Accurate identification of individual geckos (Naultinus gemmeus) through dorsal pattern differentiation

Mark–recapture methods are frequently used to obtain the data needed to inform conservation management of vulnerable species. This typically involves animals being captured, individually marked, then released and later detected by capture or resighting. This may be stressful for individual animals and can be resource-intensive. Photo-identification has emerged as an effective, and potentially less intrusive, alternative to traditional mark–recapture methods. Photo-identification can be used when animals have stable and individually identifiable natural markings that can be photographed in the field and used for long-term identification. A database of photographs and associated capture-history data can be used for robust estimation of demographic parameters such as population size and survival if an appropriate sampling regime is used. In addition, aspects of behavioural ecology, habitat use, movement patterns and home range can be examined. We outline the creation of a photographic database for jewelled geckos (Naultinus gemmeus) from Otago Peninsula and test the accuracy and speed with which human observers can use this database to differentiate between individual jewelled geckos. Jewelled geckos found during visual searches were captured, photographed and their photographs incorporated into a database. Volunteers then had to match 15 photos of randomly selected geckos to different photographs of the same animals, which were contained within a database of 855 individuals. All users correctly matched all 15 randomly selected geckos. Experience appeared to increase the speed of correct identifications. Our results show that photo-identification can provide an effective alternative to potentially more intrusive techniques such as toe-clipping or pit-tagging for jewelled geckos on the Otago Peninsula.