Development of light-weight video-tracking technology for use in wildlife research: A case study on kangaroos

Abstract

There have been significant advances in the development of animal-borne sensor technologies, orbiologgers, in recent years. This has resulted in tremendous capacity for wildlife researchers to remotely collect physiological, behavioural and social data from wildlife in circumstances that were unthinkable just decades ago. While this technology can provide us with a unique insight into the "secret lives" of wild animals, there is a need to evaluate the utility of these new sensors versus traditional wildlife research methodologies, and to critically evaluate the integrity of the data collected by ensuring that these devices themselves do not alter the physiology or behaviour of the recipient animal. This paper reports on the development of a light weight "animal borne video and environmental data collection system" (AVED), which can be deployed on animals as small as 11 kg, whilst still meeting the desired 3% body weight threshold. This AVED (referred to as the "Kangaroo-cam") simultaneously collects video footage and GPS location data for an average of 19 h. Kangaroo-cams were deployed on seven kangaroos as a proof of concept of their potential utility for the study of location specific behaviour and diet in a mediumsized terrestrial herbivore. Following device recovery and data processing, we were able to successfully score 83 foraging events which allowed us to determine diet based on visual identification (to the family level) of plants consumed. This approach could be further broadened to include a comparison of plantspecies consumed versus plant species encountered to provide a novel approach to diet selectionanalysis. When combined with GPS mapping of foraging locations, this approach would allow researchers to address questions on diet selection at both fine (within patch) and broad (habitat) spatial scales, overcoming some of the limitations of traditional diet selection methodologies. However, animal capture and collar deployment caused a significant elevation in stress hormone concentrations within the first 24 post-capture, which highlighted the need to incorporate a time-delay capacity into these devices. We conclude the paper by reviewing recent advances in the development of AVED technology and providing suggestions for the improvement of this Kangaroo-cam device.