Standardised method of spotlight surveys for crocodiles in the tidal rivers of the Northern Territory, Australia

Standardised spotlight survey procedures have been an integral part of long-term (1975-2012) monitoring programs for Saltwater Crocodiles Crocodylus porosus and Freshwater Crocodiles C. johnstoni in tidal rivers of the Northern Territory (NT) of Australia. These programs, implemented four years after depleted Saltwater Crocodile populations were protected from hunting in 1971, have been instrumental in documenting post-protection population recovery and evaluating management interventions. This article describes a standardised method for spotlight survey of crocodiles in tidal rivers, with particular emphasis on practical aspects that were not previously documented. It also shows example survey data and how it is analysed. This practical guide is primarily oriented at maintaining survey standardisation within the NT, but it should help wildlife managers to use standardised spotlight counting as a monitoring tool for crocodilian species in similar habitats elsewhere.