Making the most of by-catch data: assessing the feasibility of utilising non-target camera trap data for occupancy modelling of a large felid

Camera traps are an increasingly used tool in ecology, having the ability to capture large numbers of photographic records in short survey periods. For many surveys, the number of non-target records outweighs those of focal species, making them a potentially rich and often under-utilised data source. Occupancy analysis of non-target data represents a potential way to optimise survey output, whilst increasing "return on investment." This study assessed the feasibility of using non-target data from a Hartmann's mountain zebra Equus zebra hartmannae survey in Gondwana Canyon Park, southern Namibia, for occupancy analysis on leopard Panthera pardus. Using a survey design with 15 camera traps at water sources, 26 leopard events were detected over 72 days. Model fit was adequate and produced a model-averaged occupancy of 0.64 (SE 0.36) and a detection probability of 0.24 (SE 0.07). Whilst there was a lack of precision in the final occupancy estimate, the study provided valuable pilot data for future surveys. The results highlight the ability of camera traps to obtain information-rich datasets, which, when properly archived, can be used for providing information on a number of ecological topics, ranging far beyond that which the traps were originally deployed for.