Northern Prairie Wildlife Research Center
The following detailed look at the technique of wildlife radio-tracking is provided to familiarize administrators and biologists with the current state of the technique. This greater awareness should facilitate an understanding of any problems caused by radio-tracking and should help researchers choose the most effective and least intrusive equipment and techniques.
Radio-tracking brought two new advantages to wildlife research: the ability to identify individual animals and the ability to locate each animal when desired. These advantages have led to the wide application of radio-tracking since the first complete workable system was designed (Cochran and Lord 1963). Radio-tracking has been used to study animals as varied as snakes, crayfish, dolphins, tigers, and elephants and in most major countries.
In addition to more straightforward applications such as movement/home range analysis and mortality studies, radiotelemetry has proved useful in examining many diverse topics including disease transmission (Cheeseman and Mallinson 1980), scent marking (Peters and Mech 1975; Charles-Dominique 1977), predation and co-evolution (Mech 1967, 1980), vocalizations (Harrington and Mech 1979; Gautier 1980; Alkon and Cohen 1986), socioecology and breeding behaviors (Mech 1980), sleep characteristics (Schmidt et al. 1989), physiological studies of heart rate, respiration rate, body temperature (Kreeger et al. 1990), and nest egg condition (Howey et al. 1977, 1987; Schwartz et al. 1977; Boone and Mesecar 1989).
Advances in radio-tracking since Cochran and Lord's first system include refinements of conventional, or very high frequency (VHF), telemetry as well as entirely new systems such as satellite telemetry and GPS radio-tracking. Improvements in conventional VHF telemetry now enable researchers to determine, for examples, whether an animal is active (feeding, walking, running) or resting, and the time spent in mortality from death until the transmitter is recovered. Microphone-containing transmitters allow researchers to listen to a creature's vocalizations and ambient sounds (W. W. Cochran, personal communication).
Satellite telemetry uses satellites to relay the animal's location signal (sent by the telemetry package attached to the animal) to other receiving stations for interpretation. This allows researchers to track far-ranging animals such as some marine mammals that previously were too difficult to track using the relatively shorter range of the conventional VHF system.
GPS radio-trackingin which the telemetry package attached to the animal receives information from three or more satellites to determine an animal's location-is used to store location data in the telemetry unit for later retrieval or remote downloading. This gives researchers greater location accuracy and decreases invasiveness to animals when compared with VHF telemetry.