Photographic identification: an alternative to toe clipping for patterned lizards

Persistence, reliability and individual discrimination are essential components for animal marking systems used in behavioural ecology studies. Toe-clipping is the most established marking technique for lizards, but current threats to native populations leave some researchers questioning the use of invasive field techniques. In particular, the effects of toe-clipping on juveniles are not well understood. In this study naturally occurring toe loss in the field is analysed to provide an accurate context against which to examine alternative identification methods for patterned lizards. Pattern persistence and individuality are demonstrated in a sample group of Egernia whitii (White’s skink), an Australian lizard species. A photographic technique for use in identification is developed and the reliability of the method is tested for use in broad scale application by researchers. Field results show that less than 2% of juveniles and only those approaching adult size, appear to survive with toe loss, compared to >15% of the adult population. Pattern markings remained stable from birth to adulthood with minor contrast alterations. There was a significant association between human test subjects with a high level of training and high scores in pattern matching. INTRODUCTION Persistence, reliability and individual discrimination are essential components for animal marking systems used in behavioural ecology. Permanently marked populations are valuable for long term research (Hare & Cree 2005, Dodd 1993) in many different ecological and behavioural projects Three frequently used marking systems for lizards and amphibians are toe clipping, pit tags and pattern mapping. The most popular of these is toe clipping (Ferner 1979). Reptiles and amphibians have been marked by toe clipping at almost every level of ecological research endeavour, including life history (Hare & Cree 2005), population density (Kwiatkowski & Sullivan 2002), diversity and abundance sampling (Hobbs et al. 1994), genetic diversity (Garner et al. 2003), home range (Rocha 1999), habitat