Satellite and Ground Radiotracking of

FRANK C. CRAIGHEAD, JR. JOHN J. CRAIGHEAD CHARLES E. COTE HELMUT K. BUECHNER Smithsonian Institution

ADIOTRACKING AND MONITORING Of scribed by Maxwell at this conferenye, may R free-living animals in natural environ- prove effective for small animals. ments is providing an effective new technique This project was a joint endeavor be- for acquiring information on biological proc- tween the Smithsonian Institution and the esses, including animal orientation and navi- National Aeronautics and Space Administra- gation. To test the practicability of extending tion, conducted in collaboration with the the technique by using satellite systems for Montana Cooperative Wildlife Research tracking animals, a female elk was instru- Unit, the Environmental Research Institute, mented with an electronic collar. It con- the State University of New York at Albany, tained both the Interrogation Recording Lo- and the National Geographic Society. Pre- cation System (IRLS) transponder and a testing was conducted at the National Bison Craighead-Varney ground-tracking trans- Range, Moiese, Montana. The experiment mitter. The elk was successfully tracked was carried out at the Nztional Elk Refuge, and monitored by satellite during the month , , in cooperation with of April 1970. This was the first time an the US. Bureau of Sports Fisheries and Wild- animal had been tracked by satellite on the life, the Wyoming Game and Fish Commis- surface of the Earth. Information derived sion, the US. Forest Service, and the Na- from the present feasibility study provides a tional Park Service. Previous research under basis for assessing uses of the system, reducing NSF (617502) made possible the use of the the weight, and improving the configuration ground radiotracking system. of the instrument collar for monitoring a va- riety of large mammals. The minimum HISTORY OF PROJECT weight of the IRLS transponder, even with microminiaturization, makes its use impracti- The present project had its inception on cal for most small mammals and birds, A May 26, 1966, at a conference sponsored doppler-shift type of satellite system, as de- jointly by the Smithsonian Institution, the

99 100 ANIMAL ORIENTATION AND NAVIGATION

American Institute of Biological Sciences, PROJECllON and the National Aeronautics and Space Ad- ministration (ref. 1). At this time the possi- bilities for using the Nimbus meteorological satellites for tracking and monitoring wild animals were explored by biologists and eEgi- neers. An initial estimate of 11.3 kg for the IRLS instrument platform proved accu- rate. This transponder was heavy for use on wild animals, as it had been designed for oceanographic buoys and high-altitude weather balloons. It was apparent that a FIGURE 1. PRLS location technique: Distance large animal would be required for the first (4)between satellite and instrument platform experiments in satellite tracking of free-roam- generates a sphere with satellite at center (TI): ing animals. However, engineers calculated this sphere in space intersects the Earth in a that the weight could eventually be reduced perfect circle. Second perfect circle intersecting first at two points is formed by second interroga- by 50 to 75 percent. An elk was chosen for tion at T2.Platform position is readily selected on the first test becauze of its large size (about basis of prior information from previous orbits. 225 kg) , gentleness, and migratory behavior. In addition an accumulated background of MATERIALS AND METHODS experience in radiotracking and immobilizing elk (ref. 2) was available over a period of The experiment was carried out with the years in the Jackson Hole-Yellowstone Na- Nimbus I11 and IV satellites, using the IRLS tional Park area. Logistic support for the system to locate and interrogate the animals project was particularly favorable in the (refs. 3 to 5). The IRLS instrument was Jackson Hole area. designed with 28 channels of communication, A planning conference was held May 9- 10 of which were used in the present experi- 12, 1969, in Missoula, Montana, at which ment. One IRLS instrument was modified time biologists and engineers decided on the aild packaged into the collar for the elk, with configuration and packaging of the IRLS batteries as the source of power and solar transponder and selected parameters to be cells to maintain battery charge. To conserve monitored. A Craighead-Varney transmitter power, a timing system provided a 10-min was packaged with the IRLS transponder window for transmission during satellite over- since this ground-tracking system had a capa- passes. The radio transmitter power output bility that enabled observers to visually locate was 15 W to the antenna at a frequency of the elk, thus providing direct observations 466.0 MHz. with which to measure the accuracy of satel- The Nimbus satellites are in polar-sun- lite positioning. This 32.0 MHz tracking sys- synchronous orbits, and their exact position tem had been used to successfully track six above the Earth can be calculated. The cow elk for a total of 1216 animal tracking distance between the satellite and elk was days. In addition, one elk had been radio- determined by a radar-like interrogation. tracked from the to its This line generates a sphere, with the satellite summer range in Yellowstone National Park, at the center, that forms a perfect circle a distance of 64.4 airline km. where it intersects the Earth’s surface. An- SESSION 11: ANIMAL TRACKING 101 other circle is formed by the second interro- DATEDFRUN MO DAY YR 4 28 70 gation, intersecting the first circle at two ORBIT NUMBER 5082 points. The animal is located at one of these PLATFORM ID 105452 ELK two points; the other point is sufficiently dis- COMMANDTIME HH MM SSS tant from the animal, determined by prior 07 54 106 as FRAME 1 information, to be considered unlikely as the DATA RECEIVED animal’s position (fig. 1) . 2 UNUSED 1 UNUSED 4 ALTIMETER 3 UNUSED The Craighead-Varney ground-tracking 6 t12 VOLT BATTERY 5 RECEIVER SIGNAL transmitter (32 MHz) was installed in the 8 BATTERY TEMPERATURE 7 SKIN TEMPERATURE 10 -40 To tlO’C AMBIENT 9 0 TO +50’C AMBIENT lower compartment of the collar. Batteries 1,2 TIMER 11 t4.8 VOLT BATTERY I )UNUSED 1,3 LIGHT INTENSITY 28 and antenna for this system were located at JJUNUSED the top of the collar. The instrument collar was separable into COMPUTED PLATFORM UCATIOW TIME two parts for installation on the elk. Instru- LA1 LONG DAY Hn MM sss menting was accomplished when the animal 43 4921 110 721W 118 07 54 110 was immobilized with M99 (etorphine) . Ten FIGURE 2. Data format showing arrangement min were required to make the electronic of data on computer printout forms. connections and fasten the collar on the elk. Internal telemetry for the instrument was provided a 6-month battery lifetime by com- provided by five sensors, and external data pletely unloading the battery during the 12- were monitored by another five sensors. The hr intervals between orbital overpasses. Dur- data format corresponding to the computer ing each overpass a 10-min “power on” pe- printout is shown in figure 2. One such frame riod was initiated precisely as the satellite of data was collected during each interroga- came into radio view. The timer setting of tion of the instrument. For each overpass the the window was monitored on each orbit, satellite was programmed for up to five inter- and periodic adjustments were made by com- rogations at intervals of 1.5 min. Data were mand from the satellite to maintain syn- available to the experimenters within 1 to 2 chrony. hr of the overpass. The pressure transducer for measuring altitude failed and was inoper- PROCEDURE ative throughout the experiment. Skin tem- perature was measured by a thermistor During the summer and fall of 1969 a mounted on a tension arm attached on the mockup model of the instrument collar was inside surface of the collar. Battery voltages developed and tested on four female elk in a and temperatures were monitored directly, corral at the National Bison Range. The col- and the received signal strength was obtained lar (11.3 kg) weighed less than known at the output of the first intermediate fre- weights of elk antlers. None of the elk experi- quency stage. Two thermistors provided over- enced any apparent interference with daily lapping scales (-40 to + 10 OC; 0 to + activities, and there was no evidence of 50 ‘6) for measuring ambient temperature breakage of hair or skin abrasions from rub- within f 1 percent accuracy. For additional bing of the collar during feeding activities. information about the IUSsystem see Craig- One elk carried the collar for a period of 90 head et al. days without difficulty. Pretesting of the elec- An electromechanical timer-control unit tronic instrument collar began on January 102 ANIMAL ORIENTATION AND NAVIGATION

20, 1970, using the same female elk after it from the satellite the timer was reset, and at had been without the mockup collar for noon on February 22, data were received about 2 weeks. The pretest was highly suc- from the animal. Subsequent passes failed to cessful in terms of placing the instrument col- yield data. Visd observations of the elk lar on the elk and interrogating the instru- indicated that she remained bedded down for ment daily for the next 12 days on 16 orbits abnormally long periods of time, walked of the satellite. sluggishly, and was not feeding. The femaie On February 5, two female elk at the finally died on the morning of February 23, National Elk Refuge were immobilized and apparently of pneumonia which is not un- fitted with mockup collars to pretest the reac- common in the herd on the Refuge. The tion of these animals to the collar prior to stress of being captured may have aggravated instrumentation. an incipient infection. On February 19, an effort was made to On April 1, 1970, one of the two females place the IRLS collar on one of the two originally fitted with a mockup collar was females wearing the mockup collars. The elk instrumented with the IRLS equipment (fig. were uneasy as a result of a census of the 3). A veterinarian ascertained the health of herd made earlier that morning, and the ex- the animal. Her body temperature was nor- perimental animal was difficult to approach. mal (38.5 "C) and she appeared to be in Considerable maneuvering was required to good condition. She became immobile 5 min get one of the females within range of the after administration of the M99 drug and immobilizing gun. The shot made at long remained immobile for about 27 min, during range (60 to 70 m) missed the intended elk which time the dummy collar was removed and struck another female in the herd. She and the electronic collar was attached. Im- became immobile in about 5 min. This fe- mediately after the antidote was injected the male appeared to be a healthy individual, and except for preconditioning to the collar, equally well suited for the experiment as ei- ther of the females wearing mockup collars. Since conditioning did not appear to be es- sential, the instrument collar was fastened to this elk with the assistance of electronic engi- neers. The female recovered quickly upon re- ceiving the antidote M285 (diprenorphme) after being immobile for 30 min. The female then rose to its feet without difficulty, stood momentarily looking at the haywagons and observers without apparent alarm, and then ran to rejoin the herd. The satellite was un- able to communicate with the instrument col- lar for the first 3 days, apparently because SESSION 11: ANIMAL TRACK ING 103

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-I8 u -19 24 -21 26 1 -22 27 1 23 28 1 FIGURE 5. Visual observations vs satellite positions.

FIGURE 4. Locations of instrumented elk from direct observation or fixes with Craighead-Varney herd by 10:50 a.m. At approximately 11:OO ground-tracking system. Accuracia were within a.m., Nimbus I11 passed over the Jackson 0.5 km. Errors in satellite fixes were computed against these observations. Arrows indicate direc- Hole area and the IRLS collar transmitted tion of following observation. location, skin and air temperatures, and five parameters of the IRLS instrument (table 1) - female was placed on her brisket. Within 3 minutes she arose, looked around briefly at RESULTS the observers and then nibbled at a nearby bale of hay. The instrumented female then The resolution of locations determined by walked off about 25 m, stopped, and then the satellite varied considerably. In order to slowly ran off to join the herd about 200 m measure the accuracy of the locations it was away. When she joined the herd she immedi- necessary to derive a set of reference points ately had an encoutner with another female. from field observations of the elk. Orbital Both elk rose on their hind legs and paddled overpasses were approximately at noon, and gently with their forelegs. Such behavior some of the observation times did not coin- seems to establish dominance-subdominance cide exactly with satellite overpasses, making relationships between individuals within the some interpolation necessary in deriving the herd. This incident and the immediate a~-set of reference points. The reference points ceptance of the instrumented elk by other made on the ground are shown in figure 4. members of the herd indicated that the proc- The magnitude and direction of location er- ess of immobilizing and instrumenting had rors determined by satellite are shown in not been traumatic and that the female re- figure 5. Three locations were beyond the turned to normal behavior almost immedi- scale and were not included in the figure. ately after recovering from the drug. Within Excluding these three points the mean errors the next hour the instrumented female was were 4.8 km in latitude and 6.2 km in longi- observed feeding, standing, and walking tude. The large east-west errors (longitude), with the herd. which were typically less than the north- The elk had recovered and joined the south errors (latitude), reflected the fact that 104 AN I MAL 0 R I ENTAT IO N AND NAVIGATION

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tributed to the warming effect of the animal's body (refs. 6 and 7). 13.5 The accuracy of measuring skin tempera- ture with a thermistor at the point of contact between the collar and the animal's body re- quires further testing to determine the effects 13.0 of the collar in compacting the hair and insu- lating the thermistor, as well as the effect of

I TEMIPERATURE movement of the collar during feeding activ- ity. Individual skin readings taken at 1.5-min t10.c intervals during interrogation sequences sug- gest that the animal was at rest when the t5'C readings were constant and active when the readings were variable (table 2) . Apparently O'C movement of the collar altered its insulating 1 t -3'6 effect, producing more regular temperature FIGURE 6. Satellite monitored day-night readings when the elk was at rest. The excep- battery voltages and temperatures. tionally high skin temperature (37.5O C) , which was near body temperature, on April 10 could have resulted from continued pres- satellite locations are most accurate when the sure of the elk's neck against the thermistor satellite is between 10 and 50" above hori- as the animal lay on its side with its neck zontal. The dipole antenna used in the elk resting on the collar. In a similar manner a experiment was designed for a coverage above skin temperature of 35.9" C was recorded 45" with respect to the horizontal. In future from an awakened and alert black bear in its experiments the accuracy of locations can be winter den as it lay on a thermistor located improved with a low profile, omnidirectional, circularly polarized antenna. The monitoring of sensors showed the po- tentialities of the IRLS system for obtaining physiological and environmental information Elk at Elk rest mov- (table 1). The voltage levels of the batteries ("C) increased during the first 3 days, showing 85) that the solar panels were responsible for April 9, night. . 23.6 charging the batteries. The charge levels re- . April 7, night. 18.6 23.6 20.5 mained near maximum throughout the exper- 23.3 20.3 iment. The trends in battery and ambient 23.0 19.7 temperatures were identical (fig. 6) . Some 23.0 April9,day ... 27.8 warming was probably provided by the elk's April 17, night. . 28.0 27.2 28.3 28.1 body. In previous studies of the effects of 28.3 23.0 ambient air temperature on radio collars the 28.3 April23,day.. 30.9 battery pack and transmitter have shown an April 21, night.. 25.0 30.0 average 9.4" C increase over air temperatures 25.5 30.3 under cold weather conditions. This was at- 25.5 29.9 SESSION 11: ANIMAL TRACKING 107 between the animal's body and the insulating material of its bed (ref. 2). An inverse rela- tionship between skin and ambient tempera- tures, shown in about half the recordings (fig. 7), could reflect a decrease in insulation of the elk's integument due to compaction of the hair under the collar. The significance of the data is that they show the potentialities for studying thermoregulation by monitoring surface and subcutaneous skin temperature, along with deep body temperature, using the IUSsystem.

MOVEMENTS OF THE ELK O'C

Except for the longer movements, the 10- -5 cations obtained with the IRLS system were too inaccurate for determining the local pat- FIGURE 7. Satellite monitored skin and ambient tern of movement of the elk within the Ref- temperature readings. uge. However, satellite location of the elk could have yielded useful new information on arrived the following day in the area of Sig- migratory movements despite the low resol- nal Mountain, 28 airline km from her last ution. The collar rotated around the elk's position in the Refuge. After remaining here neck on May 1 and, in the inverted position, and in this general area for 5 days the elk contact between the elk and the satellite was began moving up Spread Creek on May 25, lost. Communication proved impossible with traveling southward into the Gros Ventre the antenna pointing groundward. Until drainage (fig. 8) to Slate Creek where a June 10, the elk was located by the ground- group of about 300 elk annually calve and tracking system. When the elk moved far or range for the summer months (ref. 8). The rapidly it was relocated by air, using a Cessna circuitous route taken by the elk to reach its 150 with a small loop antenna attached to summer range, covering about 65 km, rather the wing strut. Under favorable conditions than traveling directly up the Gros Ventre the signal was received in the airplane from a River valley for a distance of about 20 km, distance of up to 40 km at altitudes above was unanticipated. The route taken also in- ground level of 300 to 1000 m; the strength volved crossing a high divide that was still of the signals improved with altitude. snowbound. On May 15, the elk moved to the northern As the instrumented elk migrated, the portion of the Refuge and was approached, number of elk with which she was associated using the directional receiver. She was ob- gradually diminished with distance and time served to feed and run well with a band of away from the National Elk Refuge. On the 15 elk, and she appeared in better physical Refuge she was a member of a scattered herd condition than most of the other elk. Two of 3000 to 4000 animals, and this number days later she left the Refuge, moved north diminished to an average of 250 to 400 ani- along the east side of Blacktail Butte, and mals. 108 ANIMAL ORIENTATION AND NAVIGATION

time, but could have been hiding, since it is a common practice of calves to hide when dan- ger is imminent (ref. 9). Possibly the de- crease in daily movement as indicated by ra- diotrackmg was a clue to time of calving. Such noticeable changes in daily movement as revealed by radiotracking, when properly interpreted and then verified by observation, can provide insights to animal activity and behavior. For example, intermittent signals from instrumented grizzly bears have -been visually confirmed as an indication of den digging (ref. 10). An interesting result of the elk’s summer movements is that she was more or less con- stantly traveling, spending only a few days to a few weeks in any one area or drainage. The elk was last located by the ground-tracking radio on June 10. The next contact was a sighting on July 28 in the Cottonwood drain- age about 20 km east of Slate Creek. The probable route of her travels (a gradual FIGURE 8. Gras Ventre River dr-ge to which elk migrated from Refuge. Loop antenna, shown movement) after leaving the Slate at top of the photograph, was used to communi- Creek-Mount IAdy area was eastward to the cate with ground-trackingsystem. confluence of Poison Creek with Cottonwood Creek. On November 14, she was acciden- On May 15, two days before leaving the tally shot by a hunter 8 km from this location Refuge, the elk traveled with a group of 15 and just prior to her expected safe return to animals. On May 23, and from time to time .the National Elk Refuge. thereafter, she was observed alone or with Daily movement of the elk on the Refuge only one other cow. From this latter behavior that occurred before migration averaged 3.7 we suspected the imminence of parturition. km, based on 41 movements, and ranged From May 30 to June 10, sightings and from 0.6 to 14.6 airline km. Just prior to a radio fixes indicated that she moved only an long trek on April 24, ground-tracking average of 1.1 airline km per day with a showed that the elk had traveled an average range of 0.2 to 1.9 km. This was a consider- of about 2.6 airline km per day. On April 25, able reduction over her previous daily travel, she backtracked 14.6 km toward the Refuge and might have been related to calving. A feeding lots (fig. 4)- This was the longest close observation on June 8 established that single trek prior to migratory movement. the elk was in good condition, that most of Such movement back and forth in response the winter coat remained, and that no abra- to weather and snow cover is typical during sions or sores caused by the collar were evi- Apd. However, this return travel started be- dent. It also appeared that the cow was not fore a storm arrived and may have been in pregnant. A calf was not observed at this response to an approaching storm. The ba- SESSION 11: ANIMAL TRACKING 109 rometer dropped, and snow fell for the next cated a possible weight reduction of about 50 two days. percent down to about 5 kg. A fin antenna Some animals apparently can sense an ap- is now available for the instrument, which proaching storm. A change in activity asso- would eliminate the large housing required ciated with an approaching snow storm was for the dipole antenna and reduce the profile clearly demonstrated while radiotracking an of the instrument. Variable padding with instrumented to its winter den. foam rubber to adapt the instrument to a This grizzly altered her previously recorded given elk would solve the problem of the daily activity pattern one morning and collar turning around on the elk's neck. An started moving rapidly toward her den in improvement in the resolution of locations bright, sunny weather. Snow started to fall in to within 1 km would be possible with the late afternoon, and the female grizzly arrived development of a low profile, omnidirec- at her pre-excavated den that evening (ref. tional, circularly polarized antenna. Experi- 10). Apparent early detection of weather mentation with effective sensory systems changes by both bear and elk is intriguing is needed to measure deep body temperature, and may be related to the animals' possible skin temperature, heart rate, and other phy- ability to detect infrasound waves created by siological parameters. To eliminate external approaching but distant storms (ref. 11). wiring, implantable transmitters are required Satellite as well as ground radiotracking for transmission of data to receivers in the should be a useful tool in probing this phe- instrument collar. Miniaturized equipment nomenon in wild animals, perhaps even for periodic data sampling and storage prior under controlled conditions. to transmission (every 12 hr) is needed. Changes in the elk's activity and their The advantages of satellite systems are interpretation, as well as the migratory ob- described elsewhere (ref. 12). Briefly, satel- servations, indicate that behavior and migra- lites permit daily tracking and monitoring on tion of individual elk can be studied in detail a worldwide scale with instruments that are with the aid of radiotracking and bioteleme- immune to the effects of Earth's weather and try ground-satellite systems. These studies can provide data under day or night conditions. provide information of value in the manage- Where animals are isolated in polar regions, ment of elk populations, as well as contribute the oceans, or deserts, satellites are especially toward a better understanding of the phe- useful. To obtain adequate data on bird mi- nomena of animal behavior and migration. grations over long distances and at high alti- tudes or marine animals covering great dis- RESULTS tances, satellite systems are almost indispensa- ble. The uniqueness in satellite systems lies in The study was successful in demonstrat- the ability to combine continuous tracking ing the practicability of tracking large free- up to 6 months, or longer, with simultaneous roaming animals in natural environments by monitoring of physiological and environmen- satellite systems. The prototype IRLS instru- tal parameters. ment collar was somewhat bulkier and heavier Despite the advantages of satellites, radio than required, and on the basis of information contact with animals from the ground is also derived from monitoring the instrument by needed for homing in on animals for direct satellite, particularly the effect of the solar observations. An integration of the two sys- cells on battery charge, calculations indi- tems is likely to be required in most research. 110 ANIMAL ORIENTATION AND NAVIGATION

An accurate system for tracking free-liv- BUBCHNER:Yes indeed, I think it is practical. ing animals and monitoring both physiologi- We know the weight can be reduced at least one half, without doing any miniaturization. We also cal and environmental parameters will pro- know how to make a better configuration for the vide a valuable new tool for investigating the collar and we have some ideas on how to improve behavior and ecology of wild animals. Satel- the antenna system. The costs can come down. In lite systems can aid in investigating a vast ar- fact, potentially, if there are enough users, the costs ray of important biological problems, includ- could come down very quickly to something around $2000 or $3000 per instrument package. ing migratory movements and navigational We hope that next year we will be able to track guidance mechanisms of animals, patterns of an elk during the spring migration and make peri- dispersal and concentration associated with odic ground observations to correlate behavior with feeding and reproduction, the entrainment of migration movements and physiological parameters. physiological cycles by environmental param- ENRIGHT:There may be a slight difference in the elevation of the animal which could make a big eters, and patterns of vector trans-nission of difference in the apparent geographical location. Is disease by migratory animals (ref. 12). The this a real problem? knowledge gained through such studies will COTE: The elevation is certainly a factor; we help provide the scientific basis for intelligent do not assume that the Earth is a perfect sphere. In management the Earth’s ecosystems. the case of the elk, changes were in the order of of 9Om (300 ft) which did not greatly impact location accuracy. For high flying balloons or aircraft track- ACKNOWLEDGMENT ing applications the altitude becomes a critical fac- tor and must be entered into mathematical equa- We wish to thank biologists Harry V. Reynolds tions for location computation. I11 and Vincent Yannone, and graduate student WILLIAMS:You state that your readings ex- Steven M. Gilbert of the University of Montana, tended over eight to ten minutes for one point. for their assistance in this project. Joel R. Varney, How is this possible? Research Associate, Montana Cooperative Wildlife COTE: Since the satellite is in view for 4 to 5 Research Unit, University of Montana, contributed min, multiple interrogations lasting 2 sec each are significantly to this project in testing and applying programmed. This allows up to five data samples the electronic systems. James C. Maxwell, Staff under normal operational conditions where 1 min- Engineer, Ecology Program, Office of Environ- ute intervals are maintained. The two frequencies mental Sciences, Smithsonian Institution, aided in utilized in the IRLS system are 401.5 and 466.0 the pretesting of the IRLS collar. MHz. The IRLS instrument was conformed into the CARR:Did resolutions in your track-plots for collar for the elk by Radiation, Inc., Melbourne, the elk correspond to those for the buoy? That is, Florida. do you get about the same fineness in separating Tracking animals by satellite was stimulated by and locating points with the elk as you would in Sidney R. Galler, Assistant Secretary (Science), tracking the buoy? Smithsonian Institution, who organized the 1966 COTE:No. The buoy positions were more accu- conference on this subject. We are grateful for his rate since higher power equipment was used. encouragement and inspiration. George J. Jacobs, Under these conditions the satellite need not be di- Chief, Physical Biology, National Aeronautics and rectly overhead to obtain solid communication. Op- Space Administration, was particularly helpful in timum location accuracies with the higher power the development and administration of the project. equipment are obtained at elevation angles between This project was supported by a NASA con- +5 and +50° with respect to the horizontal. tract (NASW-1983) to the Smithsonian Institu- SLADEN:How did you measure skin tempera- tion. ture? COTE: Readings of external skin temperature DISCUSSION were obtained by a thermistor mounted on a ten- sion arm attached to the collar. The tension was COCHRAN:You have called this a feasibility calibrated to enable skin contact under normal ac- study. Is it practical to conduct a study on the elk? tivity conditions. SESSION 11: ANIMAL TRACKING 111

QUESTION:Do any of you object to using a 3. CRESSEY,J. R.; AND HOGAN,G. D.: The In- harness? terrogation, Recording and Location System CRAIGHEAD:Initially, we considered a harness Experiment. Proc. Natl. Telem. Conf., sec. but rejected it for a number of reasons. The elk VI, 1965. really has a very strong neck. We didn’t have many 4. COTE, C. E.: The Interrogation, Recording problems with collars reversing in the initial tests. and Location System Experiment. NASA BULLOCK:There is a source of power that has X-733-69-336, 1970, 22 pp. not yet been mentioned. This is the piezoelectric 5. COTE, C. E.: The Interrogation, Recording source. Currently engineered devices obtain energy and Location System Experiment. Geo- from the organism via its movements and produce Science Electronic Symp. Trans., IEEE, about Mth or s/ath of a mW power continuously Spec. Issue, 1970. with very high efficiency. It would be a negligible 6. CRAIGHEAD,F. C., JR.; AND CRAIGHEAD,J. J.: load for an ordinary bird in terms of extra work, to 1965. Tracking Grizzly Bears. BioScience, deflect a piezoelectric crystal to produce a milli- vol. 15, no. 2, 1965, pp. 88-92. watt. The advantage is that you are getting away 7. CRAIGHEAD,F. C., JR.; AND CRAIGHEADJ. J.: from any prepackaged foreign power source and Yellowstone Field Research Expedition V. are dealing with an endogenous source of power. State University of New York at Albany, The device, for instance, which Carl Enger Publ. no. 31, ASRC, 1965. (ref. 13) has been using in dogs takes some of the 8. ANDERSON,C.: The Elk of Jackson Hole. Wy- work from the respiratory muscles which bend a oming Game and Fish Comm., Cheyenne, small device, about 30 grams in weight, a cylinder Wyoming, 1958, 184 pp. about 50 mm long and 10 mm in diameter. The 9. MURIE,0. J.: The Elk of North America. main element is a piece of ceramic which is de- Stackpole Co., Harrisburg, Pa., 1951, 376 formed very slightly. This deformation produces the PP- power-a relatively high voltage (around 20 V) at 10. CRAIGHEAD,F. C., JR.; AND CRAIGHEAD,J. J.: low current. From this particular device they are Grizzly Bear Prehibernation and Denning getting about 300 microwatts continuously. Activities as Determined by Radiotracking. What would be needed to increase the power to Progr. Rept., 1968, Environmental Research one milliwatt is another gram of weight increasing Inst., Montana Coop. Wildlife Res. Unit, the bulk from 30 to 31 grams. This would add 1968,49 pp. enough ceramic material so that about a milliwatt 11. GREEN,J. A.; AND DUNN,P.: 1968. Correla- could be obtained continuously. The problem be- tion of Naturally Occurring Infrasonics and comes where to attach the device. They are work- Selected Human Behavior. Acoustical SOC. ing now loose in the pericardium, deformed by the of Am., vol. 44, no. 5, 1968. beating heart, and fixed to the vertebrae and ribs, 12. BUECHNER,H. K.; CRAIGHEAD,F. C., JR.; deformed by respiratory movements. This puts the GRAIGHEAD,J. J.; AND COTE, C. E.: Satel- problem back to the biologist where it really be- lites for Research on Free-living Animals. longs. There is essentially a negligible loading in re- Bioscience, Dec. 15, 1971. spect to weight and to work. 13. ENGER,C.: Proc. Artif. Heart Conf., NIH, The point is, that with this small a device you Bethesda, Md., June 1969; Nature, vol. 218, could radiate milliwatts continually and interrogate no. 5137, Apr. 13, 1968, pp. 180-181. the animal every minute or every hour, instead of compromising with an interrogation once a week. BIBLIOGRAPHY REFERENCES MACKAY,S. R. : Bio-Medical telemetry. Second Ed. 1. ANON.: Some Prospects for Using Communi- John Wiley and Sons, Inc., New York, 1970. cations Satellites in Wild Animal Research. 533 pp. AIBS, BIAC Spec. Rept. 51 , 1966,23 pp. SLATER,L. E., ed.: Bio-telemetry. Macmillan Co., 2. CRAIGHEAD,F. C., JR.; AND CRAIGHEAD,J. J.: New York, 1963,372 pp. Radiotelemetry of Large Western Mammals. SLATER,L. E., ed.: A Special Report on Bioteleme- Progr. Rept., 1965-66. AEC Contr. AT try. Bioscience, vol. 15, no. 2, Feb. 1965, pp. (45-1)-1929,1966,67 pp. 81-157.