A backpack method for attaching GPS transmitters to bluetongue lizards (Tiliqua, scincidae)

Global positioning system (GPS) transmitters provide detailed information but require external attachment of relatively large units. We describe a backpack system that we developed to attach GPS units to freeranging bluetongue lizards (Tiliqua multifasciata and T. scincoides intermedia). An inner layer of supergrip fabric was glued to an outer layer of nylon mesh, to form a vest around the animal's chest and a collar around its neck, secured with superglue and cable-ties. We fitted 16 lizards with backpacks mounted with GPS units and successfully tracked them for up to 86 days to obtained detailed data on movement patterns and habitat use. Field monitoring in northern Australia showed that the units were durable and stayed in place unless the lizard wore through the backpack or shed its skin. No lizards became entangled in vegetation.