Date of this Version
Accurate evaluation of rodent control techniques has always been a laborious undertaking. It generally involves tedious pre- and post-treatment censusing by trapping, marking, track counts, reduction of activity, etc., and results, at best, must necessarily contain a significant amount of speculation by the investigator. The biologist conducting such studies has been constantly harassed by uncontrollable parameters such as trap response, immigration, emigration, predation, disease, and many others. Thus, there has been a pressing need of a more definitive technique for evaluating rodent control trials. During the last decade, a new tool called biotelemetry has become available to the wildlife biologist. This technique has been defined as, "the instrumental technique for gaining and transmitting information from a living organism and its environment to a remote observer" (Slater 1965). As a practical tool, it is still in its infancy. Among its first reported uses in wildlife work were the telemetering of incubating temperatures of penguin eggs by Ecklund and Charltin (1959), a study of salmon movements by Trefethen et al. (1957), and a study of woodchuck movements by LeMunyan et al. (1959). Since these earlier studies, there has been a significant increase in telemetry studies of wildlife. These vary in complexity from simple movement studies to sophisticated telemetry of physiological variables. Many sizes and species of animals have been involved, such as deer mice, large ungulates, marine mammals, thrushes and buzzards. Probably the major obstacle to further advances in wildlife telemetry is the inability of the biologist to meet the cost of development. The cost of telemetric systems can be fantastic and often precludes their use by most investigators. Another earlier limiting factor was the bulk of the necessary electronic equipment to be carried by the instrumented animal. However, recent advances in the development of miniaturized components such as the solid-state transistor, mercury cell battery, and printed circuit, have essentially removed this problem. These, plus the ingenuity of biologically oriented electronics personnel, have made wildlife telemetry possible.