Suitability of radio telemetry for monitoring two New Zealand frogs (Leiopelma archeyi and L. hamiltoni)

The miniaturisation of very high frequency transmitters over the last 20 years has allowed researchers to use radio telemetry to study the movements and behaviors of increasingly smaller animals. However, the sensitive skin of many amphibians has continued to make fitting telemetry packages difficult. Here we describe the application of a waist-harness style radio telemetry package for use on two of New Zealand’s native terrestrial frogs (Leiopelma archeyi and L. hamiltoni). To determine if the harness design was suitable for field use, we conducted a laboratory trial on four captive L. hamiltoni. Individuals carried harnesses for up to 22 consecutive days without abrasions or changes in behavior. After confirming the harness would not negatively impact captive individuals, we fitted harnesses to 20 L. hamiltoni in Te Pākeka/Maud Island Scientific Reserve, northern South Island. We tracked individuals for a maximum of 8 days and recaptured L. hamiltoni showed no signs of skin irritation or skin damage at the time of harness removal. We also tested harnesses on four L. archeyi within the Wharekirauponga area of the Coromandel Forest Park, northeastern North Island. We were able to track one L. archeyi for 7 days before locating the transmitter loose in leaf litter. The harness detached from two additional individuals, one within 24 hours of frog release and another 12 hours after release. We were unable to relocate one individual. Although the use of radio telemetry on leiopelmatids is not without difficulties, the observations collected during our field trials provide strong support that a waist-harness design is a suitable and effective method to conduct short-term radio telemetry on leiopelmatid frogs.