48 FISH AND WILDLIFE TECHNICAL REPORT 30 



n=lo n=50 



o 



10 



I I 1 I I I I I r i/ i i r r 



30 40 50 100 300 



Locations/Year 



Fig. 44. Cost-benefit analysis of satellite versus conventional VHP telemetry. Kodiak brown bear example. 



We have documented a useful role for the motion sensor 

 currently in use on Telonics PTT's that is, generating 24- 

 h and 60-s activity indices. However, both indices had 

 limitations, even on those species experiencing the most 

 success. For caribou, we have not successfully calibrated 

 indices with behaviors observed in the wild. For reliable 

 estimates of activity budgets, this research is still needed. 

 Further development of the motion sensor may be neces- 

 sary to calibrate either index. It may yet be possible to 

 refine the ability of the 60-s index to discriminate among 

 activity types (e.g., standing still versus lying still, grazing 

 versus browsing), but this will require further develop- 

 ment of the sensor itself. Issues such as whether multiple 

 sensors in different configurations would produce im- 

 provements, or whether sensors might be placed in remote 

 locations on the animal, may be fruitful areas for further 

 work. Other sensors with potential applications in wildlife 

 research may include devices for measuring battery volt- 

 age, atmospheric pressure (i.e., determining the animal's 

 elevation), heart rate, and body temperature. 



An additional limitation is battery life. Most PTT's we 

 deployed had a one-year life expectancy. Some bear col- 

 lars had two years expected life spans, but none have yet 

 lasted more than one year. Many studies monitor the same 

 individuals over numerous years, requiring yearly capture 

 for replacing PTT's. Each time an animal is handled it is 

 exposed to risk of injury or death; also, research budgets 

 are strained. 



Some limitations of the present system may be over- 

 come with more sophisticated analytical treatment. Exam- 

 ples include corrections for elevations (other than those 

 assumed by Argos) by way of a sophisticated GIS, and the 

 development of correction factors for autocorrelated data 

 that would allow use of complete data sets without violat- 

 ing important statistical assumptions. The exploration of 

 time-series approaches toward wildlife data has been sug- 

 gested by some statisticians (Dunn and Gipson 1977; Pan- 

 tula and Pollock 1985). These techniques should be ex- 

 plored by biologists and statisticians confronted with 

 these problems. As methods are developed that incorpo- 



