Alberta would be thisprovince. (Special issue No. 1, alsoissued in 1981is completewithout mentionof the activitiesof Edgar T. entitled "The history of the Federation of Alberta Nat- Joneswhose name is familiar to all perusersof the uralistsand its corporatemember clubs."lSpecial Issue WBBA annual report since1972. His impressivecontri- No. 2 includesa few articlespreviously published in butionsto the bandingprogram are summarizedhere other outlets,some dating back to 1928-1940,as well as as are the many activitiesof the late Ken Trann, a most new information presentedfor the first time. enthusiasticyoung Alberta bander whosebiography is The paperby William Rowan,"The scientificaspects of included. bird-banding"is every bit as applicable today as when All in all, thisis in fact a specialissue, a very thorough it was originallywritten in 1928!This paper, produced and enjoyableintroduction of banding in Alberta, its by one of the pioneersin migrationstudies and band- statedgoal, and a fitting tribute to Ken Trann to whom ing, is an eloquentplea for accuracyand experimental it is dedicated.I can recommendit to all and at today's designin banding as well as a condemnationof the pricesit is indeed a bargain. type of "picnicbanding" which we call "ring-and-fling" today!W. Ray Salt'spaper on recoveriesof Ferruginous Charles T. Collins Hawks banded in Alberta and Kathleen Salt's light-

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