29th Annual Meeting and Symposium of the
Desert Tortoise Council, February 20-23, 2004
Abstracts

Using Automated Radio Telemetry to Monitor Wildlife Activity

Andrew Walde¹, Leslie Bol¹, David Delaney², Larry Pater² and Mickey Quillman^3
1Charis Corporation, 222 East Main St., Barstow, CA 92311
²U.S. Army - CERL, P.O. Box 9005, Champaign, IL 61826
³U.S. Army, Directorate of Public Works, Fort Irwin, CA 92310

Automated radio telemetry equipment is currently being used to study the activity patterns of desert tortoises at the National Training Center on Fort Irwin. This equipment can enable one person to monitor and document the activity of many animals continuously over an extended time, regardless of weather, light level or terrain. The basic approach is to record and analyze the radio signal received from a radio transmitter mounted on the study animal. Because of the directivity pattern of the transmitting antenna and the fact that variations in its juxtaposition to its surroundings change the radiated power, motion of the animal causes changes in the received signal. A recording of the temporal variation of the received signal contains considerable information about the movement of the animal. Interpretation of these signals is amenable to automated analysis by computer algorithms. Automated data analysis computer algorithms classify signals as active or inactive, based on moving averages of changing signal amplitude. Activity data, in conjunction with meteorological data, are being recorded to provide detailed temporal information on when tortoises are active above and below ground on a yearly basis. The automated telemetry system also measures and records temperature at the transmitter. Data from this research project should benefit the recovery and management of desert tortoise populations through refinements in a number of research areas, e.g., temperature-based tortoise handling guidelines, line distance sampling, and translocation.