CSIRO PUBLISHING
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Wildlife Research, 2004, 31, 171–176
Use of an ‘on board’ datalogger to determine lizard activity patterns, body temperature and microhabitat use for extended periods in the field G. D. KerrA,C, C. M. BullA and G. R. CottrellB A
School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia. B School of Informatics and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia. C To whom correspondence should be addressed. Email:
[email protected]
Abstract. We describe a technique developed to provide continuous long-term records of movement by individual lizards in the field. Using a small, lightweight and robust activity logger we are able to record over short intervals the number of strides taken, the body temperature and the incident light intensity on the dorsal surface of an animal. Using these data, activity patterns, behaviour and microhabitat choice can be determined in the absence of an observer, thus reducing biases due to observer presence. In our study the logger stored recordings every 2 min for 15 days. WR03048 GAeta.nlD‘.oKnebroa d’dataloger
Introduction When making field observations of animal behaviour the effects of observer presence on normal activity patterns are generally unknown (Caine 1990; Martin and Bateson 1993; MacFarlane and King 2002). These effects may vary with the level of habituation to the observer (Labra and Leonard 1999) and with the proximity and visibility of the observer (Cooper 1998). For reptiles, increased refuge use resulting from observer presence may impose a physiological cost leading to further perturbations of behavioural patterns (Martin and Lopez 1999). A second problem is that direct observations can rarely be continuous for any extended periods, and the desired behavioural data will have an intrinsic bias (Altmann 1974). A particular problem when observing reptiles in the field is that many species spend most of their time either basking or in refuges and other behaviours of short duration may be missed by an observer rotating sessions among different individuals. Thus, casual field observations during limited periods are sometimes misleading (Regal 1983). Additionally, for species that are largely solitary, it is difficult to obtain simultaneous data on sufficient numbers of individuals for rigorous statistical analysis. Hertz et al. (1986) suggest that continuous, long-term records of movement by individuals are necessary to allow interspecific comparisons of time budgets and movement patterns. In this paper we describe a technique developed to provide those records and to overcome some of the problems © CSIRO 2004
of observing behaviour in a population of the Australian sleepy lizard (Tiliqua rugosa) near Mt Mary, South Australia. The sleepy lizard is a large (up to 330 mm SVL, 900 g bodyweight) long-lived, scincid lizard. Past attempts to observe behaviour directly in this species have been frustrated by the cryptic camouflage of the lizard, the relatively short periods of daily activity (
