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Reliability of Motion-Sensitive Radio Collars for Estimating Activity of Black-Tailed Deer

1985; Wiley; Volume: 49; Issue: 4 Linguagem: Inglês

10.2307/3801377

1937-2817

Michael P. Gillingham, Fred L. Bunnell,

Animal Behavior and Welfare Studies

Radio collars containing motion-sensitive devices were attached to four adult black-tailed deer (Odocoileus hemionus columbianus). Comparisons between telemetric data and concurrent visual observations of animal behavior were made to evaluate the extent that the equipment could reliably predict activity. Mercury tip-switch devices containing a 12-minute, motion-reset switch and variable-pulse collars that varied pulse rates instantaneously with amount of movement were tested. Pulse-rate patterns were broadly indicative of activity level but could not be used to identify specific behaviors. The tip-switch collar was found to be more accurate in predicting overall activity budgets. Proportion of time active could not be estimated from these telemetry data with greater than 90% accuracy (P < 0.05) for the tip-switch collars and 75% for the variable-pulse collars. The variable-pulse collar provided a poorer estimate of activity and was more difficult to radio-locate; the reliability of the motion-reset circuit in the tip-switch collar was questionable. J. WILDL. MANAGE. 49(4):951-958 Radio-instrumentation is often the major means of obtaining location and activity information about species whose habitats or circadian rhythms impede visual observations. Use of a particular nest-site or lodge by some species may enable estimation of activity patterns from radiolocations alone (Lancia and Dodge 1977), but often this has not been possible for freeranging animals. Activity estimation from interpretation of signal quality as discussed by Cochran and Lord (1963) has been widely used (Lindzey and Meslow 1977, Lancia et al. 1979, and Erlinge 1980 among others). However, Singer et al. (1981) concluded that radio signal strength provided a poor index to the activity of European wild boar (Sus scrofa). Knowlton et al. (1968) suggested use of motion-sensitive switches in telemetry transmitters to quantify animal activity. These devices have since received wide application (e.g., Kolz et al. 1973, Garshelis and Pelton 1980). Two types of motion-sensitive transmitters are in use. Tipswitch devices alter the transmitted pulse rate using a mercury-switch to indicate changes in collar position, either from side to side or from head-up to head-down, depending on switch orientation. Reset-collars transmit one of two discrete pulse-rates depending on the presence or absence of movement during a specified interval. Garshelis et al. (1982) equipped 61 black bears (Ursus americanus) with both sensor types and provided criteria for determining activity based on pulse-modes for each. They concluded that tip-switches were more useful in making continuous judgements of activity and that they might be used to differentiate types and degrees of activity. Actual activity was not known, however, and tests were based on correlations between distance moved per hour and activity as indicated by criteria applied to collar pulse